Ellipse Curve Research Articles

Synthesis of Cu2O Nanoparticles by Ellipse Curve Micromixer.

Micromixers offer the advantage of rapid and homogeneous mixing compared with conventional macroscale reaction systems, and thus they show great potential for the synthesis of nanoparticles. An ellipse curve serpentine micromixer, which had been proposed in our prior works was employed to synthesize Cu2O nanoparticles. Cu2O are excellent photocatalysts that have been widely utilized in the degradation of organic dyes. Owing to the excellent mixing performance, the reduction of Cu(OH)2 in micromixing synthesis was more sufficient than that in conventional stirring synthesis. The Cu2O nanoparticles synthesized by micromixing had smaller size and narrower size distribution compared with those synthesized by stirring in a beaker. The smallest Cu2O nanoparticles were obtained by micromixing with Re = 100 at T = 60 °C, while the most uniform Cu2O nanoparticles were obtained at T = 80 °C owing to Ostwald ripening. Through the photocatalytic degradation experiments of Rhodamine B, the Cu2O nanoparticles synthesized by micromixing were found to have better photocatalysis than those synthesized by stirring. The research results showed that the micromixing synthesis was a more suitable choice to produce Cu2O nanoparticles with excellent photocatalysis. The ellipse curve micromixer with a simple structure and high mixing performance can be applied in the synthesis of various nanoparticles.

Utilization of steel wool fibers in AAC blocks containing a mix of flyash, CDW, and glass powder

The present article discusses the mechanical performance of autoclaved aerated concrete (AAC) blocks prepared by different constituents i.e., OPC-53, hydrated lime, flyash, and gypsum powder. These constituents are added in specific percentages obtained for AAC with a target density of 800 kg/m3 and their mechanical properties are found. Initially, flyash is used and then subsequently substituted by construction and demolition waste (CDW) and glass powder in 50% and 100% proportions along with the other constituents kept constant to make AAC blocks more sustainable. For this AAC block, the heat curing is done using an accelerated curing tank (ACT) instead of autoclaving and a mixture of alkaline solution in a ratio of (Na2SiO3/NaOH = 1.5) is used instead of aluminium powder for keeping the homogeneity constant throughout all the batches. Further, mechanical performance is enhanced when chopped steel wool fibers (CSWF) are added to the AAC blocks as reinforcement by a 5% weight percentage. For getting more improved mechanical performance heat curing is performed using an ACT at 65 °C ± 5 °C for 10 ± 2 h, which shows block density of the AAC blocks in the range of 1000–1600 kg/m3 with and without steel wool fibers. It is observed that the batches with the inclusion of steel wool fibers has 9–20% gain in compressive strength and a more than 18% increase in flexural strength of the blocks compared to those batches without CSWF. Hence, it is noted that the AAC blocks prepared with 5% CSWF have better mechanical properties. Moreover, a relationship between compressive and flexural strength is established as no Indian standard codebooks provide specific guidelines for determining the flexural strength of AAC blocks. The three different models gave three different relationships and Ellipse curve fitting showing a coefficient of determination (R2) = 0.998.

Study on the characteristics of moist soil under the condition of water supply of surface capillary

In order to explore the characteristics of moist soil under the condition of water supply of surface capillary, this research constructed device which screens the capillary source infiltration based on the tests. Embedding TDR monitoring instrument in the indoor soil box, it can detect the characteristics of moist soil under the conditions of different capillary source infiltration water percolating capacities. The results show that there is a power function relationship between the cumulative infiltration quantity and time under the condition of water supply of surface capillary. The wetting front pushes forward like semi ellipse curve, and the moist soil presents like approximate semi ellipsoid. When the infiltration time and infiltration rate are constant, the soil water content in the infiltration point tends to a stable value, the soil water and heat coupling movement is complex, and the numerical variation tendency of each monitoring point is similar. Based on the above results, we construct empirical solution equation to predict the eigenvalues of soil wetting body under the condition of water supply of surface capillary. In this research, the capillary source infiltration material is found, and the surface capillary source water supply device with low cost and high efficiency is constructed. The device makes the growth of plants with enough water for the first year, but it can still keep the roots dry enough to make the seedling root down. Preventing soil evaporation loss, slowing down water loss of the surface micro environment of the main land and other bad influence, the device can improve the efficiency of water use. Meanwhile, the device can effectively enhance the ability of seedlings against high temperature of the surface in desertification area, wind-blown sand, animal browsing stress, damage, and create a proper environment for the normal growth of plants, which enjoys broad prospects.

