Effects Of Different Configurations Research Articles

Enantiomeric separation of four pairs of alkaloids by using a C18 column tandem polysaccharide-based chiral column

Abstract Alkaloid enantiomers have different physiological and pharmacological effects, and different chiral compositions have a large impact on cigarette sensory and use safety. Studying the effects of different configurations of alkaloid enantiomers on cigarette sensory is important for the development of tobacco products, but the chiral separation of alkaloid enantiomers has become the core problem. Here, the application of a C18 column coupled with a polysaccharide-based chiral column to separate and detect four pairs of alkaloid enantiomers in tobacco and cigarette smoke of different brands was investigated. Results showed that the tandem technology of the two columns enabled the baseline separation of four pairs of alkaloid enantiomers. The resolution of enantiomers of alkaloids in different tobacco samples differed in content and ratio, showing different chiral distribution characteristics. According to the different distribution characteristics of alkaloid enantiomers, tobacco samples of different brands can be distinguished and real cigarettes can be identified.

Influence of BRDF Models and Solar Zenith Angles on Forest Above-Ground Biomass Derived from MODIS Multi-Angular Indices

Multi-angular remote sensing observation contains crucial information on forest structure parameters. Here, our goal is to examine the ability of multi-angular indices, which are constructed by the typical-angular reflectances in red and NIR bands from MODIS observations, for the retrieval of forest biomass based on the field-measured above-ground biomass (AGB) data. Specifically, we employed the updated version of the MCD43A1 BRDF parameter product as an input for BRDF models to reconstruct the MODIS typical-angular reflectances. Furthermore, we evaluated the effects of different configurations of BRDF models and solar zenith angles (SZA) on forest AGB estimation using our developed multi-angular indices. The semivariogram analysis strategy combined with Landsat ground-surface reflectance data was employed to determine the MODIS pixel heterogeneity; the survey data from field sites of homogeneous pixels was used in our analysis and validation. The results show that our developed multi-angular indices based on a hot-revised BRDF model, under a SZA of 45°, when combined with forest cover information, can account for up to 72% of the variation forest AGB, with an RMSE = 45 Mg/ha. We also found that different kernels for the BRDF models influenced the weight parameters of the biomass inversion equation but did not significantly affect the estimated AGB. In conclusion, our method can enable the better usage of MODIS multi-angular observations for forest AGB estimation.

A STUDY ON SiC SUSCEPTOR CONFIGURATION FOR MICROWAVE HYBRID HEATING

Microwave hybrid heating (MHH) is a novel method to enhance ceramic sintering at high temperatures. The heating mechanism by MHH involves two directions of heat transfer for materials: microwaves heat the sample from the inside out, while the susceptor provides conventional heating from the outside. This unique heating mechanism offers several advantages, including uniform heating, rapid sintering, and enhanced microstructure and properties of materials. This study investigates the configuration of silicon carbide (SiC) susceptors for microwave hybrid heating. The microwave oven (multi-mode, 2.45 GHz, 1.2 kW) was modified with a ceramic insulator housing to maintain the temperature in the chamber. The effects of different configurations of SiC susceptors and microwave powers on the heating rate and maximum temperature were investigated. SiC susceptor plates were placed in the microwave oven using 3 different configurations, and for each condition, the microwave power was varied at 40, 60, 80, and 100% (480, 720, 960, and 1,200 W). The temperature in the microwave chamber was recorded until it reached 900°C or after 30 min of heating. Using two plates of SiC susceptor at 100 % power resulted in the highest heating rate of 62°C/min to reach 925°C. The results of this study offer guidance for the selection of appropriate heating conditions for individual ceramic materials, which can lead to more effective sintering processes.

