Linear Stage Research Articles

THE EFFECT OF EDUCAPLAY-BASED INTERACTIVE QUIZ ON STUDENTS' LEARNING INTEREST AND LEARNING OUTCOMES IN ELEMENTARY SCHOOLS

Abstract Learning interest is one of the components that determines the success or failure of learning. In the digital era, students are easily distracted by social networks, online games, or other cyberspace. The inability to process technology carefully will affect students' interest in learning. Teachers must be able to innovate to overcome students' low interest in learning, for example, by presenting interactive digital-based teaching media. This research aims to analyze the influence of Educaplay interactive quizzes on students' interest and Mathematics learning outcomes in class IV of SD Muhammadiyah 1 Menganti Gresik. This research is quantitative research with a quasi-experimental type. The sample consisted of 28 students in class IV-A. Questionnaires and tests are used in the data collection stage. Data analysis was carried out through the linear regression test stage with simultaneous F Test and Partial T Test assisted by the IBM SPSS Statistics Version 25.0 application. The research findings indicated that the data analysis obtained was significant for the variable of interest of 0.005 and a significance value for the learning outcome variable of 0.007. This result shows that the interactive quiz media of Educaplay affects students' learning interest and Mathematics learning outcomes in class IV of the Creative School of Muhammadiyah 1 Elementary School, Menganti, Gresik.

The Psychological Interpretation of the Grieving Process

This paper presents the psychological interpretations of the grieving process and examines how professionals from Sigmund Freud, Melanie Klein, Erich Lindenmann, Gerard Caplan, Alaine Polcz, and Emőke Bagdy through Erwin Ringel to Sara Bodó have interpreted grief. We find that all of them include in their definitions the concept of loss, which is “a reaction to the loss of a loved one or an abstraction that has taken place”. We then examine the differences between male and female grief, the ambivalent feelings associated with the fact of death, and the family dynamics that all testify to the family as the primary support when experiencing grief, pain,[1] and loss. In what follows, I will write about the linear stages of the grieving process: anticipation, shock, controlled and awareness stages, along with stages of uprising emotions, search and separation, and adaptation. [1] There are two types of pain in the literature: phasic pain and tonic pain, which are mediated by separate neural pathways in the brain. Melzak, Ronald (1990): The Tragedy of Needless Pain. In: Scientific American. 262, 2. 27–33.

Simulation of β-induced Alfvén eigenmode instabilities and mode transition for HL-3 hybrid scenario

Abstract Kinetic-magnetohydrodynamic hybrid simulation is performed to investigate the Alfvén eigenmode (AE) and fishbone/fishbone-like instabilities excited by neutral beam injection (NBI) deposited energetic particles (EPs) for HL-3 hybrid scenario. The hybrid scenario is characterized by a flat q-profile in the core due to off-axis electron cyclotron current drive (ECCD). Nonlinear simulation with multiple toroidal mode numbers indicates that the n=2 β-induced AE (BAE) is excited initially in the linear stage and the n=1 fishbone has the highest nonlinear saturation level. EP distribution is modified only slightly in both real and velocity space from its initial state because of a narrow mode structure near the axis. Focusing on the n=2 mode, sensitivity analysis indicates that mode activity and transition depend on the EP pressure, injected energy and q-profile. The dominant unstable mode deviates from fishbone-like mode to BAE by raising EP pressure, and from BAE to toroidicity-induced AE (TAE) by raising NBI injected energy. The mechanism is interpreted through resonant condition and corresponding transition threshold is exhibited. In addition, extending the flat shear region could increase the BAE width, resulting in stronger EP transport. Furthermore, nonlinear simulation by only considering n=1 and n=2 modes demonstrates that the low-energy EPs, as an intermediate, gain energy from n=2 mode, which subsequently transfers energy to the n=1 mode through resonant interaction.