Composite Insulator Defect Identification and Quantitative Method Based on Random Hough Transform Ellipse Detection

To reduce the great influence on the operation of the transmission lines resulted from the external force damage of the insulator, and to improve the operation and maintenance level of the lines, a composite insulator defect identification method based on random Hough transform ellipse detection is proposed in this paper. This method takes the image of the insulator taken by drone aerial photography as the research object. First, the edge of the insulator is extracted by the Canny operator. Then, an ellipse curve fitting is applied to the extracted edge. Finally, the edge curve of the composite insulator is compared with the fitted elliptic curve, and the defect area is identified. This method cannot only identify the breakage state of the insulator, but also evaluate the degree of damage by comparing the damaged area.

The 360° Curvilinear Perspective: A Hybrid Hypercubic Angular Space Grid Based on the 1968 Barre and Flocon proposal

We analyze in detail a specific image of curvilinear perspective developed by Andre Barre and Albert Flocon in 1968 which depicts a square room from its interior by a 360° total perspective. Since its publication, their work has become an important point of reference, but they did not say how it was done. We discuss how this specific case of a pseudo-spherical projection for a hypercube was achieved by hybridized using ellipse curves in one of the spatial directions and a different spherical projection in the other direction. For this analysis we develop the mathematical expressions and study how the ellipsoidal and spherical transformations are hybridized into one solution. Barre and Flocon attempted to use both projections in an angular curvilinear grid as a practical drawing method. One of the main interests of having access to a 360° curvilinear grid arises its ability to act as a drawing guide. We provide an example of its use to demonstrate its practicality.

A cost-effective serpentine micromixer utilizing ellipse curve

Due to high mixing performance and simple geometry structure, serpentine micromixer is one typical passive micromixer that has been widely investigated. Traditional zigzag and square-wave serpentine micromixers can achieve sufficient mixing, but tend to induce significant pressure drop. The excessive pressure drop means more energy consumption, which leads to low cost-performance of mixing. To mitigate excessive pressure drop, a novel serpentine micromixer utilizing ellipse curve is proposed. While fluids flowing through ellipse curve microchannels, the flow directions keep continuous changing. Therefore, the Dean vortices are induced throughout the whole flow path. Numerical simulation and visualization experiments are conducted at Reynolds number (Re) ranging from 0.1 to 100. Dean vortices varies with the changing curvature in different ellipse curves, and local Dean numbers are calculated for quantitative evaluation. The results suggest that the ellipse with a larger eccentricity induces stronger Dean vortices, thus better mixing performance can be obtained. A parameter, named mixing performance cost (Mec), is proposed to evaluate the cost-performance of micromixers. Compared with the zigzag, square-wave and other improved serpentine micromixers, the ellipse curve micromixer produces lower pressure drop while have the capability to maintain excellent mixing performance. The ellipse curve micromixer is proved to be more cost-effective for rapid mixing in complex microfluidic systems.

Effects of pressure angle on uneven wear of a tooth profile of an elliptical gear generated by ellipse involute

This paper presents a method to establish a mathematical model of an elliptical gears pair's tooth profile slip curve. The gear has an ellipse involute tooth profile generated by a rack cutter. The profile equation was developed based on the gearing theory with centrodes and center distance and consideration to conditions for avoiding undercutting. An elliptical involute curve and design parameters of the rack cutter were established corresponding to different points on the centrode of the elliptical gear. The profile equation was developed based on the theory of gearing with given centrodes and axis distance and consideration to conditions for avoiding undercutting. An elliptical involute curve and design parameters of the rack cutter determined corresponding to different points on the centrode of the elliptical gear. Wrote a number calculation program was in Matlab to examine and select appropriate pressure angles to limit the slippage between the mating teeth, to reduce wearing and enhance the lifespan of the elliptical gear pair. Case studies were also presented to confirm the influence of the pressure angle on the profile slippage phenomenon and select the rack cutter's pressure angle to reduce uneven wearing between the teeth of one elliptical gear. The survey results show that when the pressure angle of the rack cutter is large, the profile wear will occur faster since the ramp tooth rib, shorter length of the line of action, and pointed tooth tip. These research results are meaningful in selecting the rack cutter's pressure angle to gear the non-circular gear has tooth profile is an involute ellipse curve.

