Input Angle Research Articles

Experimental investigation and optimization of process parameters of hybrid wick heat pipe using with RSM historical data design

In this paper, the influence of three procedure parameters, mass stream rate at condenser area, inclination angle and heat input and their interactions on the heat transfer coefficient of hybrid wick heat pipe was examined tentatively. The dimensions of info limitations were (a) mass stream rate of 0.02, 0.03, 0.04 kg/sec (b) tilt angle of 15°, 30°, 60°, 90° and (c) heat input of 50 to 400 in venture of 50 Watts employed to direct the trials. In this examination historical data design was utilized and a second order polynomial relapse equation model was built up and after that at last optimized by using RSM. The ideal states of strategy parameters were found as m = 0.04 kg/s, θ = 15° and heat input = 176 Watts. The examination has likewise uncovered that authentic plan information with RSM is an well-organized statistical technique for forecasting the optimum operating conditions hybrid wick heat pipe which assumes a crucial role on thermal performance.

FluLCVRT: Reflectance and fluorescence of leaf and canopy modeling based on Monte Carlo vector radiative transfer simulation

Chlorophyll fluorescence simulation is a hot topic in vegetation remote sensing as it allows to link measurements at leaf and canopy scales to the leaf photosynthetic activity. This work tries to simulate light propagation, scattering and fluorescence emission using 3-D vector radiative transfer theory that allows dealing with polarization. The model is called Fluorescence Leaf Canopy Vector Ratiative Transfer, FluLCVRT. Realistic 3-D mock-up of leaf is used to do simulation based on Monte Carlo ray tracing. Fluorescence is created when radiation passes through chloroplasts. The emission is proportional to the absorbed amount of radiation within the latter. Emitted fluorescence exits chloroplast in a random direction, therefore ray tracing is done separately for original radiation and fluorescence. Bidirectional reflectance, transmittance, and fluorescence are estimated at leaf level within a discrete tessellation for input and output angles, that are afterward saved as databases. Then at canopy level, ray tracing is done leaf by leaf, and at each iteration, original radiation is traced in addition to an auxiliary one relative to fluorescence. Both phenomena are governed by their leaf bidirectional distributions and the precalculated databases are used. Results at leaf level point out the variation of the bidirectional distributions. Particularly, reflectance and upward fluorescence are characterized by high specular effect and hot spot peak, respectively. Horizontally polarized radiation emits fluorescence less than the vertical one because its surface highly reflects radiation in the specular direction. Fluorescence in red and near-infrared increases and decreases with respect to chlorophyll content, respectively. Fluorescence is emitted from shallow chloroplasts in upward case. Meanwhile, in the downward one, it is mainly originated from shallow and deep chloroplasts in the red and near-infrared bands, respectively. At canopy level, the same chlorophyll, polarization, and bidirectional effects are observed except that hot spot peak becomes clear in reflectance. When LAI increases, fluorescence saturates at LAI equal 2 and 3 in red and near-infrared. Soil contribution in fluorescence is not too much since it does not diffuse an important amount of radiation in the chlorophyll absorption domain. A comparison between our model and Fluspect at leaf level shows differences in scattering and fluorescence. They are mainly due to the decrease of the chlorophyll efficiency in FluLCVRT due to the clumping of the chloroplasts within cell cytoplasm. Such an effect is not modeled in Fluspect.

A damped bipedal inverted pendulum for human–structure interaction analysis

The bipedal inverted pendulum with damping has been adopted to simulate human–structure interaction recently. However, the lack of analysis and verification has provided motivation for further investigation. Leg damping and energy compensation strategy are required for the bipedal inverted pendulum to regulate gait patterns on vibrating structures. In this paper, the Hunt–Crossley model is adopted to get zeros contact force at touch down, while energy compensation is achieved by adjusting the stiffness and rest length of the legs. The damped bipedal inverted pendulum can achieve stable periodic gait with a lower energy input and flatter attack angle so that more gaits are available, compared to the template, referred to as spring-load inverted pendulum. The measured and simulated vertical ground reaction force-time histories are in good agreement. In addition, the dynamic load factors are also within a reasonable range. Parametric analysis shows that the damped bipedal inverted pendulum can achieve stable gaits of 1.6 to 2.4 Hz with a reasonable first harmonic dynamic load factor, which covers the normal walking step frequency. The proposed model in this paper can be applied to human–structure interaction analysis.

