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Copyright of Journal of Ballistics / Dandao Xuebao is the property of Journal of Ballistics Editorial Department 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.)

Monitoring stress and strain at the critical details of steel bridges is essential for ensuring structural integrity. This study introduces a three‐layer flexible strain sensor produced through a spraying process, using flake‐shaped silver‐coated copper powder as the conductive filler and modified acrylic emulsion as the matrix material. The study investigated the impact of size parameters on sensor sensitivity, determining optimal dimensions of 20 mm in length, 2 mm in width, and an initial resistance value ranging from 1.0 Ω to 1.8 Ω. Analysis of the optimized sensor's performance unveiled high sensitivity and linear response capabilities under low strain conditions with a gauge factor (GF) value of up to 25.6 and a linear correlation coefficient R2 ≥ 0.971 under 300 με. Notably, the sensor exhibits an extremely low strain detection limit of 0.005% and a broad response range spanning from 0.005% to 0.19% strain. It demonstrates swift response and recovery times of 500–800 ms, showcases directional strain response, exhibits good repeatability, and endures durability tests (withstanding 3000 cycles). Furthermore, a fitting formula is proposed to accurately depict the strain and relative resistance change relationship across a wide response range. The study and initial application of this sensor's sensing characteristics and performance signify its potential for practical engineering applications. [ABSTRACT FROM AUTHOR]

In order to develop the direct normalized inelastic displacement spectrum rather than the inelastic displacement ratio or reduction factor that is suitable for self-centering structures when subjected to near-fault pulse-like (NFPL) ground motions, the nonlinear time history analysis for a single degree of freedom (SDOF) system with a generalized flag-shaped (FS) hysteretic model is realized using Matlab software. A total of 85 NFPL records are arranged as the seismic input, the inherent viscous damping ratio, ξ, is respectively determined as 0.02 and 0.05 for typical steel and concrete structures, the variation range of all considered parameters, including the ductility, the vibration period, the energy dissipation coefficient and the post-yield stiffness ratio of the hysteretic model is specified, then the constant-ductility inelastic displacement spectra for different seismic records and different model parameters are calculated and statistically studied. It is found the normalization of the natural period and the displacement by the pulse period, namely T/Tp and xm/Tp2, can significantly reduce the variation of displacement spectra. The influence of the post-yield stiffness ratio ranging from 0 to 0.20 on the normalized spectra is slight and can be neglected. Besides, as T/Tp increases, the normalized displacement first increases and then slowly decreases, the normalized period corresponding to the peak displacement is approximately 1. When T/Tp is about less than 0.7, the displacement spectra are positively correlated with the ductility, μ, followed by a negative correlation between them as T/Tp grows larger. Moreover, increasing the energy dissipation coefficient will reduce the displacement response, but when the coefficient is greater than 1, its impact on the displacement is rather small. Finally, the equation of the normalized displacement spectra as a function of T/Tp and μ is proposed, in which an adjustment factor, Ωβ, is added to account for the influence of the energy dissipation coefficient on the displacement spectra. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery 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.)

To investigate the mechanical response of X80 pipelines under lateral landslide conditions, finite element simulations of X80 pipeline under 375 lateral landslide conditions are conducted in this paper to examine mechanical behavior under varying pipe diameters and wall thicknesses, and landslide width and displacement on pipeline strain is assessed. The results indicate that under the influence of lateral landslides, The pipeline strain is predominantly induced by the bending moment, with axial strain being the most significant, constituting over 95 % of the total strain. The peak strain is primarily concentrated in the middle section of the pipeline's leading span. Based on extensive numerical simulation data, a grey relational analysis was conducted, revealing that the primary factors influencing the maximum axial strain in pipelines, in descending order of significance, are landslide displacement, landslide width, pipeline diameter, and pipeline wall thickness. Furthermore, to predict the safety of X80 pipelines under lateral landslides, a BP neural network prediction model and a fitting formula are developed based on the four influencing factors. Both the model and the formula were validated to accurately predict the maximum axial strain of X80 pipelines affected by lateral landslides. Moreover, a failure assessment method for X80 pipelines under lateral landslide conditions was established using the strain failure criterion. Results indicate that the prediction errors of the neural network model and the formula, compared to simulation outcomes, are within 10 %, the high accuracy of the failure prediction results is similarly demonstrated. • The mechanical behavior of X80 pipelines under lateral landslide forces was analyzed using finite element methods. • The impact of various factors on the pipeline's maximum axial strain was assessed. • A BP neural network model and a fitting formula were developed to predict the maximum axial strain of the pipeline. • A failure prediction method for X80 pipelines under lateral landslide conditions was established. [ABSTRACT FROM AUTHOR]

