Effective Width Research Articles

Surface induced crystallization/amorphization of phase change materials

Surface-induced crystallization/amorphization of a Germanium-antimony-tellurium nanolayer is investigated using the phase field model. A Ginzburg-Landau (GL) equation introduces an external surface layer (ESL) within which the surface energy and elastic properties are adequately distributed. Next, the coupled GL and elasticity equations for the crystallization/ amorphization are solved. For the initial surface crystalline nucleus, unphysical crystallization along the ESL appears for the ESL widthΔξ⩾2nmwhile oval growth occurs forΔξ⩽1nm. The ESL results in a faster surface nucleus growth than the sharp surface model but does not affect the crystallization rate inside the bulk. Initial homogeneous conditions cause a simultaneous crystallization in the bulk and later in the ESL. The ESL effect on amorphization is studied to determine the ESL width more precisely. For both the initial amorphous nucleus and homogenous conditions, the amorphization temperature shows a reduction from the sharp surface model to the ESL model withΔξ=0.5nmand then remains almost constant for largerΔξ. Combining the above results gives0.5⩽Δξ⩽1nmas a proper range for the ESL width. The ratio of the effective ESL width to the interface width (Δsat/Δη) and the ratio of the difference between the surface energies of transforming phases to the surface energy of the initial phase (Δγ/γin) are considered crucial parameters in determining the ESL effect on the phase transformation and a linear relation asΔsat/Δη≅6.235Δγ/γinis found based on current and previous works, which can help estimate the effective ESL width for any surface-induced transformations.

The role of SOL plasma in the confinement of NBI fast ions in W7-X

Abstract The impact of the SOL (Scrape-Off Layer) plasma on deposition, confinement and losses of NBI fast ions was investigated in W7-X plasma. The effect of SOL width, density, temperature profiles, radial electric field, and charge-exchange reactions (CX) was explored. Ionization and slowing down partly counterbalance each other, as slowing down in cold SOL plasma compensates for ionization effects in radially decaying model profiles. However, the effect of SOL plasma on more vulnerable steel components is mitigating over wide range
of different profiles as for those components the collisionality effect overrules the effect of SOL on ionization. Also, the effect of radial electric field is mitigating for steel components for experimentally observed direction of the field. Effect of CX reactions is shown to lead to widely spread low power load distribution with no clear effect on peak load. Statistical challenges caused by hugely varying triangle sizes in discretization of wall are discussed.

Experimental study on heat transfer and friction characteristics for hybrid roughened duct used in solar heat collector

ABSTRACT This study presents a novel hybrid roughness configuration for solar heat collectors (SHCs), combining wired roughness and protrusion rib roughness to address the global demand for sustainable energy solutions. By leveraging wired roughness to induce localized turbulence near the absorber plate and protrusion ribs to disrupt the laminar sublayer without adding significant material mass, the proposed design enhances thermal performance while minimizing environmental and economic costs. The experimental investigation evaluates the effects of relative roughness width (W/w), gap width (d/e), and relative rib height (e/D) on the Nusselt number (Nu), friction factor (f), and thermohydraulic performance parameter (THPP). Results highlight the optimal configuration of W/w = 5, d/e = 4, and e/D = 0.045, achieving a maximum THPP of 3.20 at a Reynolds number of 19,000. This configuration significantly improves heat transfer efficiency while maintaining hydraulic resistance within acceptable limits, offering a sustainable and cost-effective pathway to enhanced solar thermal energy systems. These findings provide a robust framework for advancing SHC technology, aligning with global sustainability goals by promoting renewable energy utilization and reducing dependence on fossil fuels.

Optimization of Operational Parameters for Agricultural Drone Spraying in Maize Crops

This research on an agricultural drone sprayer for maize crops aimed to standardize various operational parameters—such as spraying height, discharge rate, and drone forward speed—based on metrics like effective swath width, droplet density, Volume Median Diameter (VMD), Number Median Diameter (NMD), Homogeneity Factor (HF), spray volume consumed, effective field capacity, field efficiency, and spray deposition at two crop stages (stage 1: 60 DAS and stage 2: 70 DAS). Field experiments indicated that droplet density decreased as spraying height, discharge rate, and forward speed increased. The maximum droplet densities were 12.39, 12.91, and 12.80 droplets/cm² at a spraying height of 2 m, a discharge rate of 100%, and a forward speed of 3 m/s, respectively, for crop stage 1. Average VMD and NMD ranged from 234 µm to 263 µm and 139 µm to 148 µm, respectively, across different parameter levels. An HF close to one was achieved, with values of 1.71, 1.59, and 1.70 at a spraying height of 2.5 m, a discharge rate of 80%, and a forward speed of 5 m/s, respectively, for both stages. Spray volume consumption per hectare decreased with increasing spraying height, decreasing discharge rate, and increasing forward speed. The maximum effective field capacity (EFC) was found as 2.84 ha/h with 80% field efficiency (FE) at a spraying height of 3 m, and 3.02 ha/h with a 73.08% FE for crop stage 1 and 2. Based on the study, the optimal operational parameters were standardized as a spraying height of 2.5 m, a discharge rate of 80%, and a forward speed of 5 m/s.The drone sprayer significantly reduced time, covering one hectare in only 0.32 hours compared to 11.62 hours with a battery-operated manual knapsack sprayer. This research provides valuable insights for optimizing agricultural drone spraying parameters, potentially improving the efficiency of drone sprayers in crop protection practices.