Design Curves for Estimation of Amplification Factor in the Slope Topography Considering Nonlinear Behavior of Soil

Both surface and in-depth topography have significant effects on the earthquake records and inflicted damages. Despite various studies, the effects of topography have not yet been addressed comprehensively by the current construction codes. The effect of slope topography was investigated in this study considering the real (elastoplastic) behavior of the materials and the effects of the increase in stiffness with the depth on the ground surface response using numerical analysis. Such parameters as input motion frequency, slope height and angle, and the material type were evaluated. The finite-element software tool MIDAS GTS NX was used for modeling. The study results were presented as the acceleration amplification factor, which is the ratio of the maximum two-dimensional ground acceleration to the maximum one-dimensional ground acceleration. The results showed that the seismic analysis of slope topography had a significant effect on the surface amplification factor near the crest and toe of the slope. According to the evaluated parameters, the areas affected by topography on the ground types dense and medium dense reach the x/H = 1.5 and x/H = 0.67 of the crest, respectively. In this condition, the amplification factor of acceleration for the ground types dense and medium dense will be in 1–3.5 and 1.5–3 ranges, respectively.

Angular sensing system based on Y-type twin-core fiber and reflective varied-line spacing grating fabricated by electron beam lithography

A varied-line spacing grating (VLSG) inscribed by electron beam lithography was proposed and used for an experimental demonstration of angular sensing. The designed VLSG central groove density was 655 L/mm, and it had an aluminized surface to reflect light. A Y-type twin-core fiber of 600 μm diameter cores connected with a collimator lens was used to input and collect reflected light from the VLSG. The Y-type fiber input and output paths were connected to a white light source and an optical spectrum analyzer, respectively. The fabricated quasi-continuous VLSG size was 70 × 30 mm, with a fixed 23° input angle. The reflected wavelength changed from 917.3 to 1656.9 nm as the incident light spot moved to different grating positions, with a displacement sensitivity of 14.812 nm/mm. As the input angle was adjusted from 23° to 35° in 1° increments, the spot location on the VLSG changed simultaneously, and the reflection wavelength peak positions changed from 917.3 to 1584.5 nm, with a sensitivity of 57.544 nm/° and linearity of 0.993.

Dynamic Rollover Prediction of Heavy Vehicles Considering Critical Frequency

Rollover of commercial heavy vehicles can cause enormous economic losses and fatalities. It is easier for such vehicles to rollover if the driver’s steering frequency is close to the critical frequency of the vehicle’s roll motion; however, the critical roll frequency has rarely been investigated. In this study, the second-order transfer function between the steering input and roll angle was developed to calculate the critical frequency of the vehicle’s roll motion. The simulated spectrum and transfer function were then used to dynamically predict the peak lateral load transfer ratio. Laboratory experiments were conducted using a scaled vehicle to verify the critical roll frequency. The results suggest that the peak value of the lateral load transfer ratio during steering can be accurately determined from the driver’s input, and the critical roll frequency has a dominant effect on the dynamic rollover of heavy vehicles.

Grasp Posture Control of Wearable Extra Robotic Fingers with Flex Sensors Based on Neural Network

This study proposes a data-driven control method of extra robotic fingers to assist a user in bimanual object manipulation that requires two hands. The robotic system comprises two main parts, i.e., robotic thumb (RT) and robotic fingers (RF). The RT is attached next to the user’s thumb, while the RF is located next to the user’s little finger. The grasp postures of the RT and RF are driven by bending angle inputs of flex sensors, attached to the thumb and other fingers of the user. A modified glove sensor is developed by attaching three flex sensors to the thumb, index, and middle fingers of a wearer. Various hand gestures are then mapped using a neural network. The input data of the robotic system are the bending angles of thumb and index, read by flex sensors, and the outputs are commanded servo angles for the RF and RT. The third flex sensor is attached to the middle finger to hold the extra robotic finger’s posture. Two force-sensitive resistors (FSRs) are attached to the RF and RT for the haptic feedback when the robot is worn to take and grasp a fragile object, such as an egg. The trained neural network is embedded into the wearable extra robotic fingers to control the robotic motion and assist the human fingers in bimanual object manipulation tasks. The developed extra fingers are tested for their capacity to assist the human fingers and perform 10 different bimanual tasks, such as holding a large object, lifting and operate an eight-inch tablet, and lifting a bottle, and opening a bottle cap at the same time.

