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In this study, the complex dynamics behind heat transfer within photovoltaic (PV) solar modules under spectral solar illumination are investigated. A new model coupling internal heating to optical absorption is derived from equations governing light-matter interaction throughout PV module multilayered structure. Reflection and transmission at each interface between two neighboring layers inside a PV module as well as absorption in each layer are taken into account. Dielectric properties of each interface are used to calculate its wavelength dependent reflectance and transmittance according TE and TM light polarization modes. Optical properties of each layer are utilized to determine its absorption coefficient and internal source of warming. Effects of incidence angle and light polarization modes on internal heat function are also analyzed. Heat equation is then solved in steady state limiting case and Temperature profiles inside a PV module under STC and NOCT conditions are determined. [ABSTRACT FROM AUTHOR]

Copyright of Rudarsko-Geolosko-Naftni Zbornik is the property of Faculty of Mining, Geology & Petroleum Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metal foams are interesting as sound absorbers because of their strength, low mass, high hardness, and damping. To foam fabricationmore accurate and achieve higher sound absorption coefficient (SAC), the effective parameters should be optimized. In earlier study (DOI: 10.32604/sv.2021.09729), the parameters of porosity percentage, pore size (D) and pore opening size (d) were optimized by the authors. In this study, we intend to investigate the effect of optimized percentage, D size and d size on the SAC of aluminum foam in the frequency 0 to 8000 Hz with the thicknesses of 5, 10, 20, and 30 mm. The genetic algorithm was performed employing the Lu model, using MATLAB software. According to the results, the optimum values of, D, and d at different frequencies and thicknesses are not constant. That is, at any given thickness and frequency, there are specific optimum amounts. This study provides a way to improve the SAC performance of porous metal materials for various and targeted applications. [ABSTRACT FROM AUTHOR]

The propagation of acoustic waves in porous materials attenuates with distance. When the thickness of the porousmaterial is equal to the acoustic penetration depth, or critical depth, the sound absorption coefficient reaches an asymptotic value so that any additional thickness of the porous layer provides no significant increase of the sound absorption. To overcome the limitations of the critical depth, a design of sound absorbing material containing periodic holes with decreasing profile diameter is proposed in this paper. The finite element method is used to demonstrate the improved sound absorption over a large frequency band. An extraordinary improvement of the sound absorption coefficient using a periodic conical hole is demonstrated where the critical depth of the porous material is eliminated. The results using the finite element method are compared with theoretical results from a transfermatrixmethod using a double porosity model, and a good agreement is obtained. A parametric analysis is presented using finite element simulations to illustrate the effects of the different parameters of the decreasing hole profile diameter on the sound absorption coefficient. Different hole shapes with decreasing profile diameters distributed periodically inside the porous layer are compared, and the results show good acoustic performance. The proposed sound absorbing material is applied in a rectangular room as anechoic termination. The result of the reflection coefficient obtained by a mirror source method is close to zero over a large frequency band. This illustrates good sound attenuation of the proposed design. [ABSTRACT FROM AUTHOR]

This article investigates the sound absorption coefficient of materials manufactured from natural wastes. Fruit stones from some crops are one of the most available natural wastes in the Mediterranean Region. Recycled and vegetable products are becoming an interesting alternative to traditional materials to be used as sound-absorbing panels. Fruit stones can be profitable for a number of applications, such as biomass to produce energy. This research work intends to demonstrate that one of their applications can be ecological sound absorbers in building acoustics. Different four fruit stone samples, with different air gap volume percentages, display similar behaviour to multiple Helmholtz resonators (MHRs). By adding a 40 mm-thick rockwool layer, the sound absorption coefficients are compared for each sample. The experimental results allow establishing some analogies between MHRs and the new absorbing materials according to thickness, fruit type and the air gap volume. These fruit stones have been demonstrated as a good choice from acoustic and sustainable points of view. [ABSTRACT FROM AUTHOR]

The 31st FISU Summer World University Games (SWUG) was held in Chengdu, southwestern China, from July 22 to August 8, 2023. A series of control measures were carried out to ensure good air quality during the SWUG, providing an opportunity to investigate the atmospheric behaviors of light-absorbing aerosols under such a substantial disturbance caused by the control measures. To assess the impacts of emission controls on primary pollutants, a field campaign was conducted at a rural site in Chengdu to investigate the characterization of equivalent black carbon (eBC). The changes of eBC concentrations before, during, and after the SWUG were characterized. The sources of eBC were resolved, and the impacts of atmospheric processes on the absorption capacity were also investigated. During the SWUG, the eBC concentration decreased by 12.1 % and 25.3 % compared with those before and after the SWUG. A fossil fuel combustion (eBC ff) and a biomass burning (eBC bb) originated eBC were resolved using the aethalometer model. Both eBC ff and eBC bb decreased during the SWUG, indicating the effectiveness of control measures. After the SWUG, the influence of biomass burning emissions became more and more significant, and the contribution of brown carbon (BrC) to light absorption at 370–660 nm increased by 52, 19, 7, 6, and 17 % compared to those during the SWUG. As the biomass burning emitted aerosols aged, the absorption Ångström exponent and b abs (BrC 370nm) decreased gradually, which was mainly due to the photobleaching of the chromophores during the daytime. eBC ff was mainly affected by strong wind, while high eBC bb concentration was mainly attributed to the gradual accumulation of biomass-burning emissions near the observation site. The results show the significant reduction of eBC with the implementation of the air pollution mitigation campaign, and provide insights on the impacts of atmospheric processes on BC optical properties during summertime. [Display omitted] • Black carbon reduced significantly during the Summer World University Games. • Fossil fuel combustion and biomass burning were main sources of black carbon. • Higher absorption Ångström exponent was attributed to biomass-burning emissions. • Brown carbon absorption coefficient reduced as biomass-burning organic aerosol aged. [ABSTRACT FROM AUTHOR]

