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Abstract Mentha haplocalyx essential oil (MEO) has demonstrated inhibitory effects on Fusarium oxysporum. Despite its environmentally friendly properties as a natural product, the limited water solubility of MEO restricts its practical application in the field. The use of nanoemulsion can improve bioavailability and provide an eco-friendly approach to prevent and control Panax notoginseng root rot. In this study, Tween 80 and anhydrous ethanol (at a mass ratio of 3) were selected as carriers, and the ultrasonic method was utilized to produce a nanoemulsion of MEO (MNEO) with an average particle size of 26.07 nm. Compared to MTEO (MEO dissolved in an aqueous solution of 2% DMSO and 0.1% Tween 80), MNEO exhibited superior inhibition against F. oxysporum in terms of spore germination and hyphal growth. Transcriptomics and metabolomics results revealed that after MNEO treatment, the expression levels of certain genes related to glycolysis/gluconeogenesis, starch and sucrose metabolism were significantly suppressed along with the accumulation of metabolites, leading to energy metabolism disorder and growth stagnation in F. oxysporum. In contrast, the inhibitory effect from MTEO treatment was less pronounced. Furthermore, MNEO also demonstrated inhibition on meiosis, ribosome function, and ribosome biogenesis in F. oxysporum growth process. These findings suggest that MNEO possesses enhanced stability and antifungal activity, which effectively hinders F. oxysporum through inducing energy metabolism disorder, meiotic stagnation, as well as ribosome dysfunction, thus indicating its potential for development as a green pesticide for prevention and control P. notoginseng root rot caused by F.oxyosporum.

Mentha haplocalyx essential oil (MEO) has demonstrated inhibitory effects on Fusarium oxysporum. Despite its environmentally friendly properties as a natural product, the limited water solubility of MEO restricts its practical application in the field. The use of nanoemulsion can improve bioavailability and provide an eco-friendly approach to prevent and control Panax notoginseng root rot. In this study, Tween 80 and anhydrous ethanol (at a mass ratio of 3) were selected as carriers, and the ultrasonic method was utilized to produce a nanoemulsion of MEO (MNEO) with an average particle size of 26.07 nm. Compared to MTEO (MEO dissolved in an aqueous solution of 2% DMSO and 0.1% Tween 80), MNEO exhibited superior inhibition against F. oxysporum in terms of spore germination and hyphal growth. Transcriptomics and metabolomics results revealed that after MNEO treatment, the expression levels of certain genes related to glycolysis/gluconeogenesis, starch and sucrose metabolism were significantly suppressed along with the accumulation of metabolites, leading to energy metabolism disorder and growth stagnation in F. oxysporum. In contrast, the inhibitory effect from MTEO treatment was less pronounced. Furthermore, MNEO also demonstrated inhibition on meiosis, ribosome function, and ribosome biogenesis in F. oxysporum growth process. These findings suggest that MNEO possesses enhanced stability and antifungal activity, which effectively hinders F. oxysporum through inducing energy metabolism disorder, meiotic stagnation, as well as ribosome dysfunction, thus indicating its potential for development as a green pesticide for prevention and control P. notoginseng root rot caused by F.oxyosporum. [ABSTRACT FROM AUTHOR]

The effect of fatigue failure on the elastic characteristics of metastable austenitic steel AISI 321, Poisson's ratio and acoustic anisotropy parameter, was studied. The elastic characteristics were calculated based on the data of ultrasonic measurements of the propagation time of longitudinal and shear elastic waves. The volume fraction of the strain-induced martensite was determined by the eddy current method. Theoretical studies have shown that the main factors influencing Poisson's ratio are the accumulation of microdamage and changes in the phase composition. The change in the acoustic anisotropy parameter is associated with the effect of cyclic deformation on the crystallographic texture of the material matrix and the formation of oriented crystals of strain-induced martensite. Based on the analysis of experimental results, expressions have been obtained for calculating damage and relative accumulated plastic strain according to acoustic measurements, which are widely used in engineering practice to determine the fatigue life of structural materials. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature 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.)

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office 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.)

The study aims to characterize the structural features of Jordanian tar sand using analytical techniques including (FTIR, ultimate and proximate analysis, TGA, XRD, and XRF). The tar sand shows a low content of volatile matter (bitumen) with significant nitrogen content. The bitumen contains a high proportion of aliphatic hydrocarbons of which high content of it attached to oxygen atom. The minerals were mainly quartz and low concentration of carbonate with noticeable content of sulfite and potassium oxide from XRF. The recovery of bitumen was evaluated using three different extraction techniques: solvent extraction methods (ultrasound-assisted extraction, non-aqueous extraction) and thermal pyrolysis using the Fischer assay apparatus. The non-aqueous solvent extraction method gave the highest bitumen recovery using toluene as a solvent; however, the high-temperature Fischer assay method provided a low recovery. The extracted bitumen under the optimum condition was characterized using NMR, elemental analysis, and GC-MS analysis. The oil products from tar sand showed a high concentration of oxygen and noticeable concentration of sulfur atoms. The 1H-NMR revealed a high content of aliphatic hydrocarbons in good agreement with raw tar sand characteristics. The identified compounds in the GC-MS where mainly substituted with oxygen atom in the form of alcohols and ethers. [ABSTRACT FROM AUTHOR]

This research aims to improve crystal structure and pore size and adjust Brønsted to Lewis (B/L) acid site ratio of spent RFCC catalyst through ultrasound-assisted acid treatment. The catalyst performance was tested to convert palm oil into biofuel through hydrogen-free catalytic cracking. Results showed that crystallinity and pore size of the spent RFCC catalysts were improved. The B/L acid site ratio of the acid treated catalysts could be adjusted, leading to improve the catalysts activity for palm oil cracking process. The main product of the cracking process was liquid fuel product, which was ranged at 85 %–96 % mass fraction. Compared to the liquid fuel product produced by conventional acid treatment, the RFCC catalysts that have been treated using ultrasound-assisted acid treatment produced a higher yield. The GC-MS results showed that hydrocarbons, alcohols, ketones, and aldehydes are main chemical components in gasoline and kerosene.

