Centripetal Acceleration Research Articles

The Simulation on Dynamic of Rotary Inertia and Engine’s Inflamer in Light Vehicle

According to formula we can simulate their driven force and acceleration. The mechanical formula is used to obtain dynamics is used to simulate. The driven force increases when torque increases and tire diameter decreases. We need torque to increase so this is our plan. Acceleration raises when torque raises and it reduces when its weight raises. With the decreasing of radius of road the centripetal acceleration is increasing in the condition of light vehicle. It is that it decreases sluggishly before 0.35m/s2 then it maintains a steep decline to 0.62m/s2 and at last becomes sluggish again. It is valued that the economical efficiency about consumed fuel under different power. In the time of 0.2hr the fuel inflamer inclines sharply first then turns stable. It is the smallest value. Beyond it the fuel maintains a high value all the time. The discharged pollution gas decreases with the decreasing initial temperature. The low initial temperature is good to fuel gas. Meantime the smallest incline range is 300~350K which explains that it is the most save one.

A Low-Cost Method for Phenotyping Wilting and Recovery of Wheat Leaves under Heat Stress Using Semi-Automated Image Analysis.

Leaf wilting is the most common symptom of dehydration stress. Methods to analyze this phenomenon are particularly relevant to evaluate crop agronomic performance, to genetically dissect out the wilting process, and for functional analysis of genetically modified plants. In this study, a low-cost, semi-automated method to quantify leaf folding of wilting plants is described that can replace visual analysis. Standardized heat-stress conditions were applied with a thermostatic drier, on plantlets or excised leaves from three wheat genotypes (Trinakria, Cappelli, and a Water-mutant of Trinakria). The best time–temperature binomial to record both the leaf wilting and recovery phases was identified using a free time-lapse application, by a smartphone camera. The quantitative description of the wilting phenomenon was obtained through the Kinovea software, which automatically tracked the leaf angle changes over time, computed various kinematic data (angular velocity, centripetal acceleration, total degrees of displacement) and constructed the graphs. The possibility of applying standardized heat-stress conditions and quantitatively describe the leaf folding kinematics means that this instrumentation and its use represents a very low cost tool for objective phenotyping of the degree of the heat-stress tolerance of wheat and of morphologically similar species.

Analysis of the 2017 June Maoxian landslide processes with force histories from seismological inversion and terrain features

SUMMARY A devastating landslide occurred in Maoxian (China) on 2017 June 24, which generated strong signals that were recorded by a regional seismic network. We determined the landslide force history from long-period seismic waves and identified eight subevents. For each subevent, we obtained an independent force history and calculated its sliding path. The shape of the terrain before and after the landslide was found to play a critical role in the motion of the sliding mass. A combination of seismic and terrain data was used to discriminate between or relate the subevents to each other, and to locate the initiation point of each sliding path. We explain the Maoxian landslide dynamics as the combination of the rock collapse, centripetal acceleration of the sliding body, deceleration and acceleration once again after overcoming obstacles along the sliding path.

Dynamics of DiskMass Survey galaxies in refracted gravity

We aim to verify whether refracted gravity (RG) is capable of describing the dynamics of disk galaxies without resorting to the presence of dark matter. RG is a classical theory of gravity in which the standard Poisson equation is modified with the introduction of the gravitational permittivity, which is a universal monotonic function of the local mass density. We used the rotation curves and the radial profiles of the stellar velocity dispersion perpendicular to the galactic disks of 30 disk galaxies from the DiskMass Survey (DMS) to determine the gravitational permittivity. RG describes the rotation curves and the vertical velocity dispersions by requiring galaxy mass-to-light ratios that are in agreement with stellar population synthesis models, and disk thicknesses that are in agreement with observations, once observational biases are taken into account. Our results rely on setting the three free parameters of the gravitational permittivity for each individual galaxy. However, we show that the differences of these parameters from galaxy to galaxy can, in principle, be ascribed to statistical fluctuations. We adopted an approximate procedure to estimate a single set of parameters that may properly describe the kinematics of the entire sample and suggest that the gravitational permittivity is indeed a universal function. Finally, we showed that the RG models of the individual rotation curves can only partly describe the radial acceleration relation (RAR) between the observed centripetal acceleration derived from the rotation curve and the Newtonian gravitational acceleration originating from the baryonic mass distribution. Evidently, the RG models underestimate the observed accelerations by 0.1 to 0.3 dex at low Newtonian accelerations. An additional problem that ought to be considered is the strong correlation, at much more than 5σ, between the residuals of the RAR models and three radially-dependent properties of the galaxies, whereas the DMS data show a considerably less significant correlation, at more than 4σ, for only two of these quantities. These correlations might be the source of the non-null intrinsic scatter of the RG models: this non-null scatter is at odds with the observed intrinsic scatter of other galaxy samples different from DMS, which is consistent with zero. Further investigations are required to assess whether these discrepancies in the RAR originate from the DMS sample, which might not be ideal for deriving the RAR, or whether they are genuine failures of RG.