Dissolved organic matter (DOM) acts as a chemical intermediary between terrestrial and lacustrine ecosystems and significantly affects the structure and function of lakes. The trophic state of lakes, driven by terrestrial input and phytoplankton biomass, alters the optical properties of DOM. From November 2018 to July 2019, we collected 119 water samples from the Erhai watershed and analyzed them using UV–Vis and EEM-PARAFAC to study the optical properties of DOM in relation to the trophic conditions. Our result indicated that the tyrosine-like protein (C1), tryptophan-like protein (C2), and humic-like compounds (C3) were among the mostly autochthonous components of the DOM. The percentage of the C3 was higher in eutrophic lakes than in mesotrophic and light-eutrophic lakes. The ultraviolet absorption coefficients at 254 nm (a CDOM (254)) and fluorescence intensity at 355 nm (Fn(355)) increased significantly (p < 0.01) with an increased trophic state. Our findings indicate that the influence of nutrients and environmental factors (such as pH and water temperature) on DOM varies with the trophic state. The development of novel predictive models for trophic state assessment was largely based on the significant correlations between TSI and a CDOM (254) (R2 = 0.762, p < 0.01) and Fn(355) (R2 = 0.705, p < 0.01). This neural network model facilitates the creation of a novel fast assessment tool by highlighting the connection between DOM features and the trophic state index. By enabling swift experimental measurements, this model offers a high-resolution monitoring solution for tracking the eutrophication of plateau lakes and rivers. • The optical characteristics of dissolved organic matter along the trophic state gradients were investigated in the Erhai Lake Basin. • The source and components of dissolved organic matter varied significantly in different trophic states. • a CDOM (254) and Fn355 were strongly related to the trophic state index. • a CDOM (254) and Fn355 can be considered as the new indicator to predict water quality. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption of COCl 2 , O 3 , and HCN gas on C 3 N and Ti-doped C 3 N nanosheet. • Ti-doping on C 3 N results in low band gap semiconductor. • Both sheets show strong adsorbent-gas interaction. • Significant variation in optical and electronic properties was observed due to adsorption. In the present study, we designed the pristine C 3 N and Ti-doped C 3 N nanosheets to investigate the geometrical, electrical, and optical properties using density functional theory calculation. The negative value of the cohesive energy of both nanosheets indicates the structures are energetically stable. Ti-doping in C 3 N results in a conductor-to-semiconductor transition with a band gap of 0.15 eV. We studied the adsorption of COCl 2 , O 3 , and HCN gas molecules on the designed structures. The adsorption energy for COCl 2 , O 3 , and HCN gases significantly increased to −8.63, −9.80, and −5.98 eV respectively after Ti-doping. A significant variation in the band gap of Ti-doped C 3 N is observed due to gas adsorption. The complex structures show a high absorption coefficient of over 104 cm−1 in the visible range with a significant red/blue shifting of absorption peaks. The study proves the Ti-doped C 3 N to be a potential candidate for sensing COCl 2 , O 3 , and HCN gases. [ABSTRACT FROM AUTHOR]

In this study, two granular aerogel materials, both consisting of particles with sizes on the scale of 1 to 50 mm, were first investigated both theoretically and experimentally to improve our understanding of their acoustical behavior. Specifically, layers of the aerogels were evaluated in terms of their sound absorption coefficients, and loss mechanisms in the frequency region below 2000 Hz were quantified for both aerogels by using a previously-developed modeling tool based on the Biot theory. Further studies were then conducted in order to optimize the acoustical performance of potential sound packages featuring these aerogel particle stacks. For example, one of the aerogel materials was placed in series with a fibrous layer to take advantage of the low and high frequency sound absorption offered by the aerogel and the fibrous layers, respectively. The two types of aerogels were also combined in parallel to show that absorption peaks of one of the materials could be used to compensate for the absorption "dips" of the other material. After experimentally validating the design concepts mentioned above, the aerogel granule stacks' properties were tuned to realize a very low frequency and wideband sound absorption treatment when combined with the fibrous layer. [ABSTRACT FROM AUTHOR]

In recent years, the inorganic lead-based perovskites have significant consideration owing to their excellent structural stability. In this work, we explore the structural, electronic, and optical properties of α-CsPbI3 and Ge-incorporated α-CsPbI3 perovskites through first-principle calculations. The 12.5% of Ge-mixed CsPbI3 has pleasant structural stability compared to CsPbI3. The CsPb(1-x)GexI3 band gap is linearly decreased while increasing Ge concentration, and it varied from 1.45 to 1.12 eV. Besides, Ge doped CsPbI3 perovskites have a more substantial absorption coefficient in the visible regions. This result reveals, the Ge-incorporation on the B-site location enhanced structural stability and optical absorption coefficient of CsPbI3. [ABSTRACT FROM AUTHOR]

