Length Of Sheet Research Articles

An Experimental Study and Result Analysis on the Dynamic Effective Bond Length of a Carbon Fiber-Reinforced Polymer Sheet Attached to a Concrete Surface

A carbon fiber-reinforced polymer (CFRP) is a common material utilized for the enhancement in reinforced concrete (RC) constructions. Previous research indicates that the bonding performance between a CFRP sheet and concrete determines whether the bonding of CFRP material is effective. However, the majority of existing research on the bonding performance of the CFRP–concrete interface is concentrated on static loading conditions. In order to clarify the effect of dynamic load on the bonding performance of the CFRP sheet–concrete interface, this study adopts the double-sided shear test method to carry out dynamic experimental research. The test findings reveal that the damage pattern of the CFRP sheet–concrete interface remains consistent across different loading rates. The ultimate bearing capacity increases as the strain rate increases. As the strain rate increases from 10−5 s−1 to 10−2 s−1, the effect of bond length on ultimate bearing capacity increases by about 7%. As the strain rate increases, both the maximum strain of CFRP and the maximum interfacial shear stress demonstrate a corresponding increase, with respective increase rates of 60% and 20%. The effective bond length decreases by about 20% when the strain rate rises from 10−5 s−1 to 10−2 s−1. Finally, a formula for calculating the dynamic effective bond length of a CFRP sheet, grounded in the Chen and Teng formula, has been proposed and verified.

Heating in the solar atmosphere at a fin current sheet driven by magnetic flux cancellation

ABSTRACT Magnetic reconnection before flux cancellation in the solar photosphere when two opposite-polarity photospheric magnetic fragments are approaching one another is usually modelled by assuming that a small so-called ‘floating current sheet’ forms about a null point or separator that is situated in the overlying atmosphere. Here, instead we consider the reconnection that is initiated as soon as the fragments become close enough that their magnetic fields interact. The resulting current sheet, which we term a ‘fin sheet’ extends up from the null point or separator that is initially located in the solar surface. We develop here non-linear analyses for finite-length models of both fin and floating current sheets that extend the previous models that were limited to short floating current sheets. These enable the length of the current sheet and the rate of heating to be calculated in both cases as functions of the separation distance of the sources and the reconnection rate. Usually, the fin current sheet liberates more energy than a floating current sheet.

Liquid crystal-based temperature-controlled recirculating flat jet system.

In this paper, the design and implementation of a temperature-controlled recirculating flat jet system for liquid crystals (LCs)-based experiments are presented. In these experiments, the target liquid is usually exposed to medium to high laser fluences, possibly resonant with specific excitation, thus resulting in a change of local temperature and sudden degradation. To overcome this problem, each laser pulse must interact with a new volume of liquid, preferably with flat surfaces, while avoiding the use of substrates. A well-established solution consists of impinging two identical laminar jets that force the liquid into a radial expansion perpendicular to the plane formed by the jets, resulting in a consecutive chain of flat sheets bound by thick rims. In this context, LCs pose several challenges considering their viscosity, non-Newtonian behavior, and mesophase nature. Here, a precise control of temperature, thus mesophase, and pressure is demonstrated enabling the use of LCs in an impinging jet system. In particular, the system presented here delivers stable fluid chains of different sizes and thicknesses. The viscosity and non-Newtonian behavior of the LCs have a significant impact on the thickness of the chains as a function of the nozzle inner diameter, impinging angle, and radial distance from the impinging point. The flow rate, on the other hand, primarily affects the width and length of the liquid sheet.

