a new mechanical cultivator was proposed for mechanical weeding in part one. the precise point method was used to geometric design of this new cultivator. the aim of this research is selecting the suitable mechanism of the studied mechanisms in part one. the velocity and acceleration of links (kinematic) is the base of dynamic analysis of the systems. the variation of velocity, acceleration and...

We present a rigorous, but mathematically relatively simple and elegant, theory of first-order spatio-temporal distortions, that is, couplings between spatial (or spatial-frequency) and temporal (or frequency) coordinates, of Gaussian pulses and beams. These distortions include pulse-front tilt, spatial dispersion, angular dispersion, and a less well-known distortion that has been called "time ...

This paper investigates the bending vibration of rotating single-walled carbon nanotubes (SWCNTs) based on nonlocal theory. To this end, the rotating SWCNTs system modeled as a beam with a circular cross section and the Euler-Bernoulli beam theory (EBT) is applied with added effects such as rotary inertia, gyroscopic effect and rotor mass unbalance. Using nonlocal theory, two coupled sixth orde...

This paper presents a theory that encompasses both “plenoptic” (microlens based) and “heterodyning” (mask based) cameras in a single frequency-domain mathematical formalism. Light-field capture has traditionally been analyzed using spatio-angular representation, with the exception of the frequency-domain “heterodyning” work. In this paper we interpret “heterodyning” as a general theory of multi...

We report on the first flight of the balloon-borne QMAP experiment. The experiment is designed to make a map of the cosmic microwave background anisotropy on angular scales from 0. ◦70 to several degrees. Using the map we determine the angular power spectrum of the anisotropy in multipole bands from l ∼ 40 to l ∼ 140. The results are consistent with the Saskatoon (SK) measurements. The frequenc...

A novel metamaterial absorber design able to operate in the C frequency band is presented, along with an analysis and a method to improve both its bandwidth and its angular stability. Simulation results for a FR4-based design are shown for comparison with existing designs. In addition, a simplified equivalent circuit is provided for a better understanding of the great angular stability and wide...

In previous works light-field capture has been analyzed in spatio-angular representation. A light-field camera samples the optical signal within a single photograph by multiplexing the 4D radiance onto the physical 2D surface of the sensor. In this paper we develop a theory of multiplexing the radiance in the frequency domain by optically mixing different spatial and angular frequency component...

Based on the definition of the instantaneous frequency (signal phase derivative) as a local moment of the Wigner distribution, we derive the relationship between the instantaneous frequency and the derivative of the squared modulus of the fractional Fourier transform (fractional Fourier transform power spectrum) with respect to the angle parameter. We show that the angular derivative of the fra...

A holographic device is under development that aims to improve light collection in solar cells. The aim is to explore the potential of using photopolymer holographic optical elements (HOEs) to collect light from a moving source, such as the sun, and redirect it for concentration by a holographic lens. A working range of 45° is targeted for such a device to be useful in solar applications withou...