On improving low-frequency sound absorption using a compound microperforated panel backed by a panel-type resonator with tuned multi-frequency resonators

The present work is aimed to broaden the half-absorption bandwidth and improve low frequency sound absorption of a microperforated panel (MPP) by investigating the effects of tuned multi-frequency resonators attached to a flexible panel (i.e. a multi-frequency panel resonator – mMPR), as the backing of MPP so to create a compact sound absorber. The effects of different configurations of multi-frequency resonators were investigated through theoretical and experimental studies. The results demonstrated that the coupling strength among MPP, the panel and resonators at their resonant frequencies had a significant contribution to shaping the sound absorption characteristics, that were particularly influenced by the placement of resonators, quantity of resonators and the configuration of resonators, and these parameters could be tuned to extend the half-absorption bandwidth as well as the low frequency sound absorption coefficient. It was found that there was minimal mass of resonators for them to be effective in improving low frequency sound absorption characteristics and an optimal mass ratio demonstrated a better sound absorption performance in terms of bandwidth and absorption coefficient without an unnecessary increase of structural mass. A circular arrangement of multi-resonators was found to be beneficial in achieving relatively similar MPP-panel-resonator coupling of multi-resonators so to achieve a more uniform sound absorption coefficient within the particular bandwidth. It was experimentally demonstrated that a 200 mm × 200 mm MPP with the backing of a panel and circularly-arranged multi-frequency resonators of only 2 % mass ratio, could achieve a wide low-frequency half-bandwidth from 160 Hz to 550 Hz with the averaged absorption coefficient improved by 18 % to 0.72 over 150 Hz to 260 Hz, in the frequency range within which the absorption valley was previously located.

The Effect of Different Configurations of Copper Structures on the Melting Flow in a Latent Heat Thermal Energy Semi-Cylindrical Unit

Utilizing latent heat thermal energy storage (LHTES) units shows promise as a potential solution for bridging the gap between energy supply and demand. While an LHTES unit benefits from the latent heat of the high-capacity phase change material (PCM) and experiences only minor temperature variations, the low thermal conductivity of PCMs hinders the rapid adoption of LHTES units by the market. In this regard, the current work aims to investigate the thermal behavior of a semi-cylindrical LHTES unit with various copper fin configurations (including horizontal, inclined, and vertical fins) on the melting flow. The novelty of this research lies in the fact that no prior studies have delved into the impact of various fin structures on the thermal performance of a semi-cylindrical LHTES system. The nano-enhanced phase change material (NePCM) fills the void within the unit. The warm water enters the semicircular channel and transfers a portion of its thermal energy to the solid NePCM through the copper separators. It is found that the system experiences the highest charging capability when the fins are mounted horizontally and close to the adiabatic upper wall. Moreover, the presence of dispersed graphite nanoplatelets (GNPs) inside the pure PCM increases the charging power and temperature of the LHTES unit.

Effect of different configurations of multi-blockages on the fire characteristics in tunnel fires with longitudinal ventilation

A tunnel vehicle fire is usually accompanied by traffic jams and less attention has been paid to the effect of multi-blockage on the fire characteristics in longitudinal ventilated tunnel fires. Thus, this study has revealed this point based on a full-scale model tunnel(100 m in length, 12 m in width, and 6 m in height) by Fire Dynamic Simulator(FDS) considering the different configurations of blockages, namely transverse and longitudinal. Results show there exist significant differences between two typical configurations of blockages and the distances between blockages have great effects on the fire characteristics in the cases with transversely arranged blockages. Moreover, the empirical models for maximum temperature rise and longitudinal temperature decay are developed and predict the numerical results well.

