Change Of Inclination Angle Research Articles

The Change of Period and Obliquity Angle of Pulsar under Braking of Magnetic Dipolar Radiation and Magnetic Decay

The change of pulsar period and inclination angle under the braking of magnetic radiation and magnetic decay is studied. The system of equations for evolution of period and inclination angle with time is given and solved. The solution shows that the period increases, and the inclination angle decreases with time under the braking of magnetic radiation and decay. The numerical results for the change of period and inclination angle of PSRB0525+21 are given. The conclusions are drawn.

Solar Photovoltaic Optimal Tilt Angles in Public Building

Abstract The reduction of the consumption of fossil fuels that cause climate change and the encouragement of the use of cleaner renewable sources, appears to be a fundamental objective for achieving the climate aims agreed in Paris. Moreover, the sustainability of the implementation of solutions for energy efficiency in public administration buildings has played a fundamental role in recent years, strengthened also by the regulatory context of energy and environmental policies of European countries. The research fits into this context and it intends to promote a methodology that is able to evaluate the economic and environmental performance of a photovoltaic system applied in a school located in Italy when only the roof inclination angle changes. The economic and environmental performances are evaluated respectively through Life Cycle Cost Analysis and the avoided CO2 emissions. The results show that although the case study does not present the optimal roof inclination angle, there are economic and environmental advantages. Furthermore, the research notes that, considering the characteristics of the photovoltaic system concerned, the optimal roof inclination angle is equal to 40 degrees from an economic and environmental point of view. This methodology could easily support the decision-making process of designers and administrators to make the energy upgrading choices for the promotion of renewable sources. It was applied to a case study, that is a school located in Italy, in the Abruzzo region, in the province of L’Aquila, but it could be easily replicated in other existing public buildings in different locations.

The yellow stingray (Urobatis jamaicensis) can discriminate the geomagnetic cues necessary for a bicoordinate magnetic map

Elasmobranch fishes (sharks, skates, and rays) are hypothesized to use environmental cues, such as the geomagnetic field (GMF), to navigate across the ocean. However, testing the sensory and navigation abilities of large highly migratory fishes in the field is challenging. This laboratory study tested whether the yellow stingray, Urobatis jamaicensis, could detect and distinguish between the GMF cues used by other magnetically sensitive species to actively determine their location. Stingrays were divided into two cohorts for initial behavioral conditioning: one was trained to associate a change in GMF intensity with an aversive stimulus, whereas the other was trained using a change in GMF inclination angle. Individuals from each cohort remained naive to the GMF conditioning stimulus used to condition the other cohort. The combined group learned the initial association within a mean (± SE) of 184.0 ± 34.8 trials. Next, stingrays from each cohort were randomly exposed to their original GMF conditioning stimulus and the novel GMF stimulus. The original magnetic stimulus continued to be reinforced, whereas the novel stimulus was not. The group demonstrated a significantly different response to the original (reinforced) and novel (non-reinforced) stimuli, which indicates that stingrays could distinguish between the intensity and inclination angle of a magnetic field. This experiment is the first to show that a batoid (skate or ray) can detect and distinguish between changes in GMF intensity and inclination angle, and supports the idea that elasmobranchs might use GMF cues to form a magnetically based cognitive map and derive a sense of location.

Dissipative motion of a spinning heavy symmetric top

Dissipation is one of the important factors determining the motion of a gyroscope or heavy symmetric top in real life. In this work, for such motions, friction at the touchpoint with horizontal surface and drag are approximated with simple models, and they are considered as torque in Euler equations. Using this model, we study the motion of a gyroscope and a heavy symmetric top numerically. For the gyroscope, the effect of dissipation is studied while it is spinning without nutation and precession. For the heavy symmetric top, we consider two different types of motion, obtained experimentally in an earlier work in the literature. The numerical results show that results similar to those achieved experimentally, with the exception of the dissipative change in inclination angle, can be obtained numerically via this simple model, by utilizing Euler equations.