Corrections to "Inertial Sensor-Based Centripetal Acceleration as a Correlate for Lateral Margin of Stability During Walking and Turning".

In [1], the centripetal accelerations, ac, in Figures2, 4, 5, 6, 7, and 8 are presented in units of g, not m/s2 (1 g = 9.80665 m/s2).

Training GANs with centripetal acceleration

ABSTRACT Training generative adversarial networks (GANs) often suffers from cyclic behaviours of iterates. Based on a simple intuition that the direction of centripetal acceleration of an object moving in uniform circular motion is toward the centre of the circle, we present the Simultaneous Centripetal Acceleration (SCA) method and the Alternating Centripetal Acceleration (ACA) method to alleviate the cyclic behaviours. Under suitable conditions, gradient descent methods with either SCA or ACA are shown to be linearly convergent for bilinear games. Numerical experiments are conducted by applying ACA to existing gradient-based algorithms in a GAN setup scenario, which demonstrate the superiority of ACA.

A Multi-Resonant Speed Piezoelectric Beam Device for Harvesting Energy from Vehicle Wheels

<div class="section abstract"><div class="htmlview paragraph">This work analyzes a cantilevered piezoelectric beam device for harvesting energy from the simultaneous rotation and translational vibration of vehicle wheels. The device attaches to the wheel rim so that it displaces tangentially during operation. A lumped-parameter analytical model for the coupled electromechanical system is derived. The device has one natural frequency that is speed-dependent because of centripetal acceleration affecting the total stiffness of the device. Even though the device has one natural frequency, it experiences three resonances as the rotation speed varies. One resonance occurs when the rotation speed coincides with the speed-dependent natural frequency of the device. The other two resonances are associated with excitations from the vibration of the vehicle wheel. The device’s parameters are chosen so that these three resonances occur when the wheel travels near 30 mph, 55 mph, and 70 mph. There are two excitation frequencies that give these resonant speeds, and both choices differ from the conventional selection of the device’s natural frequency to match the excitation frequency. Instead, the device’s natural frequency must be either above or below the natural frequency for these resonances to occur at the intended speeds. The maximum energy harvested by the device is more than 45 milliwatts at each resonance. The speed bandwidths are quantified near each resonance, and, even though the resonances are linear, bandwidths of a few mph demonstrate the robustness of the device to changing vehicle speeds. The sensitivity of the power harvested by the device to the input vibration frequency and equivalent resistance of the electrical load is numerically examined. The power harvested by this device is sufficiently large to permit sensing and communication for next generation intelligent tire applications.</div></div>

A study of student teachers’ misconceptions on uniform circular motion

Uniform circular motion is one of the key mechanics topics in Physics that students fail to comprehend and master. In South Africa, uniform circular motion is currently not taught to Physical Sciences Matriculate learners and thus students are only introduced to it at university level. It is appreciated that poor comprehension of fundamental concepts and tenets of uniform circular motion leads to difficulties in understanding related topics such as Rotational Kinematics and Rotational Dynamics. This study investigated student teachers’ misconceptions about uniform circular motion and its pertinent underlying concepts such as tangential acceleration and centripetal acceleration. The study also attempted to figure out the source(s) of the ensuing misconceptions. The sample of the study consisted of 41 second-year Physical Sciences student teachers at a South African university. A multiple-choice test consisting of 20 questions on uniform circular motion was administered. Simple and explanatory statistical techniques were employed to analyse the data and appropriate intervention methods were proposed to curtail the identified misconceptions. The study revealed that factual misconceptions and conceptual misunderstandings were prevalent amongst the student teachers who took part in the research exercise.