Energy and Solar Irradiance Analysis for Hydroponic System

A Simulated impact of partial shadow on PV modules and the different partial shading on the PV panel effect on the PV performance is being analysed. The setting for the report is a hydroponic plant system equipped with a solar energy source and IoT at Pangsapuri Jasa, Mutiara Rini. The system control can reduce the carbon footprint and cause no pollution to the environment, while the information gathering process is faster without requiring a lot of time and energy. By collecting the data at Pangsapuri Jasa, the suitable irradiation data is used. The power consumption cannot be monitored by users. A shadow is casted over a panel which make the amount of sunlight reaching the surface is reduced. In addition, the partial shading effects continue to be one of the most demanding issues that directly influence the effectiveness of PV networks in terms of power outputs, the development of several peaks on the power-voltage (P-V) characteristic curve, and the incidence of hot-phenomena. Furthermore, the effective strategies are not being implemented that could save the energy consumption where analysis of the system performance is not practiced consistently when there are available strategies that can improve the system. The purpose of this project is to focus on analyzing the effect of the partial shading to the PV output performance. Also, to monitor the real time monitoring of electricity usage for hydroponic system. This project also covers the analysis of the effect of different configuration of shaded area of partial shadings on PV output performance. The study focuses on a specific kind of shading where photovoltaic panels as a shading device. The study focusses on the analysis of PV output performance on different partial shading conditions. Different number of shadings are being presented to display the experimental set up by using MATLAB Simulink

Transmission of a position-dependent mass system through a soft Coulomb potential

This research delves into the fascinating transmission characteristics of a system with variable mass, confined by a Coulomb-like potential. By utilizing an analytic approach to transmission probability, we were able to unveil the intriguing features that are observed experimentally in a specially designed two-dimensional lattice. This lattice was engineered to manipulate itinerant electrons through entanglement, resulting in variable masses as they traverse the lattice. To build our model system, we utilized the displacement operator approach to the position-dependent effective mass theory. This allowed us to investigate the effects of different configurations of leads, system geometries and lattice deformations on the transmission characteristics of the system. The resulting data showed that the model system was highly sensitive to these parameters, which led to various interesting features. First, we observed Andreev-like reflections, which occur when a particle is reflected as a hole, resulting in the transfer of both energy and charge. Another feature was reflectionless transmission, in which the transmission probability of a particle is close to unity, and almost no reflection occurs. We also observed complete localization of charge carriers, where the transmission probability is effectively zero, indicating that the charge carriers are completely confined within the lattice. Our findings demonstrate the remarkable versatility of the effective mass approach in the modeling of physical systems. By unraveling the intricate relationships between system parameters and transmission probability, we have gained new insights into the behavior of itinerant charge carriers in lattice structures. These insights may guide the design and development of novel electronic devices with enhanced performance and functionality.

Effect of Suspension Clamp Types on the Dynamic Bending Stress of All Aluminium Alloy 1120 Overhead Conductors

Determination of the bending stress is one of the important factors for the design or fatigue assessment of transmission power lines. Researchers and designers calculate the bending stress of overhead conductors by using the Poffenberger–Swart (P-S) formula, which was established for the conductor/metal suspension clamp system. This publication presents experimental work on the effect of different configurations of suspension clamps on the dynamic bending stress that causes fatigue in the conductor. For each type of clamp configuration, specific points of the conductors were instrumented with strain gauges for the measurement of bending strain. The prediction of bending stress by the P-S formula presented errors of up to 140% for clamp different from the one established during the formulation. A better correlation with experimental data was obtained by adjusting considering an effective length of the lever arm for elastomeric clamps.

Configurations and Control Strategies of Hybrid Powertrain Systems

The configuration and control strategy of hybrid powertrain systems are significant for the development of hybrid electric vehicles (HEV) because they significantly affect their comprehensive performance. In this paper, the types, features, and applications of the mainstream hybrid powertrain configurations on the market in recent years are summarized and the effects of different configurations on the comprehensive performance of HEVs are compared. Moreover, the technical routes for each hybrid configuration are highlighted, as configuration optimization methods have become a technical difficulty. In addition, the technological advances in the steady-state energy management strategy and dynamic coordinated control strategy for hybrid powertrain systems are studied. The optimization of the steady-state energy management strategy mainly involves assigning the working point and working range of each power source reasonably. However, with the increase in the complexity of optimization algorithms, real-time control of HEVs still needs to be improved. The optimization of the dynamic coordinated control strategy mainly focuses on the stability and smoothness of the dynamic process involving switching and shifting the working mode. The optimization of the dynamic control process for the system remains to be further improved. It is pointed out that the configurations and strategies should be optimized jointly to obtain a comprehensive improvement in the system performance. This paper provides an informative basis and technical support for the design and optimization of a hybrid powertrain system.

