Introduction Radiotherapy planning systems require many percentage depth dose (PDD) and profile measurements and there are various dosimeters that can be used to obtain these scans. As dose perturbation is particularly troublesome in smaller photon fields, using a low-perturbation, unshielded electron field diode (EFD) in these fields is of interest. The aim of this work was to investigate the ...

The addition of an accurate pressure sensor to the inverted echo sounder (IES) has allowed for the development of a new method for calibrating the IES’s acoustic travel-time record without the need for coincident conductivity– temperature–depth (CTD) or expendable bathythermograph profiles. Using this method, the round-trip traveltime measurement of the IES can be calibrated into various dynami...

Spherical Harmonic Transforms (SHTs) which are non-commutative Fourier transforms on the sphere are critical in global geopotential and related applications. Among the best known global strategies for discrete SHTs of band-limited spherical functions are Chebychev quadratures and least squares for equiangular grids. With proper numerical preconditioning, independent of latitude, reliable analys...

consider an n × n matrix polynomial p(λ). a spectral norm distance from p(λ) to the set of n × n matrix polynomials that havea given scalar µ ∈ c as a multiple eigenvalue was introducedand obtained by papathanasiou and psarrakos. they computedlower and upper bounds for this distance, constructing an associated perturbation of p(λ). in this paper, we extend this resultto the case of two given di...

An inverse annual variation is observed between surface pressure on the highest mountain, which has an elevation of approximately 4000 m, and in the lowlands of Taiwan (a subtropical island in east Asia). This inverse annual variation in surface pressure of high and low elevation in low latitudes reflects, essentially, a vertical phase reversal of the tropical circulation, which is illustrated ...

the present research attempts to explain dynamic pull-in instability of functionally graded micro-cantilevers actuated by step dc voltage while the fringing-field effect is taken into account in the vibrational equation of motion. by employing modern asymptotic approach namely homotopy perturbation method with an auxiliary term, high-order frequency-amplitude relation is obtained, then the infl...