Air cavities with particular arrangements embedded in elastic layers are generally used as anechoic coatings. In this paper, an idea of cavity numbers with gradient changes is introduced in a soft elastic medium that comprises periodical cylindrical cavities to enhance the low-frequency absorption capacity effectively. The presented model provides a sound absorption coefficient that is higher than 0.5 in the frequency ranges of 75 to 95 Hz and 380 to 720 Hz. Thus, validating the idea can effectively enhance the low-frequency absorption capacity compared with those in previous literature. Analytical results based on effective medium approximation theory are compared with those obtained numerically using the finite element method. These results indicate that the invalidity of the analytical model is due to the coupling between cavities under low lattice constant. Power density dissipation and displacement vectors are plotted to study sound absorption mechanism, thereby showing that the dissipated energy is mainly resulted from the multiple-scattering effect. The scattering between cavities induces the transverse wave caused by the wave mode conversion dissipates in the elastic medium and results in sound absorption. Simulation results show that the absorption peaks can be effectively manipulated by tuning the gradient profile of the cavity numbers. The proposed model is then verified by the corresponding experiment. Results obtained numerically and experimentally are agreed well, and its feasibility is verified. The presented model would offer a new approach for the metamaterial design on low-frequency broadband sound absorption and could have potential applications on the design of anechoic coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption of F 2 and O 3 gas on BCN and G_BN nanosheet has been studied via DFT calculation. • Both sheets show strong adsorbent-gas interaction with minimal recovery times. • Significant band gap decrement is observed due to gas adsorption. In the industry era, nanostructures-based gas sensors have been more striking for environmental monitoring. In this research, we investigated the properties and the adsorption ability of boron carbon nitride (BCN) and in-plane graphene-boron nitride (G_BN) nanosheets for toxic (F 2 and O 3) gas molecules. The geometrical, electronic, and optical properties of the selected structures are analyzed using the density functional theory. The negative value of cohesive energy signifies that both BCN and G_BN are energetically stable. Both structures show strong attractive energy for the selected gas molecules with recovery times of 0.266 ps−5.482 ns. A significant change decrease in the band gap of the adsorbents occurred after gas adsorption. All the adsorbents show a high absorption coefficient of over 104 cm−1 in the visible wavelength range. A slight variation in the optical properties is observed after gas adsorption. Both the adsorbents demonstrate significant sensitivity toward F 2 and O 3 gases. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phonon and structural stability of Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 perovskites. • Determined band energy gaps to be favorable for photovoltaic applications. • Mechanical and thermodynamic stability, reliability and compatibility for photovoltaic devices. • IR and Raman active phonon modes in the range 0–400 cm−1 for Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 perovskites. Exploring prospective materials for energy storage and production is one of the largest confrontation of the century. Solar optoelectronic energy is one of the utmost exceptional renewable resources now a days, due to their small Environmental impact and wide availability. The perovskite type double halides are promising materials for optoelectronic and solar applications. In this article, the optoelectronic characteristics of newly perovskite double halides Cs 2 SiBr 6 Cs 2 GeBr 6 and Cs 2 SnBr 6 are addressed. The calculated band gaps 2.70 eV (Cs 2 SiBr 6), 1.80 eV (Cs 2 GeBr 6), 2.90 eV (Cs 2 SnBr 6) with raising performance for optoelectronic applications. The optical properties are explored by large dielectric constants, high optical absorption coefficients, small optical loss etc. Moreover, the mechanical properties for the studied materials have been performed to confirm the mechanical stability, comactability and reliability of the materials for photovoltaic applications. The thermodynamic and vibrational stability and compatibility has been verified due to negative values of enthalpy, cohesive energies and no soft phonon mode of vibrations. These optoelectronic energy related calculations confirmed that the perovskites type double halides may Cs 2 SiBr 6 , Cs 2 GeBr 6 and Cs 2 SnBr 6 may be novel, stimulating potential materials and can be synthesized experimentally for next generation photovoltaic devices and related applications. [ABSTRACT FROM AUTHOR]

We performed a theoretical analysis on collection of equilateral triangular holes with consideration for sound wave attenuation within the tube and then calculated the sound-absorption coefficient and transmission loss. We then compared these results with experimental values. In the experiment, we measured the sound-absorption coefficient and transmission loss of a test sample using impedance measurement tubes with two and four microphones. We estimated the sound-absorption coefficient and transmission loss because of the dimensions of a collection of equilateral triangular holes through theoretical analysis and then compared these results with experimental values. In the present analysis, the propagation constant and characteristic impedance were introduced into a one-dimensional transfer matrix. Considering the effects of sound wave attenuation in the tubule from three-dimensional analysis, we derived the propagation constant and characteristic impedance. Values for the sound-absorption coefficient and transmission loss obtained through the analysis of holes as triangles rather than as circles gave calculation results closer to the experimental values. This is because this method more suitably simulates the effects of the boundary layer that occupies the space within the hole. The results show that the sound absorption coefficient and transmission loss of triangular honeycombs can be estimated with sufficient accuracy using only geometric dimensions and physical properties. © 2022 Institute of Noise Control Engineering. [ABSTRACT FROM AUTHOR]

In general, the acoustic effective length of the open end of an air column is longer than its geometric length. Here, the effective increment of the geometric length of an air column is called the open-end correction length, which is an acoustically crucial issue. The purpose of this study is to experimentally clarify the open-end correction length for a slit shape with a narrow clearance. For this reason, the sound absorption coefficient was measured using a sample in which the neck of the Helmholtz resonator was shaped as a slit with a narrow clearance. Next, the open-end correction length (i.e., mass end correction length and resistive end correction length) was calculated backward by comparing the experimental and theoretical sound absorption curves. The resistive end correction increased as the slit width became narrower within the range of 0.5 mm or less for both the center slit and the slit near the wall, indicating a significant discrepancy between the theoretical equation and the estimated value. For the mass end correction, in the case the center slit, the estimated value is close to the theoretical value of in the slit width range from 0.3 mm to 1.0 mm. The results of this study may be useful in eliminating discrepancies in correction values for open-end correction in slits with narrow clearance. © 2022 Institute of Noise Control Engineering. [ABSTRACT FROM AUTHOR]