Influence of the bevel and steeple triggers on crashworthiness of carbon fiber-reinforced composite channel section structure

To induce the progressive crushing of composite channel section structure (CCSS), the bevel and steeple trigger are proposed and designed. A nonlinear damage model considering both damage initiation and evolution of intra-ply and inter-ply is developed. The damage initiation and stiffness degradation processes of intra-ply are predicted by the maximum stress criterion and an exponential evolution law, respectively. The adhesion behavior between adjacent plies is modeled following the surface-based cohesive contact method, and the delamination failure behaviors of inter-ply are predicted using the traction-separation model. The effects of different configurations of bevel and steeple trigger on the energy absorption characteristics of CCSSs subjected to quasi-static axial loading are compared and analyzed. The results show the initial peak load of CCSS using the bevel and steeple trigger has a negative correlation function with the bevel angle. The steeple trigger can induce progressive crushing of the structure and significantly enhance the specific energy absorption (SEA).

The acoustic and daylighting effects of external façade sun shading systems

External sun shading devices are increasingly used in sustainable buildings to reduce the greenhouse effect in the summer and the glare effect due to direct solar irradiation through transparent surfaces. The acoustic effects of these devices have been investigated in recent studies that suggest the possibility of optimising these elements to improve acoustic comfort in indoor environments, even with open windows. Nevertheless, there are few studies that analyse the combined effect of these devices on acoustic attenuation and improved daylighting. In this paper, the results of acoustics and daylighting simulations are reported, considering different dimensions, distances of the louvres and orientations of the façade. The main results of previous works concerning the effect of lining the bottom side of each louvre with sound-absorbing material are also briefly summarised. The acoustic effects of different configurations of the louvres are evaluated in terms of Insertion Loss in the façade plane. For the lighting simulations (daylight factor, daylighting uniformity and daylight glare probability), the variation of the shielding effect is studied considering the spacing between the louvres and the orientation of the façade for different times and seasons for latitude in the South of Europe.

Resilience assessment of chemical industrial areas during Natech-related cascading multi-hazards

In chemical industrial areas, technological accidents triggered by natural events (Natech events) may escalate. Complex cascading multi-hazard scenarios with high uncertainties may be caused. Resilience is an essential property of a system to withstand and recover from disruptive events. The present study focuses on the change of the resilience level due to (possible) interactions between cascading hazards, chemical installations and safety barriers during the dynamic evolution of fire escalations triggered by a natural hazard (certain cascading multi-hazard scenarios). A quantitative resilience assessment method is developed to this end. The state transition of a system facing accidents in the context of resilience is explored. Moreover, the uncertainties accompanying an accident evolution are quantified using a Dynamic Bayesian Network, allowing a detailed analysis of the system performance in different time steps. System resilience is measured as a time-dependent function with respect to the change of system performance. The applicability of the proposed methodology is demonstrated by a case study, and the effects of different configurations of safety barriers on improving resilience are discussed. The results are valuable to support disaster prevention within chemical industrial areas.

Numerical investigation on melting and thermal performances of a phase change material in partitioned cavities with fins for thermal energy storage

