Influence Of Different Combinations Research Articles

Pulsatile MHD Flow of Two Immiscible Nanofluid through a Porous Channel with Slip Effects

The present study is carried out to investigate the effects of shape factor nanoparticles on the oscillatory MHD flow of a nanofluid in two immiscible liquids in a horizontal porous channel with velocity and thermal slip on the walls. Thermal radiation, Joule heating, viscous and Darcy dissipations have been accounted for in the model. We have considered and as nanoparticles, in the lower region (Region-I) and upper region (Region-II) respectively, with water as a base fluid. The effective ratio of thermal conductivity of the nanofluid is evaluated using the Maxwell-Garnetts model. Graphical behavior of velocity, temperature, and rate of heat transfer distributions have been depicted for the cases of slip and no-slip effects. This study has been made to understand the impact of different nanoparticle shape factors on temperature and heat transfer rate. For various parameters, values of shear stress distribution at the walls and the mass flux are shown in tabular form. Our study asserts that with the increase of the strength of the magnetic field, the velocity of the liquid falls and enhances the temperature of the liquid. The influence of different combinations of nanoparticles, on the flow variables, have also been discussed. In order to validate the analytical results, the numerical evaluation of the closed-form results, for the velocity distribution, has been compared with those of the numerical method, by using the NDSolve command in MATHEMATICA, and a good agreement is observed.

Influence of different combinations of high-order topological modification on contact pattern and load distribution of helical gear

An integrated model is proposed to evaluate the contact pattern and load distribution of helical gear with different combinations of high-order topological modification, which is established combining the finite element method (FEM), the analytical method (AM), and the nonlinear programming method. Based on the elastomer contact model of tooth surface, the FEM is used to separate the flexural-shear deformation of the teeth, while the contact AM is introduced to derive the local contact deformation. The contact characteristics of gears can be finally obtained by solving the nonlinear programming model with the constraints of deformation and load and finally verified by the finite element analysis. The results show that the longitudinal crowning can significantly improve the load distribution and the edge contact of the tooth. When the modified curve becomes a parabola of higher order, the contact characteristics change obviously. The pressure of double-crowned (4) gears was uniform and the amplitude decreased, but the amplitude of pressure of double-crowned (6) gears increases and the variance of load sharing ratio is more obvious at the beginning of the middle meshing period.

Demystifying the Combined Effect of Consistency and Seamlessness on the Omnichannel Customer Experience: A Polynomial Regression Analysis

Although channel consistency and seamlessness have been regarded as two critical factors in conducting omnichannel business, their combined effect has yet to be revealed. By employing a polynomial regression, this study disentangles the combined effect of channel consistency and seamlessness on customer experience in the omnichannel context. The results indicate that enhancing channel consistency and seamlessness simultaneously can improve the omnichannel customer experience. The combined effect of a high (low) level of channel consistency and a low (high) level of channel seamlessness on the omnichannel customer experience is also positive. Data vulnerability can strengthen the combined effect of channel consistency and seamlessness on customer experience in the omnichannel context. This study not only uncovers the complex influences of different combinations of channel consistency and seamlessness but also provides new insights into conducting omnichannel retail for practitioners.

Design of multi-material structures using material jetting technology: Topology optimisation, numerical analysis and experiments

This paper presents a thorough experimental/numerical validation of optimised multi-material structures fabricated by material jetting technology. The proposed methodology uses, on the one hand, non-uniform rational basis spline (NURBS) entities to represent the geometric descriptor associated with each material phase constituting the continuum and, on the other hand, a general multi-phase material interpolation scheme to penalise the stiffness tensor of the structure. Two design requirements are included in the problem formulation: the lightness and the minimum length scale of each material phase. The influence of the integer parameters intervening in the definition of the NURBS entity and the influence of different combinations of material phases on the optimised solutions are investigated. The proposed approach is applied to 2D and 3D benchmark structures subjected to prescribed displacements representative of a three-point bending test. Based on the result of the topology optimisation process one of the optimised solutions, balancing the requirements of structural stiffness, lightness, and manufacturing constraints, is selected, manufactured and tested. A comparison between experimental and numerical results (obtained by non-linear analyses) is carried out to show the effectiveness of the approach.

