40,422 research outputs found
Theory of disorder-induced multiple coherent scattering in photonic crystal waveguides
We introduce a theoretical formalism to describe disorder-induced extrinsic
scattering in slow-light photonic crystal waveguides. This work details and
extends the optical scattering theory used in a recent \emph{Physical Review
Letter} [M. Patterson \emph{et al.}, \emph{Phys. Rev. Lett.} \textbf{102},
103901 (2009)] to describe coherent scattering phenomena and successfully
explain complex experimental measurements. Our presented theory, that combines
Green function and coupled mode methods, allows one to self-consistently
account for arbitrary multiple scattering for the propagating electric field
and recover experimental features such as resonances near the band edge. The
technique is fully three-dimensional and can calculate the effects of disorder
on the propagating field over thousands of unit cells. As an application of
this theory, we explore various sample lengths and disordered instances, and
demonstrate the profound effect of multiple scattering in the waveguide
transmission. The spectra yield rich features associated with disorder-induced
localization and multiple scattering, which are shown to be exasperated in the
slow light propagation regime
Residential Docks and Piers: Inventory of laws, regulations, and policies for the Southeastern United States
While the homes threatened by erosion and the developer illegally filling in marshlands are the projects that make the headlines, for many state regulatory programs, itâs the residential docks and piers that take up the most time. When
is a dock too long? What about crossing extended property lines? And at what point does a creek have too many docks?
There are no easy answers to any of the dock and pier related questions. Each state has to craft the laws and policies that are best for its natural resources and its political and legal environment. At the same time, mistakes in judgment can be costly for the organization, the homeowner, and the natural resources.
At the request of the Georgia Coastal Management Program, the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center compiled an inventory of dock information for four statesâGeorgia, Florida, North Carolina, and South Carolina. Federal laws, state laws and regulations, permitting policies, and contact information are included in a tabular format that is easy to use.
(PDF contaions 18 pages
On Learning and Unlearning
I remember passing our lunch ladyâthe nice one with a big bleach-blond afro. She was perched on an elementary-school-sized desk, eyes fixated to the television. I glanced at the screen on the way into my classroom while my teacher hesitated in the hallway, whispering to the other adults. She reentered the room a few minutes later to explain.
In the following months, my television provided me with one of the most formative, practical and comprehensive educational experiences of my life. First it was vocabulary building, with the words like âhi-jacker,â and âterrorist.â Then it was physics, learning that inertia is the reason for absolute devastation when your plane crashes into a building. Soon, âAl-Qaeda,â âthe Taliban,â and âOsama bin Ladenâ became part of my reality, as I watched a broadcast of young men in the âMiddle Eastâ (I was learning geography too!) burning American flags. [excerpt
I Don\u27t Want to Save Your Children
A few weeks ago, the moment that Iâve been dreaming of for almost half of a year finally arrived. I started the Heston Summer Experience as an intern in Gettysburg. An embarrassing amount of my winter break was devoted to writing and rewriting my applications. After receiving an invitation for an interview, I convened my roommates to help me choose an outfit and ask me practice questions, which is not something I doâŠever. Getting my acceptance letter in the mail was the ultimate highlight of a long and difficult year. When I was home for the first few weeks of summer and people were asking me about my plans, I was initially really excited to share. (Who wouldnât be?) The more time I spent explaining the internship to my friends and family though, the more embarrassed I became. [excerpt
An Equal Opportunity Rejection
Letâs talk about applications. Weâve all been there. You write your application, work on draft after draft and then you send it all off to the college or job of your dreams. And you waitâŠand waitâŠand wait. You wait for some sort of letter or phone call that says something along the lines of, âWe love you! Youâre awesome, and smart and special, and we think youâd be a great asset!â And maybe youâre lucky and you do get that letter, but letâs be real - that doesnât always happen. It can be frustrating to receive a rejection letter (or nothing at all), because in all honesty, who wants to be told that theyâre ânot good enoughâ? Not me. [excerpt
Sexism - LMFAO
So I have a confession to make, one that Iâm really not proud of, but part of being a mature person is acknowledging, accepting, and learning from your past mistakes. Here it is:
I told a sexist joke. [excerpt
Performance characteristics of ring-cusp thrusters with xenon propellant
The performance characteristics and operating envelope of several 30-cm ring-cusp ion thrusters with xenon propellant were investigated. Results indicate a strong performance dependence on the discharge chamber boundary magnetic fields and resultant distribution of electron currents. Significant improvements in discharge performance over J-series divergent-field thrusters were achieved for large throttling ranges, which translate into reduced cathode emission currents and reduced power dissipation which should be of significant benefit for operation at thruster power levels in excess of 10 kW. Mass spectrometry of the ion beam was documented for both the ring-cusp and J-series thrusters with xenon propellant for determination of overall thruster efficiency, and lifetime. Based on the lower centerline values of doubly charged ions in the ion beam and the lower operating discharge voltage, the screen grid erosion rate of the ring-cusp thruster is expected to be lower than the divergent-field J-series thruster by a factor of 2
Slow, Continuous Beams of Large Gas Phase Molecules
Cold, continuous, high flux beams of benzonitrile, fluorobenzine, and anisole
have been created. Buffer-gas cooling with a cryogenic gas provides the cooling
and slow forward beam velocities. The beam of benzonitrile was measured to have
a forward velocity peaked at 67 m s, and a continuous flux of
molecules s. These beams provide a continuous source for high
resolution spectroscopy, and provide an attractive starting point for further
spatial manipulation of such molecules, including eventual trapping
Duty to Warn and Intervention with HIV-Positive Clients
Complex ethical and legal issues are involved when an HIV-positive client presents a danger to others as a result of engaging in unprotected sex or needle sharing. This article presents a detailed assessment-and-intervention model that is based on the integration of ethical and legal principles with information about the level of risk associated with a client\u27s behavior, the HIV status of the client, and the sexual or needle-sharing partner\u27s awareness of the client\u27s HIV status. Appropriate interventions, including the duty to warn, are identified for each of the risk levels
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