• Local view factor (VF) distributions were simulated across various building sizes using the S2S model. • A comprehensive VF formula applicable to 16 body segments was derived. • A novel and rapid VF calculation method has been validated against existing research results. • A VF calculation tool was developed with the potential to evaluate scenarios involving windows and radiant panels. In non-uniform environments, such as spaces with radiant ceilings or floors, or with hot or cold windows, view factors (VFs) of a person towards these surfaces are needed for calculating the heat exchanges between the person and the surroundings. Multi-body segmented human models can simulate the heat exchanges of individual body parts with the environment. Simulating heat transfer at the local body parts is important for assessing comfort in non-uniform environments. These models require VFs for each individual body part. Accurately determining these VFs is time-consuming, often requiring methods such as ray-tracing techniques. A fast calculation method to accurately determine the view factor (VF) for each segment has yet to be investigated. This study employed a 16-segment human model into various architectural radiation scenarios. The surface-to-surface model in computational fluid dynamics was utilized to simulate VFs for the 16 body segments in relation to radiant surfaces at different locations. Through a series of simulations, comprehensive formulas for VFs were derived for each individual at various positions within a room, encompassing 16 body segments and computing parameters for 24 building surfaces. The accuracy of these general formulas was validated by comparing the whole-body VF with results from several available studies. Additionally, this study developed a visualization tool for calculating VF and mean radiant temperatures with different room space dimension and embedded radiant surfaces. The users can use this online tool to easily calculate VFs and mean radiant temperatures for each body parts, and for the whole-body. The tool offers valuable insights for predicting thermal comfort in asymmetric radiant environments and facilitating control over building environments. [ABSTRACT FROM AUTHOR]

• Detrital clay mineral inputs consist primarily of illite, smectite, and kaolinite. • The origins of clay minerals were identified through petrology and geochemistry. • A relationship exists between the CIA and the detrital smectite content. • A high input of detrital smectite facilitated the preservation of organic matter. As major components of shales, clay minerals are important for investigating unconventional petroleum geology. However, there are few quantitative methods for investigating possible inputs of clay minerals during sedimentary processes. In this study, shales from the Shahejie Formation in the Dongpu Sag, Bohai Bay Basin, were chosen for investigating clay mineral inputs. The shales are abundant in a variety of clay minerals. The shales, uniformly derived from felsic igneous rocks, underwent mild K metasomatism. Thus, the detrital clay mineral input was primarily influenced by weathering intensity. Accordingly, representative samples subjected to varying weathering intensities were selected to identify detrital and diagenetic clay minerals. Kaolinite and chlorite are of detrital origin. Illite and illite/smectite mixed layers (I/S) have both detrital and diagenetic origins. The precursor minerals of diagenetic minerals can be identified based on their morphological and elemental characteristics. After quantifying the area proportions of various clay minerals, the detrital clay mineral compositions of selected samples were calculated. Further analysis indicated that the detrital illite content and the detrital chlorite content are closely related, while the detrital smectite content correlates well with the chemical index of alteration (CIA). Based on the preceding analysis, the fitting formulas were established to quantitatively characterize the input of detrital clay minerals. The shales from the north sag had a high input of detrital smectite, whereas the shales from the south sag had a high input of detrital illite. Consequently, the shales from the north sag contain more organic matter than those from the south sag. [ABSTRACT FROM AUTHOR]

