Sine Method Research Articles

Experimental research on creep aging behavior of Al-Cu-Mg alloy with tensile and compressive stresses

Complex aircraft panels are generally manufactured by creep age forming process (CAF). In CAF, an aluminum panel is mainly subjected to bending, in which one side of the component is in tension and the other side is in compression. The tension and compression creep aging behaviors of Al-Cu-Mg alloy are investigated through creep tests, hardness tests and transmission electron microscope observations. It is found that the creep strains under compressive stresses are smaller than those under tensile stresses. When comparing to the microstructure of creep-aged alloy, the compressive stress can promote the formation of S phase in aluminum matrix and inhibit the generation of grain boundary precipitates, which leads to the improvement of hardness of the compression creep aged alloy. A unified creep constitutive model to describe the creep aging behavior of 2524 aluminum alloy with different stress roles was established based on the Hyperbolic Sine method, and a good agreement between the experimental results and model predictions is obtained.

Predicting Emergence in a Midwestern Population of the Green June Beetle,Cotinis nitida(L.) (Coleoptera: Scarabaeidae)

Green June beetle, Cotinis nitida (L.), is an important pest of grapes, peaches, blackberries, blueberries, apples, and pears, yet cumulative degree days that this species requires for outbreak have not been delineated. We monitored green June beetle populations in Mountain Grove, Missouri, USA, for five consecutive years (2009–2013) using traps baited with isopropanol. Our results show that cumulative degree day (CDD) calculation with starting point of March 1st, single sine method of calculation, and 10°C as the base temperature may be used for forecasting green June beetle population dynamics. Five year average ± SE was 888.96 ± 36.78 CDD for the first catch of the green June beetle and 1237.68 ± 25.31 CDD for peak trap catch. Our data also suggest that in the relatively rainy environment in Mountain Grove, the departures from the five year average observed in a given year were not correlated with precipitation preceding the first flight and peak activity of green June beetle populations.

The Method of Design Sine Grating Based on Optimal PWM

In the structured light 3d optical measurement field, the sinusoidal grating design is one of the research focus. The traditional focus methods of generating sine pattern can’t be widely accepted because of many well known defects. While the another traditional binary pattern generated from Ronchi grating which need defocusing processing, its application has also been a certain limit because of its projected pattern contrast ratio is not high.In this paper, we have proposed a designing sine grating method with the spatial modulation theory based on Optimal PWM in electronic engineering. Compared with Ronchi grating, this method of generating pattern have better fringe contrast, and more simple defocusing requirements, so this method have good practical economic value.

散斑干涉相位条纹图的频域滤波处理

In order to solve the problem of serious influence of much noise in the phase fringe patterns of digital speckle pattern interferometry on the result and accuracy of phase unwrapping,an effective method of stripe sine / cosine decomposition combined with frequency domain low-pass filtering is introduced in this paper,and the high precision filter of phase fringe patterns of digital speckle pattern interferometry is realized. Basic idea of this method is that phase fringe patterns is mapped into two patterns by the sine / cosine function before the phase image filter processing,and then is synthesized into phase fringe patterns through frequency domain filter. This decomposition frequency domain filtering method can retention phase jump information effectively when filtering. Experimental results show that compared with the traditional image noise reduction method,this method can filter out the speckle noise in images better on the basis of reserving "rush"image information,and it is simple and effective,which solves the problem of loss from 10% to 40% for phase fringe patterns gray level information when traditional filtering methods are used in stripe phase fringe patterns.

Measuring tree height: a quantitative comparison of two common field methods in a moist tropical forest

SummaryTree height is a key variable for estimating tree biomass and investigating tree life history, but it is difficult to measure in forests with tall, dense canopies and wide crowns. The traditional method, which we refer to as the ‘tangent method’, involves measuring horizontal distance to the tree and angles from horizontal to the top and base of the tree, while standing at a distance of perhaps one tree height or greater. Laser rangefinders enable an alternative method, which we refer to as the ‘sine method’; it involves measuring the distances to the top and base of the tree, and the angles from horizontal to these, and can be carried out from under the tree or from some distance away.We quantified systematic and random errors of these two methods as applied by five technicians to a size‐stratified sample of 74 trees between 5.7 and 39.2 m tall in a Neotropical moist forest in Panama. We measured actual heights using towers adjacent to these trees.The tangent method produced unbiased height estimates, but random error was high, and in 6 of the 370 measurements, heights were overestimated by more than 100%.The sine method was faster to learn, displayed less variation in heights among technicians, and had lower random error, but resulted in systematic underestimation by 20% on average.We recommend the sine method for most applications in tropical forests. However, its underestimation, which is likely to vary with forest and instrument type, must be corrected if actual heights are needed.