Experimental study on dynamics characteristic parameter of turning behavior in self-driven mechanism

When changing their walking direction, pedestrians would choose different strategies for different turning angles. Step turn is for a small angle, and spin turn is for a large angle. However, previous studies on the mechanism of individual pedestrian modeling have rarely focused on this phenomenon. To clarify this point, this study performed experiments on individuals to investigate the turning process in three different physical environments—brightness, darkness with evacuation sign, and darkness without evacuation sign. Based on the self-driven mechanism, we propose a dynamical parameter to describe the features of individual turning behavior, i.e., turning scale. The experimental results indicate that when the turning radius is small, the pedestrian would apply significantly more force to increase the centripetal acceleration than the tangential acceleration to make the turn. Hereby, our work validates the existence of different turning strategies for different turning angles. Further, the difference in the choice of strategies in different physical environments is analyzed. The research achievements in this work provide a new insight to investigate pedestrian behavior, and provide data support for modeling individual pedestrian movements more accurately.

Research on Rotational Angle Measurement for the Smart Wheel Force Sensor.

The measurement of the rotational angle of the wheel is critical for the smart wheel force sensor (SWFS) to obtain the wheel forces defined in the vehicle coordinates. To simplify the structure of the SWFS and overcome the shortcomings of the traditional angular transducer, a new method to evaluate the rotational speed of the wheel and then calculate the rotational angle is proposed in this paper. In this method, the centripetal acceleration caused by the rotation is recorded by three accelerometers and used carefully. What’s more, the possible sources of error are classified and analyzed. Simulations and stand experiment are carried out to demonstrate the effectiveness of the proposed method.

Inertial Sensor-Based Centripetal Acceleration as a Correlate for Lateral Margin of Stability During Walking and Turning

There is growing interest in using inertial sensors to continuously monitor gait during free-living mobility. Inertial sensors can provide many gait measures, but they struggle to capture the spatial stability of the center-of-mass due to limitations estimating sensor-to-sensor distance. While the margin of stability (MoS) is an established outcome describing the instantaneous mechanical stability of gait relating to fall-risk, methods to estimate the MoS from inertial sensors have been lacking. Here, we developed and tested a framework, based on centripetal acceleration, to determine a correlate for the lateral MoS using inertial sensors during walking with or without turning. Using three synchronized sensors located bilaterally on the feet and lumbar spine, the average centripetal acceleration over the subsequent step can be used as a correlate for lateral MoS. Relying only on a single sensor on the lumbar spine yielded similar results if the stance foot can be determined from other means. Additionally, the centripetal acceleration correlate of lateral MoS demonstrates clear differences between walking and turning, inside and outside turning limbs, and speed. While limitations and assumptions need to be considered when implemented in practice, this method presents a novel correlate for the lateral MoS during walking and turning using inertial sensors, although further validation is required for other activities and populations.

Stabilization of Gaze during Early Xenopus Development by Swimming-Related Utricular Signals.

Locomotor maturation requires concurrent gaze stabilization improvement for maintaining visual acuity [1, 2]. The capacity to stabilize gaze, in particular in small aquatic vertebrates where coordinated locomotor activity appears very early, is determined by assembly and functional maturation of inner ear structures and associated sensory-motor circuitries [3-7]. Whereas utriculo-ocular reflexes become functional immediately after hatching [8, 9], semicircular canal-dependent vestibulo-ocular reflexes (VORs) appear later [10]. Thus, small semicircular canals are unable to detect swimming-related head oscillations, despite the fact that corresponding acceleration components are well-suited to trigger an angular VOR [11]. This leaves the utricle as the sole vestibular origin for swimming-related compensatory eye movements [12, 13]. We report a remarkable ontogenetic plasticity of swimming-related head kinematics and vestibular end organ recruitment in Xenopus tadpoles with beneficial consequences for gaze-stabilization. Swimming of older larvae generates sinusoidal head undulations with small, similar curvature angles on the left and right side that optimally activate horizontal semicircular canals. Young larvae swimming causes left-right head undulations with narrow curvatures and strong, bilaterally dissimilar centripetal acceleration components well suited to activate utricular hair cells and to substitute the absent semicircular canal function at this stage. The capacity of utricular signals to supplant semicircular canal function was confirmed by recordings of eye movements and extraocular motoneurons during off-center rotations in control and semicircular canal-deficient tadpoles. Strong alternating curvature angles and thus linear acceleration profiles during swimming in young larvae therefore represents a technically elegant solution to compensate for the incapacity of small semicircular canals to detect angular acceleration components.