To accurately solve the buckling instability problem of a rectangular plate with free boundaries on the opposite edges, the finite difference method, FDM, was introduced. The buckling differential equations and boundary conditions equations ignoring the shear effect were discretized by the FDM; the buckling instability problem was transformed into a prob-lem of solving the generalized eigenvalues of the deflection coefficient matrix. At the same time, the opposite simply supported edges subjected to unidirectional pressure were chosen as the case study,the accuracy of the FDM results and the finite element method results were verified by comparing them with the previous results. The effect of the plate thickness on critical buckling load is difficult to measure for the moderately thick plates. Therefore, a fit-ting formula was obtained to give the applicable range of geometric parameters for the FDM within a given relative error range. Finally, the effect of geometrical parameters on the critical buckling load was analyzed. And the results show that the FDM used in this paper can solve the buckling instability problem of the rectangular plate with two opposite free edges accu-rately within the geometrical parameters range given by the fitting formula,which provides a new solution to the buckling instability problem both for the thin plates and moderately thick plates. [ABSTRACT FROM AUTHOR]

In order to study the residual strength of buried pipelines with internal corrosion defects in seasonally frozen soil regions, we established a thermo-mechanical coupling model of a buried pipeline under differential frost heave by using the finite element elastoplastic analysis method. The material nonlinearity and geometric nonlinearity were considered as the basis of analysis. Firstly, the location of the maximum Mises equivalent stress in the inner wall of the buried non-corroded pipeline was determined. Furthermore, the residual strength of the buried pipeline with corrosion defects and the stress state of internal corrosion area in the pipeline under different defect parameters was analyzed by the orthogonal design method. Based on the data results of the finite element simulation calculation, the prediction formula of residual strength of buried pipelines with internal corrosion defects was obtained by SPSS (Statistical Product and Service Solutions) fitting. The prediction results were analyzed in comparison with the evaluation results of B31G, DNV RP-F101 and the experimental data of hydraulic blasting. The rationality of the finite element model and the accuracy of the fitting formula were verified. The results show that the effect degree of main factors on residual strength was in order of corrosion depth, corrosion length, and corrosion width. when the corrosion length exceeds 600 mm, which affects the influence degree of residual strength will gradually decrease. the prediction error of the fitting formula is small and the distribution is uniform, it can meet the prediction requirements of failure pressure of buried pipelines with internal corrosion defects in seasonally frozen soil regions. This method may provide some useful theoretical reference for the simulation real-time monitoring and safety analysis in the pipeline operation stage. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department 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 obtain the dynamic stress of invert and its filling in the high-speed railway tunnel under the vibration load of the train, this paper uses the field measurement method to arrange the resistance strain gauge inside the invert of the Lanzhou–Urumqi high-speed railway Fuchuan tunnel. The dynamic stress of the invert and its filling was measured, and the measurement results were verified by numerical analysis, the results obtained by the two were consistent. The results show that under the action of CRH5 electric multiple units, the dynamic stress time history curve of the invert and its filling has 16 peaks, with V-shape on both sides and W-shape in the middle. When the train load speed is constant, the dynamic stress in the tunnel invert and invert filling decreases with the increase of the depth. The dynamic stress at 0.5 m below the track bed is attenuated by about 23.1% compared to 0.2 m, the dynamic stress at 2.0 m below the track bed is attenuated by 67.5% compared to 0.2 m. Tunnel invert and its filling are the main carriers of train vibration load. The dynamic stress attenuation law of the invert and its filling conforms to the exponential function distribution. Through the data fitting, the calculation formula of the dynamic stress in different depths is given. The research results provide a new method for obtaining the dynamic stress of the invert and its filling in high-speed railway tunnel. [ABSTRACT FROM AUTHOR]