Nonconforming quadrilateral finite element method for a class of nonlinear sine–Gordon equations

Nonconforming quadrilateral finite element method (FEM) of the two-dimensional nonlinear sine–Gordon equation is studied for semi-discrete and Crank–Nicolson fully-discrete schemes, respectively. Firstly, we prove a special feature of a new arbitrary quadrilateral element (named modified Quasi–Wilson element), i.e., the consistency error is of order O(h2) (h denotes the mesh size) in H1-norm, which leads to optimal order error estimate and superclose result with order O(h2) for the semi-discrete scheme through a different approach from the existing literature. Secondly, because the consistency error estimate of the new modified Quasi–Wilson element can reach a staggering O(h3) order, two orders higher than that of interpolation error, the optimal order error estimates of Crank–Nicolson fully-discrete scheme are obtained on arbitrary quadrilateral meshes with Ritz projection. Moreover, a superclose result in H1-norm is presented on generalized rectangular meshes by a new technique. Thirdly, the global superconvergence results of H1-norm for both semi-discrete and fully-discrete schemes are derived on rectangular meshes with interpolated postprocessing technique. Finally, a numerical test is carried out to verify the theoretical analysis.

Threshold Temperatures and Degree-Day Estimates for Embryonic Development of the Invasive Apple SnailPomacea canaliculata(Caenogastropoda: Ampullariidae)

Pomacea canaliculate is a freshwater snail native to subtropical-temperate South America that has invaded several countries around the world. Temperature is probably one of the main limitations to the expansion of this and other apple snails to higher latitudes in invaded regions. Egg masses are aerial, and the duration of embryonic development varies greatly with air temperature. We compared different methods for determining the lower temperature thresholds and the cumulative degree-days (DD) required for the completion of the embryonic development of P. canaliculate. The lower temperature threshold was estimated with four methods: the least standard deviation from the mean of degree-days, the least standard deviation from the mean of days, the coefficient of variation in days and the linear regression coefficient method. The cumulative degree-days were estimated using hourly records and daily averages (calculated according to the single triangle and the single sine methods) of air temperature. The lower temperature thresholds ranged between 15.8°C and 18.3°C and the cumulative DD between 88.8°C.d and 133.8°C.d. The estimations obtained with the single triangle and the single sine methods were exactly the same. The values obtained with the method of the least standard deviation in degree-days and the corresponding cumulative DD were the poorest estimations. The estimates obtained with daily mean temperatures were close to those obtained with hourly records, indicating that recording only maximum and minimum temperatures should be sufficient. The use of degree-day models for egg development in Pomacea will serve to increase the effectiveness and efficacy of control measures targeted to egg masses through a better timing in their application, especially in localities with highly variable temperatures.

Analytical solution of electro-osmotic flow in rectangular Nano-channels by combined Sine transform and MHPM

Abstract The aim of this manuscript is to study the electro-osmotic flow through 2D Nano-channels analytically. In this work, the electro-osmotic flow is considered in a rectangular channel. A mixture of water or other neutral solvent and a salt compound such as sodium chloride and other buffers in which the ionic species are entirely dissociated, is considered as the operative fluid in the present study. The governing equations are derived from Navier–Stokes, Boltzmann distributions and Poisson–Nernst–Planck theory. Based on the assumption that the channel height and width are greater than the electric double layer (EDL), the Debye–Huckel approximation is applied solving equations. The Debye–Huckel approximation is used to convert the three coupled differential equations to one partial differential equation and this equation is solved using a new hybrid method based on combining the method of Sine transform and modified homotopy perturbation method. The validity of results is verified by comparing the present method with FDM. All results are presented for velocity profiles, electrical potential distributions, mole fraction cation and anion distributions and other physical properties. Results reveal that very large pressure drops are required to drive flows in small channels. However, useful volume flow rates can be obtained at a very low driving voltage. In this manuscript, we specifically focus on the new analytical solution with combining the Sine transform and MHPM. Results show very good agreement and high accuracy in comparison with FDM.