Design and implementation of variable inclined air pillow soft pneumatic actuator suitable for bioimpedance applications

The technological revolution has caused the modernization of human–machine relationship changing our approach in problem solving our society issues and deviated the science of robotic all together. An example for one of the most important pawn in this revolution is soft robotics, the soft robots are robots that are made of deformable materials that provide an alternative approach to rigid robots. The soft pneumatic actuator (SPA) is one of the most widely used and studied form of this type of robotics. In this study, a new geometrical parameter of the SPAs is introduced by studying the effect of the change of the air pillow Inclination angle on the SPA work envelope and tip reaction force against wide range of positive and vacuum pressure applied on SPAs inner surfaces. We are elaborating this effect by using nonlinear static Finite Element Analysis. (FEA) basing it on the hyper-elastic material model identified by testing a specimen from the SPA fabricated material. Three SPAs are fabricated using Fused Deposition Modeling (FDM) 3D printer for the experimental validation of two aspects the work envelope and the tipping force. The test was performed by the image processing of the work envelope comparing the FEA and the experimental work envelope results and the tipping force was validated by using the load force scales. Based on the FEA and the experimental results, two different grippers with two work envelopes and tips was created to observe the change in the effect of the gripper on the weight and surfaces of the grasped object. By the integration of the SPA gripper with bio-impedance measurements, the SPA gripper was enabled to be translated to an agricultural application for fruit picking. A device that is monitored by having soft gripper to have no detrimental effect on the collected fruit's tissues, hybrid with Electrochemical Impedance Spectroscopy (EIS) test for quality assurance. Finally, this work can be interrogated in the future to a gripper that have modifiable synchronized work envelope and tip force for each object.

Lattice Boltzmann Simulation of MHD Rayleigh–Bénard Convection in Porous Media

Lattice Boltzmann method is used to investigate the Rayleigh–Benard convection of magnetohydrodynamic fluid flow inside a rectangular cavity filled by porous media. The Brinkman–Forchheimer model is considered in the simulation to formulate a porous medium mathematically, and the multi-distribution function model is considered to include the magnetic field effect with different inclination angles. The water is considered as the working fluid, which is electrically conducting. A comprehensive analysis of the impact of governing dimensionless parameters is performed by varying Rayleigh (Ra), Hartmann (Ha), and Darcy (Da) numbers, porosity ( $$\epsilon $$ ), and inclination angles ( $$\phi $$ ) of the applied magnetic field. Numerical results are evaluated in the form of streamlines, isotherms, and the rate of heat transfer in terms of the local and average Nusselt number as well as the entropy generation due to the irreversibility of the fluid friction, temperature gradient, and magnetic field effects. The results imply that increasing Ha and decreasing Da reduce the rate of heat transfer. The average Bejan number $$\hbox {Be}_\mathrm{{avg}}$$ increases for increasing the Hartmann number. On the other hand, augmenting Ra and $$\epsilon $$ improves the heat transfer rate. It is also found that the change of the magnetic field inclination angle $$\phi $$ changes the rate of heat transfer and entropy generation.

Experimental study and finite element analysis on the joining performance of GF/PP rivets

To improve the performance of thermoplastic composite joints and reduce the weight of joints, glass fiber (GF)/polypropylene (PP) thermoplastic composite rivets (GF/PP rivets) were prepared and tensile test and simulation analysis of GF/PP-riveted single-lap joints were carried out. Based on the tensile test, the optimum extension length of GF/PP rod with different diameters was determined by taking the specific joint strength (the ratio of joint strength to the weight of fasteners) as the evaluation index. The effects of the rivet diameter and the thickness of composite laminates on the specific joint strength and the weight reduction of GF/PP-riveted single-lap joints were studied. The joining mechanism and the failure behavior of GF/PP-riveted joints were analyzed by finite element simulation. The experimental results indicate that the specific joint strength of GF/PP-riveted joints decreased with increasing rivet diameter and laminate thickness. For the same specific joint strength, the weight of fasteners at joints could be reduced by 81.4% and 73.9%, respectively, by using GF/PP rivets instead of steel bolts and aluminum blind rivets. The simulation results show that the change of inclination angle of rivet body would cause the change of failure mode of joints.