Design of photocatalyst with high stability, efficiency to achieve rapid separation of photogenic carrier and enhanced photocatalytic activity is a key challenge. Herein, integrating hollow CdS nanospheres on the surface of the metal-organic frameworks UMCM-1 to form a novel CdS/UMCM-1 heterojunction by solvothermal method, and the structure of the catalyst was characterized by SEM, TEM, FT-IR spectra and PXRD. The properties of CdS/UMCM-1 photocatalyst was evaluated by eliminating organic pollutants (Rhodamine b(RhB), Tetracycline(TC)) and hydrogen production under visible light, and the results showed that CdS/UMCM-1 heterojunction exhibited excellent photocatalytic performance compared with the pristine CdS nanospheres and UMCM-1. A S-type photocatalytic mechanism was proposed based on radical trapping experiments, electron spin resonance (ESR) analyses and the degradation pathway of RhB and TC. CdS/UMCM-1 heterojunction possessed a great stability and reusability making them interesting for applications in the environmental and clean energy fields. [Display omitted] • A novel S-scheme hollow CdS/UMCM-1 photocatalyst with intensive photocatalytic properties was successfully constructed. • Compared with hollow CdS spheres monomer and UMCM-1 monomer, hollow CdS/UMCM-1 photocatalyst had absolute advantages in photocatalytic degradation performance (RhB and TC) and photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Background: Agricultural by-products rich in lutein such as pistachio hull can be applied in pharmaceutical, cosmetics and food manufacturing. The development of rapid and cost-effective extraction methods of lutein from pistachio hull to optimize lutein recovery is of great interest to transpose to an industrial scale. Herein, we optimized the extraction protocol of lutein from the Iranian pistachio hull using experimental design and ultrasonic method. Methods: Fresh raw un-hulled pistachios were harvested and dehulled, then hulls were dried and finely powdered to use for further analysis. Soxhlet process was carried out to obtain pistachio hull oleoresin and response surface methodology (RSM) was used for the optimization of saponification and ultrasonic methods. The lutein contents were quantitatively analyzed and validated using LC-MS/MS system. Results: Our results showed that lutein in pistachio hull is mainly in free form, therefore the saponification method is not necessary for its extraction. Under optimal experimental design conditions, the maximum amount of lutein predicted and observed was 7.90 and 7.97 mg/100 g, respectively. Ethyl acetate was applied as an extraction solvent with the ultrasonic method followed by the setting up of the extraction time, temperature and solvent/sample ratio as variables. Under optimal experimental conditions corresponding to 45 min extraction time at 50 °C and 35.5 mg/ml of the solvent/sample ratio, the amount of lutein obtained from dried pistachio hull was 5.14 mg/100 g. Conclusion: Pistachio waste products are rich in lutein which is in free from, so the administration of ultrasonic extraction using Ethyl acetate as a green and cost-effective method can be applied for lutein extraction from other plant materials and suggested for application on an industrial scale. [ABSTRACT FROM AUTHOR]

Arch rib is the key mechanical component of concrete-filled steel tubular arch bridge. It is of great engineering value to detect the void of arch rib efficiently and accurately. Aiming at the problem that the ultrasonic method can not realize the quantitative detection of the void height of the arch rib, a simplified calculation formula for the detection of the void height of concrete-filled steel tubular by the ultrasonic method based on the speed of sound is derived and established by combining the theoretical derivation, the model experiment and the real bridge experiment. The feasibility and accuracy of the calculation formula are verified by the model experiment and the real bridge experiment. The results show that the simplified calculation for the detection of the void height of concrete-filled steel tubular by the ultrasonic method based on the speed of sound has high accuracy, which can be used for the discrimination of the void condition of concrete-filled steel tubular and the simplified calculation of the void height, and provides a theoretical basis for the quantitative evaluation of the void height of concrete-filled steel tubular arch rib. [ABSTRACT FROM AUTHOR]