Low-Cost and High-Efficiency Method for Detecting Vertical Bends of Subsea Pipelines

Subsea pipelines often bend upward due to vertical buckling or downward due to spanning and seabed settling. Typically, harsh environments and the difficulty of accessing underwater pipelines make the inspection and monitoring of subsea pipeline bends a challenging task. This paper demonstrates a low-cost, high-efficiency, and quasi-real-time method for detecting the vertical bends of subsea pipelines by using an in-pipe spherical detector (SD) with rolling features and a low blockage risk. When the SD rolls forward inside a bent pipeline, its rolling speed will change as it moves uphill and downhill, which can be indicated by the centripetal acceleration—the DC component of the recorded rolling acceleration signals. To achieve a high bend detection performance, the mass of the SD should be distributed in a centered disc area to make the SD capable of stably rolling around one of the sensitive axes of the accelerometer, and the accelerometer should be kept as far from the rotation axis as possible. It is experimentally demonstrated that a convex/concave DC component indicates that the pipe is bent downward/upward, and the bend detection resolution can reach 1 cm for a 12 m pipeline.

A Purely Geometrical Method of Locating a Smartphone Accelerometer

In a paper (posthumously) co-authored by Isaac Newton himself, the primacy of geometric notions in pedagogical expositions of centripetal acceleration has been clearly asserted. In the present paper we demonstrate how this pedagogical prerogative can inform the design of an experiment involving an accelerometer-equipped smartphone rotating uniformly in a horizontal plane. Specifically, the location of the sensor itself within the body of the smartphone will be determined using a technique that is purely geometrical in nature, relying on nothing more than the notion that centripetal accelerations are centrally pointing. The complete absence of algebraic manipulations obliges students to focus exclusively on the development of their geometrical reasoning abilities. In particular, it provides a healthy challenge for those algebraically accomplished students for whom equations, calculations, and data tables represent a means of avoiding a direct confrontation with the imposing spectre of material that is otherwise purely conceptual in nature.

Principal physical parameters of the conical pendulum calculated directly from the orbital period

The analysis, calculations and graphical charts presented here in this paper are based directly on a recently published paper by the first two of the above-named authors. In the present paper, it is clearly demonstrated that all of the following nine (or eleven including the centripetal acceleration and total mechanical energy) principal physical parameters can be calculated directly by using only the rotational period of a conical pendulum, assuming that the pendulum mass, string length and local gravitational acceleration are known precisely: string tension force, centripetal force (yielding the centripetal acceleration by simple direct calculation), orbital radius, orbital speed, apex angle, rotational moment, magnitude of the angular momentum, potential energy, kinetic energy and consequently the total mechanical energy. All of these physical parameters were calculated for a range of pendulum lengths 0.400 ⩽ L ⩽ 2.00 m (in nine equal interval steps of 0.200 m) and are illustrated with appropriate charts showing how these physical parameters vary as a function of the orbital period. The limiting values of the parameters as the multiple chart lines approach the horizontal and vertical exes (where this is appropriate) are explained in detail, along with any specifically interesting observations that can also be made, for example, axis intercept gradients and any points of curve inflexion (which are readily explained and calculated using calculus). For the three situations in which inflexions have been demonstrated, appropriate (and very simple) equations for the locus of points have been determined.