Purpose: The study's objectives were to (1) evaluate benefit from a novel bimodal fitting formula (Adaptive Phonak Digital Bimodal Fitting Formula [APDB]), and (2) compare outcomes with APDB and a traditional fitting formula (NAL-NL2). Methods: This prospective study evaluated outcomes in ten adults with unilateral Advanced Bionics (AB) cochlear implants (CI). Participants were tested bimodally with NAL-NL2 and APDB programed on Naída Link UP HAs. Measures of speech perception, sound quality, and preference were obtained with two bimodal configurations (CI + HANAL-NL2 and CI + HAAPDB). Participants used the CI + HAAPDB configuration for an acclimation period, after which measures were repeated. Results: Significant bimodal benefit was measured from both HA fitting formulae for speech perception in noise compared to the CI-only condition. Improved individual outcomes with the APDB were observed, but group differences were not statistically significant. Participants reported subjective benefit from APDB on blind comparisons of preference and sound quality. Conclusions: Significant benefit was found with both bimodal conditions compared to the CI-only condition; however, bimodal speech perception results were not significantly different. Users reported benefit from the APDB formula over NAL-NL2 formula. Due to individual improved speech perception and overall subjective preference for APDB, clinicians should consider APDB with AB CI recipients. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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 effects of different sintering temperatures on the system of Ba0.5Sr0.5TiO3–La0.8Ca0.2MnO3 (BST‐LCM) material were investigated by means of scanning electron microscopy, X‐ray, resistance‐temperature measurements, and X‐ray photoelectron spectroscopy. X‐ray diffraction and X‐ray photoelectron spectroscopy confirm that BST‐LCM is completely miscible and BST is the main phase, which under the premise of following the theory of small polaron conduction, titanium ions interact with manganese ions, which affects the electrical properties of the system of BST‐LCM material. For the electrical properties of related, the LCM content is inversely proportional to the activation energy. Through the linear fitting of the experimental data, the empirical formula between the sintering temperature B value and the content of solid solution is obtained, and the approximate B value within a certain range can be preliminarily calculated. [ABSTRACT FROM AUTHOR]

In order to study the residual strength of buried pipelines with internal corrosion defects in seasonally frozen soil regions, we established a thermo-mechanical coupling model of a buried pipeline under differential frost heave by using the finite element elastoplastic analysis method. The material nonlinearity and geometric nonlinearity were considered as the basis of analysis. Firstly, the location of the maximum Mises equivalent stress in the inner wall of the buried non-corroded pipeline was determined. Furthermore, the residual strength of the buried pipeline with corrosion defects and the stress state of internal corrosion area in the pipeline under different defect parameters was analyzed by the orthogonal design method. Based on the data results of the finite element simulation calculation, the prediction formula of residual strength of buried pipelines with internal corrosion defects was obtained by SPSS (Statistical Product and Service Solutions) fitting. The prediction results were analyzed in comparison with the evaluation results of B31G, DNV RP-F101 and the experimental data of hydraulic blasting. The rationality of the finite element model and the accuracy of the fitting formula were verified. The results show that the effect degree of main factors on residual strength was in order of corrosion depth, corrosion length, and corrosion width. when the corrosion length exceeds 600 mm, which affects the influence degree of residual strength will gradually decrease. the prediction error of the fitting formula is small and the distribution is uniform, it can meet the prediction requirements of failure pressure of buried pipelines with internal corrosion defects in seasonally frozen soil regions. This method may provide some useful theoretical reference for the simulation real-time monitoring and safety analysis in the pipeline operation stage.

Detailed study of Jensen's polarization-consistent vs. Dunning's correlation-consistent basis set families performance on the extrapolation of raw and counterpoise-corrected interaction energies of water dimer using coupled cluster with single, double, and perturbative correction for connected triple excitations (CCSD(T)) in the complete basis set (CBS) limit are reported. Both 3-parameter exponential and 2-parameter inverse-power fits vs. the cardinal number of basis set, as well as the number of basis functions were analyzed and compared with one of the most extensive CCSD(T) results reported recently. The obtained results for both Jensen- and Dunning-type basis sets underestimate raw interaction energy by less than 0.136 kcal/mol with respect to the reference value of − 4.98065 kcal/mol. The use of counterpoise correction further improves (closer to the reference value) interaction energy. Asymptotic convergence of 3-parameter fitted interaction energy with respect to both cardinal number of basis set and the number of basis functions are closer to the reference value at the CBS limit than other fitting approaches considered here. Separate fits of Hartree-Fock and correlation interaction energy with 3-parameter formula additionally improved the results, and the smallest CBS deviation from the reference value is about 0.001 kcal/mol (underestimated) for CCSD(T)/aug-cc-pVXZ calculations. However, Jensen's basis set underestimates such value to 0.012 kcal/mol. No improvement was observed for using the number of basis functions instead of cardinal number for fitting. [ABSTRACT FROM AUTHOR]