To enhance the degradation rate of methylene blue (MB) in water, ultrasonication and solvothermal methods were used to prepare Fe3O4/ZIF-9 composite catalysts. The morphology of the catalyst revealed the attachment of cubic ZIF-9 particles to spherical-like Fe3O4 particles. The particle sizes of these ZIF-9s slightly varied, which might be due to the influence of the increased number of nucleation sites originating from the addition of Fe3O4 on the nucleation and growth of ZIF-9s as well as the effects of the variation in Fe3O4/Co salt ratio on the nucleation quantity and growth rate of ZIF-9s. Using this catalyst at a Fe3O4/Co salt molar ratio of 1∶1, 95.1% of the MB was degraded within 30 min. Its pseudo-first-order kinetic constant for a 10-min catalytic reaction reached 0.101 min−1, and it remained stable and had high catalytic performance within the pH range from 5 to 9. X-ray photoelectron spectroscopy results showed that the valence state changes of Fe and Co in Fe3O4/ZIF-9 after MB degradation, verifying the electron transfer between the Fe and Co sites. Meanwhile, the divalent unsaturated Fe and Co sites in the Fe3O4/ZIF-9 structure were likely to synergistically transfer electrons based on the fast degradation kinetics mentioned above. Consequently, compared with the pure ZIF-9, the addition of Fe ions can effectively reduce the reduction potential of Co ions and accelerate the valence state changes of Co ions and the corresponding redox cycle. Furthermore, electron paramagnetic resonance results demonstrated that Fe3O4/ZIF-9 can activate peroxymonosulfate to generate singlet oxygen (1O2), sulfate radicals(SO\begin{document}${}_4^- $\end{document}·), and hydroxyl radicals (·OH), with 1O2 being the primary active species, as further confirmed by the free radical quenching test. Hence, such a redox cycle of Fe and Co sites continuously generated 1O2, SO\begin{document}${}_4^- $\end{document}·, and ·OH, which degraded the MB molecules into carbon dioxide and water. Moreover, a saturation magnetization value of 7.6 A·m2·kg−1 was measured using the vibrating sample magnetometer method, indicating that the Fe3O4 imparts good ferromagnetic properties to the composite catalyst, facilitating its collection and recovery after the catalytic reaction. In addition, after four cycles of use, the catalyst maintained its structure and high degradation rate without significant changes, thereby demonstrating excellent reusability. In conclusion, this study systematically explored the influence of the Fe3O4/Co salt molar ratio on the structure and catalytic performance of the catalyst, qualitatively analyzed the active species during catalysis, and further elucidated the mechanism by which Fe3O4/ZIF-9 improves the catalytic efficiency. This study offers insight into techniques for the organic dye remediation.

The paper presents the results of calculations and measurements of the first natural frequency of castings of solid and ventilated brake discs made of gray cast iron of the EN-GJL-200 class. The tests were carried out for three types of chemical composition, taking into account the permissible minimum and maximum content of alloying elements. Numerical simulations of natural vibrations were carried out on the basis of our own production material databases. To determine the elastic properties of cast iron, the ultrasonic method with the measurement of the propagation velocity of longitudinal and transverse waves was used. Measurements were made directly on casts of raw discs of various thicknesses. The values of Young's modulus and Poisson's number calculated from ultrasonic measurements were used to define the stiffness matrix in the equilibrium equation, which is solved by the solver of the MSC Nastran program. A high compatibility between the results of numerical simulations and the results of experimental FRF frequency analysis was obtained. The differences between the calculated and actual values were at the level of several hertz, while the estimated average error of numerical simulations was 0.76%. It was also found out that cast iron melts for brake discs must be subject to strict control in terms of chemical composition. Slight deviations of the eutectic saturation coefficient from the optimal value cause a significant change in the first natural frequency of the brake discs, regardless of their geometry.

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office 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 order to estimate the thickness of adhered thin liquid film on lubricating surface using ultrasonic method, a synthetic wave of reflected waves at the solid-liquid interface and multiple reflected waves in the thin liquid film was calculated and the fundamental relationship between the amplitude (echo ratio) and frequency spectrum (resonant frequency) was investigated with respect to the film thickness. As the film thickness increases, the echo ratio begins to decrease from a thickness around 1/8 of the wavelength λ2 in the liquid, reaches a minimum around λ2/4 and then increases in the thick film region. On the other hand, the resonant frequency during this process only decreases monotonically as the film becomes thicker, unlike the echo ratio. Therefore, the estimation of the film thickness becomes easier by using the resonant frequency. However, it is impossible to estimate the film thickness below λ2/8 using these indices. For thickness estimation of such a thin adherent film, the difference wave obtained from the difference in amplitude between the reflected wave at the dry surface and that of adhered film is effective, and the difference echo ratio determined by its maximum amplitude decreases monotonically as the film becomes thicker in the region below λ2/8. These fundamental relationships were similarly observed in the experiments with ethanol as the adhered film, and they almost agree with the calculation results for each of the above-mentioned indices using the actually measured ultrasonic frequency spectrum. Thus, the difference echo ratio is effective for estimating the adhered film thickness in very thin film region, while the resonant frequency determined by the period of the resonant or difference wave and the echo ratio of the reflection or difference wave are effective for the estimation of the adhered thickness in thicker film region.

A three-dimensional porous bacterial cellulose/graphene oxide (BC/GO) composite hydrogel (BC/GO) was synthesized with multi-layer graphene oxide (GO) as the modifier and bacterial cellulose as the skeleton via an ultrasonic shaking process to absorb lead ions effectively. The characteristics of BC/GO were investigated through TEM, SEM, FT-IR, NMR and Zeta potential experiments. Compared to bacterial cellulose, the ultrasonic method and the carboxyl groups stemming from GO helped to enhance the availability of O(3)H of BC, in addition to the looser three-dimensional structure and enriched oxygen-containing groups, leading to a significantly higher adsorption capacity for Pb(II). In this paper, the adsorption behavior of BC/GO is influenced by the GO concentration, adsorption time, and initial concentration. The highest adsorption capacity for Pb(II) on BC/GO found in this study was 224.5 mg/g. The findings implied that the pseudo-second-order model explained the BC/GO adsorption dynamics and that the data of its adsorption isotherm fit the Freundlich model. Because of the looser three-dimensional structure, the complexation of carboxyl groups, and the enhanced availability of O(3)H, bacterial cellulose exhibited a much better adsorption capacity.