The multilayer impedance composite sound absorption structure of the new muffler is proposed by combining the microporous plate structure with the resonant sound absorption structure of the porous material. Firstly, the acoustic impedance and acoustic absorption coefficient of the new muffler structure are calculated by acoustic electric analogy method, and then the noise attenuation is calculated. When the new muffler structure parameters change, the relationship among the noise frequency, the sound absorption coefficient and the noise attenuation is calculated by using MATLAB. Finally, the calculated results are compared with the experimental data to verify the correctness of the theoretical calculation. The variation of resonance peak, resonance frequency and attenuation band width of each structural parameter is analyzed by the relation curve. The conclusion shows that it is feasible to use multilayer sound absorbing materials as the body structure of the new muffler. And the influence relationship between the change of various parameters of the sound absorption structure with the sound absorption coefficient and noise attenuation is obtained. [ABSTRACT FROM AUTHOR]

The main objective of this study is to improve the retrieval of phytoplankton absorption coefficients using ocean and land color instrument (OLCI) bands (413, 443, 490, 510, 560, and 665 nm). In this study, the Raman-scattering correction was considered in an analytical forward model, and the corresponding Raman excitation OLCI band centers were calculated. The coefficients and exponents for the power law model of phytoplankton absorption were determined by a neural network classifier using a combination of sun elevation, photosynthetically active radiation, and remote sensing reflectance at OLCI bands (413, 443, 490, 510, 560, 620, 665, and 683 nm). Two optimizations were executed. The shape of the colored detrital matter (CDM) spectrum was allowed to change during the second optimization. Based on comparisons of the phytoplankton absorption coefficients at 443 nm (a[443]) predicted by the improved inversion with field measurements taken from cruise surveys of the Pearl River estuary and Daya Bay and the SeaWiFS Bio-optical Archive and Storage System dataset and NASA bio- Optical Marine Algorithm Dataset, the modified inversion procedure could provide a good performance (r2 = 0.86). The results showed that the contribution of Raman scattering to the remote sensing reflectance at 665 nm exceeded 22% in the open ocean. Moreover, the residual from the first optimization was compared with that from the second optimization, demonstrating that the variable CDM spectral slope in the analytical forward model could improve the accuracy of the forward model. [ABSTRACT FROM AUTHOR]

A structure that possesses a continuous pore space packed with a granular material exhibits acoustic characteristics based on the principle similar to that of a porous material. Such a structure is used in low-noise pavement and ballast track. Therefore, predicting the sound absorption characteristics of a clearance generated in a granular material from the particle diameter and the physical property of gas is useful for engineering. This article deals with two packing models, namely, the simple cubic lattice model and the hexagonal lattice model, to measure the sound absorption coefficient of the structure packedwith a granularmaterial whose particle diameter is a few mm. Furthermore, a simple and accurate theoretical analysis that uses a one-dimensional transfer matrix method, which does not require numerous parameters, was performed. Comparing experimental values, when the particle diameter of the granularmaterialwas 4 mm, the percentage of the boundary layer in the clearance was moderately larger than when the diameter was 8 mm; therefore, the effect of viscosity on it was larger, and its sound absorption coefficient peak was higher.Moreover, comparedwith the simple cubic lattice, the hexagonal lattice had a higher percentage of boundary layer in the clearance because of its smaller volume of pore space. Then, the influence of friction due to the viscosity on it was higher, and its sound absorption coefficient peak was higher. In addition, the theoretical values obtained by the proposed analysis method typically matched the experiment values. [ABSTRACT FROM AUTHOR]

Impedance tubemethod is widely used tomeasure acoustic properties ofmaterials. Although thismethod yields reliable acoustic properties for soft texturedmaterials, uncertainty levels of measured acoustic properties for hard materials, including biocomposites, can be quite large, mainly due to uncertain mounting conditions. Here, the effects of mounting conditions on the acoustic properties of biocomposites in an impedance tube are investigated. First, nominally identical biocomposite samples with a diameter equal to the inner diameter of impedance tube are manufactured and their acoustic properties are determined. As hard materials practically cause fitting problems in the impedance tube, the diameters of samples are reduced, as in practice, by small amounts and acoustic properties of modified samples are determined. Furthermore, in order to match the diameters of samples to the inner diameter of impedance tube, different materials such as tape, petroleum jelly and cotton are applied around samples to close the air gap between the samples and the tube's inner wall. All the results are compared, and the uncertainty levels caused by differentmounting conditions on the acoustic properties of biocomposites are identified. The results show that the transmission loss (TL) measurements are dramatically affected by the mounting conditions while the sound absorption conditions are less sensitive to the mounting conditions. The deviations in the measured TL levels are highest for the sampleswith tape andwax (10-15 dB).Onthe other hand, the deviations in the measured sound absorption coefficients are highest for the samples with cotton and tape (1-2%). [ABSTRACT FROM AUTHOR]

This article aims to investigate the sound absorbing properties of a thick microperforated panel (MPP) with tapered sections with finite element analysis (FEA) models. The FEA model was validated by using the measured sound absorption coefficients of a classic MPP sample and a proposed MPP sample. The FEA simulation and the experiments indicate that the tapered section can enhance the sound absorption coefficient. Moreover, the FEA model shows that the structural parameters of the tapered section can be optimized. The resonance frequency of the sound absorption coefficient moves to the high-frequency range, and the maximum sound absorption coefficient increases in three conditions, the tapered section moving toward the backing cavity, and the increase of the thickness and the bottom radius of the tapered section. Although the optimized configurations of the tapered section may vary with the structure parameters of the MPP, the tapered section can improve the sound absorbing properties of the classic MPP and could be promising in the noise and vibration engineering projects. [ABSTRACT FROM AUTHOR]

