Spiral Path Research Articles

Effect of Role-Playing Strategy on the Development of Descriptive Skills for Cosmic Occurrences Among Grade 11 General Academic Strand Students in Las Piñas City National Senior High School – CAA Campus

study responded to the spiral path of Senior High School Science curricula, so the study chose the sample from the Grade 11 General Academic Strand Students in Las Piñas City National Senior High School – CAA Campus. The researcher divided the students into two different groups in content and roles. Moreover, the researcher allowed the students to exchange roles. Also, the researcher planed three consecutive class lessons for the concept of the solar eclipse, the lunar eclipse, and the solar system. After completing the stage of defining the research question and the general framework of the study steps, the principal agreed to the procedures to implement the research plan. Then, the researcher held a training session for teachers that included a brief presentation of the research objectives, tools, and procedures. Furthermore, the researcher took the voluntary official approvals to participate in the research from the study sample. Then the researcher began planning lessons, preparing educational resources, and assessment tools. The researcher determined the educational patterns of the learners by following them closely for three consecutive days and in cooperation with the directed teacher. In the implementation phase of the study, the researcher applied a blueprint for dramatic texts and distributed roles to students according to the plan. Then, the researcher distributed a written and visual guide to enable students to understand the phenomenon and simulate it. Students showed a simulation of the solar eclipse accompanied by a single worksheet that measures understanding and record learning descriptions. Following, the students introduced the lunar eclipse phenomenon, accompanied by another worksheet, and the student completed the learning progress record. Then the students wrote reflections on their learning experience. After completing the research investigation, the researcher interviewed the focus groups. Finally, the researcher tabulated all data and analyzed it to produce learning implications that explain and evaluate the impact of this strategy on learning.

나선형 파동유도관 결합을 통한 초음파센서의 탐지범위 개선

This paper presents a method to improve the detectable range of an ultrasonic sensor for distance measurements by coupling the sensor with a helical waveguide. In particular, this study aimed to decrease the effective length of circularly curved waveguides, in addition to reducing the minimum and maintaining the maximum detectable distances. To this end, finite element analyses were used to predict the ultrasound propagation in a waveguide with a uniform circular cross-section along the spiral path. Two types of cross-sectional sizes were compared: one with a diameter identical to that of the sensor face and another with a diameter twice this value. Furthermore, experiments were performed with fabricated prototypes to evaluate the detectable range by measuring the minimum and maximum detectable distances. Notably, by coupling the helical waveguide with the ultrasonic sensor, the minimum detectable distance was reduced to 1/3 times that for a sensor without the waveguide, while the maximum detectable distance was maintained. Moreover, the effective length of the helical waveguide was decreased, as compared with that of linear or circularly curved waveguides.

Analytical solution to logarithmic spiral trajectories with circumferential thrust and mission applications

This study made use of a shape-based method to analyze the orbital dynamics of a spacecraft subject to a continuous propulsive acceleration acting along the circumferential direction. Under the assumption of a logarithmic spiral trajectory, an exact solution to the equations of motion exists, which allows the spacecraft state variables and flight time to be expressed as a function of the angular coordinate. There is also a case characterized by specific initial conditions in which the time evolution of the state variables may be analytically determined. In this context, the presented solution is used to analyze circle-to-circle trajectories, where the combination of two impulsive maneuvers and a logarithmic spiral path are used to accomplish the transfer. The determined results are then applied to the achievement of the Earth—Mars and the Earth—Venus transfers using actual data from a recent thruster developed by NASA.