Shaping the tooth profile of elliptical gear with the involute ellipse curve

Non-circular gears (NCGs) with the advantage of compactness and simple mechanical structure in creating transmitters with variable gear ratios in the industry, so this is a topic that is being studied by many scientists. However, up to now the research usually focuses on NCGs with tooth profile that is an involute circle called involute tooth profile, while other curves have not been applied in the design of the non-circular gears. In this paper, the author proposes to apply the involute ellipse curve in shaping the tooth profile of the pair of elliptical gears with a rack cutter. A rack cutter with tooth profiles is trapezoidal weight is determined from the involute ellipse curve selected as the NCGs teeth. In order not to undercut and tip sharpening when shaping the gear, two algorithms for correcting the base ellipse according to the even distribution of teeth on the gear and undercutting avoidance condition are performed. A numerical computational software module is written according to the theory and the algorithm is implemented to explore the different cases in the design process. The results of this study show that the teeth are evenly distributed over the entire circumference of the ring elliptical gear, overcoming the phenomenon of uneven teeth in geometry and size when using the involute of a circle as other studies have shown. Also, with the tooth profile that is involute ellipse curve, the pressure angle is increased to improve efficiency the transmission capacity of a pair of gears. Therefore, this is the advantage of the new profile in creating variable automatic transmission for different script applications in industries such as the automotive industry or modern medical equipment.

Bond-parametric function and size factor model for formation in binary rare earth metal-based amorphous alloys

Herein, the formation of binary rare earth metal-based amorphous alloys is systematically studied by the bond-parametric function and size factor model. The theoretical results have been obtained for the 1230 binary alloys based on the 15 rare earth metals (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The results revealed that the formed amorphous constituent elements region and the unformed amorphous constituent elements region can be separated precisely from each other by an ellipse curve, and the elliptic equation of $$ \frac{{\left( {x - m} \right)^{2} }}{{c^{2} }} + \frac{{\left( {y - n} \right)^{2} }}{{d^{2} }} = 1 $$ . The constants m, n, c, and d in the elliptic equation are positively correlated to the parameters R, y, (µR3)−1/2, and E for each host metal, respectively. The overall reliability of the calculation upon comparison with the experimental data for 92 binary rare earth metal-based amorphous alloys was found to be 92.4%. This indicates that the theoretical results are in very good agreement with the experimental data.

Information security and storage of Internet of Things based on block chains

With progress in science and technology and the rapid development of the Internet of Things, we have entered the intelligent era of the Internet of Things. With many devices connected to the Internet, hackers have opportunities to attack; thus, the security of the Internet of Things has attracted increased attention. In the era of big data, the demand for information storage is increasing. This paper considers block chains and proposes an ECC (Ellipse Curve Cryptography) asymmetric algorithm to encrypt information. For storage, this paper proposes compressed sensing for data compression reconstruction to improve information storage speed in the Internet of Things. The experimental results show that the proposed algorithm is superior to comparable algorithms in security and storage performance.

Motion generators of quadric surfaces

This paper presents research work on synthesis of the mechanisms that generate translations on circular, cylindrical, and conical surfaces. As these three kinds of surfaces are all basic quadrics, the synthesized mechanisms are called motion generators of quadric surfaces. Firstly, the characteristics of these quadrics are analyzed, which result in an easy way to express them. Secondly, the motion sets of one-degree-of-freedom (one-DoF) joints are described by finite screws, leading to a simple and non-redundant manner for mechanisms’ motion description. Based upon this, the motion generators of circular, cylindrical, and conical surfaces are respectively synthesized, and all the serial kinematic chains that generate these quadrics are obtained. The results are verified through simulations in MATLAB software. Finally, as an application of the motion generators of quadrics, closed-loop linkages constituted by the generators of cylindrical and circular surfaces with specific geometric conditions are synthesized, which purely generate one-DOF translations along ellipse curves. Some new serial kinematic chains and closed-loop linkages are invented in this paper. These new mechanisms have simple mechanical structures, and they have potential applications in design of robots used in machining and manufacturing of complex surfaces and curves.

Operation modes and control algorithms of anisotropic permanent magnet synchronous motor (IPMSM)

This paper represents control strategy of anisotropic permanent magnet synchronous motor (IPMSM) in the field-weakening region. Field weakening controller allows to increase maximum achievable speed with output torque reduction. Proposed control system consists of four general modes: MTPA (maximum torque per ampere), MC (maximum current), FW (field weakening), and MTPV (maximum torque per voltage) which must be chosen accordingly to motor speed, current and torque references. Operation point is found as an intersection of torque hyperbola and voltage ellipse curves in d-q motor’s current reference frame involving motor parameters’ limits. However, due to nonlinear dependence between torque and voltage equations, it is quite complicated to obtain both right control mode selection and reference output calculation. In order to solve this problem, a unified control algorithm adopted for wide speed and torque reference with online constraints calculation is proposed. Matlab/Simulink control model of PMSM motor and control system were designed in order to show developed strategy performance. Simulation results shows increasing of speed limit by more than 2.5 times related to nominal speed with high controller’s response. However, speed limit increasing leads to a decrease in motor’s output torque. Due to this fact, presented control strategy is not suitable for applications where nominal torque level is essential for all speed operation points.