Development of a repeatable single-droplet generator using a step motor and PWM control of a two-way solenoid valve

A device capable of repeatedly generating a single droplet was developed. A piston pushes the liquid into a cylinder, creating droplets that are emitted from the nozzle outlet. A one-dimensional linear stage connected to a stepper motor was used for piston displacement. To repeat the generation of single droplets, a method that consists of generating droplets, supplying liquid into the cylinder, and blocking the inflow of external air through the nozzle outlet during the process of supplying liquid into the cylinder was developed. To prevent the inflow of external air into the cylinder through the nozzle outlet, a two-way solenoid valve was installed in the supply passage between the cylinder and the reservoir holding the liquid supply. The sudden opening of the two-way solenoid valve is prevented by PWM (pulse width modulation) control of the current supplied to the solenoid, and the air inflow into the cylinder through the nozzle outlet can be successfully blocked by this method. PWM control of the driving current in the solenoid enabled the repeated generation of single droplets. A single-droplet-generation experiment was repeatedly conducted while varying the nozzle diameter and the hydraulic head difference h between the nozzle outlet and the liquid reservoir. The ratio of the droplet diameter to the nozzle diameter was 5.45 with a nozzle diameter of 0.23 mm and convergence to 2.1 with an increase in the nozzle diameter to 1.51 mm. When repeated measurements were taken under fixed experimental conditions, the droplet diameter deviation % (=stdev/average*100) showed a distribution of 1 ~ 6%.

Evaluation of Aeolian Sand Collapsibility Based on Physical Indicators in the Mu Us Desert, China

The collapsibility of aeolian sand has hindered the development of oil and gas resources and the construction of oil and gas stations in the Mu Us Desert. This study considered aeolian sand on the southern edge of the Mu Us Desert as the research object. Based on a water immersion load test, standard penetration test, and indoor geotechnical test, four evaluation indicators were selected, the water content, dry density, void ratio, and saturation. Combined with the support vector machine method, we established a method for evaluating the collapsibility of aeolian sand based on basic physical indicators. The results showed the following: (1) The degree of collapsibility was slight, with a small portion showing no collapsibility. And the load-settlement curve (P-s) was divided into three stages: the linear elastic deformation stage, the elastic–plastic deformation stage, and the collapsible deformation stage. (2) There was a strong relationship between the collapsibility coefficient and the four evaluation indicators for aeolian sand. Based on these indicators, we could accurately predict and evaluate the collapsibility coefficient. (3) Machine learning methods, such as the support vector machine, can effectively solve prediction and evaluation problems between variables when there is no clear mathematical relationship between multiple independent variables and a single dependent variable.

Coupled wave instability in pure-quartic dispersive and noninstantaneous Kerr media in presence of walk-off

The letter explores modulational instability (MI) in birefringent optical media with pure-quartic dispersion, relaxed Kerr nonlinearity, and walk-off effects. The linear stage of MI is studied using coupled biharmonic nonlinear Schrödinger equations, and the stability of their continuous wave solutions is used to calculate the growth rate of MI. The latter is then used to characterize MI under the combined effects of nonlinear responses, group-velocity mismatch, and quartic dispersion, with a focus on the pure-quartic soliton regime. The nonlinear stage of MI is also studied through direct numerical simulations, which support the analytical predictions and emphasize the impact of quartic dispersion, relaxed Kerr nonlinearity, and the walk-off effect on the emergence of various nonlinear patterns. These findings provide valuable insights into signal generation and processing in pure-quartic optical materials and have potential applications in nonlinear optics and lasers.

A switched full duplex MIMO architecture with digital linear and nonlinear cancellation

Enabling full duplex (FD) in MIMO systems is challenging due to increased hardware complexity and increased training overhead required for canceling not only self-interference (SI) but also cross-link-interference (CLI) signals, considering both linear and nonlinear effects on each stream. In this paper, we propose switched FD MIMO (FD-SW-MIMO) architecture as a low-complexity, low-overhead solution, which enables stream-based nonlinear estimation to be performed independently from channel estimation, so that those nonlinear reference signals are fed to linear SI and CLI cancellation stages. For improved performance at high transmit power levels, the Random Fourier Features - Least Mean Squares (RFF-LMS) algorithm is employed on the residual SI and CLI signals per stream. Our experiments conducted on a software-defined radio based 2x2 FD MIMO test setup reveal that the proposed FD-SW-MIMO architecture can provide up to 12 dB enhancement over linear only digital cancellation. The proposed architecture requires only minor hardware modification(s), avoiding active analog cancellation circuitry and extra Tx/Rx chains. Requiring the same training overhead as linear only cancellation, FD-SW-MIMO architecture can quadruple the rate of HD SISO for low to moderate transmit power levels, and for high transmit power levels, the HD SISO rate is tripled due to slightly increased overhead.