Numerical study on the effect of oscillation on the deformation behavior of single point incremental formed part

The paper reports the deformation behavior of single point incremental formed part with sheet oscillation. Single point incremental forming is an emerging manufacturing technology. This technology provides the competition to the other innovative technologies such as electric-assisted manufacturing, hydroforming, high-speed forming, etc., to produce the lightweight and highly deformed components. Single point incremental forming is the die-less sheet metal forming process in which the single point tool incrementally forces any single point of sheet metal at any processing time to undergo plastic deformation. In single point incremental forming, the part stays fixed and the tool pin makes the planar and downward motion to shape the part. It has several advantages over the conventional process such as high process flexibility, elimination of die, complex shape, and better formability. Previous literature provides enormous research on the formability of metal during this process, process with various metals and hybrid metals, the influence of various process parameters, but research on the deformation behavior of the part through the oscillation of the tool was limited. In this paper, the single point incremental forming was simulated on ABAQUS finite-element software. The spiral tool path was studied. First, the part was formed without oscillation. Then the oscillation of the sheet with the help of a die and blank holder was set with a frequency to deform the part. The variation of frequency and amplitude was also studied. The formability of the part was analyzed and compared. The deformation, profile shape, strain path, thickness, and force requirement were analyzed and presented. It was found that with lower cycles the maximum stress increases with an increase in amplitude. Also, with an increase in the number of cycles the achieved strain values were lower as compared to the no oscillation case for the same cup height and thus higher deformation is possible with oscillation.

Joint formation mechanism of different laser transmission welding paths

Abstract In this study, the rectilinear, sine, and spiral paths of polymer transmission welding were used to perform welding comparative experiments, and the influence of various parameters in the polymer transmission welding of different laser paths on the joint performance and the formation of molten pool was discussed. The spiral path exhibited the highest joint strength, that increased by more than 50% compared with conventional rectilinear welding. The molten pool formed by spiral welding had a high depth-to-width ratio. Microscope observations revealed that the glass fiber flow signs in the molten pool were obvious, the glass fiber in the molten pool was abundant, and the bubble generation rate in the molten pool was lower. In this paper, Fortran language was used to construct Gaussian body heat source movement model with different paths. Results show that the spiral welding had higher welding stability than traditional rectilinear welding, welding defects caused by the lack of heat in the previous period can be properly compensated by selecting the appropriate welding period, Therefore, good joint performance can be achieved. In addition, amplitude and period are two important process parameters of spiral welding, and their sizes have important effects on joint strength and molten pool formation

Performance Investigation of EMFO-Based Perpetual Online Tuned Variable SR-Controller in Simulated Real Environment

This study uses the enhanced moth flame optimization (EMFO) algorithm with an online tuning approach to optimize the parameters of a variable range split range PID (SRPID) controller. Before implementing the developed EMFO algorithm in the actual plant, it is necessary to investigate the performance of the same in the simulated real environment. Therefore, in the present work, an electrical analogous model of the practical environment is simulated for investigation by considering several effects, namely imperfect insulation, density, viscosity, and compressibility. Further, to check the effectiveness of the proposed algorithm, the controller performance using the EMFO algorithm is compared with the performance using the original MFO algorithm. The validation results show a substantial improvement in the case of EMFO-based controller with an online tuning method in comparison to MFO-based controller. EMFO algorithm exhibits superior performance as it combines the benefits of three modifications (change the spiral path, opposition learning-based initialization, and change in flames selection) in the original MFO algorithm. Furthermore, the system is also investigated for the effect of system dynamics and process disturbance. It is concluded that the developed EMFO algorithm gives superior performance in a simulated real environment paving the way for possible implementation in practical situations.

Automatic generation of 3d spiral tool path for incremental sheet metal forming of mechanical parts with complex geometry

Incremental sheet metal forming is a flexible manufacturing technology that allows to form of various components on the same milling machine, without expensive tools. A hemispherical tool moves along a CNC-controlled tool path and deforms the sheet into the desired shape. The tool path has a significant role in the geometric accuracy of the final part. There has been very little research on the problem of the forming of sophisticated parts with asymmetric wall angles. This paper presents a new approach to generating optimized tool paths for single-point incremental sheet forming (SPIF). At first, a strategy is proposed for the automatic generation of a 3D tool path during forming in a single-step operation. Then, a systematic technique of creating intermediate shapes is investigated by defining tool paths interpolated from the final part shape. The proposed methodology is applied to form a hip cup prosthesis. This part has a complex asymmetric geometry with important angles, a multi-step approach is used. The proposed methodology to define the different tool paths was implemented in Matlab. A numerical simulation of the incremental forming process is performed to predict the final geometry of the aluminum sheet. A comparison of desired and predicted geometries shows the reliability of the proposed method.