Direct Imaging of a Prolonged Plasma/Current Sheet and Quasiperiodic Magnetic Reconnection on the Sun

Magnetic reconnection is widely believed to be the fundamental process in the solar atmosphere that underlies magnetic energy release and particle acceleration. This process is responsible for the onset of solar flares, coronal mass ejections, and other explosive events (e.g., jets). Here, we report direct imaging of a prolonged plasma/current sheet along with quasiperiodic magnetic reconnection in the solar corona using ultra-high-resolution observations from the 1.6 m Goode Solar Telescope at the Big Bear Solar Observatory and the Solar Dynamics Observatory/Atmospheric Imaging Assembly. The current sheet appeared near a null point in the fan–spine topology and persisted over an extended period (≈20 hr). The length and apparent width of the current sheet were about 6″ and 2″, respectively, and the plasma temperature was ≈10–20 MK. We observed quasiperiodic plasma inflows and outflows (bidirectional jets with plasmoids) at the reconnection site/current sheet. Furthermore, quasiperiodic reconnection at the long-lasting current sheet produced recurrent eruptions (small flares and jets) and contributed significantly to the recurrent impulsive heating of the active region. Direct imaging of a plasma/current sheet and recurrent null-point reconnection for such an extended period has not been reported previously. These unprecedented observations provide compelling evidence that supports the universal model for solar eruptions (i.e., the breakout model) and have implications for impulsive heating of active regions by recurrent reconnection near null points. The prolonged and sustained reconnection for about 20 hr at the breakout current sheet provides new insights into the dynamics and energy release processes in the solar corona.

Thermal conductivity of boronated-holey graphene under mechanical strain: Insights from molecular dynamics

Non-equilibrium molecular dynamics is used to elucidate the thermal properties of 2D boronated-holey graphene (C2B) nanostructures under different mechanical strain levels. First, the thermal conductivity of strain-free monolayers was explored over a wide range of sheet width and length and system temperature. At room temperature, the thermal conductivity of C2B was calculated to be ∼40 W/(m.K) which was lower than its C2N counterpart with k = ∼60 W/(m.K).Next, the thermal conductivity of C2B (and C2N) monolayer was examined under both uniaxial and biaxial tensile strains. Interestingly, the thermal conductivity shows a maximum in both types of strains. Further examinations revealed that the rippling in C2B (C2N) decreases under applying strain up to 2 % (12 %) and 2–6% (4 %) for uniaxial and biaxial strains, respectively, which is responsible for the primarily enhanced thermal conductivities. Finally, a machine-learning model was applied to estimate the thermal conductivity of C2B at desired length and strain level.

Assessing the potential spray drift of a six-rotor unmanned aerial vehicle sprayer using a test bench and airborne drift collectors under low wind velocities: impact of atomization characteristics and application parameters.

The unmanned aerial spraying systems (UASS) have gained widespread use for plant protection in recent years. However, spray drift from UASS is a major concern when controlling weeds over large areas and warrants a thorough investigation. This study examined the atomization characteristics of the herbicide florpyrauxifen-benzyl under downwash airflow using a UASS spray test platform. Potential spray drift was assessed using a test bench (TB) and airborne drift collectors (ADCs) in the field under low wind speeds (<1 m s-1). Atomization characteristics were significantly affected by the spray liquid, adjuvant, nozzle type and spray pressure. The addition of an adjuvant reduced the liquid sheet length, improved physicochemical properties and increased droplet size under the downwash airflow field. Drift evaluation in the field using the TB revealed that sediment spray drift predominantly occurred from the middle to the entire length of the device when fine-to-medium droplets were produced after the sprayer passed. ADC assessment found that higher flight altitudes and finer droplets resulted in higher drift values, whereas the addition of an adjuvant and the use of an air-induction nozzle reduced drift <3 m aboveground. The combination of using TB in the target area and ADCs in the off-target area as an alternative method to determine residual droplets in the current airflow provided valuable insights into airborne drift assessment for UASS. © 2024 Society of Chemical Industry.