Flow Behavior and Constitutive Model Using Piecewise Function of Strain for TC11 Alloy

Abstract For TC11 alloy, this paper presented a more accurate constitutive model based on Arrhenius-type hyperbolic sine method by the cubic piecewise function of strain. During this modeling, compression tests of thermal simulation were carried out firstly. The effect of the flow factors on material flow stress was analyzed secondly. On analysis of the test data, the cubic piecewise functions of strain were proposed to ensure the Arrhenius-type hyperbolic sine model of high precision. Comparison with test results shows that the model presented is with high precision and simulation testing proposed show that this model is reliable.

Seeding Rate and Planting Arrangement Effects on Growth and Weed Suppression of a Legume–Oat Cover Crop for Organic Vegetable Systems

Brennan, E. B., N. S. Boyd, R. F. Smith, and P. Foster Agron. J. 101:979–988 (2009) The growing degree days(GDD) values shown in the original Fig. 1 were mistakenly calculated in °F with a baseline threshold of 39°F. The corrected figure here shows them calculated in °C with a baseline threshold of 4°C using the online calculator at the University of California Statewide Integrated Pest Management (http://www.ipm.ucdavis.edu). Cumulative precipitation and daily average air temperature from the California Irrigation Management Information System in Year 1 (2003–2004) and Year 2 (2004–2005) at Salinas (A, B, Station 89) and Hollister (C, D, Station 126) available at http://wwwcimis.water.ca.gov [verified 13 Apr. 2009]. The 13-yr average rainfall between November and April (1993–2007) was 395 mm (Hollister) and 346 mm (Salinas). Dry matter harvest dates, growing degree day (GDD) accumulation, and days after planting (DAP) are indicated for each site and year. The GDD were calculated with the single sine method with a baseline threshold of 4°C using the online calculator at the University of California Statewide Integrated Pest Management web site, http://www.ipm.ucdavis.edu [verified 13 Apr. 2009]. The authors regret the errors and apologize for any inconvenience this may have caused readers.

Comparison of Rye and Legume–Rye Cover Crop Mixtures for Vegetable Production in California

Brennan, E. B., N. S. Boyd, R. F. Smith, and P. Foster Agron. J. 103:449–463. doi:10.2134/agronj2010.0152. Some incorrect values in Table 1 and Fig. 1 were unfortunately published in the article above. Cumulative precipitation, air temperature, and growing degree days (GDD) from data from the California Irrigation Management Information System (CIMIS) (http://wwwcimis.water.ca.gov) in Year 1 (2003–2004) and Year 2 (2004–2005) at Hollister (CIMIS station no. 126) and Salinas (CIMIS station no. 89). The 13-yr average rainfall between November and April (1993–2007) was 395 mm (Hollister) and 346 mm (Salinas). The GDD are calculated with the single sine method with a baseline threshold of 4°C using the online calculator at the University of California Statewide Integrated Pest Management (http://www.ipm.ucdavis.edu). The updated table is shown below. The corrected values in the § footnote are highlighted in boldface type. In the published version the values in the footnote were reported in $/lb rather than $/kg. The growing degree day (GDD) shown in the original Fig. 1 were calculated in °F with a baseline threshold of 39°F. The corrected Fig. 1 here shows them calculated in °C with a baseline threshold of 4°C using the online calculator at the University of California Statewide Integrated Pest Management (http://www.ipm.ucdavis.edu).’ The authors regret the errors and apologize for any inconvenience this may have caused readers.

Analysis, Synthesis, and Classification of Nonlinear Systems Using Synchronized Swept-Sine Method for Audio Effects

A new method of identification, based on an input synchronized exponential swept-sine signal, is used to analyze and synthesize nonlinear audio systems like overdrive pedals for guitar. Two different pedals are studied; the first one exhibiting a strong influence of the input signal level on its input/output law and the second one exhibiting a weak influence of this input signal level. The Synchronized Swept Sine method leads to a Generalized Polynomial Hammerstein model equivalent to the pedals under test. The behaviors of both pedals are illustrated through model-based resynthesized signals. Moreover, it is also shown that this method leads to a criterion allowing the classification of the nonlinear systems under test, according to the influence of the input signal levels on their input/output law.