Modelling Steering Resistance to Save Energy

In this paper, the design and vehicle model implementation of a spiral path steering system for a lightweight vehicle is presented. The lateral sliding caused by imperfect rolling in corners means considerable loss, for lightweight vehicles. A spiral path steering mechanism provides an alternative solution for steering generated loss reduction. Theoretically, with the application of a spiral path steering system, ideal Ackerman steering geometry is feasible in all corners. The system is able to replace the common rack and pinion solution in purpose-made vehicles. The main design concepts of spiral path steering are introduced in this article. The described system was realized and installed in an experimental vehicle, where field tests were carried out, to measure the cornering losses during operation. The process of cornering loss measurement is also presented in this paper. The resistance model of cornering is elaborated in a Matlab Simulink environment, based on the measurement results. Vehicle losses are characterized by an extended resistance force model, which can be used by simulations for energy saving purposes. The optimization of vehicle operation can be achieved by simulations, where the corresponding velocity profiles of the vehicle is determined. An accurate steering model is essential for proper vehicle modelling and for the following optimization process.

Extremely low frequency wave localization via elastic foundation induced metamaterial with a spiral cavity

We proposed a metamaterial which exhibits elastic wave localization at extremely low frequencies. First, we opened an extremely low bandgap via elastic foundations. Subsequently, we investigated wave localization by imposing normal defect, which is widely used to capture waves in conventional wave localization systems. However, there were limitations: wave localization was not achieved when a weak bandgap is generated, and the operating frequency of localization is still in the upper part of the bandgap. To overcome wave localization via the normal defect, we proposed a novel metamaterial with a spiral cavity which can tune the resonating frequency depending on the length of the spiral path. By imposing on the spiral cavity inside the elastic foundation-induced metamaterial, we can shift the resonating frequency of the cavity down. Finally, we carried out wave simulations, not only to support the previous eigenfrequency study for the supercell, but also to verify that the finite-size metamaterial can also achieve wave localization at the extremely low frequencies. Through wave simulations, we could observe wave localization even at 77.3 Hz, which is definitely the lower part of the extremely low bandgap.

Processing and Profile Control of Microhole Array for PDMS Mask with Femtosecond Laser.

Polydimethylsiloxane (PDMS) is hailed as one of the foundational materials that have been applied to different products in various fields because of its chemical resistance, low cost, excellent flexibility, and high molding capability. With the aim to achieve surface texture with high efficiency by means of electrochemical micromachining with PDMS mask, a femtosecond laser is utilized to process a precision array of micro-through-holes on PDMS films as the molds. The ablation process of PDMS with a femtosecond laser was investigated via numerical simulation verified with experiments indicating a laser energy density of 4.865 mJ/mm2 as the ablation threshold of PDMS with the melting temperature of 930 K. The spiral scanning path with optimized radial offset was developed to ablate materials from the PDMS film to form the laminated profiles, and a tapered through hole was then formed with multilayer scanning. The profile dimension and accuracy were examined as control targets in terms of laser pulse energy and scanning speed, showing that a 12 μJ femtosecond laser pulse energy and 1000 mm/s scanning speed could bring about a nearly circular laminating profile with expected smaller exit diameter than the entry diameter. All the cross-section diameters of the microcone decreased with the increase of laser scanning speed, while the taper increased gradually and then saturated around a laser scanning speed of 800 mm/s due to the energy absorption resulting in smaller ablation in diameter and depth.

Influence and suppression of periodic contour error of tool path and velocity deviations on surface error.