Functional model of barrel mixer of bulk solids

The description of the researched barrel mixer with flat blades is carried out. Basing on experimental data, the authors have derived regression equations between barrel filling degree and drive power input and barrel capacity and angle of its setting, between coefficient of variation and mixing duration, between the share of the check component and barrel capacity and angle of its setting. An integrated functional model has been developed for the relationship between the main indicators of the mixer and the studied factors. Discrepancy between experimental data and calculated values of the functional model is about 15% of the calculated granularity of mixture. Inclination of the barrel at the angle of 15° to the horizontal is rational. Production of dry compound feed mixtures (with the density of 500-600 kg/m3) on farms in the existing small-capacitance mixers is irrational in view of long duration of mixing. Mixers need upgrading with the help of beaters’ construction change.

Legitimacy in International Tax Law-Making: Can the OECD Remain the Guardian of Open Tax Norms?

The fight against tax avoidance and tax evasion has become a policy priority of many states. Unilateral action is, however, not an appropriate solution. Global problems of tax avoidance and evasion can only be successfully addressed through international cooperation. In this context, the efforts of the OECD for enhancing cooperation in international taxation have been impressive over the last decade. Reference can, for example, be made to the various initiatives relating to information sharing and the Base Erosion and Profit Shifting (BEPS) Project. Although these initiatives seem legitimate, the role of the OECD in international tax law-making has been criticized. The more influential the OECD’s initiatives are and the more the decision-making authority in relation to taxation shifts from the national to the international level, the more its legitimacy is questioned. The purpose of this article is to examine whether the OECD indeed lacks legitimacy and, if so, what could be done to overcome such a legitimacy deficit. The article starts by analysing in more detail the role that the OECD has played (and is still playing) in international tax law-making and what legal value should be attached to the instruments that have been developed by the OECD. The authors then proceed to assess the legitimacy of the OECD during the BEPS Project. A conceptual framework is needed to assess an international institution’s legitimacy. In this respect, the political science-oriented angle of input, output and throughput legitimacy was taken as a basis. The research shows that the OECD lacked input and output during the BEPS Project, but the authors also identified many flaws in the decision-making process itself. The authors argue that whatever international (rule-making) body is developed to take on a role in international tax law-making, legitimacy issues will remain in the absence of appropriate decision-making procedures. Whilst turning the OECD into a sounding board under the auspices of another organization may therefore not be very helpful, the organization should acknowledge that it needs to monitor its decision-making procedures if it wants to remain the guardian of open tax norms in international taxation. More transparent and equal participation by states, other stakeholders and the public at large, as well as more robust accountability mechanisms, may restore the OECD’s legitimacy.

Practical bending-angle calculation for an automated surgical plate bending apparatus

Surgical plates used for reconstructive surgery require a repetitive manual bending process to fit the plate to the defect during reconstruction. However, this process may not produce a plate that fits well, and repetitive bending may significantly increase the risk of plate fracture due to the accumulation of residual stress. In this study, the input angle is calculated using a proposed finite element process that considers the spring-back effect and improves the accuracy of the bending results without the need for repetitive bending. Bending tests for two arbitrary target angles (15° and 30°) are performed using the apparatus to demonstrate its effectiveness. Accurately bent plates are obtained from a single bending trial, unlike the use of another input angle that does not consider spring-back. Therefore, the proposed bending procedure could potentially replace the repetitive manual bending process and reduce the residual stress within the plate, thus lowering the risk of plate failure.

Constraint handling technique for four-bar linkage path generation using self-adaptive teaching–learning-based optimization with a diversity archive

This article proposes an alternative constraint handling technique for the four-bar linkage path generation problem. The constraint handling technique that is traditionally applied uses an exterior penalty function, and has been found to be inefficient, particularly when dealing with constraints on the input angles. The new technique deals with both input crank rotation and Grashof's criterion. Four classical path generation problems are used to test the performance of the proposed technique. A new adaptive teaching–learning-based optimization (TLBO) scheme is used to solve several optimization problems. This technique is referred to here as teaching–learning-based optimization with a diversity archive (ATLBO-DA), and was specifically developed for this design problem. The results show that this new design concept gives better results than those of previous work, and that ATLBO-DA is superior to the original version and other metaheuristic algorithms.