Laser Perforated Dual-Scale Porous Electrodes Considering the Interdigitated Flow Field for Vanadium Redox Flow Battery

The conflict between the specific surface area and hydraulic permeability of carbon-based porous electrodes limits the further improvement of redox flow battery (RFB) system performance. Dual-scale electrode design is a feasible approach to overcome this contradiction. In this study, we prepared dual-scale electrodes by perforating graphite felts using an infrared laser. Based on the symmetry of the interdigitated flow field structure, we proposed three dual-scale structure designs with different combinations of large and small pores and tested their performance on a vanadium redox flow battery (VRFB) single cell. The results showed that the design with perforations under the center of the rib could increase the maximum power density by approximately 2.4 times compared to the original electrode. Furthermore, to investigate the effect of the large pores formed by laser perforation on the local electrolyte velocity, active species concentration, and reaction rate distribution, we proposed a pore-network model and investigated the influence of different combinations of large and small pores and different operating conditions on overall performance through numerical simulation. The results showed that the optimal combination of large and small pores is related to the flow rate and other operating conditions, and that setting large pores under the rib near the outlet channel is expected to provide more performance gains in VRFBs equipped with interdigitated flow fields under typical operating flow rates.

INFLUENCE OF FUSED DEPOSITION MODELING REGIME PARAMETERS ON MANUFACTURING TIME OF UAV PARTS

Purpose. Investigate the regularities of FDM process parameters influence on the manufacturing time of parts.
 Research methods. The samples for research were produced by the FDM method on a Profi+midi 3D printer. Slic3rPE software were used for CAD model slicing and G-code preparation. The samples were printed using ABS+ filament. The STATISTICA software package was used for statistical processing of the results.
 Results. The influence of different combinations of FDM process parameters (printing speed, layer height, infill geometry, infill density) on the manufacturing time of products was examined. The main factors affecting the manufacturing time were established: printing speed, layer height, infill density and the interaction of these factors
 Scientific novelty. Analysis of the manufacturing time dependence on the layer height and the infill density showed that when selecting a layer height of 0.15 mm and 25 % infill and a layer height of 0.3 mm and 100% infill, the manufacturing time turned out to be nearly identical. It can be concluded that for a lower layer height, increasing the infill density significantly increased the manufacturing time, while setting a higher layer and increasing the infill density led to a small increase in the manufacturing time. It was found that for a layer height of 0.15 mm at a printing speed of 40 mm/s, the manufacturing time significantly increased compared to a printing speed of 80 mm/s, while when selecting a layer height of 0.3 mm, the manufacturing time is less and a decrease in the printing speed led to a small increase of manufacturing time compared to a layer height of 0.15 mm. It was established that an increase in printing speed led to a decrease in manufacturing time and an increase in infill density led to an increase in manufacturing time. Thus, the manufacturing time at a printing speed of 40 mm/s and infill density of 25 % differed slightly from a printing speed of 80 mm/s and infill density of 100 %.
 Practical value. A regression equation was obtained which allowed predicting the influence of the FDM process parameters on the manufacturing time of parts.

Quantitative analysis of pyrazinamide polymorphs in ternary mixtures by ATR-FTIR and Raman spectroscopy with multivariate calibration

The polymorphism of drugs exists widely in solid chemical drugs. It will affect the physical and chemical properties of drugs, as well as bioavailability. So it is very necessary to establish an quantitative method to improve the quality control level of polymorphic drugs. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and Raman spectra have been included in many countries’ pharmacopoeia as the drug polymorph analytical technique, and they have many unique advantages. However, for multiple mixed systems, due to the complexity of optical signals, it is difficult to obtain an ideal content prediction model by classical linear regression, so the application of chemometric methods shows advantages. Pyrazinamide is a typical polymorphism drug, three polymorphic forms (α, δ, γ) were obtained. The model prediction ability of two kinds of spectroscopy combined with three kinds of stoichiometric methods was investigated by orthogonal experiment. On this basis, the influence of different combinations of five data preprocessing methods on improving modeling quality was investigated. In this research, Raman spectra combined with partial least squares (PLS), multiplicative scatter correction (MSC), denoise, median and first derivative at the whole spectral range resulted in a better calibration model. It had a RMSEP of 5.3%, 21.6%, and 20.8% for polymorphs α, δ, and γ, respectively. Several methods were used for preprocessing the spectral data could remove unimportant baseline (offset) interference from samples or to correct scattering effects and emphasize spectral the interesting signals. PLS can derive a few components from the independent variable system. Therefore, it may be an effective method to establish a quantitative model for a multi-polymorphism component mixed system.