Objective: With the Polygonatum sibiricum as raw material, to develop a process for the combined extraction of Polygonatum sibiricum sponins (PSSs) and polysaccharides (PSPs), and the inhibitory activities of the extract and their complexes (PSSs-PSPs) on α-glucosidase and α-amylase were investigated. Methods: PSSs and PSPs were performed using ultrasound combined with enzymatic hydrolysis. The effects of solid-liquid ratio, ultrasonic time, and ultrasonic temperature on the yield of PSSs, the types of multi-enzymes, the proportion of complex enzymes, enzymolysis time, enzyme dosage, solid-liquid ratio, hot water extraction time, and hot water extraction temperature on the yield of PSPs were investigated, and the Box-Behnken experiment design was used to optimize the extraction of PSSs and PSPs. Results: The optimum extraction parameters of PSSs and PSPs were as follows: ultrasonic temperature was 50 ℃, ultrasonic time was 50 min, ultrasonic solid-liquid ratio was 1∶25 (g/mL), enzymolysis time was 2 h, enzyme dosage was 3 053 U/g, solid-liquid ratio was 1∶25 (g/mL), hot water extraction temperature was 80 ℃, and hot water extraction time was 1 h. Under the control of these conditions, the total yield of PSSs and PSPs was 12.22% and the 27.07%. The inhibitory activities of the extract and their complexes (PSSs-PSPs) on α-glucosidase and α-amylase were verified, and their complexes also have a good inhibitory effect on those enzymes. Conclusion: The process conditions for the efficient synergistic extraction of polygonatin and polysaccharide were obtained after optimization. Compared with a single component, the hypoglycemic activity of their complexes was improved.

In order to obtain the fundamental information for the measurement of thin oil film thickness adhered on lubrication surface using ultrasonic method, the ultrasonic calculation considering the scattering attenuation at each interface and the influence of frequency spectrum of ultrasonic waves were performed. The echo ratio of the wave reflected from the adhered film is hardly affected by the roughness on general lubrication surfaces with Rq≦1μm. On the other hand, the echo ratio is strongly affected by the frequency spectrum, and the relationship between the adhered film thickness and the echo ratio (calibration curve) calculated assuming the center frequency and frequency spectrum of the measured wave almost agrees with the experimental results. Based on the echo ratio distribution measured by the cylinder sliding type oil film thickness observation device, adhered film thickness distribution of the engine cylinder was plotted. Adhered oil film thickness increases and decreases symmetrically on the inlet and outlet sides of the piston ring when the oil supply is sufficient. However, the thickness of the adhered oil film becomes thin and its distribution is flattened throughout the stroke when the oil flow rate is reduced. On the other hand, the relationship between the film thicknesses LA on the cylinder and the film thickness LR on the piston ring for a sufficient oil flow rate is close to the shape of infinity (∞), and adhered film thicknesses of the lower side of top ring (LAT) and of the upper side of second ring (LAS) show a negative correlation. Therefore, these correlations of film thickness behavior have a potential to be one of the indicators of deterioration of lubrication conditions.

In order to optimize the wood internal quality detection and evaluation system and improve the comprehensive utilization rate of wood, this paper invented a set of log internal defect detection and visualization system by using the ultrasonic dry coupling agent method. The detection and visualization analysis of internal log defects were realized through log specimen test. The main conclusions show that the accuracy, reliability and practicability of the system for detecting the internal defects of log specimens have been effectively verified. The system can make the edge of the detected image smooth by interpolation algorithm, and the edge detection algorithm can be used to detect and reflect the location of internal defects of logs accurately. The content mentioned above has good application value for meeting the requirement of increasing demand for wood resources and improving the automation level of wood nondestructive testing instruments. [ABSTRACT FROM AUTHOR]

In ancient, human used silver and silver salts but silver nanoparticles (AgNPs) have recently been found to be accepted as the result of green synthesis. Now a day, silver nanoparticles (AgNPs) have become extremely popular in the field of the sensor due to their remarkable and significant optical, chemical, and electrical properties. In this paper, we have reported the green and reasonably priced synthesis of silver nanoparticles using Acacia confusa leaf extract which acts as both capping as well as reducing agents. The optical sensing and morphology of the as prepared AgNPs were determined using ultraviolet-visible (UV-Visible) and scanning electron microscopy (SEM) analysis. The sensing of Hg2+ ion through colorimetric and optical have been studied by UV-Vis spectroscopy as well as the naked eye. Moreover, the SEM analysis showed that the volume of the extract had no considerable effect on the morphology except for size. The colorimetric and optical sensing study revealed that the as-synthesized AgNPs exhibited a good response with colorimetric and optical sensing activity specifically towards the toxic Hg2+ ion. [ABSTRACT FROM AUTHOR]

A three-dimensional direct problem of ultrasonic nondestructive testing of a railroad rail treated as a linear elastic medium is solved by applying a grid-characteristic method on curved structured Chimera and Cartesian background meshes. The algorithm involves mutual interpolation between Chimera and Cartesian meshes that takes into account the features of the transition from curved to Cartesian meshes in three-dimensional space. An analytical algorithm for generating Chimera meshes is proposed. The convergence of the developed numerical algorithms under mesh refinement in space is analyzed. A comparative analysis of the full-wave fields of the velocity modulus representing the propagation of a perturbation from its source is presented. [ABSTRACT FROM AUTHOR]