On the Problem of Tangency of Ellipse Curve

Given a ellipse curve and a point in the exterior region, there are always two tangents from the given point to the curve.

Direct-Lyapunov-Based Control Scheme for Voltage Regulation in a Three-Phase Islanded Microgrid with Renewable Energy Sources

In this paper, the local control structure of a microgrid is partially modified by a Lyapunov-based controller. This controller is derived based on direct Lyapunov stability theory (DLST) in order to calculate proper switching functions for the stable operation of the local controller as well as proper local performance of each inverter-based distributed generation (DG) unit. The main contribution is the use of DLST-based controller in a hierarchical primary control structure along with a DC-side voltage regulator. A current-based droop controller is also introduced along with a voltage harmonic compensation technique. The control limits of droop equations are calculated based on steady-state and dynamic capability curve as well as voltage-frequency ellipse curve. The effect of the variations of voltages and circuit parameters on the capability curves are also investigated and the microgrid (MG) steady-state operation area is obtained. In the proposed method, the DC-voltage variations are regulated by an additional voltage control loop based on a current reference correction signal. The above-mentioned approaches are derived thoroughly with mathematical equations. The effectiveness of the designed controllers is verified by a MATLAB/SIMULINK simulation platform (Matlab/Simulink R2014a, Mathworks, Inc.) with harmonically distorted intermittent loads. The results show the appropriate performance of the proposed controllers during both steady-state and transient dynamic conditions.

Research on Exact Location Algorithm of Pupil Center Based on Ellipse Fitting

In order to realize the requirement of precise eye tracking in clinical, a pupil center location algorithm based on the least square method is proposed. First, the eye image was captured by the camera under the infrared light, and then the two-valued image was obtained after preprocessing. Use the number of pixels that form the outline which was Extracting from the two-valued image to carry out the rough filtration of the pupil. The ellipse curve was fitting by the randomly select 6 pixels on the filtered contours, and then calculated the variance of distance between the center and the edge of the ellipse. The ellipse center is ellipse center, where the variance of the distance is Minimum. The algorithm has advantage of accurate identification the pupil center when there is white spot interference and squint. Experiments show that the pupil center can be located quickly and real-timely by this algorithm.

Adjustable vertical vibration isolator with a variable ellipse curve mechanism

SummaryThis paper presents a passive vertical quasi‐zero‐stiffness vibration isolator intended for relatively small objects. The present isolator has features of compactness, long stroke, and adjustability to various load capabilities. To realize these features, we use constant‐force springs, which sustain constant load regardless of their elongation, and propose a variable ellipse curve mechanism that is inspired by the principle of ellipsographs. The variable ellipse curve mechanism can convert the restoring force of the horizontally placed constant‐force springs to the vertical restoring force of the vibration isolator. At the same time as converting the direction, the vertical restoring force can be adjusted by changing the ratio of the semi‐minor axis to the semi‐major one of the ellipse. In this study, a prototype of a class of quasi‐zero‐stiffness vibration isolator with the proposed variable ellipse curve mechanism is created. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the prototype can reduce the response acceleration within the same specified tolerance even when the mass of the vibration isolated object is changed. Copyright © 2017 John Wiley & Sons, Ltd.