Antimony sulfide (Sb2S3) is an emerging photovoltaic material that comprises earth-abundant, non-toxic constituents and has a high absorption coefficient (>104 cm-1). Nevertheless, the serious bulk recombination phenomenon and the slow electrochemical reaction kinetics on the surface of Sb2S3 electrode restrict its application in the photoelectrochemical (PEC) water splitting. Herein, we have designed a polyaniline (PANI)/Sb2S3 p-n junction photoanode successfully to address these issues. With the modification of in-situ anchored PANI, the composite electrode exhibits enhanced light-absorption and accelerated charge transfer efficiency. As a result, the photocurrent density of optimized PANI/Sb2S3 photoanode is about twice of pristine Sb2S3, being a promising material for PEC water splitting. [ABSTRACT FROM AUTHOR]

Sound-absorbing asphalts are particularly useful for reducing noise emissions from vehicular traffic. This solution is perfectly suited for urban areas, in fact the use of sound-absorbing asphalt represents a noise control measure with a negligible environmental impact. In the present work, the results of an experimental investigation on sound-absorbing asphalts were reported. First, the characteristics of the sound-absorbing asphalts used were experimentally found. Then, the measurements of the sound absorption coefficient of the asphalt specimens were investigated. In the final part, numerical simulation model with artificial neural networks of the acoustic coefficient were compared with the data obtained from the measurements. The neural network model showed good Pearson correlation coefficient values (0.894) which can be used with good accuracy to predict the sound absorption coefficient. [ABSTRACT FROM AUTHOR]

The advancement of UV-LEDs has made them excellent alternative to the UV lamps. UV-LED reactors have been used for water treatment. However, the limited ability of UV light to penetrate in liquid foods makes designing liquid foods reactors difficult. This study investigates the effect of different reactor geometries, different location of inlet and outlet pipes, different body material (PTFE and non-reflective), and different operating conditions including, flow rates of 0.05, 0.1, 0.2, and 0.4 L / min , absorption coefficients of 250, 500, 1000, and 2000 m−1, and radiant power of 30, 60, 120, and 180 mW on the performance of the reactor designed for liquid foods using CFD. The efficiency of the reactor increased from 24.58% to 59.62% by changing the reactor geometry. Higher efficiency is achieved by increasing the absorption coefficient from 250 to 2000 m−1 and the flow rate from 0.05 to 0.4 LPM. However, increasing the UV-LED radiant power from 30 to 180 mW reduces reactor efficiency. Moreover, for the fluid with a high absorption coefficient (500 m−1), the body material of reactor 4–8 almost has no effect on microbial inactivation. • Twelve configurations have been investigated for disinfection of liquid foods in UV-LED reactor. • The efficiency of 59.62% has been found in UV-LED reactor for liquid foods. • Increasing the absorption coefficient leads to higher efficiency of the UV-LED reactor. • Non-reflective material can be used as body material of UV-LED reactor for liquid foods. • UV-LED reactors can be used for juices and beverages treatment. [ABSTRACT FROM AUTHOR]

In the theoretical investigation of Cs 2 TlBiX 6 (X = Cl, Br, I) perovskites, it was observed that Cs 2 TlBiI 6 exhibits excellent thermodynamic phase stability, a direct bandgap of 1.83 eV (HSE06), a remarkably high light absorption coefficient of 105 cm−1, and an elevated spectroscopic limited maximum efficiency of 25.93%. [Display omitted] • The first-principles methods are utilized to investigate the geometrical and electronic structures, photoelectric properties, and defect effects of Cs 2 TlBiX 6 (X = Cl, Br, I) perovskites. • The calculated results reveal that these compounds exhibit excellent structural stability, ideal direct bandgaps, and notable light absorption coefficients (105 cm−1). • Mechanical and thermal stability are evaluated based on structure factors, elastic constants, and regions of stable chemical potential. Numerous endeavors are committed to investigating innovative perovskite materials characterized by superior thermal stability, aimed at their application in the next-generation of photovoltaic technologies. We employ density functional theory to compute the geometrical and electronic structures and to quantify the photoelectric properties of Cs 2 TlBiX 6 (X = Cl, Br, I) perovskites. These compounds exhibit excellent structural stability, ideal direct bandgaps, and high light absorption coefficients (105 cm−1), rendering them well-suited for application as photovoltaic absorbers. We assess mechanical and thermal stability by evaluating structure factors, elastic constants, and regions of stable chemical potential. Additionally, we explore the impact of defects in Cs 2 TlBiI 6 on its photovoltaic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • First principle investigations of OsS 2 in pyrite type structure. • The semiconducting nature with a narrow band gap is expected. • The doping of Os site with Fe and Ru improves the band gap. • Enhancement of optical properties like absorption coefficient, reflectivity, refractive index, and optical conductivity when doped.. In the present manuscript, we report a systematic investigation of the structural, electronic, and optical properties including the elastic behaviour of erlichmanite (OsS 2), using FP-LAPW method. The effect of exchange correlation functional when treated with GGA, this ductile semiconductor shows an electronic band gap of 0.34 eV that has been enhanced to 0.75 eV when mBJ potential is employed. The band gap of OsS 2 further widens when Os site is doped with Fe/Ru with its highest value of 1.83 eV when 75 % of Os is replaced with Fe. The addition of dopant also improves the refractive index of the sample with highest amplitude when 75 % Fe doping and the optical absorption coefficient reaches its highest limit of 8.7 × 105 cm−1 and 9.1 × 106 cm−1 in the visible energy range for 75 % Fe and Ru doping, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Industria Textila is the property of Institutul National de Cercetare-Dezvoltare pentru Textile si Pielarie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, a theoretical analysis of the acoustic characteristics of a pin holder structure was conducted. In addition, the sound absorption coefficient, entering its clearance through the geometrical dimension of the clearance or the physical property of air, was calculated. The analysis model approximates the aperture of a pin holder structure as the clearance between two parallel surfaces. Thus, the propagation constant and characteristic impedance were obtained and treated as a one-dimensional transfer matrix. Subsequently, the sound absorption coefficient was calculated using the transfer matrix method and was compared with the experimental results. In the experiment, a two-microphone impedance tube was used to measure the sound absorption coefficient of the test samples. We attempted to perform a simple yet accurate estimation using these procedures. The theoretical analysis values exhibited a similar tendency to that of the experimental values. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A fibrous sound absorbing material, such as a polyester nonwoven, can be covered with a layer of fabric for its protection and decoration, with an improvement of its sound absorption characteristics. In this work, the sound absorption coefficient of a multilayer textile material composed by a 45mm polyester nonwoven and a layer of stuffed fabric, is measured using an impedance tube. Design of experiments is used to optimize two characteristics of the fabric like weft density and use of stuffing picks, so the highest sound absorption coefficient is obtained in all the studied frequencies. Results show the combination of the studied factors that maximizes sound absorption. [ABSTRACT FROM AUTHOR]