Surface treatments and substrate-coating interface effects on damage accumulation kinetics in hard-coated WC-Co hardmetals under cyclic multi-axial high-temperature loading

Coated hardmetals are commonly used tool materials for metal cutting applications. For these applications, the substrate- and the coating surface qualities are improved by grinding, polishing, or blasting. The focus of the current work was to study the influence of different combinations of substrate-coating surface processing techniques on the induced damage in Al2O3/TiCN hard-coated WC-12 wt% hardmetal substrates and the depth to which the damage reaches into the substrate. The substrate and coating surfaces were prepared by grinding, polishing, dry blasting, wet blasting, or remaining in the deposited state. Investigations were performed using cyclic indentation with a novel ball-in-cone test method in a vacuum at 700 °C, under conditions that imitate the combined shear-compression loads that occur at the cutting edges of metal cutting tools. Additionally, finite element simulations were performed to characterize the stress state arising during ball-in-cone testing. The kinetics of defect formation and accumulation in the hardmetal substrate as a function of the loading situation during the ball-in-cone test will also be discussed. The defects that formed in the substrate during cyclic loading were studied using scanning electron microscopy in cross-sections prepared by focused ion beam milling. A larger increase in defect frequency was observed for rougher coating surfaces and substrate-coating interfaces than for smoother ones. Furthermore, 6 μm thick coatings exhibited a higher defect frequency after cyclic loading than 15 μm thick coatings. Most of the observed defects were in the nm-size range close to the substrate-coating interfaces and tended to have increased in size after cyclic loading. The ball-in-cone test set-up enables the study of the damage mechanisms in coated hardmetal substrates with different treatments prior to and after deposition under tunable milling-like stress and temperature conditions.

Influence of Planting Date and Planting Distance on Population Density of Onion Armyworm

Onion is an important crop in the province of Nueva Ecija, Philippines. Currently, its productionis being constrained by onion armyworm (OAW; Spodoptera exigua). The impact of plantingdates and distance on the infestation of OAW was studied across two productions. The aim isto evaluate the influence of different combinations of planting dates (November, December, andJanuary) and row spacing [5 cm x 10 cm, 8 cm x 10 cm, 10 cm x 10 cm, and farmer’s practiceor waray (6–10 cm x 6–10 cm)] on the damage and population density of OAW. The count ofobserved OAW larvae from the earliest month (November) and during the month of the usualproduction period (November–December) was negligible to minimal. However, a significantincrease in the OAW population during late planting (January). In terms of leaf damage causedby the OAW feeding, November, December, and January planting had an increasing percentageas the OAW population also increased. There was an increase in bulb diameter as the row spacingwidens (10 cm x 10 cm), as well as an increase in the number of marketable bulb onions whenit is narrow (5 cm x 10 cm). This study showed that planting dates and distances should be oneof the major considerations in onion production and insect pest management.

Математическое и компьютерное моделирование колебания системы «груз-балка» козлового крана

Introduction. Gantry grappling cranes are the main equipment for cargo transportation in the technological processes of mining and enrichment of rocks. During the operation of the crane, undesirable effects such as the rocking of the payload occur, which in turn affects the dynamic state of the crane beam. Materials and methods. To solve this problem, methods of mathematical and computer modeling of a system with two degrees of freedom were used. To identify the influence of different combinations of the combination of payload mass and cable length on oscillation frequencies, a computational experiment was carried out and the response surface of the oscillation frequency function was constructed. The natural oscillation frequencies of the beam were determined by the finite element method in the NASTRAN program. Results. The results of mathematical modeling were graphs of changes in the angle of deviation of the cable from the vertical and the movement of the trolley, the response surface of the frequency of oscillation of the payload from the length of the cable and the weight of the cargo. Discussion. A comparison of the simulation results of cargo vibrations and crane beam vibrations showed the proximity of the values of the frequencies of the payload vibrations and the gantry crane design, which justifies the need for further analysis of the frequency response of the crane beam to the disturbance of the payload vibration force. Conclusion. The frequency of vibrations of the load significantly affects the static and vibration strength of the crane beam of the gantry crane Resume. The research results can be useful in the development of technical solutions for the engineering implementation of promising gantry crane designs.