Highlights • Finite element models of BBC joints were established and verified. • The uniaxial compression bearing capacity of the BBC joint was defined. • Influence factors on the ultimate load of BBC joints were studied. • Formulae of the ultimate load of BBC joints were proposed. Abstract Bolted ball-cylinder joint (BBC joint) is an innovative joint system applied in non-purlin spatial truss structures. According to the theoretical analysis, the fitting formulae of the uniaxial compression bearing capacity of the BBC joint were proposed in this paper. Experiments on 5 BBC joints were introduced briefly at first. The finite element (FE) models were established using ABAQUS and verified by the experimental results. The numerical and experimental results agreed well with each other in failure modes and load-displacement curves. Subsequently, parametric study was conducted to investigate the effects of the dimensions of hollow cylinder, rectangular tube and ribbed stiffener on the bearing capacity of the joint. Finally, the formulae to estimate the uniaxial compression bearing capacity of the BBC joint were obtained by means of regression analysis. And the increasing coefficients of bearing capacity were obtained on the basis of parametric study. The calculation results were verified against the experimental and numerical results. It is indicated that the practical calculation formulae can estimate the uniaxial compression bearing capacity accurately. [ABSTRACT FROM AUTHOR]

The ultimate strength of medium-thick composite pressure shells under hydrostatic pressure was studied by experimental test and finite element method in this paper. The ultimate strength, damage form and strain response of cylindrical shells were obtained by hydrostatic destruction test, which carried out for two T700 carbon fiber/epoxy composite cylindrical pressure shells with different length. Meanwhile, finite element models were built to predict the strength failure pressure based on the progressive damage mechanism of composite materials and its initial defects. The finite element results were in close agreement with the experimental results. A parametric study was carried out to discuss the effect of radius-length ratio and radius-thickness ratio on ultimate strength. Based on the numerical results, an empirical formula was proposed as a function of radius-length ratio and radius-thickness ratio to predict the ultimate strength of medium-thick composite pressure shells. • The hydrostatic test of composite cylindrical shells was carried out to obtain the ultimate damage load and strain response of the shells. • A numerical calculation model for the ultimate strength of composites was established based on the progressive damage mechanism. • The effects of different structural geometry parameters on the ultimate strength of cylindrical shells were revealed. • An empirical formula for predicting the ultimate strength of composite cylindrical shells was proposed. [ABSTRACT FROM AUTHOR]

The effects of load,speed and material parameters on the amplitude of central pressure and pressure spike were investigated under line contact EHL condition. Based on the analysis of mass numerical data and regression,the fitting formulas of amplitude of central pressure and pressure spike of line contact EHL state were proposed and the accuracy of fitting formulas was verified. The result shows that in a fairly wide range of the parameters,the accuracy of fitting formulas is satisfactory,which can completely meet the demands of engineering designs.

This paper presents a novel computing method of optical efficiency fitting formulas and its applications for parabolic trough solar collectors, by combining the Monte Carlo ray-tracing methodology with the population-based particle swarm optimization algorithm. The expressions of the optical efficiency fitting formulas are deduced by means of analyzing the Monte Carlo ray-tracing data samples with a variable reduction technique, while the fitting formula coefficients are obtained using the particle swarm optimization algorithm. The computing time of the annual optical efficiency reduces to less than 10 −7  s, from about a day as previously calculated by a once powerful Monte Carlo ray-tracing model. Thus, it makes the once time-consuming long-time average optical efficiency calculations or corresponding population-based optimizations much more feasible and efficient. A dynamic particle swarm size factor is also proposed to improve the particle swarm optimization performance, which reduces nearly 90% of the particle swarm optimization computing time. Numerical results calculated by the Monte Carlo ray-tracing model and the obtained optical efficiency fitting formulas were compared with the corresponding reference data. Good agreements were obtained, proving that the computing method and model are reliable. The obtained optical efficiency fitting formula of parabolic trough solar collectors is then applied successfully to efficiently study the characteristics of long-time average optical efficiencies under different geometrical configurations, geographical locations, tracking models and corresponding optical or geometrical optimizations. This proposed novel method offers a useful option of high potential for further applications on efficient optical efficiency related analyses and corresponding population-based optimizations for parabolic trough solar collectors. [ABSTRACT FROM AUTHOR]