Numerous industries, like the military, the oil and gas industry, etc., rely heavily on dissimilar welding. The welding process leaves the structure with a variety of defects, such as residual stress, that degrade its performance and static and fatigue properties. Consequently, weld residual stress must be accurately measured. In this study, ultrasonic and finite element techniques are developed to assess the residual stress in dissimilar St37/St52 welding. In addition, hole-drilling technique is employed to confirm FEM and ultrasonic data. Probe fixture is designed and built for ultrasonic stress measurement, and the acoustoelastic coefficient is measured in St37 and St52. In welding finite element analysis, the Goldak model is used as the heat source, the Brekstad model is employed as the heat loss, and the Dflux subroutine is developed to apply the heat source to the weld line using the sedimentary method. The FEM and ultrasonic data are in good correlation with the hole drilling results (maximum error of 9%). The findings indicate that there is a high degree of concordance between the data gathered by FEM and ultrasonic technique (with error less than 1.75% at the weld zone). [ABSTRACT FROM AUTHOR]

The paper presents the results of calculations and measurements of the first natural frequency of castings of solid and ventilated brake discs made of gray cast iron of the EN-GJL-200 class. The tests were carried out for three types of chemical composition, taking into account the permissible minimum and maximum content of alloying elements. Numerical simulations of natural vibrations were carried out on the basis of our own production material databases. To determine the elastic properties of cast iron, the ultrasonic method with the measurement of the propagation velocity of longitudinal and transverse waves was used. Measurements were made directly on casts of raw discs of various thicknesses. The values of Young's modulus and Poisson's number calculated from ultrasonic measurements were used to define the stiffness matrix in the equilibrium equation, which is solved by the solver of the MSC Nastran program. A high compatibility between the results of numerical simulations and the results of experimental FRF frequency analysis was obtained. The differences between the calculated and actual values were at the level of several hertz, while the estimated average error of numerical simulations was 0.76%. It was also found out that cast iron melts for brake discs must be subject to strict control in terms of chemical composition. Slight deviations of the eutectic saturation coefficient from the optimal value cause a significant change in the first natural frequency of the brake discs, regardless of their geometry. [ABSTRACT FROM AUTHOR]

Nano materials are now used in different industries as they can solve many environmental issues. In this line, cooling towers as important parts of petrochemical industries have always received special attention where their role in increasing the environmental issues are taken into account. In this study new samples of organic-metallic nickel nanostructures were synthesized as new nanofluid options in the field of dry cooling towers and using ultrasonic method. Synthetic samples were analyzed by SEM, XRD and FTIR analyses. The results showed that the nanofluids developed have a uniform morphology and that their crystal properties were confirmed by the XRD model. As the application of nanofluids in the dry cooling tower is expected; hence, they can improve the thermal specifications and that the analysis results of TG-DSC confirmed this claim.

Methane is the main cause of sewer explosion accidents, and the available monitoring methods mainly use portable gas sensors for on-site detection. However, these methods cannot grasp the dynamic changes in methane in a sewer in real time or make good predictions of methane explosion accidents. Here, we present a low-power online monitoring system for sewer methane in order to ensure the safety of urban sewers. A low-power ultrasonic gas sensor was used to monitor the methane content in biogas. Due to the impacts of changes in CO2, temperature, and humidity in the sewer on the ultrasonic methane measurement results, a corresponding compensation method was proposed. The effectiveness of the compensation method was verified through experiments, which measured the methane concentration under different influences, and the methane values measured before and after compensation were compared. The power consumption was only 1.28 mW when the system worked in intermittent operation mode, and it could operate for about 1.5 years using a lithium battery with a capacity of 5 Ah. The experimental results showed that gas detection accuracy could meet commercial requirements and compensated for the impacts of carbon dioxide, temperature, and humidity. [ABSTRACT FROM AUTHOR]

A historical overview of the issues of reliability and engineering safety of hydraulic structures is given. Most of the large hydroelectric facilities were put into operation in the middle of the last century. The results of an integrated survey of reinforced-concrete structures of the Zhigulevsk Hydroelectric Power Plant after a half-century period of operation are discussed. The results of technical evaluation of hydraulic structures, including HPP buildings, flow paths of hydraulic units, spillway dam, are presented. [ABSTRACT FROM AUTHOR]

To enable the diagnosis of the gas insulated switchgear(GIS) partial discharge fault type, the images of resolved partial discharge (PRPD) and Gramian angular field (GAF) were obtained from the GIS partial discharge test using the ultra-high frequency (UHF) and ultrasonic signals method. A GIS partial discharge type identification algorithm was proposed based on an adaptive convolutional neural network. The hyperparameters of the convolutional neural networks (CNN) were optimized. A GIS partial discharge type identification model framework was established based on decision-level multi-information fusion. The accuracy and intrinsic influencing factors of different GIS partial discharge type identification methods were studied. The results show that the decision-level multiinformation fusion method based on UHF and ultrasonic signals can further improve the identification accuracy of GIS partial discharge types, with the identification accuracy above 98% . The identification accuracy of the proposed decision-level multi-information fusion method is higher than the feature-level multi-information fusion method. The research results can provide technical support for the identification of GIS partial discharge types. [ABSTRACT FROM AUTHOR]