Dynamic modeling and mesh phasing-based spectral analysis of quasi-static deformations of spinning planetary gears with a deformable ring

Abstract With a focus on high-speed, lightweight planetary (or epicyclic) gears, this work develops an analytical dynamic model with the sun, carrier, and planets modeled as rigid bodies coupled to an elastic continuum ring having bending, extensional, and shear deformations. The model allows for simultaneous rotation of the sun, carrier, and ring, or for any one of them to be stationary. Coriolis and centripetal accelerations generated by ring and carrier rotation are included. The coupled ordinary (sun, carrier, and planets) and partial (elastic ring) differential equations are cast into a standard gyroscopic system form that is solved using Galerkin discretization. Steady deformations and measured spectral content of the ring deflections are examined with a quasi-static model reduced from the dynamic one. The steady deformations calculated from the analytical model compare well to those from a finite element/contact mechanics model. Ring extensional effects meaningfully influence steady deformations, especially as a result of high-speed rotation of the compliant ring gear, but ring shear effects are small. The spectra of ring deflections measured by sensors fixed to the rotating ring, space-fixed ground, and the rotating carrier are much different, even though the sensors are simultaneously directed at the same ring. Planet mesh phasing significantly affects the measured spectral content. Simple rules are derived to explain the spectra for all three sensor locations for in-phase and out-of-phase systems.

Discovering Quantities of Circular Motion of a Light-Emitting Toy Train Using a Smartphone Light Sensor

In recent years, smartphone sensors have been frequently used in educational demonstrations to improve students’ understanding of certain physical kinematic topics. In particular, the sensors on modern smartphones enable students to use their phones as physics mini-laboratories, and they have been used to analyze objects’ speeds and accelerations and to investigate the conservation of energy and magnetic field properties. As a particular example, one of the sensors on smartphones capable of being used to measure the speed and acceleration of light-emitting objects, and the value of g and spring constant, is the smartphone’s light sensor. In similar fashion, we now outline how a smartphone’s light sensor may be used to find the angular velocity, linear velocity, and centripetal acceleration of a light-emitting toy train moving on a circular track.

ANALISA SIFAT FISIK DAN KANDUNGAN GIZI PRODUK KRIM SUSU MENGGUNAKAN TEKNOLOGI SENTRIFUGASI

Susu mengandung komponen nutrisi yang lengkap seperti lemak, protein, kalsium, vitamin dan mineral lain. Untuk menghasilkan susu skim dan krim diperlukan teknologi sentrifugasi. Sentrifugasi adalah metode yang menggunakan prinsip sedimentasi, di mana percepatan centripetal digunakan untuk memisahkan substansi dengan kepadatan lebih besar dan lebih kecil. Dengan sentrifugasi dimungkinkan untuk memecah emulsi dan memisahkan dispersi tetesan cairan halus, meskipun dalam hal ini fase tersuspensi adalah dalam bentuk tetesan cair yang akan menyatu setelah pemisahan. Tujuan dari penelitian ini untuk menganalisis pengaruh dari perlakuan suhu dan kecepatan putaran sentrifugasi terhadap sifat fisik dan kandungan gizi pada krim susu. Penelitian ini menggunakan dua parameter yaitu kecepatan sentrifugasi dan suhu. Variasi suhu yang digunakan sebesar 30, 40 dan 50°C dan kecepatan sentrifugasi sebesar 6000.G, 7000.G dan 8000.G. Hasil penelitian menunjukkan bahwa sentrifugasi menggunakan Conical Disc Centrifuge mampu memisahkan lemak dari susu segar. Kandungan lemak tertinggi 20,42% dan protein tertinggi sebesar 1.577% pada kecepatan sentrifugasi 6000.G . Peningkatan suhu dan kecepatan putaran akan meningkatkan rendemen, densitas, kadar air dan konduktivitas krim susu. Di sisi lain mampu mempersingkat waktu proses, menurunkan viskositas dan titik didih krim susu.

Theoretical and experimental studies on centripetal acceleration using the Phyphox application

Theoretical and experimental studies on centripetal acceleration using the Phyphox application

Instability and Convection in Rotating Porous Media: A Review

A review on instability and consequent natural convection in rotating porous media is presented. Taylor-Proudman columns and geostrophic flows exist in rotating porous media just the same as in pure fluids. The latter leads to a tendency towards two-dimensionality. Natural convection resulting from density gradients in a gravity field as well as natural convection induced by density gradients due to the centripetal acceleration are being considered. The former is the result of gravity-induced buoyancy, the latter is due to centripetally-induced buoyancy. The effect of Coriolis acceleration is also discussed. Linear stability analysis as well as weak nonlinear solutions are being derived and presented.