2方向水平力を受ける鉄筋コンクリート造立体隅柱梁接合部の耐震性能および立体破壊モデルに基づく曲げ終局耐力の評価

Static loading tests to reinforced concrete (R/C) three-dimensional (3D) corner column-beam subassemblage specimens were carried out by Katae and Kitayama (2014) to investigate the effect of column compressive axial load on failure mechanics of joint-hinging proposed by Shiohara. The Shiohara's proposal pointed out that failure mode of a R/C beam-column-joint frame depends greatly on a column-to-beam capacity ratio and joint-hinging failure tends to develop when a column-to-beam capacity ratio is close to unity. Note that a column-to-beam capacity ratio can be varied by changing not only the magnitude of column axial load but also the amount of column longitudinal reinforcement. Therefore three 3D corner column-beam subassemblage specimens (two without slabs and one with a slab having a thickness of 70 mm) were tested under bi-lateral loading and constant column axial load where a column-to-beam capacity ratio of 1.5 and 2.6 was set by placing column longitudinal reinforcement of 8-D16 and 8-D19 respectively. All 3D subassemblage specimens failed in joint-hinging with an increase in story drift. It is revealed by Katae and Kitayama (2014) that the ultimate flexural capacity of corner column-beam joints under bi-lateral loading can be estimated based on the new mechanism of joint-hinging by assuming that the orbit on the rectangular coordinates plane defined by joint-hinging capacities in both directions orthogonal to each other traces an ellipse curve under bi-lateral loading. Three-dimensional (3D) failure surfaces and stress flow conditions in a corner column-beam joint under bi-lateral loading, however, are not clarified yet. Then a 3D joint-hinging failure model was constructed for a corner joint based on test results referring to a plane joint-hinging failure model proposed by Kusuhara and Shiohara. A quick evaluation method for the ultimate joint-hinging capacity was proposed based on the 3D failure model in a corner column-beam joint under bi-lateral loading. General conclusions are drawn from the study as follows. (1) When a column-to-beam capacity ratio increased from 1.5 to 2.6, the ultimate joint-hinging capacity computed as a resultant force of two orthogonal story shear forces under bi-lateral loading increased to 1.19 times by large amount of column longitudinal reinforcement. This indicates that the ultimate joint-hinging capacity was enhanced by the increase in a column-to-beam capacity ratio due to increasing the amount of column longitudinal reinforcement. (2) When a column-to-beam capacity ratio was changed from 1.5 to 2.6 by the increase in the column compressive axial load in past tests or the amount of column longitudinal reinforcement in this tests, the column compressive axial load had a greater influence on enhancement of the ultimate joint-hinging capacity under bi-lateral loading than the amount of column longitudinal reinforcement. (3) A slab contributed to enhancing the ultimate joint-hinging capacity by 1.07 times that without a slab for 3D corner column-beam subassemblages with a column-to-beam capacity ratio of 1.5, failing in joint-hinging. Torsional moment at the end of a transverse beam caused by tensile force of slab reinforcing bars in the longitudinal direction, whose rotating direction is counter to that of upper and lower columns, is carried to a beam-column joint and restrains rotation of the upper and lower columns. This is the reason for enhancement of the ultimate joint-hinging capacity due to a slab. (4) Proposed method based on 3D failure model herein can adequately evaluate the ultimate joint-hinging capacity of a corner column-beam joint under bi-lateral loading since there is a discrepancy within 10 % between predicted ultimate capacity and test result.

Application of Approximate Iterative Method on Section Precision Forming of Boom-type Roadheader

The decision of the inflection point is the key to ensure automatic section cutting precision using a boom-type road header. In this paper, cutting precision model was set up for the first time to trapezoidal section and a method deter- mining inflection point is given. Considered the cutting head' projection at section is elliptical with the cantilever's joint variable. The relationship between ellipse curve and cutting section boundary was investigated, and thereby sets up the cutting precision model. Approximate iterative method is used to finding the optimal inflection point, of which takes the cutting precision as the objective function. Compared with the traditional process path planning method, the forming ac- curacy can be improved greatly and controlled within 1mm. Through MATLAB simulation, it is proved that this method is correct and valid.

Geometric design and simulation of tooth profile using elliptical segments as its line of action

A mathematical model of gear tooth profiles using the ellipse curve, whose curvature is convenient to control by changing the mathematical parameters as its line of action, was built based on the meshing theory. The equation of undercutting condition was derived from the model. A special epicycloidal tooth profile was also presented. An example gear drive with variation of the ellipse parameters was taken to illustrate the proposed method. The contact ratio of the gear drive designed by the proposed method was analyzed. A comparison of the property of the gear drive designed with the involute gear drive was also carried out. The results confirm that the proposed gear drive has higher contact ratio in comparison with the involute gear drive.

An approach to ERO problem in displacement eddy current sensor

Eddy current (EC) sensors are widely applied in displacement (proximity) measurement as well as nondestructive testing and evaluation for defect detection or material characterisation. For displacement measurement, one of the research aims is to overcome measurement uncertainties due to material variation and inhomogeneity. This problem is called as electrical runout (ERO) problem. In this paper, an approach to ERO problem is presented based on the coaxial ellipse distribution (CED) pattern of the EC sensor. In the CED pattern, the real and the imaginary parts of the magnetic flux density in the z-component (B z ), with the variation of the sample conductivity under the different lift-offs, are located on an ellipse curve. Furthermore, the CED pattern is verified by the different sensor specifications, such as excitation frequency and probe coil geometry. According to the CED pattern, the ERO problem in EC sensors can be overcome well when the sample is magnetised to saturation.