A Numerical Modelling of V-Bending

In the study, a sheet metal is bent to analyze the punch force, Von Misses stresses and plastic strains on the metal for friction and non-friction cases. The 2-D v-bending forming is modelled in program. Model includes a die, a punch and a blank. Solid mechanics physics interface has been used in program. The analyze has been run with friction and non-friction cases for different strain-hardening exponents and sheet metal thicknesses. The sheet lengths and widths are 60 mm. Thickness of sheet metal is varied between 1.0 to 3.0 mm. The strain hardening exponent has been altered from 0.1 to 0.5. It is computed that the punch force has been increased as thickness of sheet metal and strain hardening exponent decreases. The achieved maximum punch force is at values of 1.12x105 N, 3.75x105 N and 4.05x105 N for thickness of 1.0-mm, 2.0-mm and 3.0-mm respectively when strain hardening exponent is 0.3. Also, as the strain hardening exponent increases from 0.1 to 0.5, the maximum punch force lowers from 2.03x105 N to 8.08x104 N for 1 mm thickness at friction case. Moreover, the maximum punch force reached up to 9.13x104 N for 1 mm thick sheet metal at non-friction case when the strain hardening exponent is 0.1. It is concluded that the maximum Von Misses stress has been calculated at the tip of sheet metal.

Bending of Sheet Metal (st37) Using 90 Degree to Estimate Blank Dimensions

Several factors must be considered whendesigning parts that are being made by bending. Theprimary factor is minimum radius and angle of bending thatcan be bent successfully without metal cracking. Lowcarbon steel metal (st37), manufactured by Libyan Iron andsteel Company, was used in this study. Various bendingprocesses by Vee die for different radii and calculatethickness were conducted and bending zones were tested tofind the mean radius and calculate the bending allowance.These calculations depend upon the inner bend radius andthickness of the sheet metal. The thickness was reduced andthe neutral axis were moved up in the direction ofcompression side. Form the values of reduction in thicknessand different radii of bending a chart was drawn. Anotherchart was drawn to minimums the process of trial and errorfor estimating the blank length of the bending sheet metal.Form these charts, the initial blank sizes can be determined,so that products can bend without loss and crack in thematerial. As a result time and material can be saved. Theresults of the present study can have practical applicationsfor this material (st37) which is in common use by theLibyan industry.

Diverse behaviors of marine ice sheets in response to temporal variability of the atmospheric and basal conditions

Abstract The observed retreat of the grounding line of the present-day ice sheets and the simulated grounding-line retreat of ice sheets under changing climate conditions are often interpreted as indications of marine ice-sheet instability (MISI), driven by a positive feedback between the ice discharge and conditions at the grounding line. However, the arguments that support this feedback are valid only for steady-state conditions. Here, we assess how unconfined marine ice sheets may behave if atmospheric conditions and basal conditions evolve with time. We find that the behavior of grounding lines can exhibit a range from unstoppable advance and retreat to irregular oscillation irrespective of the stability of the corresponding steady-state configurations obtained with time-invariant conditions. Our results show that numerical simulations with a parameterization of the ice flux through the grounding line used in large-scale ice-sheet models produce markedly different results from simulations without the parameterization. Our analysis demonstrates that the grounding-line migration can be driven by the temporal variability in the atmospheric and basal conditions and not by MISI, which assumes unchanging conditions. Instead, the grounding-line advance or retreat is determined by interactions between ice flow, basal processes and environmental conditions throughout the length of a marine ice sheet in addition to the circumstances at its grounding line.

Investigation of the Effect of CFRP and GFRP Sheet Length on the Final Capacity of Reinforced Concrete Beams of Buildings in Coastal Areas

In the last two decades, the use of FRP (Fiber Reinforced Polymer) composites for flexural, shear, torsion, and enclosing reinforcement of various structural components has grown exponentially. In this paper, the effect of using FRP composite with carbon fibers and glass with different lengths on the behavior of reinforced concrete beams is investigated. Eight reinforced concrete beams with a length of 150 cm, a width of 15 cm, and a height of 20 centimeters were modeled by composite fibers with lengths of 80 cm, 100 cm, 120 cm and 140 centimeters. Then, the sample reinforced concrete beam was modeled in ABAQUS® , which the results were compared with the laboratory samples. It were observed that with increasing the length of FRP sheets, the strength of reinforced concrete beams compared to the sample concrete beam, increased by about 61%, 82%, 86%, and 87%, respectively. It was due to the high cost of FRP sheets and compressive strength required in these sheets that used optimally. Therefore, the length of FRP strengthening sheets can be optimized to reduce the cost of FRP sheets and use them efficiently.