Influence of different combinations of impact mass and velocity with identical kinetic energy or momentum on the impact response of RC piles

Marine engineering structures may be subjected to various levels of vessel collisions, causing different degrees of damage to the RC piles. However, the influence of different combinations of impact mass and velocity under the same initial kinetic energy or momentum on the impact behavior of RC piles has not been explored. A numerical investigation of the impact responses of RC pile structures (including plumb piles and inclined pile groups) considering the material strain rate effect is carried out using the software ABAQUS/Explicit in this paper. Parametric studies are conducted based on the validated finite element models of RC piles subjected to horizontal impact. The internal force distributions, as well as the effect of the impact kinetic energy and the momentum (including different combinations of impact mass and initial velocity) on the impact response of RC piles, are discussed. The results indicate that the development path of the bending moment‒overall structural displacement curves in the plastic hinge regions of RC piles are almost identical under both impact and static loading conditions. Compared to momentum, the impact response of RC piles is insensitive to the variation of impact kinetic energy with different combinations of impact mass and velocity. Therefore, the impact kinetic energy is more suitable for evaluating the structural deformation of RC piles after impact. Finally, a performance-based impact-resistance design framework for RC piles is proposed.

Study on the impact of photovoltaic electrochromic modular smart window on indoor environment

Both electrochromic window (EC) and photovoltaic (PV) shading technology can control the indoor lighting environment. However, their combination form has great impact on the performance. The innovative smart windows with photovoltaic electrochromic (PV-EC) modules are designed, and consisted with photovoltaic areas, EC areas and transparent areas. Because the position of different modules can be adjusted freely, the system can select the most suitable combination mode for different building applied conditions. The PV-EC modular smart window test rig was established to learn the influence of different combinations of the windows on lighting condition. The combination(d) has the largest useful daylighting illumination among them, and which reaches 75.26%. PV area is installed at the lower layer, EC area is installed at the middle layer, and transparent area is installed at the upper layer in combination (d). Compared with ordinary windows, the window system can save up to 15.79% energy. And for different floors, radiation areas and space types, the system can select the corresponding combinations to adjust the lighting environment. It shows that the window system could improve the lighting environment and energy saving of the building, and effectively copes with different building condition.

Evaluation of Sample Preparation Importance for Digital Image Correlation during Cold Deformation

In this paper, tests were performed by monitoring changes of strain amounts and their distribution by digital image correlation during static tensile testing of steel. The influence of different combination of speckles application on the sample surface (white speckles on the black sample surface and black speckles on the white sample surface) during cold deformation of steel was tested with the non-contacting digital image correlation. Strain amounts obtained by digital image correlation analysis of tested samples, with white on black and black on white painted speckle patterns, were compared. Different analysis for determining and monitoring strain amounts, provided by digital image correlation software, were used in this paper. The strain amounts were compared during cold deformation until the occurrence of sample fracture in both combinations of speckles application on the sample surface. Research has shown the importance of proper sample preparation for determination strain amounts and insignificant minor differences of strain amounts, between different sample preparations for digital image correlation, during cold deformation of tested steel.

Antibacterial activity of chitosan and zinc oxide impregnated in PVA-based membranes

The development of alternatives to conventional antibiotics against superbugs represents an important step to avoid the increasing resistance of bacteria observed in conventional treatments. Herein, it was evaluated the influence of different combinations of two active antibacterial components (chitosan and zinc oxide) and a host poly (vinyl alcohol - PVA) in membranes produced by the solvent casting technique. Those systems were evaluated in terms of the biofilm inactivation, kill-time assays and inhibition haloes against S. aureus (ATCC 25923) in membranes that must release reactive components while preserving their integrity and favoring the generation of reactive species to improve the antibacterial activity. The results suggest the potential of the combination of chitosan, zinc oxide and poly (vinyl alcohol) to inhibit the growth of S. aureus colonies since the PVA improved the dispersion of the components, whereas chitosan-ZnO chelate improves the mutual activity of the metal oxide and the natural polymer template.