Effects of pulse rise rate and pulse width on the dynamics of secondary streamers and radical production in atmospheric-pressure air

Abstract The role of the secondary streamer in radical production has been extensively studied, while most of studies analyzed the secondary streamer by assuming a constant electric field in the secondary streamer, thereby ignoring the dynamic nature of the secondary streamer. In this study, the dynamics of the secondary streamer and the effects of pulse rise rate and pulse width are investigated using simulations. The temporal evolution of the secondary streamer under pulsed voltage is analyzed using a novel model. The results shows that the electric field in the secondary streamer first decreases linearly with the length of the secondary streamer, and then changes with the pulsed voltage after the cessation of the secondary streamer. The decrease of the electric field in the secondary streamer is the dominant factor responsible for the cessation of the secondary streamer. As a result, radicals are predominantly produced prior to the the cessation of the secondary streamer. By understanding the dynamics of the secondary streamer, it becomes possible to control the electric field and length of the secondary streamer by adjusting the pulse rise rate and pulse width, respectively, to enhance the energy efficiency of radical production. The increase in the length of the secondary streamer is always advantageous for improving energy efficiency, as it leads to greater energy deposition within the secondary streamer. For N(4S), the optimal electric field is approximately 600 Td, which cannot be achieved in the secondary streamer. In contrast, for O(3P), the optimal electric field is around 180 Td, which can be attained by regulating the voltage waveform.

A Micro Insight of Water Permeation in Polyurethane: Navigating for Water Transport

Polyurethane (PU) grouting materials are widely used in underground engineering rehabilitation, particularly in reinforcement and waterproofing engineering in deep-water environments. The long-term effect of complex underground environments can lead to nanochannel formation within PU, weakening its repair remediation effect. However, the permeation behavior and microscopic mechanisms of water molecules within PU nanochannels remain unclear. In this paper, a model combining PU nanochannels and water molecules was constructed, and the molecular dynamics simulations method was used to study the effects of water pressure and channel width on permeation behavior and microstructural changes. The results reveal a multi-stage, layered permeation process, with significant acceleration observed at water pressures above 3.08 MPa. Initially, water molecules accelerate but are then blocked by the energy barrier of PU nanochannels. After about 20 ps, water molecules overcome the potential barrier and enter the nanochannel, displaying a secondary acceleration effect, with the maximum permeation depth rises from 1.8 nm to 11.8 nm. As the channel width increases, the maximum permeation depth increases from 7.5 nm to 11.6 nm, with the rate of increase diminishing at larger widths. Moreover, higher water pressure and wider channels enhance the stratification effect. After permeation, a hydrophobic layer of approximately 0.5 nm thickness forms near the channel wall, with a density lower than that of the external water. The middle layer shows a density slightly higher than the external water, and the formation of hydrogen bonds between water molecules increases toward the channel center.

Concrete Block Paving Tested as Articulated Slabs

This paper describes the experimental evaluation of articulated slabs composed of concrete block paving laid and compacted within a steel frame. By testing the paving in isolation from the bedding sand, basecourse and other elements of a complete block pavement it proved feasible to study the load spreading and other structural characteristics of the pavers themselves. This provided insights into the structural behaviour of concrete block paving under load. Factors studied in the project included the effects of paver shape, laying pattern, joint width, spacer nibs and load repetition. Each of these factors was shown to significantly influence the structural capacity of the paving course. By analysing the paver performance as a quasi-elastic slab it was possible to quantify the behaviour of block paving in a form suitable for inclusion in mechanistic pavement design and analysis. Where appropriate these measures were compared with data obtained both from Accelerated Trafficking Tests and Falling Weight Deflection studies of full scale block pavements.