Analytical study on flexural strengthening of narrow RC beams with hybrid anchored CFRP sheets

Premature debonding of fiber-reinforced polymer (FRP) sheets commonly occurs in purely bonded reinforced concrete (RC) beams. A hybrid strengthening method for narrow FRP-strengthened RC beams has been proposed to solve this problem. Experimental results have verified the effectiveness of the novel strengthening system in preventing the end debonding and impeding the intermediate debonding of the FRP sheet. However, the mechanism of its strengthening efficiency has not been studied deeply enough. Therefore, this paper developed a non-linear three-dimensional finite element (FE) model to study the flexural behavior of the FRP-strengthened narrow RC beams hybrid anchored with end self-locking system. The FE model was verified against the available experimental studies and showed good agreement, with a R2 of 0.97. Based on the verified model, parametric studies were performed to study further the influences of four major factors: FRP sheet length, steel rebar ratio, concrete compressive strength, and number of FRP sheet layers. The efficacy of hybrid strengthened beams was reduced with longer FRP bond lengths and higher steel rebar ratios. Conversely, increasing concrete compressive strength and FRP sheet layers to a certain degree enhanced the efficacy. Finally, an analytical model to predict the load-deflection curve of the beam was proposed.

Two-Dimensional Wave Interaction with a Rigid Body Floating near the Marginal Ice Zone

The interaction problem of waves with a body floating near the marginal ice zone is studied, where the marginal ice zone is modeled as an array of multiple uniformly sized floating ice sheets. The linear velocity potential theory is applied for fluid flow, and the thin elastic plate mode is utilized to describe the ice sheet deflection. A hybrid method is used to solve the disturbed velocity potential; i.e., around the floating body, a boundary integral equation is established, while in the domain covered by ice sheets, the velocity potential is expanded into an eigenfunction series, and in the far-field with a free surface, a similar eigenfunction expansion is used to satisfy the radiation condition. The boundary integral equation and the coefficients of the eigenfunction expansions are solved together based on the continuous conditions of pressure and velocity on the interface between the sub-domains. Extensive results for the equivalent Young’s modulus of the ice sheet array and hydrodynamic force on the body are provided, and the effect of individual ice sheet length as well as wave parameters are investigated in detail.

Research on breakup length and atomization characteristics of the swirl liquid sheet in perforation disintegration mode

Pressure swirl nozzles usually operate in aerospace or aviation engines by discharging a swirl liquid sheet. Understanding the disintegration characteristics of the swirl liquid sheet is beneficial to control the combustion instability. In this study, a swirl liquid sheet was injected into the atmosphere. The whole breakup process was numerically simulated by Gerris, an open-source code that anticipates gas–liquid interface using the volume of fluid approach. With the increase in Reynolds number, there were three distinct disintegration modes including rim mode, perforation mode, and wave mode. Then, a perforation disintegration model (PDM) was proposed to predict the droplet size of the perforation disintegration mode. The droplet sizes predicted by PDM are consistent with the numerical results with an average error of 11.09%. A breakup length model (BLM) was also proposed for the swirl liquid sheet using energy conservation. The breakup length results of BLM are in good agreement with the numerical simulation results with an average error of 10.97%. Moreover, with the increase in the liquid surface tension coefficient, the droplet size of the swirl liquid sheet atomization gradually increases. With the increase in liquid density, the droplet size gradually decreases, but the trend of decrease is not obvious.

A Molecular Dynamics Simulation Study of In- and Cross-Plane Thermal Conductivity of Bilayer Graphene.

