A highly nonlinear photonic crystal fiber with eight ring octagonal structure is proposed. Chalcogenide glass of As2S3 is used as the material for this photonic crystal fiber structure. The finiteelement method with perfectly matched boundary layer is employed to analyze the guiding properties. Non linearity of 13,584.5 per W-km is obtained at 1.55 μm with reasonable flattened dispersion of -25...

We report on the first implementation of a single photon avalanche diode (SPAD) in 130nm CMOS technology. The SPAD is fabricated as p+/nwell junction with octagonal shape. A guard ring of p-well around the p+ anode is used to prevent premature discharge. To investigate the dynamics of the new device, both active and passive quenching methods have been used. Single photon detection is achieved b...

In this paper, a temperature-to-frequency transducer suitable for thermal monitoring on FPGAs is presented. The dependence between delay and temperature is used to produce a frequency drift on a ring-oscillator. Different sensors have been constructed and characterized using XC4000 and XC3000 chips, obtaining typical sensibilities of 50 kHz per °C. In addition, the utility of the Xilinx OSC4 ce...

This paper deals with nonholonomic motion planning including obstacle avoidance capabilities. We show that the methods developed in absence of obstacles can be extended to the problem of obstacle avoidance, provided that they verify a topological property. Such steering methods allow us to design exact and complete collision-free path planners for a large family of systems. We show that the ste...

In this paper we relate the Fefferman–Graham ambient metric construction for conformal manifolds to the approach to conformal geometry via the canonical Cartan connection. We show that from any ambient metric that satisfies a weakening of the usual normalisation condition, one can construct the conformal standard tractor bundle and the normal standard tractor connection, which are equivalent to...

A hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. The design of the transducer was performed using the FE method with ABAQUS software, with the aim of combining the longitudinal and torsional vibration modes. The transducer horn is then fabricated using a 4-axis milling machine. The PZT stacks are employed in order to excite the transducer. The t...

Automatic control of agricultural vehicles has been a research goal for many years. Previous attempts have failed largely due to sensor limitations. With the advent of modern GPS receivers, a single low-cost sensor has been synthesized in which centimeter-level position and attitude measurements of the vehicle state are available using Carrier-Phase Differential Global Positioning System (CDGPS...

We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold (23)Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tra...

In a ®eld trial (1985±1996) on a sandy loam soil the effects of tractor traf®c and fertilisation on earthworm populations were investigated. The tractor traf®c treatments compared normal farm practice (`normal') with reduced tractor traf®c (`low'). In the fertilisation treatments, three different cattle-manure management methods were compared. The cattle manure was applied as diluted slurry, as...