Numerical analysis of a microfluidic mixer and the effects of different cross-sections and various input angles on its mixing performance

Micromixers have better efficiency in terms of both the time-scale of chemical kinetics and diffusive transport compared to the conventional macro-mixers. The mixing efficiency in micromixers is an important performance indicator in mixers. This paper presents a numerical study of how the design of a micromixer along with the design of the mixing process affects the mixing efficiency. Specifically, two different types of cross-sections of the channel in micromixers, namely circular and rectangular cross-sections, together with the inlet angle of the channel, were studied. The process parameters, such as the inlet velocity of fluids and diffusion coefficient, were studied as well. The result shows that the circular cross-section can sustain a large pressure difference without undergoing any remarkable distortion and deformation, and it can achieve better performance. The result further indicates that the inlet velocity and diffusion coefficient have significant effects on mixing efficiency; specifically, the low inlet velocity and high diffusion coefficient value can lead to a better mixing performance. However, different input angles alone could not make the mixing efficiency change noticeably. In other words, the mixing performance of such micromixers relies more on the inlet velocity and diffusion coefficient than on the fluid flow angle in the inlet.

Three‐dimensional impact angle‐constrained adaptive guidance law considering autopilot lag and input saturation

AbstractThis work investigates three‐dimensional accurate guidance problem in the presence of impact angle constraint, input saturation, autopilot lag, and external disturbance, and presents a robust adaptive guidance method for maneuvering targets. More specifically, based on integral Lyapunov control algorithm, a robust guidance law, which can drive both terminal line‐of‐sight angle error and its rate to a small region around zero, while resisting the terrible influence caused by external disturbance, is proposed in this work. To deal with input saturation, guidance command is separated into two parts: real input and saturation error, and an adaptive control technique is employed to compensate the influence resulting from external disturbance and saturation error. Moreover, regarding autopilot lag as a first‐order dynamics, a backstepping designed controller with an adaptive term is proposed. Numerical simulations are carried out and their results demonstrate the proposed properties.

Stacked volume holographic gratings for extending the operational wavelength range in LED and solar applications

A novel stacking procedure is presented for volume phase holographic gratings (VPHGs) recorded in photopolymer material using Corning Willow Glass as a flexible substrate in order to achieve broader angular and spectral selectivity in a diffractive device with high efficiency for solar and LED applications. For the first time to our knowledge, we have shown a device designed for use with a white LED that has the same input and output angles and high efficiency when illuminated by different wavelengths. In this paper, two VPHGs were designed, experimentally recorded, and tested when illuminated at normal incidence. The experimental approach is based on stacking two individual gratings in which the spatial frequency and slant have been tailored to the target wavelength and using real-time on-Bragg monitoring of the gratings in order to control the recorded refractive index modulation, thereby optimizing each grating efficiency for its design wavelength. Lamination of the two gratings together was enabled by using a flexible glass substrate (Corning Willow Glass). Recording conditions were studied in order to minimize the change in diffraction efficiency and peak diffraction angle during lamination and bleaching. The final fabricated stacked device was illuminated by a white light source, and its output was spectrally analyzed. Compared to a single grating, the stacked device demonstrated a twofold increase in angular and wavelength range. The angular and wavelength selectivity curves are in good agreement with the theoretical prediction for this design. This approach could be used to fabricate stacked lenses for white light LED or solar applications.

Study on the envelope process of the flexspline of harmonic reducer based on the angle of wave generator

Harmonic reducer is the core part of robot joint, its tooth shape design theory and meshing characteristics will directly affect the motion control accuracy and vibration characteristics of robot. This paper studies the meshing process of the circular spline and flexsplines of the harmonic reducer based on the double arc profile and the elliptical wave generator. The main innovation of this research is to take the input angle of the wave generator as an independent variable, which more clearly represents the enveloping process and meshing interval distribution of the tooth profile. The results show that the secondary meshing process of the double circular arc tooth profile exists on both sides of the long axis of the wave generator. But the second conjugate contact interval is small, so the optimization of tooth shape should focus on the first conjugate interval. This study provides a theoretical basis for the design of tooth profile parameters of harmonic reducer.

Numerical simulation of sediment deposition and trapping efficiency estimation in settling basins, considering secondary flows

In this paper, sediment deposition and trapping efficiency in shallow rectangular reservoirs were numerically estimated considering secondary flows. In order to do this, three dimensional (3D) steady, incompressible, Reynolds-averaged Navier-Stokes (RANS) equations with the standard k−ε turbulence model were used as the governing equations. The drift-flux model also was used to model the solid phase. In the next step, the developed model was validated using the available data. Then it was used to simulate the sediment deposition and trapping efficiency in shallow rectangular reservoirs, considering secondary flows. The results show the sediment is trapped in the inlet corner of the reservoir, and two pairs of large vortices on the sides and two pairs of small vortices at the inlet corner of the reservoir are observed. Finally, the effects of the input angle of the reservoir to the trapping efficiency are evaluated and the results are discussed.