Efficient thermal management of modern electronics requires the use of thin films with highly anisotropic thermal conductivity. Such films enable the effective dissipation of excess heat along one direction while simultaneously providing thermal insulation along the perpendicular direction. This study employs non-equilibrium molecular dynamics to investigate the thermal conductivity of bilayer graphene (BLG) sheets, examining both in-plane and cross-plane thermal conductivities. The in-plane thermal conductivity of 10 nm × 10 nm BLG with zigzag and armchair edges at room temperature is found to be around 204 W/m·K and 124 W/m·K, respectively. The in-plane thermal conductivity of BLG increases with sheet length. BLG with zigzag edges consistently exhibits 30-40% higher thermal conductivity than BLG with armchair edges. In addition, increasing temperature from 300 K to 600 K decreases the in-plane thermal conductivity of a 10 nm × 10 nm zigzag BLG by about 34%. Similarly, the application of a 12.5% tensile strain induces a 51% reduction in its thermal conductivity compared to the strain-free values. Armchair configurations exhibit similar responses to variations in temperature and strain, but with less sensitivity. Furthermore, the cross-plane thermal conductivity of BLG at 300 K is estimated to be 0.05 W/m·K, significantly lower than the in-plane results. The cross-plane thermal conductance of BLG decreases with increasing temperatures, specifically, at 600 K, its value is almost 16% of that observed at 300 K.

Driving Signal and Geometry Analysis of a Magnetoelastic Bending Mode Pressductor Type Sensor.

The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors' RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet's length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors.

Geometric control of tilt transition dynamics in single-clamped thermalized elastic sheets.

We study the finite-temperature dynamics of thin elastic sheets in a single-clamped cantilever configuration. This system is known to exhibit a tilt transition at which the preferred mean plane of the sheet shifts from horizontal to a plane above or below the horizontal. The resultant thermally roughened two-state (up/down) system possesses rich dynamics on multiple timescales. In the tilted regime a finite-energy barrier separates the spontaneously chosen up state from the inversion-symmetric down state. Molecular dynamics simulations confirm that, over sufficiently long time, such thermalized elastic sheets transition between the two states, residing in each for a finite dwell time. One might expect that temperature is the primary driver for tilt inversion. We find, instead, that the primary control parameter, at fixed tilt order parameter, is the dimensionless and purely geometrical aspect ratio of the clamped width to the total length of the otherwise-free sheet. Using a combination of an effective mean-field theory and Kramers' theory, we derive the transition rate and examine its asymptotic behavior. At length scales beyond a material-dependent thermal length scale, renormalization of the elastic constants qualitatively modifies the temperature response. In particular, the transition is suppressed by thermal fluctuations, enhancing the robustness of the tilted state. We check and supplement these findings with further molecular dynamics simulations for a range of aspect ratios and temperatures.

Effects of workpiece size on bending angle in laser forming of al 6061-T6 sheet

In the laser forming process, the effect of workpiece size, including variations in width and length, plays a crucial role in determining product quality. To better understand the deformation behavior and obtain the desired bending angle with varying workpiece sizes, the size effect on laser forming of Al 6061-T6 aluminium alloy has been investigated. Due to the fact that Al 6061-T6 alloy sheets have more deformability and high strength properties, they have been studied in this paper. A three-dimensional numerical model that considers temperature-dependent properties of the material, and convection-radiation heat losses is constructed to investigate the sheet deformation. The numerical model is verified by performing experimental tests under the considered operating conditions. The suggested model is found to be in reasonable agreement with the experimental findings, and it is shown to have a maximum error less than 8 % when predicting the bend angle. Computed results through the numerical model show that the bending response is increased with the increase in workpiece width; however, it is marginally affected with workpiece length. Based on simulation results, the edge effect is also explored in relation to workpiece size. Edge effect increases as sheet width increases; whilst it decreases as sheet length increases. This investigation will be helpful in laser-based forming industries for obtaining desired bending of Al 6061-T6 sheets.