The experiment was to optimize the extraction process of proopioid and allocryptinine from the root of Macleaya cordata with the aid of ultrasound. The optimal conditions of extraction time, liquid to solid ratio and extraction times were selected by single factor test, and the optimal extraction conditions were determined by orthogonal test. Proopioid and allocryptomine were purified by silica gel chromatography, and the products were characterized by liquid chromatography, infrared spectroscopy and ultraviolet spectroscopy. The results showed that the ratio of liquid to solid 30 mL/g, once extraction and the extraction time 30 min, the extraction rate of protoopium and allocryptomine was the highest, which were 92.64% and 90.93%, respectively. The results of characterization showed that the extracts purified by column chromatography were identified as allocryptomine and protoopioid. The experiment indicates that the method used in the experiment is simple and fast, which can provide reference for the utilization of the medicinal material resources. [ABSTRACT FROM AUTHOR]

In manufacturing high-precision rolling bearings for aviation and urban machinery, the key tasks are to reduce the cost of production of such products, increase their efficiency and resource, and ensure their reuse after performing appropriate repair work. The results of many years of research show that these tasks can be successfully solved by cleaning the working surfaces of the parts of such precision tribonodes by non-contact pulse methods, particularly by using variable electromagnetic fields. The article describes the process of deep cleaning the working surfaces of parts of various high-precision ball bearings (from overall to miniature). During this cleaning, ferromagnetic and other impurities in the form of micro-, sub-micro- and nanoparticles were removed on a developed stand that can be used on an industrial scale. Further studies of cleaned bearings showed improved operational parameters such as reduced noise and vibration and the degree of magnetization. To achieve the specified results, appropriate cleaning methods were developed and tested.

Suitable and accurate flow measurement in pumped storage hydropower plants (PSP) is a challenging task due to the entirely different hydraulic behaviour of the penstock. This study presents a novel approach to choosing a suitable flow measurement method and position. The focus is on the flow measurement in a specific short penstock of the largest peak-load hydropower plant, Orlík, after its transformation to a PSP. Our approach is based on three main pillars: numerical modelling of fluid flow (ANSYS CFX), standards, and scientific literature. First, the steady-state numerical model output for the current state is compared to historical measurements of point velocities using current meters and measured hydraulic losses in the penstock. Subsequently, for the planned conversion to the reversible Francis turbine, including shape modifications of the flow paths, a steady numerical simulation of the flow in the penstock was performed in both turbine and pump modes. By analysing the resulting pressure and velocity fields and comparing them to standards and scientific literature, the values of the uncertainty in the flow measurement were calculated. The outcome is a straightforward evaluation and comparison of three main flow measurement methods: current meter, pressure–time, and ultrasonic transit time. [ABSTRACT FROM AUTHOR]

In the present study, Ni-M-Tb/Al 2 O 3 (M: Mg, Ca, Sr and Ba) nanostructured catalysts with different ratios of the alkali metals were synthesized by the ultrasonic-assisted one-pot method. The catalytic performance was investigated in terms of CO 2 conversion, CH 4 selectivity, and stability via the H 2 -TPR analysis. The structural properties were delineated using XRD, SEM, TEM and BET equation. The results showed that the 2Ni-5Mg-5Tb/Al 2 O 3 catalyst with a maximum CO 2 conversion of 75.37% and CH 4 selectivity of 100%, at the operating temperature of 400 °C in the molar ratio of H 2 :CO 2 :3.5 for 100 h, had the best performance. This could benefit from the particular electronic structure of Tb in combination with Mg and Ni, reducing agglomeration, as demonstrated by the SEM and BET results. Based on the current findings, novel catalysts with high conversion efficiency of CO 2 to CH 4 might be achieved by tuning a decent combination of alkaline and rear earth elements as the promoters of Ni-based catalysts. [Display omitted] • The Ni-M-Tb/Al 2 O 3 (M: Mg, Ca, Sr, and Ba) nanocatalysts synthesized by Ultrasonic method. • The powerful CO 2 methanation process was developed using a 2Ni-5Mg-5Tb/Al 2 O 3 nanocatalyst. • The process was tested under high feed flow rate of 18,000 ml/gcat h with Molar ratio of (H 2 :CO 2 :3.5). • The 75.35% CO 2 conversion and 100% CH 4 selectivity were obtained at 400 °C. • Particular electronic structure of M, and reducing agglomeration might be the reason for this behavior. [ABSTRACT FROM AUTHOR]

Among the developed electrocatalysts, NiCr-layered double hydroxides (NiCr-LDH) are one of the most effective electrocatalytic materials for water oxidation. However, applications of such a kind of materials are practically limited due to their poor electric conductivity. In this work, the single-walled carbon nanotube (SWCNT) was doped to NiCr-LDH, and the LDH-based nanocomposites were synthesized using the one-step ultrasonic-assisted method. Physicochemical properties of the NiCr-LDH/SWCNT composites were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), field emission−scanning electron microscopy (FE−SEM), and linear sweep voltammetry (LSV). The NiCr-LDH/SWCNT composites were used as effective nanomaterials for oxygen evolution reaction (OER) at a near neutral medium. The LSV results confirm that the overpotential of the NiCr-LDH/SWCNT-0.006 sample decreased to about 120 mV at pH = 9.5, as compared with that of the NiCr-LDH or NiCr-LDH-SWCNT-0.006 (prepared by the two-step method) sample. The high oxygen evolution activity of NiCr-LDH/SWCNT-0.006 was associated with the co-presence of the homogeneously dispersed NiCr-LDH, good electrochemical activity, and high electrical conductivity. In addition, the as-prepared optimized NiCr-LDH/SWCNT electrocatalyst was highly stable for the OER reaction. • SWCNT was doped in to NiCr-LDH using the one-step ultrasonic method. • Optimized NiCr-LDH/SWCNT shows overpotential of 120 mV at pH = 9.5 for OER. • The highly performance of NiCr-LDH/SWCNT is due to its fast charge transfer. [ABSTRACT FROM AUTHOR]