An Interpolator for a Non-Uniform Rational B-Spline Curve with a High Efficiency and Accuracy Using Polynomial Representations

This paper introduces an efficient and accurate interpolator for NURBS (non-uniform rational B-spline) curves, addressing the challenge of regulating feedrate under machining accuracy and dynamic constraints, particularly at sensitive corners. A recursive matrix representation and polynomial conversion are utilized to enhance the computation of NURBS curve intermediate points and derivatives. An improved adaptive planning method is presented to adjust the feedrate at sensitive corners, ensuring that chord error and dynamic constraints are met. The method integrates linear acceleration and deceleration stages to mitigate abrupt changes in acceleration and jerk. Additionally, a prediction–correction scheme-based interpolator is developed, employing an asynchronous mechanism to improve computational efficiency. The proposed method’s effectiveness and correctness are validated through simulation tests and machining experiments.

The Trickster archetype: education to stupefy

Abstract Contra the teleological paradigm of the Hero, this article argues that incorporating an ethic of the Trickster archetype may facilitate greater critical thinking and metacognition within contemporary neoliberal Education Studies learning environments in UK Higher Education. Echoing Lewis’ call for an education to stupefy, as well as Bojesen’s argument for treating Education Studies as a labour of the negative, I present the Trickster archetype as a valuable mode of educational engagement (an endeavour which itself must be done in a paradoxical fashion, for the Trickster ethic cannot be neatly prescribed). In this manner, the ethos of Trickster practices is, I suggest, one of generativity and what Greene calls ‘releasing the imagination’. As opposed to fixing us to any supposed Archimedean standpoint, Trickster practices encourage us to consider radical alternative possibilities from within normative discourse through immanent critique. I argue that the Trickster ethic foregrounds contingency over apparent necessity. I also explore how the Trickster may, paradoxically, be given a concomitant atelic aspiration in association with both Perry’s linear stages of contextual reasoning and metacognition. I conclude by elucidating the ethical and practical problems that accompany attempts to instantiate a Trickster ethic, given that it threatens, and faces possible repudiation from, those with vested interest in upholding dominant mores.

Particle transport and deposition in wall-sheared thermal turbulence

We studied the transport and deposition behaviour of point particles in Rayleigh–Bénard convection cells subjected to Couette-type wall shear. Direct numerical simulations (DNSs) are performed for Rayleigh number ( $Ra$ ) in the range $10^{7} \leq Ra \leq ~10^9$ with a fixed Prandtl number $Pr = 0.71$ , while the wall-shear Reynolds number ( $Re_w$ ) is in the range $0 \leq Re_w \leq ~12\,000$ . With the increase of $Re_w$ , the large-scale rolls expanded horizontally, evolving into zonal flow in two-dimensional simulations or streamwise-oriented rolls in three-dimensional simulations. We observed that, for particles with a small Stokes number ( $St$ ), they either circulated within the large-scale rolls when buoyancy dominated or drifted near the walls when shear dominated. For medium $St$ particles, pronounced spatial inhomogeneity and preferential concentration were observed regardless of the prevailing flow state. For large $St$ particles, the turbulent flow structure had a minor influence on the particles’ motion; although clustering still occurred, wall shear had a negligible influence compared with that for medium $St$ particles. We then presented the settling curves to quantify the particle deposition ratio on the walls. Our DNS results aligned well with previous theoretical predictions, which state that small $St$ particles settle with an exponential deposition ratio and large $St$ particles settle with a linear deposition ratio. For medium $St$ particles, where complex particle–turbulence interaction emerges, we developed a new model describing the settling process with an initial linear stage followed by a nonlinear stage. Unknown parameters in our model can be determined either by fitting the settling curves or using empirical relations. Compared with DNS results, our model also accurately predicts the average residence time across a wide range of $St$ for various $Re_w$ .