Permeable membranes (PMs), which are air-permeable fabrics made from various natural or chemical fibers that are thinly woven or non-woven, are attractive sound-absorbing materials. The simplest PM absorber is a single-leaf PM absorber (PMSG) with a non-locally reacting rigid backed air cavity in which a PM is placed in front of a rigidly backed air cavity. A honeycomb-backed single-leaf PM absorber (PMHC), which has a locally reacting air cavity, is alsowell known.However, the two PMabsorbers have shortcomings in their diffuse field absorption coefficients attributable to the backing air cavity design. To overcome those shortcomings, we introduce a PM absorber array (PMAR): a single-leaf PM absorber with multiple locally reacting air cavities of different depths. As described herein, to present PMAR benefits, we experimentally compare the diffuse field absorption characteristics of the three single-leaf PM absorbers with different air cavity designs. Reverberation absorption coefficient measurements were taken using nine thin permeable membranes made of three chemical fibers, each having different flow resistance and surface density. Results show that PMAR is an effective sound absorbing structure to overcome the shortcomings related to the diffuse field absorption coefficients of PMSG and PMHC. Material property effects on permeable membranes are also demonstrated. [ABSTRACT FROM AUTHOR]

• Highest carbon dioxide removal efficiency was obtained as 57.5% with 0.03 M MEA / 0.07 M PZ solvent in hybrid systems. • The highest absorption capacity, mass transfer coefficient and the highest absorption rate obtained with 0.03 M MEA/ 0.07 M PZ. • PZ blends with MEA were successful absorbent as the organic physical solvent whereas NMP blends didn't show improving effect. • Generally, blended solvents show better absorption performance compared with single absorbents. In this research the carbon dioxide absorption using Monoethanolamine (MEA), Piperazine (PZ) and N-Metil-2-pirolidon (NMP) solvents and their different blends (MEA/NMP, PZ/NMP, MEA/PZ) in packed column reactor filled with Raschig rings was investigated and compared for efficient carbon dioxide absorption. The process was followed in a countercurrent regime under a liquid flow rate of 200 mL/min, gas flow rate of 2.5 L/min, and CO 2 concentration of 50,000 ppm. Carbon dioxide removal efficiency (%), absorption capacity (mol CO 2 /mol solvent), overall mass transfer coefficient (1/min) and absorption rate (mol/l.s) were monitored. The highest obtained values for carbon dioxide removal efficiency, absorption capacity and overall mass transfer coefficient were 57.5%, 0.148 mol CO 2 /mol solvent and 2.178 min−1 respectivelly when 0.03 M MEA/0.07 M PZ in a hybrid system was used. It was concluded that PZ blends with MEA were successful absorbent as the organic physical solvent whereas NMP didn't show improving effect in blends with MEA on the absorption efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • W2GaX (X = C, N, and F) based novel MAX phases. • First-Principles Calculations. • Cohesive Energies Investigations. • Nonmagnetic Metallic Behavior. • High Optical Reflectivity. • Promising Candidates for Electronic and Optical Devices. This study examines the electronic and optical characteristics of W 2 GaX (X = C, N, and F) MAX phases using first-principles approach. The cohesive energies of W 2 GaC, W 2 GaN, and W 2 GaF are determined as 7.31, 6.40, and 5.05 eV, respectively, demonstrating excellent agreement with existing literature and confirming their stability. The W- d , Ga- s , and X- p states are symmetrically dispersed across the spin-polarized electronic structures, resulting in a nonmagnetic metallic behavior of W 2 GaX. Due to their metallic behavior, they reflect more than 60 % of infrared and up to 50 % of visible light. These compounds demonstrate considerable absorption of infrared, visible, and ultraviolet (UV) light, with absorption coefficients of approximately ∼104 cm−1, ∼105 cm−1, and ∼106 cm−1, respectively. The refractive indices of W 2 GaX MAX phases remain greater than one for incident light energies below 10 eV. Additionally, W 2 GaC shows the highest optical conductivity among the investigated compounds when exposed to light, making it a promising material for various conduction applications. Our present study sheds light on the optical and electronic properties of W 2 GaX MAX phases and highlights their potential for applications in advanced electronic and optical devices. [ABSTRACT FROM AUTHOR]