Changes in leaf inclination angle as an indicator of progression toward leaf surface storage during the rainfall interception process

During rainfall events, rain and throughfall drops impact on individual leaves exerting a force that divides the drops into multiple droplets and produces momentary increases in the leaf inclination angle. A portion of the splash residue from the raindrop impact accumulates on the leaf surface and adds mass to the lamina of leaf. This lab-based study examined changes in leaf inclination angle after the impact of a sequence of raindrops of two different volumes (10 µl and 30 µl) on leaf surfaces of three different tree species (Acer saccharinum L., Ulmus pumila L., and Quercus gambelii Nutt.). Leaf inclination is measured as the angle between the lamina surface normal and the horizontal. The differences between the initial leaf inclination angle before raindrop impacts and the steady-state leaf inclination angles after each raindrop impact were examined to explore the hypothesis that rainsplash residue accumulated on leaves after raindrop impact will incrementally increase the steady-state leaf inclination angle as the leaves approach leaf surface storage. The difference between the initial leaf inclination angle and the steady-state leaf inclination angle after two 10 µl raindrops increased by 0.23° for Q. gambelii, 0.84° for A. saccharinum, and 1.29° for U. pumila. The difference between the initial leaf inclination angle and the steady-state leaf inclination angle after two 30 µl raindrops increased by 0.56° for Q. gambelii, 1.45° for U. pumila, and 2.05° for A. saccharinum. For each species, the mass of the accumulated water incrementally increased the steady-state leaf inclination angle after each raindrop impact. As expected, larger raindrops produced more rainsplash residue on the leaf surface based on the incremental increase in steady-state leaf inclination angle after sequential raindrop impacts. With repeated raindrop impacts, leaves in the canopy accumulate more water (mass) as the maximum leaf surface storage is achieved. Observing changes in steady-state leaf inclination angles after raindrop impact may serve as an indicator for rainfall interception totals during rainfall events.

Analysis of Mechanical Strength and Failure Morphology of Prefabricated Closed Cracked Rock Mass Under Uniaxial Compression

In order to obtain the mechanical strength and failure characteristics of fractured rock masses with prefabricated closed crack, Based on the indoor uniaxial compression test, the parameters of the prefabricated closed crack specimens were calibrated. The PFC3D software was used to perform the uniaxial compression simulation test on the prefabricated closed crack rock-like material. The change rules of mechanical parameters of fractured specimens with different prefabricated closed cracks and the failure morphology of rock specimens were obtained. The results showed that: most of the parameters such as elastic modulus, secant modulus, deformation modulus, peak strength and peak strain of the specimen showed a downward trend with the increase of crack diameter and inclination. Among all the parameters, the change of crack inclination angle and diameter had the greatest impact on the Peak strength, and the least influence on Secant modulus; Micro cracks mainly occurred around the prefabricated crack, and when the diameter of prefabricated cracks was small, micro cracks outside the prefabricated cracks were more likely to appear; With the increase of crack diameter and inclination angle, the stress at the moment when the first micro crack appears first decreased and then increased; The growth process of the number of micro cracks had gone through three stages: the stage of no micro cracks, the stage of unstable growth of micro cracks and the stage of rapid growth of micro crack.