All-fiber supercontinuum absorption spectroscopy for mid-infrared gas sensing

The development of compact fiber-based light sources emitting over a wide wavelength range in the mid-infrared and their application to the detection of greenhouse gases and volatile organic compounds still remain of critical interest. In the present work, we make use of several dedicated infrared fibers for implementing a mid-infrared optical device pumped by a thulium doped-fiber laser around 1.965 μm that simultaneously enables a first nonlinear stage of frequency conversion and supercontinuum generation and a second linear stage of gas absorption spectroscopy. As a proof-of-principle, we carry out mid-infrared supercontinuum absorption spectroscopy of methane around 7.7 μm by means of a hollow-core fiber-based gas cell combined to a commercial Fourier-transform infrared spectrometer. Our all-fiber configuration operating in the femtosecond regime at megahertz repetition rate allows the detection of methane concentrations as low as 20 ppm.

Crossflow-Induced Breakdown and Transition Correlation for a Hypersonic Swept Plate Flow

The crossflow-induced transition for a Mach 6 flow over a swept plate with a 35 mm nose radius and a sweep angle of 45 deg is investigated using direct numerical simulations (DNSs). In order to shed light on the complete transition process, the evolution of a stationary crossflow wave is first simulated. Then, unsteady wall blowing/suction perturbations are introduced to trigger transition to turbulence. The results show that both the type I and III secondary modes are excited, and they subsequently undergo a linear stage of amplification before breakdown. The type II mode is undetected despite its amplification predicted by the two-dimensional eigenvalue stability approach. Overall, the type I mode achieves a dominant amplitude and plays a key role in the transition. Furthermore, a transition correlation method is proposed based on the dominant secondary instability and threshold amplitude concept, and in order to verify and calibrate it, wall perturbations with different amplitudes are introduced to mimic the varying intensities of the background noise. The transition locations predicted by the most amplified secondary mode agree well with those by DNSs, validating the secondary-instability-based criterion for hypersonic crossflow transition.

Evaluation of the shear behavior of RC beams strengthened with prestressing BFRP grids

The shear behavior of reinforced concrete (RC) beams strengthened with prestressing basalt-fiber-reinforced polymer (BFRP) grids was experimentally evaluated. Parameters, including grid type, concrete strength, and prestress direction and level, were numerically investigated. Equations for the shear capacity of prestressing grid-strengthened beams were derived. The results showed that using BFRP grids with a 30 % prestress level increased the number of mid-span flexural cracks in the strengthened beam but reduced their length. Compared to the control beam, the load capacity under the serviceability limit state was enhanced by 48 %. The strain responses of the grids exhibited a linear stage followed by a nonlinear stage due to diagonal cracks. The maximum strains of longitudinal and transverse grid tendons in the prestressed strengthened beam decreased by 15 % and 30 %, respectively, compared to the non-prestressed beam. The BFRP grids showed a comparable strengthening effect to low-modulus carbon-fiber-reinforced polymer grids. Increasing concrete strength greatly improved the shear capacity of RC beams. The enhancement effect was greater for transverse tendons with a 30 % prestress level than for longitudinal tendons with a 60 % prestress level. The derived equation accurately predicted shear capacities in experiments or simulations within an error range from −4.7–1 %.

Precision straightness and displacement measurement based on phase-modulated interferometric scheme with different modulation depths

In this study, a novel straightness and displacement measurement method using a Wollaston prism-sensing phase-modulated homodyne interferometer (WPHI) is proposed to accurately measure straightness errors and the position of linear stages. In the proposed WPHI, a Wollaston prism assembly along with a semi-reflector serves as a sensing element to generate two straightness and one displacement measuring beams. By using an electro-optic phase modulator to modulate the linearly polarized laser beam at 45° to its optic axis, different modulation depths are introduced into the straightness and displacement measuring beams to obtain phase-modulated interference signals. Thus, the straightness error can be directly obtained from the change in the optical path difference between the two measuring beams, thereby avoiding any additional errors introduced by separately measuring the changes in the optical path of each beam. Moreover, a 2 × 2 array photodetector is used to simultaneously measure the displacement and rotational angles of stage to compensate for the influence of rotational errors on the displacement result. The experimental results showed that within a range of 4 m, the standard deviations of the straightness error and displacement measurements between the proposed WPHI and a commercial interferometer were 0.50 and 0.59 μm, respectively. Thus, the proposed WPHI has substantial applications in the fields of ultraprecision machine-tool control, precision motion stage testing, and displacement sensor calibration.