머리전달함수 측정법의 실험적 비교

Three methods(the stepped sine method, the statistical method(random excitation method) and the maximum-length sequence(MLS) method) for head-related transfer functions(HRTFs) are experimentally compared in view point of accuracy and efficiency. First, the stepped sine method has high signal-to-noise ratio, but low efficiency. Second, the statistical method is fast measurement speed, but weak to noise than the other methods. Finally, the MLS method shows both good efficiency and high signal-to-noise ratio, but it needs additional software or equipment such as MLS signal generator. For comparison of measurement accuracy, HRTFs of KEMAR dummy are measured for various azimuths and elevations. Error norms for magnitude and phase of HRTFs are defined and calculated for the measured HRTFs. The calculated error norms show that the methods give similar results in magnitude and phase except a little phase difference in the MLS method.

Thermal Time Clock for Estimating Phenological Development ofSchistocerca Piceifrons PiceifronsWalker (Orthoptera: Acrididae) in Northeastern Mexico

The Central American locust, Schistocerca piceifrons piceifrons Walker, is an economically important agricultural pest in Mexico and Central America. This species is characterized by its ability to gregarize and migrate long distances. High infestations of S. p. piceifrons have occurred in northeastern Mexico since 1998, particularly in the Huasteca region (South Tamaulipas, East San Luis Potosi, North Veracruz and the State of Hidalgo). The aim of this study was to develop a model that relates the life cycle of the Central American locust with the climatic conditions of northeastern Mexico. The model is expressed in terms of a Thermal Time Clock calculated from mean monthly temperatures and photoperiod. Historic temperature data of 20 y, from 20 meteorological stations, were used to calculate average monthly (Ψmonth) and yearly (Ψyear) values for thermal time (units are °C-days). For these calculations we used the Allen sine method, a lower temperature threshold (k1 =15.3 °C) and an upper thermal threshold (k2 = 38.5 °C). An average Thermal Time Locust Development Clock (TTLDC) was calculated using the relationship (Ψmonth/Ψyear)*360, which quantifies the monthly angular contribution on the clock (Ψ = 10.6 α). Essentially, the clock is a translator between thermal time and calendar time (or vice versa) and may be used to forecast locust-stage development dates, starting from a given “Bio-fix” point. This clock can be used to program management activities of this pest. Field observations from 2001 to 2008, on population density and development stages of the Central American locust, were consistent with the development times recorded in the TTLDC.

Study on Error Measurement Method for Actuator Frequency Characteristic Test System

System error measurement is key step in actuator frequency characteristic test and practical system error measurement methods must be studied to provide qualified results for system error compensation. Two error measurement methods (swept sine and FFT: fast Fourier transform) are explored, a strong anti-jamming frequency characteristic algorithm is perfected for swept sine and digital smoothing is introduced for improving accuracy of FFT. Numerical examples verified accuracy and robustness of swept sine and validity of FFT. These methods were applied to measure system error in missile actuator test system, the experiments showed that swept sine method could gain smooth and stable results and FFT method could achieve rather close results with swept sine. This study is part of general test system of some missile and provides valid technology analysis and reliable measurement results of system error for its actuator test.

An Improved Tree Height Measurement Technique Tested on Mature Southern Pines

Abstract Virtually all techniques for tree height determination follow one of two principles: similar triangles or the tangent method. Most people apply the latter approach, which uses the tangents of the angles to the top and bottom and a true horizontal distance to the subject tree. However, few adjust this method for ground slope, tree lean, crown shape, and crown configuration, making errors commonplace. Given documented discrepancies exceeding 30% with current methods, a reevaluation of height measurement is in order. The sine method is an alternative that measures a real point in the crown. Hence, it is not subject to the same assumptions as the similar triangle and tangent approaches. In addition, the sine method is insensitive to distance from tree or observer position and can not overestimate tree height. The advantages of the sine approach are shown with mature southern pines from Arkansas.