Rayleigh–Bénard convection of a viscoplastic liquid in a trapezoidal enclosure

The objective of this paper is to clarify the role of sloping walls on convective heat transport in Rayleigh–Bénard convection within a trapezoidal enclosure filled with viscoplastic fluid. The rheology of the viscoplastic fluid has been modeled with Bingham fluid model. The system of coupled nonlinear differential equations was solved numerically by Galerkin's weighted residuals scheme of finite element method. The numerical experiments are carried out for a range of parameter values, namely, Rayleigh number (5.103 ≤ Ra ≤ 105), yield number (0 ≤ Y ≤ Yc), and sidewall inclination angle (ϕ = 0, π/6, π/4, π/3) at a fixed Prandtl number (Pr = 500). Effects of the inclination angle on the flow and temperature fields are presented. The results reveal that inclination angle causes a multicellular flow and appears as the main parameter to govern heat transfer in the cavity. The heat transfer rate is found to increase with the increasing angle of the sloping wall for both Newtonian and yield stress fluids. On the other hand, the plug regions also found to increase with increasing φ, which is unusual but perhaps not unexpected behavior. In the yield stress fluids, the flow becomes motionless above a critical yield number Yc because the plug regions invade the whole cavity. The critical yield number Yc is also affected by the change of inclination angle and increases significantly with the increase of φ.

Does Functional Cup Orientation Change at Minimum of 10 Years After Primary Total Hip Arthroplasty?

BackgroundCup orientation has been shown to influence the postoperative risk of impingement and dislocation following total hip arthroplasty (THA) and may change over time due to changes in pelvic tilt that occur with aging. The purpose of this study is to determine if there is a significant change in acetabular cup inclination and anteversion over a 10-year period following THA. MethodsA retrospective, multisurgeon, single-center cohort study was conducted of 46 patients that underwent THA between 1995 and 2002. A total of 46 patients were included, with a median age at surgery of 56 years, and a median time between initial postoperative radiograph and the most recent one being 13.5 years (minimum 10 years). Cup orientation was measured from postoperative and follow-up supine anterior-posterior pelvic radiographs. Using a validated software, inclination and anteversion were calculated at each interval and the change in cup anteversion and inclination angle was determined. Furthermore, the difference in the sacro-femoral-pubic angle was measured, reflecting the difference in pelvic tilt between intervals. ResultsNo significant difference was detected between measurements taken from initial postoperative radiograph and measurements a minimum of 10 years later (P > .45), with the median (interquartile range) change in anteversion, inclination, and sacro-femoral-pubic being 0° (−1° to 3°), 1° (−3° to 2°), and 0° (−2° to 3°), respectively. ConclusionOur study found no significant change in functional cup orientation a minimum of 10 years after THA. No shifts in functional cup orientation as a result of altering spinopelvic alignment seemed to be present over a 10-year period.

The Influence of the Occipital Chamfer Inclination Angle on the Wedge-Ripper Force Loading

The tillage implement plowshare acts on the soil similarly to a wedge-ripper. This is the most loaded and fast wearing part. The wedge-ripper blade when worn usually becomes dull quickly, and an occipital chamfer is formed on the back side. It creates additional traction resistance, prevents the blade introduction into the processed area, reduces the productivity and quality of agricultural implements work. (Research purpose) To determine the occipital chamfer inclination angle influence of the wedge-ripper in the range of 5-25 degrees on the resultant loading force characteristics. (Materials and methods) The authors conducted laboratory tests of wedge-ripper experimental samples made with different occipital chamfer inclination angle on the blades edges back sides. The authors used installation for accelerated testing of soil-cutting parts and strain gauging equipment. On all samples, the wedge-ripper front surface inclination was set to 30 degrees. They changed the occipital chamfer inclination angle from 5 to 25 degrees. (Results and discussion). The authors found out that a change in the occipital chamfer inclination angle was accompanied by a change in energy indices during its movement in a sandy area. It was determined that the lower layer of the sandy area in the zone of the occipital chamfer did not fully penetrate the lower layers, and with an increase in the occipital chamfer inclination angle, a part of the sandy layer was unloaded in front of the blade and hit the wedge-ripper front surface. (Conclusions) The authors found out that with an increase in the occipital chamfer inclination angle at the blade edge, the wedge-ripper resistance increased when it was moved in a granular area. It was found out that in the contact zone between the occipital chamfer and the lower layers of the processed area at small inclination angles up to 5 degrees, the layer was crushed, and when the angle was increased to 25 degrees, additional unloading of the area in front of the blade was observed, which increased the working body resistance and the total energy consumption of the work process. The authors showed that for a direct wedge-ripper, the vector inclination angle of the resultant force to the horizontal decreased from 20 to 17 degrees.