Columnar aerosol loading and surface level atmospheric black carbon (BC) concentration over the Antarctic are examined using the measurements carried out at the Indian Antarctic stations, Bharati and Maitri, as part of the 36th Indian Scientific Expedition (2016–17) to Antarctica (ISEA). The mean aerosol optical depth (AOD) at wavelength 500 nm at Bharati is observed to be 0.101 ± 0.01, whereas that at Maitri is 0.047 ± 0.003. Columnar aerosol loading at Bharati is found to be more than two times that measured at Maitri. The daily mean surface level atmospheric BC concentration at Bharati in the Austral summer from December 2016 to February 2017 is 24 ± 16.5 ngm−3. Comparison of this measurement with earlier reported values over the same region indicates an increase in surface-level atmospheric BC concentration. Long-term (1997–2017) trend analysis carried out using MERRA-2 aerosol reanalysis data also corroborates the increasing trend in AOD and BC concentration with 0.005 (0.007) yr−1 and 0.3 (0.27) ngm−3 yr−1 over Bharati (Maitri) respectively. Spectral variations of aerosol absorption coefficients show absorption angstrom exponent values (AAE) close to unity (1.096 ± 0.029), which indicates that fossil fuel emission is the primary source of absorbing aerosols over this region. During the study period, air mass back trajectory analysis indicates that the sources are from the Antarctic, coastal, and southern ocean regions with no long-range transport from other continents in the southern hemisphere. [ABSTRACT FROM AUTHOR]

Standardized multilayer microperforated panel fabricated by laser beam machining of the spring steel was proposed for noise reduction in this study. Geometric parameters of the standardized multilayer microperforated panel, which include diameter of the hole, thickness of the panel, distance between the neighbor holes, and length of the cavity, were optimized for the better sound absorption performance. Sound absorption coefficient of the standardized multilayer microperforated panel was theoretically modeled based on the Maa's theory. The optimization of geometric parameters of the standardized multilayer microperforated panel was obtained by the Cuckoo search algorithm, and the finite dimension of 30 mm was treated as the additional constraint condition. Preliminary verification of the obtained optimal parameters was conducted through the constructed finite element simulation model. Actual sound absorption coefficients of the standardized multilayer microperforated panels with layer number of 1 to 4 were measured by standing wave method, which were consistent with theoretical data and simulation data, and the corresponding average values in the frequency range of 100--6000 Hz were 57.45%, 70.85%, 71.99%, and 72.28%, respectively. By theoretical modeling, parameter optimization, simulation, and experimental validation, an effective method was proposed to develop practical sound absorbers, which would promote their applications in noise reduction. [ABSTRACT FROM AUTHOR]

Highlights • The relationships between informative bands with absorption features were explored. • Informative bands of efficient indices were not those at absorption peaks. • Efficient indices used the wavelengths with relatively high absorption coefficients. Abstract Hyperspectral indices have proven to be useful for quantifying various plant parameters including a number of biochemical components. However, it remains a great challenge to unveil the physical and physiological mechanisms of wavelengths used by these statistically/empirically identified indices, and this unveiling is a critical step towards developing generally applicable indices. In this study, we have introduced a dummy variable to the well-accepted leaf scale radiative transfer model (PROSPECT-4) and have conducted a series of virtual experiments by tweaking different absorption features (intensity, peak wavelength, and half-width) of the dummy variable for investigating the underlying mechanisms of those wavelengths used by efficient indices. Results clearly indicated that the informative bands used in efficient indices, instead of the target parameter’s absorption peaks, are generally concentrated among wavelengths that the targeted parameter has relatively high specific absorption coefficients compared with other biochemical components. This finding has also been validated by replacing the dummy variable with carotenoids based on PROSPECT-5B simulated dataset. Further analysis reveals that although the concentrations of chlorophyll are higher than other pigments in most leaves, the commonly recommended wavelength of 550 nm may be disturbed by other pigments and may only be applicable when anthocyanins are minor. Results obtained in this study have largely explained why specific wavelengths are used in efficient indices, and thus this should lay a basis for understanding the underlying mechanisms and help to develop robust indices for estimating vegetation biochemical parameters. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The stability is improved due to the doping of lighter atoms. • Distinct blueshift implied reduction of optical properties in mixed structures. • Different doping positions in same phases are considered. • CH 3 NH 3 Pb(I 0.75 Br 0.25) 3 was chosed as the most potential optical material. Abstract Recently, extensive studies have widely fabricated and demonstrated that organic-inorganic hybrid perovskite-type solar cells, CH 3 NH 3 PbI 3 , have the superior optoelectronic properties. We explore the structural, electronic, optical properties and stability of tetragonal phase mixed halide perovskites CH 3 NH 3 Pb(I 1-y X y) 3 (X = Cl, Br; y = 0, 0.25, 0.5, 0.75), using first-principles calculations. The calculation of electronic structure reveals that the valance band maximum is governed by the halide p -orbitals and Pb 6 s -orbitals while the conduction band minimum formed by the mixed contribution from the p orbitals of Pb atom and s orbitals of I atom. For the stability and optical properties of CH 3 NH 3 Pb(I 1-y X y) 3 , the absorption coefficients show a blueshift of the absorption onsets but their stabilities show gradually increase with the increasing of X contents. Three different doping occupation phases of MAPb(I 0.5 X 0.5) 3 demonstrate that the impact of doping positions in linear optical property cannot be neglected but there is no change in stability. On the basis of all calculated results, we conclude that the best accouplement between absorption coefficiency and stability can be achieved at y = 0.25 in CH 3 NH 3 Pb(I 1−y Br y) 3 perovskites. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV)-based advanced oxidation processes (UV-AOPs) are broadly used methods for the removal of organic contaminants from drinking water. Degradation kinetics, reaction mechanisms, radical formation, effects of water matrixes, and the formation of by-products in UV/Cl 2 , UV/NH 2 Cl, UV/ClO 2 , UV/peracetic acid (PAA) are reviewed in this paper. UV-AOPs mainly rely on the formation of a large number of free radicals through UV photolysis to degrade pollutants. The molar absorption coefficients of the major oxidants in these processes range from 8 to 371 M−1 cm−1, while the quantum yields range from 0.2 to about 0.88 mol Einstein−1. HO• is the most common radical among these processes. A rough order of comparison in terms of degradation efficiency is UV/Cl 2 ＞ UV/NH 2 Cl ＞ UV/ClO 2 ＞ UV/PAA. The effect of different substances in the water will also have an effect on the rate and pathway of the reaction and the formation of by-products. NOM and carbonates can inhibit degradation efficiency while halogens and ammonium will influence reaction pathway and have impact on by-product formation and toxicity. A rough order of comparison in terms of by-product formation is: UV/Cl 2 ＞ UV/NH 2 Cl > > UV/ClO 2 ≈ UV/PAA. UV/Cl 2 remains the most efficient process for contaminant removal, although it has the highest risk of disinfection by-product formation. UV/NH 2 Cl can lower the possibility of producing by-products but may lead to increased water toxicity and nitrogen contamination. UV/ClO 2 has an advantage of the lowest by-product formation among three chlorine-containing UV-AOPs, while maintaining relatively considerable removal efficiency. UV/PAA, as an alternative to UV/H 2 O 2 , remains minimal by-product formation potential, while the effect on organic content in water should also be noted. Selection of suitable UV process and reaction conditions according to the characteristics of pollutants as well as reduce or dispose of the generated by-products will be the future research direction. [Display omitted] • Free radicals generated in UV-AOPs could accelerate micropollutant abatement. • Water matrixes can influence radical formation and by-product formation. • Both the degradation efficiency and by-product formation follow the same order. • Halogens can significantly increase by-product formation and toxicity. [ABSTRACT FROM AUTHOR]