Experimental Study on Horizontal Resistance Parameter of Gravelly Soil Considering Slope Gradient Factor

Horizontal resistance can be significantly different for gravelly soil slope sites with different gradients. The impact of slope gradient on the horizontal resistance of soil based on a three-dimensional physical simulation test has been investigated, and the displacement of the pile top and soil pressure for four piles under various gradients (slope gradient 0–45°) was analyzed. The research reveals that ① The soil resistance exhibits a linear increase stage, non-linear steep increase stage, and gradually stabilizing stage with the increase in load. ② The ultimate soil resistance is significantly affected by depth and displacement, and hyperbolic variation characteristics related to the displacement stage. It has a slope weakening effect, and the steeper the slope gradient, the lower the ultimate soil resistance of the pile sides, which effect is negligible when the depth exceeds 0.6–0.7 times that of the pile buried depth. ③ Based on the characteristics of horizontal ultimate resistance-displacement-depth variation in soil, a gradient factor, which is only related to the slope gradient, was used to describe the impact of gradient on the soil resistance modulus (kini) and ultimate resistance (pu). kini is reduced close to the ground surface and gradually increases with depth until it becomes equal to the value of level ground. The ratio between pu in slope ground and level ground was determined for slope angles. The above horizontal resistance parameters were expressed as a function based on the test data to calculate the lateral ultimate bearing capacity of gravelly soil considering the slope gradient factor. The research results developed the theory of foundation design for building structures, promoting the reliability evaluation of pile soil systems towards a more scientific and rigorous direction.

Characteristics of coal crack development and gas desorption in the stress affected zone of rock pillar

Coal (Rock) pillar retaining in the mining of protective layer would cause gas dynamic disaster in the protected layer. Based on the gas geological conditions of the two-layer coal seam in Jinhe Coal Mine of Yaojie Mining District, the stress evolution law of coal seam in the rock pillar affected area was studied by theoretical analysis and numerical simulation, and the crack development law of coal seam in different loading stages under conventional triaxial loading was studied by CT scanning technology. With the analysis of the stress evolution and crack development of coal in rock pillar affected area, the gas extraction effect under different stress states and the gas desorption law after pressure relief antireflection were studied on site. The results showed that the stress of coal in the rock pillar affected area is in the approximate elastic stage of the conventional triaxial stress-strain curve, and the cracks of coal are mainly closed at this stage. Meanwhile, the increase of stress leaded to the decrease of coal permeability and the poor gas extraction effect. CT scanning tests under conventional triaxial loading were carried out in the laboratory, and three-dimensional visual models of coal sample cracks were constructed at different loading stages. When loading to the linear elastic stage, the crack volume and surface area were reduced by 74% and 71% compared with the ones in initial state. At the same time, the expression between stress σ and crack density T was further established. After comprehensive control measures such as intensive drilling discharge, presplitting blasting and coal water injection were taken to the coal in rock pillar affected area, the crack density T could reach the crack development level of the conventional triaxial loading softening stage, realizing the crack development of the coal under low stress. The enclosed gas in front of the coal could desorption flow during the roadway driving. And the predict index value K1 also decreased from 0.57 mL/(g·min1/2) to 0.17 mL/(g·min1/2) continuously. The safety of coal roadway in rock pillar affected area was realized, and the accuracy of numerical simulation and laboratory test results was verified, which had certain reference significance for coal roadway excavation under this similar conditions.

Effect of central plasma pressure on high-order harmonics of 1/1 quasi-interchange instability in a central weak magnetic shear tokamak configuration

Abstract Numerical investigations of linear and nonlinear stages of quasi-interchange instability in a cylindrical tokamak geometry with a flat q-profile in the core region are conducted using eigenvalue and initial value codes, respectively. It is found that there exists a dependent relationship between the central plasma pressure p 0 (of the initial pressure profile) and the dominant harmonic of the quasi-interchange instability. As p 0 increases, m = n > 1 mode would be dominant in the linear stage and even in the nonlinear stage, where m and n are the poloidal and toroidal mode number, respectively. In addition, with p 0 increasing, the fast growth of other harmonics is inevitable and will deeply affect the evolution of m = n dominant quasi-interchange instability.