The influence of changes in leaf inclination angle and leaf traits during the rainfall interception process

Rainfall interception is a dynamic process where raindrops exert a force on leaf surfaces causing splashing and changes in leaf inclination angles. Leaf biomechanical properties determine the resistance to changes in leaf inclination angle due to raindrop impacts. The hydrophobicity of leaf surfaces may influence water movement off the leaf. A laboratory experiment incorporating a raindrop generator and high-speed video camera was used to examine the relationships between raindrop impact, leaf biomechanics, and water droplet retention of three tree species (Acer saccharinum, Ulmus pumila, and Quercus gambelii). Specifically, we explored if the impact of a falling raindrop resulted in the maximum leaf inclination angle exceeding the water droplet retention angle, allowing for the leaf to shed the intercepted raindrop. This study found that changes in leaf inclination angle after a single raindrop impact could explain water movement off more than 6.7% of the leaf surfaces associated with the three tree species. The change in leaf inclination angle over time produced a decaying sinusoidal curve after raindrop impact. The amplitude of the change in leaf inclination angle was greater with larger drops; however, this change varied with species. Quercus gambelii was least affected by drop impact compared with Acer saccharinum and Ulmus pumila. For species with stiff leaves, such as Quercus gambelii, the resistance of movement after raindrop impact could be a factor in inhibiting the amount of precipitation shed from the canopy. The influence of raindrop impact during rainfall events and leaf biomechanical properties may inform and enhance modeling of the dynamic process of rainfall interception.

Optimization of a Maneuver of a Small Change in an Orbit Inclination Angle of an Interorbital Transport Vehicle with a Limited Power Propulsion System and an Energy Accumulator

Optimization of a Maneuver of a Small Change in an Orbit Inclination Angle of an Interorbital Transport Vehicle with a Limited Power Propulsion System and an Energy Accumulator

Shear mechanism of steel fiber reinforced concrete deep coupling beams

Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

Numerical simulation with LBM of the cooling of electronic component: Effect of the inclination angle

As electronic devices become smaller and more powerful they generate a huge amount of heat, effective cooling becomes very challenging and critical. The air-cooled heat sinks attached to heat-generating components must have the appropriate surface area and airflow to dissipate the heat to avoid any failure or conditions caused by reaching the critical component temperature.The main objective of this paper is a numerical study with the LBM of cooling an electronic component present as a heat source in a square cavity with a change of inclination angle of the cavity, while the Rayleigh number is kept fixed on Ra = 106, Numerical investigations are done with different angles of inclination 0°, 30°, 60° and 90°. Results shows that the change of the cavity angle of inclination has an effective effect on the cooling of the electronic component. The choice of LBM as a simulation method is related to the quality and power proved by this method for solving problems of fluid flow calculations at different length scales.

Tool wear estimation in machining based on the flank wear inclination angle changes using the FE method

In this study, a FEM-based tool wear approach with a focus on the geometry of the worn tool, especially the changes of flank wear land inclination angle, was developed. The relationship between the variables of the wear rate equation and the average nodal temperature on the flank wear land through integrating FE-simulations of the cutting process and Response Surface Methodology (RSM) was determined in order to define the temperature as a function of wear rate model parameters. Then, that data was used to calibrate the wear rate equation which was obtained by establishing the relationship between the Usui wear rate equation and the geometry of the worn tool, using a MATLAB program. This approach was validated by comparing the predicted flank wear rates and experimental measurements. The estimated flank wear shows some improvement compare to the model with a constant inclination angle.