When using multi-axis machines with a pneumatic tool to polish large-aperture optical surfaces, the paths generated by the computer numerical control system deviate from the desired ones. This causes periodic contour errors and surface ripples. In addition, because of the different machine layouts, the tool end velocity also can change. We introduce a multi-axis machine and analyze the surface error and power spectral density (PSD) of three commonly used paths (raster, spiral, and random path) in terms of the contour error using different position interpolation methods. A cubic polynomial is introduced to smooth the axis motion, and a velocity compensation method is considered to diminish the velocity deviation from the machine layout. The results show that the circular interpolation method exhibits a balanced performance in terms of both the contour error and the PSD for various paths. In addition, the optimization can be performed before G-code generation without affecting the characteristics of the original optimization system.

Incidence of Phage Capsid Organization on the Resistance to High Energy Proton Beams

The helical geometry of virus capsid allows simple self-assembly of identical protein subunits with a low request of free energy and a similar spiral path to virus nucleic acid. Consequently, small variations in protein subunits can affect the stability of the entire phage particle. Previously, we observed that rearrangement in the capsid structure of M13 engineered phages affected the resistance to UV-C exposure, while that to H2O2 was mainly ascribable to the amino acids’ sequence of the foreign peptide. Based on these findings, in this work, the resistance to accelerated proton beam exposure (5.0 MeV energy) of the same phage clones was determined at different absorbed doses and dose rates. Then, the number of viral particles able to infect and replicate in the natural host, Escherichia coli F+, was evaluated. By comparing the results with the M13 wild-type vector (pC89), we observed that 12III1 phage clones, with the foreign peptide containing amino acids favorable to carbonylation, exhibited the highest reduction in phage titer associated with a radiation damage (RD) of 35 × 10−3/Gy at 50 dose Gy. On the other hand, P9b phage clones, containing amino acids unfavorable to carbonylation, showed the lowest reduction with an RD of 4.83 × 10−3/Gy at 500 dose Gy. These findings could improve the understanding of the molecular mechanisms underlying the radiation resistance of viruses

A spiral path generation method for achieving uniform material removal depth in aspheric surface polishing

A spiral path generation method for achieving uniform material removal depth in aspheric surface polishing

Recent Advances and Applications of Spiral Dynamics Optimization Algorithm: A Review

This paper comprehensively reviews the spiral dynamics optimization (SDO) algorithm and investigates its characteristics. SDO algorithm is one of the most straightforward physics-based optimization algorithms and is successfully applied in various broad fields. This paper describes the recent advances of the SDO algorithm, including its adaptive, improved, and hybrid approaches. The growth of the SDO algorithm and its application in various areas, theoretical analysis, and comparison with its preceding and other algorithms are also described in detail. A detailed description of different spiral paths, their characteristics, and the application of these spiral approaches in developing and improving other optimization algorithms are comprehensively presented. The review concludes the current works on the SDO algorithm, highlighting its shortcomings and suggesting possible future research perspectives.

Solving the Datum Search as a Partially Observed Stochastic Game

The Flaming Datum (FD) problem refers to the search for a hostile Evader that is fleeing after momentarily revealing its position. If Evader’s direction is fixed but unknown, while its maximal speed is known, Koopman argued in 1980 that the best trajectory for Searcher is a spiral starting from the revealed position. The objective of our study is to verify the hypothesis of a spiral search path, by formulating the FD problem in the framework of a finite two-player zero-sum partially observed stochastic search game, where the opponent plays repeatedly a fixed but unknown pure strategy. Using a realistic sensor model, current information about the position of Evader is represented by an occupancy map, updated in the Bayesian framework. The utility is computed as the entropy reduction of the occupancy map. The game was implemented in software and solved using the maxmin method. By running repeatedly the described search game, we have found that the search pattern, although random (due to the uncertainties in sensing and mixed strategies), is indeed a spiral on every play of the game, thus confirming the hypothesis.

Imaging Synaptic Glutamate Release with Two-Photon Microscopy in Organotypic Slice Cultures.