Semi-device-independent information processing with spatiotemporal degrees of freedom

Nonlocality, as demonstrated by the violation of Bell inequalities, enables device-independent cryptographic tasks that do not require users to trust their apparatus. In this article, we consider devices whose inputs are spatiotemporal degrees of freedom, e.g. orientations or time durations. Without assuming the validity of quantum theory, we prove that the devices' statistical response must respect their input's symmetries, with profound foundational and technological implications. We exactly characterize the bipartite binary quantum correlations in terms of local symmetries, indicating a fundamental relation between spacetime and quantum theory. For Bell experiments characterized by two input angles, we show that the correlations are accounted for by a local hidden variable model if they contain enough noise, but conversely must be nonlocal if they are pure enough. This allows us to construct a "Bell witness" that certifies nonlocality with fewer measurements than possible without such spatiotemporal symmetries, suggesting a new class of semi-device-independent protocols for quantum technologies.

A new control approach for automated drifting in consideration of the driving characteristics of an expert human driver

This paper presents a new control approach for automated drifting in consideration of how expert drivers conduct drifting. The expert drivers stabilize their vehicles at high sideslip angle using not prior knowledge of tire dynamics and equilibrium but current vehicle states. By mimicking how these expert drivers control their vehicles at high sideslip angle, the proposed controller is able to control the vehicle at high sideslip angle using only current vehicle states, i.e without prior knowledge of tire and drift equilibria. Specifically, the proposed controller can perform steady state drifting without the knowledge of the equilibrium of the vehicle system. The proposed controller consists of three consecutive parts. First, the supervisor determines the desired yaw rate and rear longitudinal slip ratio. Second, the upper-level controller calculates the desired front lateral force and rear longitudinal force to track the desired motions. Third, the lower-level controller converts the upper-level controller’s desired forces into steering wheel angle and gas pedal input, which are actual control inputs of vehicles. The proposed algorithm has been investigated via vehicle tests. A rear wheel driven mid-sized vehicle with limited slip differential and internal combustion engine was utilized for testbed. The test results indicate that the proposed algorithm can successfully conduct automated drift maneuvers. Furthermore, the stability of the closed-loop drift control system has been proved by using Lyapunov stability analysis and estimating Region of Attraction (RoA). The vehicle test results are superimposed on the estimate of RoA, and it has been shown that vehicle states within the estimate of RoA converge well to the desired motions. In addition, the comparison of the proposed algorithm with the previously developed drifting control algorithm was conducted. In contrast to the drifting control algorithm that was based on drift equilibrium, the proposed control algorithm is capable of conducting drift maneuvers on both high friction roads and low friction roads without prior knowledge of the tire model and road friction coefficient.

An experimental investigation on heat transfer performance of pulsating heat pipe

Heat input and inclination angle are essential factors influencing heat transfer performance of a pulsating heat pipe (PHP). The heat transfer performance at different inclination angles is studied in this paper. The temperature distribution of a PHP at different inclination angles is obtained by using a thermocouple combined with an infrared thermal imager. The experimental results show that heat is distributed symmetrically under gravity assisted operation, and the average minimum thermal resistance is 0.17 K/W when the angle is 45°. When gravity inhibits circulation of the working fluid, temperature is distributed uniformly, and the thermal resistance increases up to a maximum value of 0.33 K/W. Meanwhile, during the gravity assist and suppression operation mode, the inclination angle only impacts the oscillating mode of the temperature. Particularly, when the angle is 90°, the PHP has the best mode of oscillation, with its heat resistance at 0.077 K/W.

Measurement of the angular dependence of the spontaneous Raman scattering in anisotropic crystalline materials using spherical samples: Potassium dihydrogen phosphate as a case example.

A specialized experimental configuration was developed to allow for more-accurate characterization of the spontaneous Raman scattering properties in anisotropic materials. This need stems from the challenges, arising from the complexity of light propagation, in obtaining accurate measurements of the angular dependence of the Raman scattering cross section in birefringent materials. The nonlinear optical material KH2PO4 (KDP) is used as a model medium. This study is motivated by the need to improve our understanding and management of transverse stimulated Raman scattering in KDP crystals and its deuterated analog, DKDP, typically used for frequency conversion and polarization control in large-aperture laser systems. Key to this experimental platform is the use of high-quality spherical samples that enable one to measure the Raman scattering cross section in a wide range of geometries using only a single sample. The effect of polarization rotation of both the pump light and the collected Raman signal must be carefully considered in data analysis and can give rise to artifacts, which can, in part, be mitigated by reducing the input and collection cone angles.