Electronic band evolution between Lieb and kagome nanoribbons

Abstract We investigate the electronic properties of nanoribbons made out of monolayer Lieb, transition, and kagome lattices using the tight-binding model with a generic Hamiltonian. It allows us to map the evolutionary stages of the interconvertibility process between Lieb and kagome nanoribbons by means of only one control parameter. Results for the energy spectra, the density of states, and spatial probability density distributions are discussed for nanoribbons with three types of edges: straight, bearded, and asymmetric. We explore for different nanoribbon terminations: (i) the semiconductormetallic transition due to the interconvertibility of the Lieb and kagome lattices, (ii) the effect of both nanoribbon width and inclusion of the next-nearest-neighbor hopping term on the degeneracy of the quasi-flat states, (iii) the behavior of the energy gap versus the nanoribbon width, (iv) the existence and evolution of edge states, and (v) the nodal spatial distributions of the total probability densities of the non-dispersive states.

Effective demagnetizing tensor incorporating finite width effect for magnetic nanowire design in racetrack devices

Effective demagnetizing tensor incorporating finite width effect for magnetic nanowire design in racetrack devices

Effect of laminate channel width on the performance of MgAl-layered double hydroxide film-based nanogenerators driven by water evaporation

Effect of laminate channel width on the performance of MgAl-layered double hydroxide film-based nanogenerators driven by water evaporation

Study on PCD tool wear in pulsed laser assisted turning Al-50wt % Si alloy

Al-50wt % Si alloy is widely used in aerospace, automotive, electronic packaging and other fields due to its excellent material properties. However, the presence of reinforced particle phase differing in hardness from the alloy matrix phase leads to significant tool wear during turning with PCD tools. Therefore, this paper proposes a pulsed laser assisted turning (PLAT) method combining pulsed laser with conventional turning, which has unique advantages in reducing PCD tool wear. The effects of laser power, pulse width and frequency on tool wear during PLAT were studied by comparative experiments. And the potential mechanism of PLAT to reduce tool wear was revealed by finite element simulation. The results shown that PLAT effectively reduces PCD tool wear compared with conventional turning (CT). The increase of laser pulse width will aggravate tool wear. While, the increase of laser pulse frequency will reduce tool wear. Temperature is the main factor affecting the wear form. The tool mainly experiences abrasive wear at low temperature. However, the predominant type of tool wear shifts to adhesion as the increasing temperature. At the same time, EDS analysis shows that the rise in temperature results in an elevation of the O element content within the wear region, which proves that temperature is also the decisive factor affecting oxidative wear. This study provides valuable insights into actual machining involving Al-50wt % Si alloys and gives strategies for reducing PCD tool wear using PLAT.

Numerical study on the back slope effect of trapezoidal canyon slope under oblique incidence of P-SV waves

The incident angle of seismic waves influences the dynamic response of rock slopes. However, the relationship between the back-slope effect in strong earthquake areas and the incident angle has not been well-explained. Based on the equivalent nodal force method and the viscoelastic artificial boundary theory, the oblique incidence of seismic P-wave and SV-wave are carried out in FLAC3D software. The accuracy of the proposed method is verified by comparing it with the results of the theoretical solution and another numerical result. The dynamic response of trapezoidal canyon slope under oblique incidence of P-waves and SV-waves was studied, and the effects of different slope angles and canyon widths were analyzed. The study reveals a pronounced back-slope effect under the action of the P-wave and SV-wave, and the slope’s horizontal direction dynamic response plays an important role. At the same location on the slope surface, the relative horizontal acceleration of the slope increases with the incident angle of P-waves and SV-waves, and the maximum value on the back-slope side is approximately 19 times and 6.8 times that of the front-slope side, respectively. Slope angle significantly affects the back-slope side’s dynamic response, showing an increase with increasing slope angle, while canyon width has a limited impact.

Geometrical Analysis of Parabolic Trough Solar Collector

The geometric of the parabolic trough collector (PTC) is a field that should be paid special attention, knowing that a better geometry induces a better efficiency and lower costs. Nowadays, many types of geometry exist, such as LS-2, LS-3, Euro trough, ENEA, SGX-2, Sener trough, Helio trough, Sky trough, Ultimate trough. This paper deals with a geometrical analysis of PTC. The analysis is based on the coefficient of deviation angle to highlight the effect of PTC (LS-2) parameters on the optical efficiency. The effects of focal length, tube diameter, and collector width on the coefficient of deviation angle have been considered using a two-dimensional problem, and the simulation has been done employing MATLAB software. The derived results confirm that the tube diameter is the parameter most influencing compared to the other parameters. In addition, the width and length of the Euro trough, Helio trough, and Ultimate trough were considered to simulate thermal efficiency. The best observed performance is that of the Ultimate trough, which presents a 2% higher difference in efficiency and also represents a better size, which allows reducing the number of units to be assembled in the solar field. That leads to reducing the count of motors, sensors, connection joints, foundations, controllers, pylons.