Integrating machine learning with linguistic features: A universal method for extraction and normalization of temporal expressions in Chinese texts

Background and ObjectiveWith the rapid development of information dissemination technology, the amount of events information contained in massive texts now far exceeds the intuitive cognition of humans, and it is hard to understand the progress of events in order of time. Temporal information runs through the whole process of beginning, proceeding, and ending of events, and plays an important role in many natural language processing applications, such as information extraction, question answering, and text summary. Accurately extracting temporal information from Chinese texts and automatically mapping the temporal expressions in natural language to the time axis are crucial to understanding the development of events and dynamic changes in them. MethodsThis study proposes a method integrating machine learning with linguistic features (IMLLF) for extraction and normalization of temporal expressions in Chinese texts to achieve the above objectives. Linguistic features are constructed by analyzing the expression rules of temporal information, and are combined with machine learning to map the natural language form of time onto a one-dimensional timeline. The web text dataset we build is divided into five parts for five-fold cross-validation, to compare the influence of different combinations of linguistic features and different methods. In the open medical dialog dataset, based on the training model obtained from the web text dataset, 200 disease descriptions are randomly selected each time for three rounds of experiments. ResultsThe F1 of multi-feature fusion is 95.2%, which is better than the single-feature and double-feature combination. The results of experiments showed that the proposed IMLLF method can improve the accuracy of recognition of temporal information in Chinese to a greater extent than classical methods, with an F1-score of over 95% on the web text dataset and medical conversation dataset. In terms of the normalization of time expressions, the accuracy of the IMLLF method is higher than 93%. ConclusionsIMLLF has better results in extracting and normalizing time expressions on the web text dataset and the medical conversation dataset, which verifies the universality of IMLLF to identify and quantify temporal information. IMLLF method can accurately map the time information to the time axis, which is convenient for doctors to intuitively see when and what happened to the patient, and helps to make better medical decisions.

A Vertically Modularized Reconfigurable Wireless Power Transfer System: Architecture, Modeling, and Design

It is known that megahertz (MHz) wireless power transfer (WPT) is particularly beneficial in terms of spatial freedom of power transfer and circuit compactness. Meanwhile, design complexity is a main obstacle to the spread of MHz WPT. In this article, a new modular design concept is proposed to conveniently reconfigure a MHz WPT system for different applications. Multiple predesigned functional unit modules can easily be combined to form a complete new WPT system with a different power level and transfer distance. A vertically stacked architecture is especially chosen to save space in actual applications. Detail analytical derivations are conducted to analyze the modular design, including the influence of different combinations of the unit modules. A new interleaved coil design is developed to reduce the proximity effect and cross coupling among the vertically stacked modules. Finally, the modular design concept is validated by experiments and demonstrates the desired scalability in both power levels and transfer distances. Through 15 combinations of the unit modules, the experimental WPT system can be reconfigured to provide an output power from 4 to 116 W. The effective transfer distance can be also extended from 30 to 90 mm and 80% system dc–dc efficiency is achieved within a 70-mm transfer distance using 100-mm-diameter printed circuit board coils.

Study on influence of ring hole array metamaterial on performance of pyroelectric terahertz detectors

In order to improve the detection performance of 0.1–1THz terahertz wave, a new lithium tantalate pyroelectric terahertz detector based on ring hole array metamaterial is proposed. The quantitative influences of the characteristic parameters such as inner diameter, outer diameter, period and thickness on the transmission bandwidth and transmittance of ring hole array metamaterials are analyzed by simulation. The mechanisms of the influences of different combinations of ring hole array metamaterials and pyroelectric detectors on the detection bandwidth and detection rate of terahertz waves are clarified. The lithium tantalate pyroelectric terahertz detectors of the ring hole array metamaterial ware are fabricated by the MEMS technology. The transmission of the ring hole array metamaterial and the noise equivalent power of the metamaterial detector at different frequencies are tested. The results show that the transmittance of the fabricated ring hole array metamaterial is greater than 40% at 0.25–0.65 THz, and bandpass filtering is realized. When the ring hole array metamaterial and the pyroelectric detector maintain a sufficient distance, the noise equivalent power of the detector at 0.315 THz is 11.29 μW/Hz<sup>0.5</sup>, which is 6.3% of the 0.1 THz noise equivalent power (outside the bandpass band), so the bandpass detection is achieved. When the ring hole array metamaterial is attached to the detector, the noise equivalent power of the metamaterial detector at 0.315 THz is 4.64 μW/Hz<sup>0.5</sup>, which is 29.4% that of the detector without the ring hole array metamaterial, so the narrowband detection is achieved. The above conclusions show that the pyroelectric terahertz detector based on the ring hole array metamaterial can realize the bandpass and narrowband detection of specific frequency band in applications such as biological imaging and macromolecular detection.