Repairing of reinforced concrete continuous beams by CFRP sheets

Although continuous beams may be found in a range of projects such as garages, bridges, and multi-story structures, studies have been still restricted to a limited field. Flexural cracks are a common issue in continuous beams; therefore, this article outlines an investigation study used to assess the performance of two-span reinforced concrete beams repaired by attaching (CFRP) sheets. The program included seven beam specimens with a length of 2800mm and rectangular cross sections of 150*250mm. All beams were strengthened externally on the tension zones via CFRP-sheet considering changing the ratio of sheet length to beam span which is 0.5, 0.7, and 0.9 except one was chosen as a reference beam. Repaired beams were preloaded with damage ratios of 45% and 65% with respect to the reference beam. The findings showed that using style 0.7L for both positive and negative regions achieve an appropriate restored percentage of ultimate capacity of about 101.7% and 98.2%. In addition, eliminating the sheet length in the positive moment regions gives higher stiffness. it is also found that when the CFRP sheet length in the tension part is increased, the tensile rupture of the sheet was the dominant failure mode.

A comparative study of resistivity models for simulations of magnetic reconnection in the solar atmosphere

Context. Magnetic reconnection is a fundamental mechanism in astrophysics. A common challenge in mimicking this process numerically in particular for the Sun is that the solar electrical resistivity is small compared to the diffusive effects caused by the discrete nature of codes. Aims. We aim to study different anomalous resistivity models and their respective effects on simulations related to magnetic reconnection in the Sun. Methods. We used the Bifrost code to perform a 2D numerical reconnection experiment in the corona that is driven by converging opposite polarities at the solar surface. This experiment was run with three different commonly used resistivity models: 1) the hyper-diffusion model originally implemented in Bifrost, 2) a resistivity proportional to the current density, and 3) a resistivity proportional to the square of the electron drift velocity. The study was complemented with a 1D experiment of a Harris current sheet with the same resistivity models. Results. The 2D experiment shows that the three resistivity models are capable of producing results in satisfactory agreement with each other in terms of the current sheet length, inflow velocity, and Poynting influx. Even though Petschek-like reconnection occurred with the current density-proportional resistivity while the other two cases mainly followed plasmoid-mediated reconnection, the large-scale evolution of thermodynamical quantities such as temperature and density are quite similar between the three cases. For the 1D experiment, some recalibration of the diffusion parameters is needed to obtain comparable results. Specifically the hyper-diffusion and the drift velocity-dependent resistivity model needed only minor adjustments, while the current density-proportional model needed a rescaling of several orders of magnitude. Conclusions. The Bifrost hyper-diffusion model is as suitable for simulations of magnetic reconnection as other common resistivity models and has the advantage of being applicable to any region in the solar atmosphere without the need for significant recalibration.

Utilization of surfactant assisted zinc oxide nanodisk against breast cancer cells

The current work displayed the efficacy of the nanodisk shaped zinc oxide nanostructures (NDs-ZnONSs) processed via hydrothermal solution process and studies the cytotoxicity against human breast cancer cells (MCF-7). The NDs-ZnONSs were analyzed by using instruments such as X-ray diffraction pattern (XRD), Field emission scanning electron microscopy (FESEM), and Fourier transform infra-red spectroscopy (FTIR). The XRD and FESEM shows the crystallinity and morphology of NDs-ZnONSs states the estimated width size of each sheet diameter and length are ∼20-25 nm and 2-3 µm respectively. The cytotoxicity of MCF-7 cells with NDs-ZnONSs at different concentrations (1, 2, 5, 10, 25, 50 and 100 µg/mL) were examined via MTT and NRU assays. The results showed that at initial (1, 2 and 5 µg/ml) concentrations of NDs-ZnONSs didn’t show any cytotoxicity in cancer cells but higher concentrations (25, 50 and 100 µg/mL) of NDs-ZnONSs displayed a remarkable inhibition in cancer cells growth and morphology. Further, the reactive oxygen species (ROS) generation was also examined with NDs-ZnONSs at different concentrations and result showed that it increased with increasing the concentration of NDs-ZnONSs in MCF-7 cells. The expression of apoptotic genes (p53, bax, casp-3) including control via qRT-PCR, reveals that mRNA level of apoptotic genes with NDs-ZnONSs were upregulated.