The practical application of solid-liquid phase transition latent thermal energy storage devices is restricted by the low value of thermal conductivity in phase change materials (PCMs). To alleviate this problem, a proposal for a newly developed thermal energy storage unit with metal multiple partitions and flat fins coupled is presented in this paper. The design was constructed by dividing the typical vertical rectangular thermal energy storage unit into several partitions (1, 2, 4, and 8), including 4-fins and 8-fins in different partitions. A 2D transient solid-liquid phase change numerical model was firstly validated and then the effect of different configurations was numerically determined to obtain the thermal energy storage characteristics, velocity field, solid-liquid interface, temperature distributions, and thermal transfer performances. The results show that the optimized metal partitioned cavities lower the PCM's melting time with the maximum melting time reduction occurring at a value of 76.8 % compared to the common wooden partition. Because of increased thermal networks or enhanced local natural convection, increasing the cavity partitioning and fins shortens the melting time of the PCM. The 8-partitions cavity coupled with 8-fins generates the shortest melting time. Increasing the quantity of cavity partitioning and fins also leads to a reduction in the time needed to attain the largest amount of stored energy and an increase in the Nusselt number and power.

Numerical simulation study on the optimization of the central ejector intake tube

A CFD numerical simulation study was conducted for the primary flow non-axial inlet L/Y intake tube ejector. The effects of different configurations of the inlet piping on the secondary flow of the ejector were analyzed in terms of total pressure loss, separation zone volume, and velocity uniformity. The results showed that: the volume of the separation zone decreases with the increase of secondary flow total pressure. The L intake tube causes a larger separation zone under the same working condition. When the total pressure of secondary flow is 20kPa, the volume of the separation zone caused by the L intake tube reaches 15 times that of the Y intake tube, and the total pressure loss is 2.3 times that of the Y intake tube. A smaller separation zone has less effect on the flow field structure, resulting in better velocity uniformity in the mixing chamber inlet section of the Y intake tube ejector.

Effects of Tidal Stream Energy Exploitation on Estuarine Circulation and Its Seasonal Variability

Residual flows are of major importance in coastal areas, driving environmental processes such as sediment transport or nutrient dispersion. Consequently, in those areas where a large tidal stream energy resource is available, prior to the installation of a tidal farm, it is imperative to assess how energy extraction affects the residual flows and, in particular, upwelling events. In this paper, the potential effects of different configurations of tidal stream farms on the residual circulation and its seasonality are analysed by means of a case study: Ria de Ortigueira, the westernmost of the Galician Rias Altas (NW Spain). For this purpose, a 3D numerical model was implemented and validated against field measurements. Next, a total of eight case studies, including the operation of bottom-fixed and floating converters under typical summer and winter scenarios, considering upwelling favourable winds, were studied. Overall, when a tidal farm operates, regardless of its configuration and the forcings considered, the resulting general residual flow pattern does not experience significant modifications. This pattern is characterized by a 2D circulation in the inner ria and a positive estuarine circulation in the middle and outer ria. The largest modifications of the residual flow are apparent in the vicinities of the plant, with maximum values of about 0.05 ms−1. Outside this area, the alteration is lower than 0.01 ms−1 and virtually negligible at some distance from the farm where upwelling events develop.

Effects of bolted connections’ properties on natural dynamic characteristics of corner-supported modular steel buildings

Corner-supported modular steel building, made of volumetric units, is an efficient construction system for the next generation of industrialised building construction. The mechanical performance of joints, including inter-modular connections and beam-to-column connections, or so-called intra-modular connections, and their effects on the dynamic behaviour of these structures have remained a research hotspot in the design of modular buildings. This paper studies the effect of bolted vertical inter-module and intra-modular connections’ characteristics on the dynamic properties of a corner-supported modular steel frame using an experimental program and numerical simulations. To that end, a half-scaled vertically stacked 3-storey modular building, instrumented with highly sensitive accelerometers, is used to scrutinise the effect of different configurations of inter- and intra-modular connections on the dynamic characteristics of the structure. The acceleration responses of the system under randomly generated artificial vibrations and pure ambient vibrations are synchronously recorded. Then, dynamic characteristics of the modular building are extracted by employing the Operational Modal Analysis (OMA). Finally, finite element models are developed, and a comprehensive parametric study is conducted to verify the experimental results and evaluate the influence of connections’ behaviour on the frequencies of the structure. The results indicate that while the behaviour of inter-connection has no significant effect on the natural frequency of the building, variation of intra-connections’ properties and their configurations can lead to a change in fundamental frequency of modular buildings. Shear stiffness of connections was found to be the most effective factor influencing the frequencies of modular structures.

