Simulation of activation and propagation delay during tripolar neural stimulation

Computer simulations were perfonned to investigate the influence of stimulus amplitude on cathodal activation delay, propagation delay and blocking during stimulation with a bipolar cuff electrode. Activation and propagation delays were combined in a total delay term which was minimized between the excitation and blocking thresholds

Four-dimensional light shaping: manipulating ultrafast spatio-temporal foci in space and time

Spectral dispersion of ultrashort pulses allows simultaneous focusing of light in both space and time creating so-called spatio-temporal foci. Such space-time coupling may be combined with existing holographic techniques to give a further dimension of control when generating focal light fields. It is shown that a phase-only hologram placed in the pupil plane of an objective and illuminated by a spatially chirped ultrashort pulse can be used to generate three dimensional arrays of spatio-temporally focused spots. Exploiting the pulse front tilt generated at focus when applying simultaneous spatial and temporal focusing (SSTF), it is possible to overlap neighbouring foci in time to create a smooth intensity distribution. The resulting light field displays a high level of axial confinement, with experimental demonstrations given through two-photon microscopy and non-linear laser fabrication of glass

Perancangan Evaporator Jenis Tube In Tube Heat Exchanger pada Sistem Adsorpsi Kapasitas 5000 BTU/h dengan Pasangan Karbon Aktif-Metanol sebagai Adsorben-Adsorbat

Global warming and high electrical energy consumption issues have been attention all human in the world. Among various technologies especially refrigeration that being developed to prevent those problem. The refrigeration vapor compression cycle, which impaction on the ozone layer and potential damage of global warming because contains HCFC and CFC and Beside that, the highly electrical energy consumption might be happen. In this research proposed a designing and manufacturing of adsorption cooling system with a double bed adsorbed with capacity 5000 Btu/h. The methanol was used as adsorption and activated carbon as adsorbent, which have characteristic zero Ozone Depletion Potential (ODP) and zero Global Warming Potential (GWP) that was expected to be able to decrease damage to the ozone layer and minimize the electrical energy consumption. The method used in this research was the design. The adsorption cooling system contained two adsorbed in a U-tube and circular plate fin with tube from copper and circular plate fin structure from aluminum which a distance fins of 5 mm. An evaporator and a condenser (tube in tube of heat exchanger) with a tube from copper with total heat transfer area was 0.457 m² for evaporator, with desorption/ adsorption phase time was 20 minutes

Robust interferometer for the routing of light beams carrying orbital angular momentum

We have developed an interferometer requiring only minimal angular alignment for the routing of beams carrying orbital angular momentum. The Mach–Zehnder interferometer contains a Dove prism in each arm where each has a mirror plane around which the transverse phase profile is inverted. One consequence of the inversions is that the interferometer needs no alignment. Instead the interferometer defines a unique axis about which the input beam must be coupled. Experimental results are presented for the fringe contrast, reaching a maximum value of 93±1%

Solid-state magnetic traps and lattices

We propose and analyze magnetic traps and lattices for electrons in semiconductors. We provide a general theoretical framework and show that thermally stable traps can be generated by magnetically driving the particle's internal spin transition, akin to optical dipole traps for ultra-cold atoms. Next we discuss in detail periodic arrays of magnetic traps, i.e. magnetic lattices, as a platform for quantum simulation of exotic Hubbard models, with lattice parameters that can be tuned in real time. Our scheme can be readily implemented in state-of-the-art experiments, as we particularize for two specific setups, one based on a superconducting circuit and another one based on surface acoustic waves.Comment: 18 pages, 8 figure

Control of automated systems with a structured light illumination source

Autonomous mobile devices can self-locate, navigate and receive control signals using structured illumination from a light-emitting diode array. We present a prototype system and discuss the properties of the optical wireless control

Positioning and data broadcasting using illumination pattern sequences displayed by LED arrays

Illumination of a scene with a time-sequence of spatial light patterns enables clients within the scene to navigate, receive broadcast wireless data, or make subsequent space-division multiple access connections to a high bandwidth wireless system. We have developed dedicated binary pattern sequences, for use with arrays of light-emitting diodes (LEDs), which are projected on the area of interest. The LED arrays can be in either active-matrix or matrix-addressable format. The properties of the different sequences are compared theoretically and experimentally, highlighting a trade-off between position update rate and resilience against pixel cross-talk and interference

Toward Expressive and Scalable Sponsored Search Auctions

Internet search results are a growing and highly profitable advertising platform. Search providers auction advertising slots to advertisers on their search result pages. Due to the high volume of searches and the users' low tolerance for search result latency, it is imperative to resolve these auctions fast. Current approaches restrict the expressiveness of bids in order to achieve fast winner determination, which is the problem of allocating slots to advertisers so as to maximize the expected revenue given the advertisers' bids. The goal of our work is to permit more expressive bidding, thus allowing advertisers to achieve complex advertising goals, while still providing fast and scalable techniques for winner determination.Comment: 10 pages, 13 figures, ICDE 200

Requirements for an Inductive Voltage Adder as Driver for a Kicker Magnet with Short Circuit Termination

At CERN pulse generators based on Thyratron switches and SF6 gas filled pulse forming lines, used for driving kicker magnets, are to be replaced with semiconductor technology. Preliminary investigations show the inductive voltage adder is suitable as a pulse generator for this application. To increase the magnetic field without raising the system voltage, a short-circuit termination is often applied to a kicker magnet. Because of the electrical length of a transmission line magnet, wave propagation needs to be considered. To allow for the wavefront reflected from the short-circuit termination back to the generator, a novel approach for an inductive adder architecture has been investigated. It is based on a modified generator interface, circulating the current back into the load, until the stored energy is absorbed at the end of the pulse. This approach allows for a smaller magnetic core size compared to a conventional design with a matched load. Moreover, it enables more energy-efficient operation involving smaller storage capacitors. This paper summarizes the conceptual design features and furthermore gives an overview of the parameter space for possible applications at CERN

From interannual to decadal: 17 years of boundary current transports at the exit of the Labrador Sea

Over the past 17 years, the western boundary current system of the Labrador Sea has been closely observed by maintaining the 53°N observatory (moorings and shipboard station data) measuring the top-to-bottom flow field offshore from the Labrador shelf break. Volume transports for the North Atlantic Deep Water (NADW) components were calculated using different methods, including gap filling procedures for deployment periods with suboptimal instrument coverage. On average the Deep Western Boundary Current (DWBC) carries 30.2 ± 6.6 Sv of NADW southward, which are almost equally partitioned between Labrador Sea Water (LSW, 14.9 ± 3.9 Sv) and Lower North Atlantic Deep Water (LNADW, 15.3 ± 3.8 Sv). The transport variability ranges from days to decades, with the most prominent multiyear fluctuations at interannual to near decadal time scales (±5 Sv) in the LNADW overflow water mass. These long-term fluctuations appear to be in phase with the NAO-modulated wind fluctuations. The boundary current system off Labrador occurs as a conglomerate of nearly independent components, namely, the shallow Labrador Current, the weakly sheared LSW range, and the deep baroclinic, bottom-intensified current core of the LNADW, all of which are part of the cyclonic Labrador Sea circulation. This structure is relatively stable over time, and the 120 km wide boundary current is constrained seaward by a weak counterflow which reduces the deep water export by 10–15%