Metal rubber (MR) is an excellent sound absorptionmaterial which can be utilized in extremely harsh environments. Traditional experimental studies are incomplete for MR with random structural parameters. In this article, the general regression neural network (GRNN) method is developed to comprehensively predict the sound absorption behaviors of MR with random structural parameters. Sixty samples are utilized and divided into training and test set. Training set contains 50 samples to establish the GRNN model. Input training parameters include the porosity, wire diameter and thickness, while the target dates consist of sound absorption coefficients at six central frequencies as well as their average values. The remaining 10 samples constitute the testing set; sound absorption coefficients can be obtained by inputting their structure parameters. Results indicate that the proposed approach is reliable to design and predict the sound absorption properties of MR in engineering field. [ABSTRACT FROM AUTHOR]

This study investigated the effect of the suspended ceiling panel with low-frequency resonant panel absorber on heavyweight floor impact sound. The resonant panel absorber was designed with a perforated top panel, an air gap with or without glass wool, and a bottom panel to ensure a high absorption coefficient in the low-frequency range around 100 Hz. Absorption coefficient measurements were carried out first in the reverberation chamber for resonant panel absorbers varying with the hole diameter of the top panel, the thickness of the glass wool and the air gap between the top and bottom board. As a result, the glass wool had the greatest influence on the absorption coefficient, and the highest absorption coefficient of the resonant panel absorber was about 0.6 in the band of 100 Hz. Floor impact sounds after installing the suspended ceiling with the best resonant panel absorber were also measured in test building using heavyweight floor impact sound sources (bang machine and rubber ball) and compared with result for normal suspended ceiling with gypsum board. Heavyweight floor impact sound by the resonant panel absorber was decreased by 2 dB and 4 dB in single number quantity ( L i,Fmax,Aw ) for bang machine and rubber ball, respectively. In particular, the resonant panel absorber reduced by 6 dB in 125 Hz octave band with the largest absorption coefficient. [ABSTRACT FROM AUTHOR]

The capillary absorption test is one of the most frequently performed material characterization tests. It provides the capillary absorption coefficient and the capillary moisture content, both are important material properties. Currently, full consensus concerning the experimental protocol and data processing of the capillary absorption test has not been reached yet. This paper studies the potential impact factors during the test and compares different methods for processing the raw data. Measurements on calcium silicate, ceramic brick, sintered glass and autoclaved aerated concrete are carried out, and published literature results are reviewed. The impact of sample size, sealing method, initial moisture content, temperature and personnel have been thoroughly analyzed, and proper recommendations are provided accordingly. Moreover, a new data processing model with a solid physical background for calculating the capillary absorption coefficient and the capillary moisture content has been proposed. It shows obvious advantages over other published models and is applicable for both ideal and irregular capillary absorption patterns. [ABSTRACT FROM AUTHOR]

The Firefly algorithm is a population-based optimization algorithm. It has become popular in the field of optimization and has been applied to engineering practices. Recent works have failed to address how to find the global minimum because their algorithm was trapped in the local minimum. Also, they were not able to provide a balance between exploration and exploitation. In this paper, the Tidal Force formula has been applied to modify the Firefly algorithm, which describes the effect of a massive body that gravitationally affects another massive body. The proposed algorithm brings a new strategy into the optimization field. It is applied by using exploitation (Tidal Force) and keeping a balance between the exploration and exploitation on function suitability. Plate shaped, Steep Ridges, Unimodal and Multimodal benchmark functions were used to compare experimental results. The study findings indicate that the Tidal Force Firefly algorithm outperforms the other existing modified Firefly algorithms. [ABSTRACT FROM AUTHOR]