ASSESSING THE PROGNOSTIC VALUE OF THE HEMOGLOBIN-TO-RED CELL DISTRIBUTION WIDTH RATIO IN EMERGENCY DEPARTMENT PATIENTS WITH ACUTE CORONARY SYNDROME

Objective: Acute coronary syndrome (ACS) is a critical condition requiring rapid evaluation in the emergency department. The hemoglobin-to-red cell distribution width ratio (HRR) has emerged as a potential prognostic biomarker, reflecting the combined effects of hemoglobin and red cell distribution width. This study aims to evaluate the prognostic value of HRR in patients presenting to the emergency department with ACS. Material and Methods: A retrospective cohort study was conducted at a single center, involving adult patients who were diagnosed with acute coronary syndrome upon presentation to the emergency department. HRR was calculated as the ratio of hemoglobin to red cell distribution width, and its association with 30-day cardiac mortality (CM), all-cause mortality (ACM), and major adverse cardiovascular events (MACE) was analyzed using Receiver Operating Characteristics (ROC) curve analysis. Results: The study included 688 patients, with a mean age of 61.9±12.3 years and 57% males. Lower HRR was significantly associated with higher 30-day CM, ACM, and MACE rates. ROC curve analysis showed HRR had acceptable discriminatory power with AUC values of 0.764 for 30-day CM, 0.718 for 30-day ACM, and 0.739 for 30-day MACE. An HRR cut-off value of 0.9 was determined, with sensitivities of 87.8%, 90.2%,and 88.7%, and specificities of 47.6%, 48.4%, and 48.9% for CM, ACM, and MACE, respectively. Conclusion: HRR is a useful prognostic marker for 30-day outcomes in ACS patients. Its easy accessibility and rapid availability makes it a practical tool for risk stratification in the emergency department.

Analysis of imperfect interfaces in cobalt ferrite plates using a linear spring model: a comparative study with terfenol-D

PurposeThis research aims to explore the transmission of seismic surface waves through a two magneto-strictive materials i.e. cobalt ferrite and Terfenol-D when embedded in a plate-substrate configuration with non-ideal interface. The study focuses on understanding the impact of width of the plates, imperfect parameter, heterogeneity parameter on both the materials cobalt ferrite and Terfenol-D under magnetically open and short conditions.MethodologyTo achieve this, the study employs a variable-separable technique following Direct Sturm-Liouville method and appropriate boundary conditions to derive frequency relations for both magnetically open and short circuit scenarios. Numerical simulations are conducted to investigate the effects of width of the plates, imperfect parameter, heterogeneity parameter on both the materials cobalt ferrite and Terfenol-D under magnetically open and short conditions.FindingsThe research findings indicate that the phase velocity is increasing more in Terfenol-D as compared to Cobalt ferrite, either the case magnetically open or closed. Graphical comparisons highlight the impact of width plates, imperfect parameter, heterogeneity parameter on the characteristics on wave propagation clearly.Research limitationsThe study is confined to linear wave propagation and does not consider nonlinear effects. Additionally, the analysis is based on idealized material properties and interface conditions.Practical implicationsThe results of this research can contribute to the design and optimization of sensors, energy harvesters, and wave manipulation devices utilizing piezomagnetic materials. Understanding the behaviour of surface waves in these structures is crucial for their effective application.OriginalityThis study offers a comprehensive analysis of surface wave propagation in two different types of piezomagnetic composite structure by considering heterogeneity and interface conditions. The comparative study of different piezomagnetic models and the incorporation of heterogeneity and interface conditions contribute to the originality of the research.

Simulation of the temperature distribution of kidney stones induced by thulium fiber laser and Ho: YAG laser lithotripsy.

