449 research outputs found
Control of the temporal and polarization response of a multimode fiber
Control of the spatial and temporal properties of light propagating in
disordered media have been demonstrated over the last decade using spatial
light modulators. Most of the previous studies demonstrated spatial focusing to
the speckle grain size, and manipulation of the temporal properties of the
achieved focus. In this work, we demonstrate temporal control of the total
impulse response integrated over all the spatial and polarization modes
propagating through a multimode fiber. We notably demonstrate a global
enhancement of light intensity at a chosen arrival time, as well as attenuating
light intensity at an arbitrary delay. We also demonstrate the full
polarization control of such engineered states and a multiple control at
different delay times, which opens interesting perspectives for non-linear
imaging through complex systems and high power fiber lasers.Comment: 10 pages including main and supplemental documents. 5 figures in the
main manuscript, 4 figures in the supplementa
Relative Abundance of Sixgill Sharks (Hexanchus griseus) in Elliott Bay, Seattle, Washington
The Sixgill Shark Research Project is designed to address gaps in the body of scientific knowledge on bluntnose sixgill sharks (Hexanchus griseus) in Puget Sound. This project utilizes three interwoven techniques: (1) genetics research, (2) visual marker tagging, and (3) video analysis. Seattle Aquarium biologists monitor sixgill shark sightings reported by local divers (since 1999) and study their relative abundance in Elliott Bay under the Aquarium’s pier (since 2003). Here we report on our findings of relative abundance.
Bluntnose sixgills are a species of conservation concern. Sixgills are listed as “near threatened” on the IUCN Red List. Living mainly at abyssal depths but also in the shallow waters of the Salish Sea, sixgills are thought to be long-lived and slow-growing, and appear to have established movement corridors and home ranges that remain relatively fixed over time. As apex predators they are important members of marine communities; and, owing to their life history characteristics such as a slow rate of maturity and low reproductive rates, are thought to be extremely vulnerable to exploitation.
Here we present our findings of relative abundance of sixgill sharks in Elliot Bay during the two time periods that the research was conducted: 2003-2005 and 2008-2015. We present the number of individual sharks seen each night, number of sharks tagged, number of returning tagged sharks, sex ratios, estimated number of sixgills residing in Elliott Bay (using capture-mark-recapture techniques), and seasonal and long-term trends in abundance
Observations on abundance of bluntnose sixgill sharks, Hexanchus griseus, in an urban waterway in the Salish Sea, 2003-2012
The bluntnose sixgill shark, Hexanchus griseus, is a widely distributed but poorly understood large, apex predator. Anecdotal reports of diver-shark encounters in the late 1990’s and early 2000’s in the Pacific Northwest stimulated interest in the normally deep-dwelling shark and the reason for its presence in the shallow waters of the Salish Sea. Analysis of underwater video documenting sharks at the Seattle Aquarium’s sixgill research site on Seattle’s waterfront and mark-recapture techniques were used to identify individual sharks to answer simple questions about abundance and seasonality. Temporal changes in relative abundance in Puget Sound were reported from a controlled study site from 2003-2012. At the Seattle Aquarium study site, 45 sixgills were observed and tagged with modified Floy visual marker tags, along with an estimated 116 observations of untagged sharks. Mark/Recapture statistical model estimates based on video observations ranged from a high of 98 sharks observed in July of 2004 to a low of 0 sharks observed in several research events from 2008-2012. Both analyses found sixgills significantly more abundant in the summer months at the Aquarium’s research station from 2003-2005 than at any other time during the study
(POSTER) Internal Restoration and Modernization of a 1948 WWII era Jukebox
Using Six Sigma guidelines under the sponsorship of The University of Indianapolis in cooperation with the client, Brugh Industrial Engineering, this project is to modernize the functionality and interface of a Rockola Model 1428 Jukebox while maintaining its vintage appeal. The process of modernization includes meeting today\u27s industrial safety standards, incorporating ethernet protocol, and utilizing a programmable logic controller, PLC. The jukebox is a showcase of current automation technology. Lighting has been upgraded from fluorescent and incandescent bulbs to addressable nano pixel LEDs. The amplifier, coin system, and record selection system were revitalized to OEM operation standards. All switches within those systems however have been upgraded to micro switch technology. Phase 1 determined that the jukebox will require the audio amplifier, coin system, and the entire control system to be rebuilt, as well as modifying the turntable to accept records that play at a speed of 45 rpm and 78 rpm. All internal electrical modifications will result in a decreased current consumption while meeting UL 508A and NFPA 70 standards. The second phase of the DesignSpine was to find the most realistic design alternatives and solutions within the given budget. The client budget for the project is 3765.62 under budget. During the third phase of the DesignSpine the team assembled the jukebox and tested the system in order to drive efficiency and useability while also eliminating unforeseen design flaws
Laguerre-Gaussian mode sorter
Light's spatial properties represent an infinite state space, making it
attractive for applications requiring high dimensionality, such as quantum
mechanics and classical telecommunications, but also inherently spatial
applications such as imaging and sensing. However, there is no demultiplexing
device in the spatial domain comparable to a grating or calcite for the
wavelength and polarisation domains respectively. Specifically, a simple device
capable of splitting a finite beam into a large number of discrete spatially
separated spots each containing a single orthogonal spatial component. We
demonstrate a device capable of decomposing a beam into a Cartesian grid of
identical Gaussian spots each containing a single Laguerre-Gaussian component.
This is the first device capable of decomposing the azimuthal and radial
components simultaneously, and is based on a single spatial light modulator and
mirror. We demonstrate over 210 spatial components, meaning it is also the
highest dimensionality mode multiplexer of any kind
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