Experiments to test the breakdown voltage (Ub) of centimetre-scale vacuum gap using the coaxial electrodes under microsecond pulses are carried out. The vacuum gaps are set as 5.75 cm, 7.67 cm and 10.2 cm, respectively. The ratio of the outer diameter to the inner diameter of the coaxial electrodes for each gap is set as constant to produce a fixed field enhancement factor. The experimental results show that Ub increases while the electric breakdown field (Eb) decreases as the vacuum gap increases. In addition, the increasing and the decreasing tendencies are nonlinear. Since both the gap distance (g) and the electrode area (A) change for each set of experiments, both the two factors are taken into account together to obtain a unified formula to describe the Eb dependencies on g and A. The fitting results show that Eb is linearly dependent on g−α and A−β, where α is about 0.3 and β is about 1/5.6. Both the gap effect and the area effect are consistent with those of the plane-plate electrodes. The mechanism responsible for the coaxial long-gap vacuum breakdown under microsecond pulses is also discussed. [ABSTRACT FROM AUTHOR]

To systematically study the wind vibration characteristics and wind vibration coefficient of super large cooling towers over 190 m height limit of standard, a domestic under-construction super large cooling tower with 200 m height was used as the research object. The large eddy simulation of numerical simulation was carried out to simulate the average and pulsating wind load, and the simulation, national code and actual measurement results were compared to verify the effectiveness of the large eddy simulation method. On this basis, the dynamic property, wind-induced response and wind vibration coefficient were analyzed systematically by finite element method. The value obtained methods of wind vibration coefficient based on meridional axial force of windward side, von Mises stress of windward side, radial displacement, meridional axial force and circumferential monent were discussed. The two-dimensional wind vibration coefficients of super large cooling tower with 200 m height level has outstanding spatial distribution characteristics and are generally larger at the bottom and lee regions of the cooling tower. The recommended values and fitting fornulas of two-dimensional wind vibration coefficient for this kind of super large cooling towers were given. The research can provide scientific basis for the wind-resistant design of super large cooling towers with 200 m height level. [ABSTRACT FROM AUTHOR]

Local buckling may occur on the compressive edge of steel plates in bolted side-plated (BSP) beams, which usually leads to premature failure analogous to over-reinforced concrete beams. This paper presents the results of an experimental study of eight local buckling test specimens. The plate thickness, the bolt spacing, the configuration of longitudinal and transverse stiffeners is varied to investigate their influence on the overall buckling resisting performance of the bolted steel plates. Significant enhancement in term of both the buckling strength and deformability is observed as the increasing of the plate thickness and the decreasing of the bolt spacing. Further improvement is found when the longitudinal stiffeners of different sectional size are employed. However, the additional transverse stiffeners impose no beneficial effect to the overall buckling performance. The test results can provide benchmark data for further theoretical and numerical studies. A previous finite element analysis is also introduced and great compliance is found between the experimental and numerical results. [ABSTRACT FROM AUTHOR]

Experiments were carried out to investigate the influences of nozzle geometric parameters and injection pressure on jet breakup characteristics using a high-speed photography (HSP) technique. The flow rates and spraying ranges of sprinkler with different nozzles were measured. In this research, HSP technique was also used to photograph the drops emitted by sprinkler with different nozzles at different pressures, photographs were taken at different horizontal distances from the sprinkler and the equivalent circle diameter was used to represent the particle sizes. Based on HSP technology, the effects of flow velocity and nozzle geometric parameters on jet breakup length were studied, and the droplet diameters with different nozzle types were obtained. The result showed that for the sprinkler with different nozzles, the breakup length decreased with the increases of pressures. At the nearby (3-9 m) region and distant (12-18 m) region of sprinkler, the droplet diameters of sprinkler with type B nozzle were the largest, which meant the sprinkler with type B nozzle was the optimal choice by synthesizing the droplet diameter distribution. The fitting relationship of jet breakup length with Reynolds number and Weber number (Re and We), and the regression equation of the end droplet diameters were deduced with errors of less than 5% and 4% respectively. [ABSTRACT FROM AUTHOR]