The strength of an excitatory synapse relies on the amount of glutamate it releases and on the amount of postsynaptic receptors responding to the released glutamate. Here we describe a strategy to investigate presynaptic release independently of postsynaptic receptors, using a genetically encoded glutamate indicator (GEGI) such as iGluSnFR to measure synaptic transmission in rodent organotypic slice cultures. We express the iGluSnFR in CA3 pyramidal cells and perform two-photon glutamate imaging on individual Schaffer collateral boutons in CA1. Sparse labeling is achieved via transfection of pyramidal cells in organotypic hippocampal cultures, and imaging of evoked glutamate transients with two-photon laser scanning microscopy. A spiral scan path over an individual presynaptic bouton allows to sample at high temporal resolution the local release site in order to capture the peak of iGluSnFR transients.

Dynamic rotating-tool turning of micro lens arrays

Diamond micro milling of high-quality micro lens arrays suffers from low machining efficiency, due to the inevitable milling marks along tangential feed direction and the slow spiral tool path interpolated by multiple linear axes. In this article, an advanced cutting process is proposed, namely dynamic rotating-tool (DRT) turning, in which a U-axis attachment on a rotary stage is developed to enable synchronous cutter rotation and radial feed motions of a diamond turning tool. This method is experimentally verified and compared with milling, with significantly enhanced surface quality and machining efficiency, thus bringing a new perspective into ultra-precision machining.

Helical drilling of carbon fiber reinforced polymer by a femtosecond laser.

Carbon fiber reinforced polymer (CFRP) has been widely used in the aerospace industry and other fields, but its processing is still subject to many restrictions. A femtosecond laser helical drilling device is proposed. It can realize beam deflection and translation through a scanning galvanometer and a pair of lenses, respectively, and finally obtain the effect of beam oblique focusing. With the combination of a spiral scanning path and focus feed, the non-taper and high-quality drilling of materials can be realized. CFRP materials were processed through this method, and the influences of process parameters on the heat affected zone and machining taper were studied. The distribution and influence degree of the heat affected zone and the formation mechanism of the machining taper were analyzed. Finally, a high-quality straight hole processing effect of CFRP with up to a 9.7: 1 aspect ratio, less than 15 µm heat affected zone outside the hole, and no delamination in the hole was realized. This new drilling method is expected to further expand CFRP applications.

A smooth tool path generation method for ultraprecision turning discontinuous multi-freeform-surfaces with high machining efficiency

The typical tool path of turning freeform surfaces is spiral. Usually, this kind of tool path only can deal with continuous surfaces within a circular area. If the designed surfaces are not continuous, the spiral tool path will break, which will lead to a significant increase in servo following error of ultraprecision lathe during machining. In order to reduce the servo following error, the processing speed needs to be significantly reduced, which will greatly decrease the machining efficiency. To solve this problem, a smooth tool path interpolation algorithm in the non-cutting area for ultraprecision turning discontinuous multi-freeform-surfaces is proposed. In addition, more than circular area, this method can generate smooth tool paths for discontinuous generic surfaces of quasi-revolution based on the optimized space Archimedean spiral. Finally, the effectiveness and adaptability of the method are proved through two examples.

Numerical Analysis of Thermal, Fluid, and Electrical Performance of a Photovoltaic Thermal Collector at New Micro-Channels Geometry

Abstract In this article, different paths (direct, spiral, and curved) for water flow in a photovoltaic/thermal (PV/T) system are studied, and they are compared together. The intensity of radiation to the cell surface is taken 800 W/m2, and the fluid flow is considered to be laminar in the micro-channels. The PV cell absorbing radiation is of an aluminum type. The numerical solution of the three geometries is carried out using the finite volume method using ansys-fluent software. The pressure decomposition, momentum and energy discretization, and the solution of the pressure–velocity coupling are performed based on the standard method, the second-order upwind method, and the semi-implicit method for pressure-linked equations (SIMPLE) method, respectively. The convergence factor is considered to be respected and for continuity and energy equations. The results indicate that the cell surface temperature and the outlet fluid temperature decrease by increasing the Reynolds (Re) number. Moreover, electricity efficiency increases with the increased Reynolds number. The curved path has the highest electrical efficiency in comparison to other two paths. The decrease in fluid pressure of the curved path in Re = 600 is 4% and 1.3% higher than the direct and spiral paths, respectively.