The dispersion of nickel catalysts is crucial for the catalytic ability of CO2 methanation, which can be influenced by the fabrication method and the operation process of the catalysts. Therefore, a series of fabrication methods, including ultrasonic, hydrothermal, microwave, and co-precipitation, have been applied to prepare 25Ni-5Er-Al2O3 catalysts. The fabrication method can partially influence the structural and catalytic activity of the nickel aluminate catalysts. Among the catalysts modified by Erbium prepared with various methods, the catalyst fabricated by ultrasonic pathway exhibited better catalytic performance and CH4 selectivity especially, at a temperature (400 ℃). The impact of the temperature of the reaction (200–500 °C) was examined under a stoichiometric precursor ratio of (H2:CO2) = 4: 1, atmospheric pressure, and space velocity (GHSV) of 25000 mL/gcath. The results demonstrate that the ultrasonic method is strongly efficient for fabricating Ni-based catalysts with a high BET surface area of about 190.33 m2g−1. The catalyst composed via the ultrasonic technique has 69.38 % carbon dioxide conversion and 100 % methane selectivity at 400 °C for excellent catalytic performance in CO2 methanation reactions. The fabrication effect can be associated with its high surface area, which is achieved via the hot spot mechanism. Besides, the addition of Erbium promotes the Ni dispersion on the supports and stimulates the positive reaction because of the erbium oxygen vacancies.

Under ultrasonication, cuprous oxide (Cu2O) microparticles (

The authors propose a new method of predictive replacements of belt sections in a conveyor belt loop with their refurbishment based on their condition recognized by specially designed diagnostic devices: DiagBelt and BeltSonic. Selection of the moment for belt replacement is made on the basis of forecasted state of its wear, when steel cable failure density exceeds the selected threshold or the percentage of belt covers abrasion exceeds the permissible level. The use of double belt refurbishment extends the total belt operation time, but without diagnostics, the reconditioning success rate is relatively low. Visual inspection allows only an uncertain assessment of cable condition. New devices give precise assessment of their condition and allow the selection of a non-linear rate of belt condition based on consecutive scans. The assessed condition of the cables is the key factor in successful belt refurbishment and obtained cost savings. Additionally, diagnostics can help extend belt life. Identified failures can be repaired in order to prevent accelerated belt degradation. The use of diagnostics in the current replacement strategy significantly improves the economic efficiency of belt reconditioning. The reuse of the belt core ensures efficient use of resources and reduces the level of waste, which fits into the circular economy. [ABSTRACT FROM AUTHOR]

Thermosetting composites based on dicyclopentadiene (DCPD) in the presence of Grubbs' catalyst and soybean flour were prepared by ring‐opening metathesis polymerization. Soybean flour/DCPD suspensions were sonicated to enhance the dispersion degree before adding catalyst. The curing extent, thermal‐mechanical properties, morphology and thermal stability of the cured soybean flour/DCPD composites were systematically investigated using Soxhlet extraction, DSC, DMA, TMA, tensile test, SEM, and TGA. The results showed that the tensile strength of the soybean flour/DCPD composites increased from 60.7 MPa to 75.8 MPa with the increase of soybean flour loading from 0% to 25%, and the Tg obtained from DMA also showed an increasing trend from 129.4°C to 155.1°C. Overall, the introduction of soybean flour into DCPD resin improved the thermal‐mechanical properties of the composite and offered decreased cost and enhanced bio‐based content. [ABSTRACT FROM AUTHOR]

Novel composite based on rubber and modified bentonite clay (Clay) was investigated. The modified bentonite clay was developed by dispersing in ethanol solutions (Et-OH) using ultrasonic method. The effect of Et-OH on the dispersion of bentonite clay at various mixing temperatures in case of different type of rubber matrix, i.e., natural rubber (NR), epoxidized natural rubber (ENR25, ENR50) on dynamic mechanical rheology, Payne effect, XRD and mechanical properties of rubber composites were studied in detail. The bentonite clay dispersion in Et-OH at a mixing temperature of 80 °C improves the intercalation and exfoliation in rubber chains. Bentonite clay is highly intercalated in ENR 50-Clay composite, which can be confirmed from its superior mechanical properties. The results indicated that sonication of bentonite clay in Et-OH improves the interlayer spacing of bentonite clay by partial intercalation of rubber matrix. [ABSTRACT FROM AUTHOR]

The occurrence of Severe Plastic Deformation (SPD) on any material has a critical effect over the surface and material features such as elastics constants and residual stress, etc. Among various deformation processes, such as Equal Channel Angular Pressing (ECAP), machining, etc. machining (slot or end milling) has a vital role in various sectors, due to its versatility and ease of material removal and surface finish. In this study, the slot milling operation has been carried out on Nimonic 263 alloy and this operation is governed by various Machining Environments (ME) (wet, dry and Minimum Quantity Lubrication (MQL)) and machining parameters (cutting feed and cutting speed) to analyze its influence on the material characteristics of machined samples associated to the as-received (Nascent) samples using X-Ray Diffraction (XRD) spectral analysis and ultrasonic pulse echo method. Through the above experimentation, it is found that the machined samples have undergone SPD over the machined surface which lead to cause superior enrichment in surface features such as bulk modulus, young's modulus, wear resistance, etc. [ABSTRACT FROM AUTHOR]