In this paper, the pressure drops and interfacial heat transfer coefficient in metal foam with different pore density which was constructed by tetrakaidecahedron models were numerically studied under high velocity by Computational Fluid Dynamics (CFD). The velocity fields, temperature fields and pressure fields in the computational domain of metal foam were investigated. The equation of pore density and hydraulic diameter of metal foam was obtained. Influence of flow rate on the whole porous zone was also studied and obtaining the fitting formula to predict pressure loss in porous metal which was applied to the pore density range from 10PPI(Pore Per Inch)to 40PPI at high flow rate. Comparing with the previous literatures, the maximum error of pressure drop value was 12.23%. Meanwhile, the relationship between Reynolds number and interfacial heat transfer coefficient was studied, the results shown that the values of heat transfer coefficient increase with the rising of Reynolds number, but the lifting rate decreases gradually. And according to the data points, the numerical formula of interfacial heat transfer coefficient in porous metal was obtained which had a great correctness through contrasting with other data. As a result, the fitting formula could accurately predict the convection heat transfer coefficient of the metal foam interface and provide relevant data for the Thermal Non-equilibrium Model. • The heat transfer and fluid flow characteristics in foam metal under high Reynolds numbers were numerically studied based on tetrakaidecahedron model. • A new correlation for pressure drop in foam metal under high Reynolds numbers was obtained. • A new correlation for interfacial heat transfer coefficient in foam metal was obtained. [ABSTRACT FROM AUTHOR]

In this paper, a digital audio processing chip which uses a wide dynamic range compression (WDRC) algorithm is designed and implemented for implantable hearing aids system. The designed chip operates at a single voltage of 3.3V and drives a 16 bit parallel input and output at 32 kHz sample. The designed chip has 1-channel 3-band WDRC composed of a FIR filter bank, a level detector, and a compression part. To verify the performance of the designed chip, we measured the frequency separations of bands and compression gain control to reflect the hearing threshold level. [ABSTRACT FROM AUTHOR]

Background and Objectives: For the hearing-impaired population, quality of sound when listening to speech on mobile phone is often dissatisfactory. Even with a turning up the volume, they feel mobile speech unclear and desire the mobile sounds to be amplified as suited for the hearing characteristics. The purpose of this study was to estimate the appropriateness of NAL-NL1 fitting formula for the hearing-impaired mobile communication. Materials and Methods: NAL-NL1 and a modified fitting formula (M-formula) were applied for sound amplification in consideration of individual hearing loss. Amplified speech material was presented for a word-recognition score (WRS) test in each subject. To simulate actual mobile phone sound, all speech material was filtered in 8 kHz low-pass filter and presented through a mobile phone to the subjects. Speech material was categorized into a speech-without-noise group and noisy speech group. Results: Amplified sound with NAL-NL1 formula had a slightly better WRS than amplified speech with M-formula in speech-without-noise environments. However, in the noisy speech group, M-formula showed better WRS than NAL-NL1. Conclusions: For a good speech-perception in mobile phones, more high-frequency speech components need to be provided, especially for noisy environments. This study showed the possibility that specified fitting strategies may be applied for mobile phones to improve hearing in various environments, as with hearing aids. [ABSTRACT FROM AUTHOR]

In this paper, a digital audio processing chip which uses a wide dynamic range compression (WDRC) algorithm is designed and implemented for implantable hearing aids system. The designed chip operates at a single voltage of 3.3V and drives a 16 bit parallel input and output at 32 kHz sample. The designed chip has 1-channel 3-band WDRC composed of a FIR filter bank, a level detector, and a compression part. To verify the performance of the designed chip, we measured the frequency separations of bands and compression gain control to reflect the hearing threshold level. [ABSTRACT FROM AUTHOR]