ImpuR: A Collection of Diagnostic Tools Developed inRin the Context of Peak Impurity Detection in HPLC-DAD but Potentially Useful with Other Types of Time-Intensity Matrices

HPLC-DAD systems generate time intensity (absorbance) matrices called spectrochromatograms. Under good experimental conditions, spectro-chromatograms of elution peaks of pure analytes are bilinear products of a time peak and an absorbance spectrum. Co-eluting impurities create deviations from this pure bilinear structure. Unfortunately, other imperfections, such as scan averaging, large optical windows, imperfect lamp alignment, mobile phase fluctuations, etc. also create departures from the pure bilinear structure. This makes it hard to distinguish low concentration impurities from artifacts and hampers safe detection of contaminants. There are two main ways to deal with such artifacts: removal and simulation, and ImpuR provides R functions to do both and to integrate both approaches. More specifically, ImpuR provides a set of tools to explore time-intensity matrices with respect to their bilinear structure and departures from it. It includes exploratory graphs for bilinear matrices (bilinear residual graphs and singular value decompositions), spectral dissimilarity curves via window-evolving factor analysis with heteroscedasticity correction and the sine method, methods for removal of artifacts, and a comprehensive simulation tool to assess the impact of potential artifacts and to allow for the construction of guide curves for use with the sine method.

Toothed whale monophyly reassessed by SINE insertion analysis: The absence of lineage sorting effects suggests a small population of a common ancestral species

Morphological data have indicated that toothed whales form a monophyletic group. However, research published in the last several years has made the issue of the monophyly or paraphyly of toothed whales a subject of debate. Our group previously characterized three independent loci in which SINE insertions were shared among dolphins and sperm whales, thus supporting the traditional, morphologically based hypothesis of toothed whale monophyly. Although in recent years a few additional molecular works proposed this topology, there is still skepticism over this monophyly from the view point of molecular systematics. When the phylogeny of rapidly radiated taxa is examined using the SINE method, it is important to consider the ascertainment bias that arises when choosing a particular taxon for SINE loci screening. To overcome this methodological problem specific to the SINE method, we examined all possible topologies among sperm whales, dolphins and baleen whales by extensively screening SINE loci from species of all three lineages. We characterized nine independent SINE loci from the genomes of sperm whales and dolphins, all of which cluster sperm whales and dolphins but exclude baleen whales. Furthermore, we characterized ten independent loci from baleen whales, all of which were amplified in a common ancestor of these whales. From these observations, we conclude that toothed whales form a monophyletic group and that no ancestral SINE polymorphisms hinder their phylogenetic assignment despite the short divergence times of the major lineages of extant whales during evolution. These results suggest that a small population of common ancestors of all toothed whales ultimately diverged into the lineages of sperm whales and dolphins.

Factorization method and stability of ϕ4 and Sine–Gordon theory

In this paper, we consider ϕ 4 and Sin–Gordon theory and also we construct the general form of the stability equation. In order to discuss the stability, we use factorization method. Using the associated Jacobi differential equation , we obtain the exactly bound states of the ϕ 4 and Sine–Gordon theory. According to the supersymmetry approach, these bound states are represented by two pairs of first order differential operators.

Calculation of the tilts of curved lines

From time to time, we encounter some dependence in a form of a curve. For the sake of comparison, the tilt of the curve could be taken as its characteristics. We present two methods for calculating a ratio of tilts of the curved lines. The first one consists in singular value decomposition of the data matrix. If the variability in the data is caused by single effect, i.e., the first singular value is about 99 times larger than the second one, then the first loadings vector reflects the ratio of tilts. As the useful variants of this method, the evolving and gliding calculation on the reduced data matrices were investigated; if they give the same (overlapping) results the method is considered as adequate. The other method comprises calculating suitable cosine and sine functions of amplitudes, respectively. In this cos–sine method each vector, and consequently each curve, is represented by two coordinates (xf, yf) of a point and the whole data matrix can be visualised as a cluster of points which can be circumscribed by confidence ellipses. If the shorter half-axis in such an ellipse is negligible, then the norms of the point vectors are in ratio of curve tilts.