Measurement of partial discharges (PD) is a generally accepted method of diagnosing the insulation of electrical equipment worldwide. Today, the trend is to move from conventional offline testing to online monitoring to predict the service life of insulation. For testing and calibration of the developed new methods with the contact method, a laboratory stand has been developed in accordance with GOST R 55191-2012 (IEC 60270:2000). The article suggests the use of acoustic and electromagnetic methods for a system of continuous non-contact non-destructive testing of the technical condition of insulation equipment, which will allow monitoring insulation equipment online and predicting its residual life. On their basis, a system of «on-line» diagnostics of high-voltage insulators has been developed.

AA7050-T7451 is a heat-treating aluminum alloy with high mechanical strength, ideal for producing lightweight structural components. Common types of welding lead to structural changes in the material that could decrease their mechanical properties affecting the fatigue life of the joints; however, a solid-state process known as friction stir welding (FSW) have been increasingly used as an alternative solution to reduce these severe effects. This work attempts to study the FSW behavior over 7050-T7451 aluminum alloys through the characterization of the resulting residual stresses and propose a manufacturing quality index based on their magnitude and distribution. An ultrasonic method employing longitudinal critically refracted (LCR) waves was used to determine the longitudinal residual stresses at different distances from the centerline in plates welded with different parameters.The resulting stress distribution is consistent with the literature review, presenting maximum values around 200 MPa at the center of the weld. A quality index was calculated through the average of all stresses in that region. It was found that higher residual stresses are produced with higher traverse and rotational speed (400 mm/min and 908 RPM). Therefore, to improve the process regarding the level of residual stresses, it is recommended to use lower welding tool velocities.

With the gradual formation of China's oil and gas pipeline network, pipeline safety assessment is increasingly important. On this basis, the principle of acoustic elasticity and the ultrasonic stress measurement technology were briefly introduced. In order to meet the needs of the service safety evaluation of high-grade oil and gas pipelines, a non-destructive residual stress measuring system with ultrasonic method was developed. Besides, the near-zero stress calibration technology of test blocks was also developed, which is to linearly cut the annealed zero-stress test block for further stress release, so that the zero stress can be calibrated accurately. Further, curved probes were designed according to the actual requirements of inspection. The study on nondestructive residual stress measurement of X80 pipeline was carried out with the abovementioned system, and the results were verified with the small hole method, which indicate that the test accuracy is reliable and repeatable. Thus, the study provides a good technical means for online stress measurement of oil and gas pipelines, as well as an effective technical method for pipeline operation, repair and evaluation.

Methane is the main cause of sewer explosion accidents, and the available monitoring methods mainly use portable gas sensors for on-site detection. However, these methods cannot grasp the dynamic changes in methane in a sewer in real time or make good predictions of methane explosion accidents. Here, we present a low-power online monitoring system for sewer methane in order to ensure the safety of urban sewers. A low-power ultrasonic gas sensor was used to monitor the methane content in biogas. Due to the impacts of changes in CO2, temperature, and humidity in the sewer on the ultrasonic methane measurement results, a corresponding compensation method was proposed. The effectiveness of the compensation method was verified through experiments, which measured the methane concentration under different influences, and the methane values measured before and after compensation were compared. The power consumption was only 1.28 mW when the system worked in intermittent operation mode, and it could operate for about 1.5 years using a lithium battery with a capacity of 5 Ah. The experimental results showed that gas detection accuracy could meet commercial requirements and compensated for the impacts of carbon dioxide, temperature, and humidity.

A line contact tribo-pair is a key mechanism unit in rolling bearings, which is often characterized by ultra-high contact pressure and ultra-thin oil film. Elastohydrodynamic lubrication is often adopted to characterize the lubrication state of such a tribo-pair. As a primary parameter for elastohydrodynamic lubrication, the oil film thickness is often evaluated with simplified theoretical models or complicated measurements. So far, a comprehensive verification of the lubrication states in a real line-contact tribo-pair, however, is rarely reported. Focusing on the roller/ring tribo-pair of a wet-lubricated rolling bearing under pure rolling conditions, this study investigates the lubrication states by integrating multiple theories. Five regions including isoviscous hydrodynamic, piezoviscous hydrodynamic, elastohydrodynamic lubrication, mixture lubrication, and boundary lubrication regions can be identified using the framework. Then, validation experiments are carried out on a line contact tribo-pair test rig under the same operating conditions applied in the theoretical analysis. The oil film thickness is measured by the ultrasonic method. The analysis results demonstrate that only two regions, the elastohydrodynamic lubrication and mixture lubrication regions, can be identified using the experimental data. The identified elastohydrodynamic lubrication and mixture lubrication regions are consistent with theoretical analysis; and the Blok equation and elastohydrodynamic lubrication theory are suggested to calculate the oil film thickness in the elastohydrodynamic lubrication and mixture lubrication regions, respectively. Moreover, the oil film thickness calculated by the Dowson equation is larger than that based on the elastohydrodynamic lubrication theory due to a different viscous pressure equation. [ABSTRACT FROM AUTHOR]

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