The outflow of the effervescent atomization spray is simulated by a comprehensive numerical model based on the Navier-Stokes equation and the particle tracking method. The droplet mean diameter under different operating conditions and liquid properties were calculated. Based on the extensive computations, a formula relating droplet Sauter mean diameter to the operating conditions and liquid physical parameters were obtained with curve fitting technique. The results calculated from the formulae were compared with the experimental data and a good agreement was obtained. The formulae can be used to predict the droplet mean diameter for various Newtonian liquid in axisymmetric effervescent atomization spray conveniently and effectively. [ABSTRACT FROM AUTHOR]

It is widely known that coastal buildings are eroded by salt, and hygroscopic performance of the building materials significantly affects the building energy consumption. Therefore, for buildings in marine atmospheric zones, it is necessary to explore the impact of salt on the hygroscopic properties of cement mortar. In this study, cement mortar specimens with different salt contents were prepared to measure their hygroscopic properties at different humidity levels, and acquire the regulation of equilibrium moisture content with changes in the salt content and relative humidity. In addition, based on a variety of commonly used adsorption formulae, combined with the influencing factors of salt content proposed in this study, a hygroscopic fitting formula for salt-containing materials was established. The experimental results revealed the following: the higher the salt content, the longer the stability time; the maximum increase in moisture absorption occurred in the early stage of the experiment, which gradually decreased and tended to be stable in the later stage; at any level of relative humidity, the equilibrium moisture content of the specimen increased with an increase in the salt content, and the promoting effect could be enhanced by more than three-fold; furthermore, the maximum moisture content appeared under conditions of high salt and high humidity. In addition, the fitting formula based on the BET formula and salt influence factor had a good fitting effect, and the goodness of fit could reach 0.98. [ABSTRACT FROM AUTHOR]

In this study, the material and stability of 10 axial compression aluminum alloy columns are systematically tested at five temperatures. The material grade of the aluminum alloy used in the tests is 6082-T6. The experimental results demonstrate that flexural buckling occurs in all the column specimens under different temperature environments. A finite element (FE) model of the experiment is established, and the obtained results are compared with the experimental results to verify the accuracy of the FE model. To study the stability at different temperatures, 765 FE models considering geometry and material nonlinearity are created in five different temperature environments. Three section types (H-type, rectangular, and circular tube sections), three sectional dimensions for each section type, and 17 slenderness ratios are considered in the models. Based on the FE results and the statistical regression method, the formula for calculating the stability coefficient for the columns with different slenderness ratios at different temperatures is fitted. The fitting formula is compared with the test results, Chinese Code (GB), and European Code (EC9). The comparison results demonstrate that the fitting formula can provide a more accurate stability coefficient for the columns at different temperatures. • Ten 6082-T6 aluminum columns under axial compression at five temperatures were tested. • 765 FEM with different parameters were analyzed at five different temperatures. • Formula for calculating the stability coefficient for the columns at different temperatures is fitted. • The fitting formula provide a more accurate stability coefficient at different temperatures than GB and EC9. [ABSTRACT FROM AUTHOR]

• CPHPTO efficiency at a wide range of operating points is studied. • ICCs are introduced to handle the 4-D data from efficiency test or numerical fitting. • ICCs can guide the optimal design and efficient operation. • Stable operating region can be defined while plotting the operating curves of ICCs. Power take-off is an indispensable link in wave energy utilization, and its efficiency should be comprehensively investigated at both full load and part load for the effective conversion in variable wave conditions. However, up to now, the research about this issue is still scarce because of its complexity and difficulty. To overcome this obstacle, this paper studies the overall conversion efficiency of the constant-pressure hydraulic power take-off (CPHPTO) of a floating-pendulum wave energy converter, at a wide range of the system pressure, system flow-rate and shaft speed, via the efficiency test and fitting formulas. Furthermore, the integrated characteristic curves, which consist of the characteristic curves and operating curves, are proposed to deal with the four-dimensional data obtained from the experiment or fitting. The results show that the integrated characteristic curves of the CPHPTO are available and play an important role in the optimal design and efficient operation. The stable operating region can also be defined when plotting the operating curves. In general, the integrated characteristic curves are suitable for the preliminary design and further optimization of the similar CPHPTOs for different kinds of oscillating-body wave energy converters. [ABSTRACT FROM AUTHOR]