Artificial Intelligence Algorithm-Based Arrangement Optimization of Structural Isolation Bearings

The determination of an isolation-bearing scheme usually depends on experience, and needs numerous iterative calculations, especially when considering many factors such as total cost of the scheme, various design indicators, eccentricity of stiffness center of isolation bearings and the center of gravity of superstructure, and so on. Moreover, during the usual optimization process, the isolation scheme is often limited in several kinds of sizes and fixed predetermined distribution of types of isolation bearings based on experience or trial calculations due to computational efficiency, which would make it incapable of exploring other possible schemes. In this paper, artificial intelligence technology is applied to optimize the layout of isolation bearings. Types of isolation bearings are predicted through a Convolutional Neural Network, and sizes of isolation bearings are optimized by Hunter–prey optimization algorithm to improve computational efficiency and optimal arrangements of bearings. To simplify the optimization process, an optimization objective function considering a seismic decrease coefficient, story drift ratio and total cost of isolation bearings is proposed. In this function, weight coefficients reflect significance of various factors during the optimization process. In order to investigate influence of different combinations of weight coefficients on the optimal layout, 12 groups of combinations of weight coefficients are designed and analyzed. The results show that the optimal layout method of isolation bearings based on the artificial intelligence algorithm has good convergence efficiency of optimization and makes it possible to search more practical isolation scheme with good performance. When focusing on total cost of bearings, the ideal weight coefficient of the total cost would be larger than 0.4. While the structural performance factors are mainly considered, the weight coefficient of the maximum story drift ratio or seismic decrease coefficient should be larger than 0.2. For factors that designers pay more attention to, the corresponding weight coefficient should be larger than others.

A Spatial Model for Repairing of the Dam Safety Monitoring Data Combining the Variable Importance for Projection (VIP) and Cokriging Methods

The safe operation of dams is related to the lifeline of the national economy, the safety of the people, and social stability, and dam safety monitoring plays an essential role in scientifically controlling the safety of dams. Since the effects of environmental variables were not considered in conventional monitoring data repairing methods (such as the single time series model and spatial interpolation model), a spatial model for repairing monitoring data combining the variable importance for projection (VIP) method and cokriging was put forward in this paper. In order to improve the accuracy of the model, the influence of different combinations of covariates on it was discussed, and the VIPj value greater than 0.8 was proposed as the threshold of covariates. The engineering verification shows that the VIP-cokriging spatial model had the advantages of high precision and strong applicability compared with the inverse distance weighting (IDW) model, the ordinary kriging model, and the universal kriging model, and the overall error can be reduced by more than 60%, which could better realize the expansion of the monitoring effect variable to the whole area of the dam space. The engineering application of the PBG dam showed that the model scientifically correlated the existing monitoring points with the spatial location of the dam, and reasonably repaired the measured values of the stopping and abnormal measured points, effectively ensuring that the spatial regular of the monitoring data could truly reflect the actual safety and operational status of the dam.

Supercritical CO2 extraction of spices: A systematic study with focus on terpenes and piperamides from black pepper (Piper nigrum L.)

Black pepper (P. nigrum L.) is considered one of the most valuable spices and a promising candidate in natural product research. In this study, the influence of different combinations of pressures (100–300 bar) and temperatures (40–60 °C) on the supercritical CO2 (SC-CO2) recovery of several key compounds from black pepper was evaluated systematically. The extraction curves showed that terpenes were recovered in a short time under all studied conditions. In contrast, higher pressure values were required to extract piperamides efficiently. Furthermore, the differences in the extraction kinetics of piperine, piperettine, pellitorine, guineensine, and N-isobutyl-2,4,14-eicosatrienamide were linked with several structural features, such as the nature of the amine group or the terminal part of the fatty acid. The data from the isocratic experiments represented the starting point for designing a two-step pressure gradient SC-CO2 process in which one terpene-rich and one piperamide-rich product were successively obtained.