Simulation studies on temperature distribution in laser ablation help predict ablation rates, laser settings, and thermal damage. Despite the limited number of reported numerical studies on the temperature distribution of kidney fluid, there is no simulation study for kidney stone temperature distribution. We employ a numerical approach to study the kidney stone temperature distribution and predict ablation rates, which is an important parameter for clinical lithotripsy. The study looked at how the thulium fiber laser and the Ho:YAG laser differ in terms of temperature profile and ablation depth of kidney stones like calcium oxide monohydrate. The ablation depth increased from 152.7µm to 489.7µm when the TFL laser (operated at 10Hz repetition rate and 1ms pulse width) fluence increased from 764J/cm2 to 1146J/cm2. Correspondingly, the depth increased from 21µm to 68µm for the Ho: YAG laser operated at 3Hz and 0.22ms pulse width. We attribute this to an increase in temperature with laser energy. We further investigated the effect of pulse width on ablation depth by considering three different TFL pulse widths: 0.5ms, 0.75ms, and 1ms. There was a decrease in ablation depths from 402.5µm to 242.6µm when the pulse width increased from 0.5ms to 1ms. Because of lower water absorption coefficients, the Ho:YAG laser (70mJ/10Hz) produced a smaller ablation depth and temperature profile than the thulium fiber laser (70mJ/10Hz). Experimental results from the literature validated the simulation. We found that the Ho:YAG laser worked better for ablation when it was set to 0.2J/100Hz for the Ho:YAG laser and 0.4J/50Hz for the TFL laser, which were clinical laser settings that we found in the literature. This indicates that, in addition to laser absorption by water, the laser parameters also significantly influence temperature distribution and ablation.

Flexural behavior of RC beam strengthened by FRP grid-reinforced ECC overlay and U-wrap anchor: 2-D FE modeling and parametric analysis

ABSTRACT Fiber-reinforced polymer (FRP) grid-reinforced engineered cementitous composites (ECC) exhibit great potential as the overlay for strengthening aging reinforced concrete (RC) beams, particularly in conjunction with U-wrap FRP anchors to mitigate the interfacial debonding. In this paper, finite element (FE) modeling considered the combination use of these two strengthening methods has been conducted. The interfacial behaviors between the RC beam and the strengthening overlay or the U-wrap are carefully simulated using the cohesive contact interface or spring connecters. The FE model was validated through comparison with the measured data in experiments conducted by the authors. Then, a parametric analysis based on 162 models was conducted to investigate the effect of overlay thickness, FRP-grid strength, U-wrap thickness, and width on the ultimate load-carrying capacity of the specimens and interfacial slip at the two bonding interfaces. Based on the parametric study outcomes, the pivotal factor influencing the failure mode and load-carrying capacity was identified as the total axial strength of the FRP grid reinforcement, in which an increase of 25 times in this factor would result in an average increase of 55% in load carrying capacity. Moreover, it exhibited a substantial influence on the interfacial slip distributions between the RC beam and overlay or U-wrap.

Modelling the effect of depth, width, and velocity of tillage tine on soil stress and draught using the finite element method

Modelling the effect of depth, width, and velocity of tillage tine on soil stress and draught using the finite element method

Optimization Design and Atomization Performance of a Multi-Disc Centrifugal Nozzle for Unmanned Aerial Vehicle Sprayer

The nozzle is a crucial component in unmanned aerial vehicle (UAV) sprayers. The centrifugal nozzle offers unique advantages; however, there is a scarcity of published research regarding the structural parameters, spraying parameters, and practical applications specifically for UAV spraying. Furthermore, there is a need for UAV-specific nozzles that demonstrate high efficiency and excellent atomization performance. In this present study, a multi-disc centrifugal nozzle (MCN) capable of controlling droplet size was designed and optimized. The droplet size spectra with different atomizing discs were tested, and indoor and field tests were conducted to investigate the atomization and spray deposition characteristics of the MCN. It was found that the MCN with six atomizing discs with a curved groove, a disc angle of 120°, and a disc diameter of 77 mm demonstrated better atomizing performance. The volume median diameter was 96–153 μm, and the relative span was 1.0–1.3. Compared with the conventional hydraulic nozzle, this nozzle increased the effective spray swath width from 2.5–3.0 m to 4.0–5.0 m and promoted the average deposition rate by 132.4% at a flying height of 1.0 m and a flying speed of 3.0 m/s, which tends to raise the operation efficiency by four to five times. This study can provide a reference for the design and optimization of centrifugal nozzles for a UAV sprayer and the selection of operating parameters in aerial spraying operations.

Numerical Investigation of the Shear Lag Effect on a Cable-Stayed Bridge with an Extra-Wide Composite PK Girder

The composite PK (Pasco-Kennewick) girder cable-stayed bridge (CSB) is a trendy structure with a super-wide girder, excellent lateral rigidity, and high wind resistance. However, the shear lag effect (SLE) of the composite PK girder grows severe due to the super-wide deck. Meanwhile, the SLE of the composite PK girder CSB subjected to huge axial forces significantly differs from that of bridges subjected to only bending moment. Therefore, global and local analyses are conducted on a composite PK girder CSB to determine the SLE during construction and after completion. Furthermore, the effective slab width (Beff) of the composite PK girder under combined bending moment and axial force is analyzed. The results can offer guidance and reference for the design and construction of composite PK girder cable-stayed bridges.