Large-area coverage–transmission near-infrared measurement of dried laver to determine crude protein content

A large-area coverage (LAC)–transmission near-infrared (NIR) measurement scheme was demonstrated to determine the crude protein content of a dried laver sheet. Because dried laver sheets are large (approximately 19 cm × 21 cm) and the algae packing over the sheet is not homogeneous with including numerous void spots, acquisition of sample-representative and reproducible spectra is necessary for reliable quality evaluations. The proposed scheme incorporated a fixed NIR illumination in the y direction and an xz-direction linear motor stage, allowing for a snake scan over an area of 10 cm × 7 cm. This scheme successfully acquired sample-representative and reproducible NIR spectra of nonhomogeneous laver-sheet samples. The predicted crude protein contents of the samples correlated closely with those determined using conventional Kjeldahl analysis, which required destructive sample digestion. The proposed LAC-NIR scheme demonstrated its suitability as a quality assurance tool in real-world field analysis.

Effect of wall microstructure on conical hypersonic boundary layer flow

As an effective boundary layer flow control method, wall microstructure has an important application prospect in heat and drag reduction of hypersonic. In this paper, based on experimental techniques such as high-frequency pressure fluctuation testing, the effects of different microstructure configurations (V-shaped and rectangular) and distribution modes (streamwise and transverse) on the flow of hypersonic conic boundary layer under the condition of Mach 6 hypersonic incoming flow are studied. The experimental results show that compared with the flow of the smooth wall boundary layer, the wall microstructure has a greater influence on the eigenfrequency of the second-mode wave in the boundary layer, and the streamwise increases by about 20 kHz to the rectangular microstructure and decreases by about 30 kHz to the transverse rectangular microstructure. At the same time, the transverse V-shaped microstructure can increase the amplitude of the second mode in the boundary layer by 5.5 times compared with the smooth wall. For the evolution of boundary layer flow, the microstructure arranged along the flow direction will accelerate the linear development of the disturbance wave during the transition, so that the laminar flow will be transformed into turbulent flow in a shorter distance. The microstructure arranged along the transverse direction prolongs the linear development stage of the disturbance wave during the transition, so that the laminar flow turns into turbulent flow over a longer distance. Downstream of different structures, it is shown that transverse rectangular microstructure has lowest temperatures.

Chromatic focus variation microscopy for surface metrology

Optical metrology plays a vital role in a wide range of research and inspection areas in the industry. At present, the market offers a variety of optical metrology instruments, among which the focus variation microscope stands out for its capability of measuring steep surfaces with high slopes. The traditional focus variation (FV) instrument mechanically scans the surface by sweeping the focal plane of the objective lens using linear motion stages and simultaneously capturing images at different scanning positions, forming a stack of images. The mechanical motion stages require regular maintenance and calibration to ensure accuracy over time. Another issue associated with the mechanical scanning methods is their physical size, which creates a limiting factor to compactness for in-situ measurement applications. This work proposes a chromatic focus variation (CFV) method that replaces mechanical scanning with a wavelength scanning mechanism to overcome the above limitations. Unlike traditional focus variation, the CFV system employs a dispersive objective lens (i.e. chromatically aberrated objective lens) to axially shift the focus along the optical axis to provide vertical/depth scanning. This approach brings significant enhancements in measurement speed and reduces the instrument size for on-machine metrology tasks. In this paper, a detailed analysis of the optical performance of the dispersive objective lens is conducted, and then the measurement performance of the proposed CFV system is validated using samples including a step height of 30 µm and a sine wave shape with a peak-to-valley amplitude of 19 µm. The experiment results were compared to those from the state-of-the-art commercial instrument (Alicona G5), which showed a good agreement between the two. Furthermore, a detailed analysis and discussions are provided to investigate the measurement’s accuracy.