Suppression Of Natural Convection And Radiation Heat Losses In Solar Cavity Receivers: A Novel Approach

The concentrating solar power technology has great potential to be used for energy production and it is a promising alternative to conventional fossil fuel-based energy technologies, such as coal power plants, due to the abundance of solar energy as an energy resource, as well as its minimal impact on the environment. The parabolic dish receiver assembly is one such promising concentrating solar power technology. It usually consists of a reflector in the form of a dish with a downward-facing receiver at the focus of the dish. A cavity receiver is used to maximise the absorption of the concentrated flux. However, the receiver is subjected to environmental variations, as well as changes in receiver inclination angle, which lead to heat losses that affect the overall receiver’s performance. The need for the commercialisation of economically viable parabolic dish systems necessitates further in-depth investigation into cavity receiver designs. As the cavity receiver plays a critical role in transferring solar heat to the engine, any heat loss from the cavity receiver can significantly reduce the efficiency and, consequently, the system’s cost effectiveness. It is therefore essential to assess and effectively minimise heat loss in the cavity receiver to improve the thermal performance of the system, which can contribute to the commercialisation of this type of technology. This novel approach of suppressing natural convection heat loss in a cavity receiver was investigated. The proposed model has not been observed in literature. A cavity receiver with plate fins attached to the inner aperture surface was investigated as a possible low-cost means of suppressing natural convection heat loss in a cavity receiver. Employing air as the working fluid, laminar natural convection heat transfer from the cavity receiver with plate fins attached to the inner aperture surface was investigated for a range of Rayleigh numbers, inclination angles, and fin heights and thicknesses

Analysis of stress-strain relationship of brittle rock containing microcracks under water pressure

Brittle rock contains many microcracks under natural conditions. The theoretical models of brittle rock containing microcracks under the effect of water pressure, axial stress, and confining pressure have not yet been fully elucidated. Therefore, a new model based on a wing crack model and an improved Weibull model was established to analyse the effects of water on the progress of crack initiation, growth, and coalescence. In this improved wing crack model, the water pressure was introduced as a variable, and the analytical stress-crack relationship considering the water pressure was revealed. The relationship between the stress and strain was also obtained. The results revealed that the cracks more readily propagated and failure occurred under higher water pressure. The proposed theoretical curves agree with the experimental data obtained under various water pressures. The effects of water pressure with the change of the crack inclination angle, friction coefficient, crack initiation length, and wing crack length on the wedging force, internal stress, and stress-strain relationship were analysed. The analytical results were validated by experiments. The effect of water pressure on the stress-strain relationship was quantified using an analytical equation whereby the most disadvantageous angle cases, that is, cases wherein the wedging force was maximum, with zero friction were determined.

Application of a two-dipole model to PSR J1640–4631, a pulsar with an anomalous braking index

Abstract Recent timing observation provides an intriguing result for the braking index of the X-ray pulsar PSR$\:$J1640$-$4631, which has a measured braking index $n=3.15\pm 0.03$. The decrease of the inclination angle between the spin axis and the magnetic axis can be responsible for such a high braking index. However, the physical mechanisms causing the change of the magnetic inclination angle have not been fully understood. In this Letter, we apply a two-dipole model given by Hamil, Stone, and Stone (2016, Phys. Rev. D., 94, 063012) to explain the decrease of the magnetic inclination angle of PSR$\:$J1640$-$4631. The rotation effect of a charged sphere and the magnetization of ferromagnetically ordered material produce magnetic moments $M_{\,1}$ and $M_{\,2}$, respectively. There exists a minimum of the potential energy for the magnetic moment $M_{\,2}$ in the magnetic field of $M_{\,1}$, hence the $M_{\,2}$ will freely rotate around the minimum energy position (i.e., equilibrium position), similar to a simple pendulum. Our calculation indicates that the magnetic moment $M_{\,2}$ would evolve towards alignment with the spin axis for PSR$\:$J1640$-$4631, and cause the magnetic inclination angle to decrease. The single peak in the pulse profile favors a relatively low change rate for the magnetic inclination angle.