Synergistic effect of different configurations on the anionic redox reaction in Na-deficient oxides for sodium ion batteries

Utilizing the anionic redox reaction in P2 layered compounds is one way to improve the specific capacity of cathodes for sodium-ion batteries. In this work, we compare the difference and synergistic effects of various configurations including Na-O-Mg, Na-O-Zn and Na-O-Cu on the anionic redox reaction through systematic studies of Na0.67Mn0.7M0.3O2 and Na0.67Mn0.7M10.2M20.1O2 (M, M1, M2 = Mg, Cu, Zn). The work demonstrates that the reversibility of the anionic redox reaction and the structural stability of the oxides can be tailored by modulating different configurations. In (ex)-situ X-ray diffraction and the phase stabilities by DFT calculations indicate that with the increased bond strength from Mg-O, Zn-O to Cu–O bond in the TM layers, the structural phase transition from P2 lattice to O2 lattice in the compounds is much suppressed. In these compounds, the cathode material Na0.67Mn0.7Cu0.2Zn0.1O2 combining Na-O-Zn and Na-O-Cu configurations balances the anionic redox activity and the structural stability. Our experiments and calculations reveal that the relatively strong Zn-O and Cu–O interactions in Na0.67Mn0.7Zn0.1Cu0.2O2 account for the structural stability and improved electrochemical properties. The findings gained here may inspire the design and development of cathodes employing anionic redox chemistry for sodium-ion batteries.

Method of Calculating Inductance Gradient for Complex Electromagnetic Rail Launcher

Electromagnetic rail launch technology has made impressive progress; however, the analytical method of calculating the inductance gradient for a complex electromagnetic launcher is still insufficient. By fully considering the characteristics of electromagnetics and current distribution in a device, this paper describes a model of the current skin effect by simplifying the line current distribution in the device. Based on Biot–Savart Law, an analytical method of calculating inductance gradient for an electromagnetic rail launcher with complex structure is proposed. This method has the advantages of fast calculation speed and accurate calculation results. Because of error analysis, the calculated value relatively corresponds to the simulation result of the eddy current field. To reflect the transient electromagnetic emission process, the effects of different configurations, current frequency, and armature position on the inductance gradient are further summarized. The results show that the error rate of this method in calculating the inductance gradient is about 4%, which meets the requirement for calculation accuracy. The inductance gradient of the enhanced four-rail electromagnetic launcher is about 2.22 times that of the nonenhanced one due to the equal conditions; the inductance gradient decreases with the increase in current frequency and decreases as the armature approaches the muzzle.

100-MW-Level Experiments of a Gyromagnetic Nonlinear Transmission Line System

The wideband high-power microwave systems have the advantages of wide energy spectrum, electron beam independence, compactness, and low cost. The gyromagnetic nonlinear transmission line (GNLTL) has drawn much attention for its potential as a novel solid-state, frequency-agile, and compact wideband source. The working mechanism of GNLTL is different from that of the traditional electric vacuum tubes, and the strong dispersion and nonlinear characteristics make it difficult to be accurately theoretically calculated and simulated. In this article, a 100-MW-level GNLTL system based on a Tesla-type driver was designed and constructed. A series of test experiments were then carried out to investigate the effects of different configurations, including delay line length, ferrite cores’ assembly orientation, transmission line length, bias magnetic field magnitude, and excitation voltage. The changing laws of the key parameters of the output microwaves including the peak power, modulation depth, center frequency, and percentage band are summarized and the underlying physical mechanisms are analyzed. The results may be instructive for the predesign of GNLTLs, especially for the devices operating at high power. In addition, a multiple center frequency points’ phenomenon was discovered in the output signal, which may bring new application possibilities for GNLTL.