14 research outputs found
Itâs Always Sunny in America: Renewable Energy Policy and the Solar Economy
Renewable energy, especially solar, has become increasingly popular over the past two decades. It is clear that the United States must take a stand to decrease carbon emissions and its related impact on the environment and climate change. What is not clear, however, is whether this increase in popularity has been due to policies implemented by the government or more traditionally market supply and demand. Taking a broad historical approach I examine relevant renewable energy policies since 1978 and the impact these polices have had on fostering the solar energy market. I argue that that favorable renewable energy policies have allowed for the creation of the current solar energy economy. For this to be true, I would expect to see the fastest growth in the solar energy market on the tail of favorable policies. This thesis has found numerical and anecdotal evidence showing that there is a connection between federal policies and growth-promoting investments in solar energy. I therefore conclude by providing policy recommendations to keep the solar economy growing in a similar fashion
The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared
High spatial resolution observations in the 1 to 3.5 micron region of the
Galactic Center source known historically as IRS 13 are presented. They include
ground-based adaptive optics images in the H, Kp (2.12/0.4 micron) and L bands,
NICMOS data in filters between 1.1 and 2.2 micron, and integral field
spectroscopic data from BEAR, an Imaging FTS, in the HeI 2.06 micron and the
Br line regions. Analysis of all these data provides a completely new
picture of the main component, IRS 13E, which appears as a cluster of seven
individual stars within a projected diameter of ~0.5'' (0.02 pc). The brightest
sources, 13E1, 13E2, 13E3 (a binary), and 13E4, are all massive stars, 13E1 a
blue object, with no detected emission line while 13E2 and 13E4 are high-mass
emission line stars. 13E2 is at the WR stage and 13E4 a massive O-type star.
13E3A and B are extremely red objects, proposed as other examples of dusty WR
stars. All these sources have a common westward proper motion. 13E5, is a red
source similar to 13E3A/B. This concentration of comoving massive hot stars,
IRS 13E, is proposed as the remaining core of a massive star cluster, which
could harbor an intermediate-mass black hole (IMBH) of ~1300 M_sol. This
detection plays in favor of a scenario in which the helium stars and the other
hot stars in the central pc originate from the stripping of a massive cluster
formed several tens of pc from the center. The detection of a discrete X-ray
emission (Baganoff et al. 2003) at the IRS~13 position is examined in this
context.Comment: 14 pages, 6 figures (3 in color), LaTeX2e, accepted in A&
The Galactic Centre Source IRS 13E: a Post-LBV Wolf-Rayet Colliding Wind Binary?
IRS 13E is an infrared, mm and X-ray source in the Galactic Centre. We present the first Chandra X-ray spectrum for IRS 13E and show that it is consistent with a luminous and highly absorbed X-ray binary system. Since the X-ray luminosity is too large for a solitary star, our interpretation is that of an early-type long-period binary with strong colliding winds emission. This naturally explains the observed X-ray spectrum and count rate as well as its lack of significant short term variability. Due to the short lifetime of any nebula 0.2 pc from the putative central super-massive black-hole, we argue that the primary of IRS 13E has exited the LBV phase in the last few thousand years
Star Formation and Dynamics in the Galactic Centre
The centre of our Galaxy is one of the most studied and yet enigmatic places
in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre
(GC) is the ideal environment to study the extreme processes that take place in
the vicinity of a supermassive black hole (SMBH). Despite the hostile
environment, several tens of early-type stars populate the central parsec of
our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and
inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the
SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The
formation of such early-type stars has been a puzzle for a long time: molecular
clouds should be tidally disrupted by the SMBH before they can fragment into
stars. We review the main scenarios proposed to explain the formation and the
dynamical evolution of the early-type stars in the GC. In particular, we
discuss the most popular in situ scenarios (accretion disc fragmentation and
molecular cloud disruption) and migration scenarios (star cluster inspiral and
Hills mechanism). We focus on the most pressing challenges that must be faced
to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in
expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A.,
'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201
The Initial Mass Function in the Galactic Center
The Galactic Center contains the most massive young clusters in the Galaxy
and serves as the closest example of a massive starburst region. Our recent
results suggest that the Galactic Center environment produces massive clusters
with relatively flat initial mass functions, as might be expected on
theoretical grounds. I will discuss these recent results, along with evidence
for star formation in the immediate vicinity of the super massive black hole at
the Galactic Center. The results of this work might be useful in extrapolating
to other galactic centers with similar conditions, as well as other starburst
regions
An analysis of availability factors used in Naval Mobile Construction Battalion project planning.
http://archive.org/details/analysisofavaila00lib
Efficacy of acupuncture for health conditions in children: a review
Acupuncture has been used to treat a variety of childhood problems; however, the efficacy and safety of pediatric acupuncture remains unclear. This article reviews the existing empirical literature relating to the use of acupuncture for medical conditions in children. A systematic search of the literature revealed that acupuncture has been used to treat five main conditions in children, including pain, nocturnal enuresis, postoperative nausea/vomiting, laryngospasm/stridor, and neurological disorders. Despite a number of methodological issues, including limited sample sizes, lack of randomization, and inappropriate control groups, it is concluded that acupuncture represents a promising intervention for a variety of pediatric health conditions. To further address the safety, effectiveness, and acceptability of acupuncture in children, large-scale randomized controlled trials are needed
A sustainable supply chain management: an integrated marketing communications perspective
Sustainability has become an increasingly important issue in todayâs business world. All firms operating in domestic and global business must be cognizant of all the myriad aspects of sustainability. All areas of Marketing, including Supply-Chain Management {SCM} have to operate in this new environment. This paper looks at sustainability and its importance in today's business world from the perspective of marketing and Integrated Marketing Communications {IMC}. More and more online marketing is helping businesses build and develop new, innovative and successful IMC programs, and special attention will be given to this function and how it works with other components.
This paper will focus on the interaction between IMC and SCM in terms of sustainability. The paper first examines SCM macro aspects. Next several SCM micro examples are used to show how various SCM members tackle the challenge of sustainability from the perspective of IMC. These firms and organizations will be selected from different components of the supply-chain. For example, there will be a railroad {CSX}, a trucking company {YRC-The merged Yellow Freight and Roadway Express}, a distribution center {Giant Food}, a freight forwarder {UPS}, and a port {Port of Baltimore}. The paper will wind up with a relevant summary and conclusions section. The paper emphasizes the synergistic importance in developing excellent IMC programs to promote sustainability and for individual SCM members to promote their sustainability efforts
Low noise temperature control: application to an active cavity radiometer
We have designed low noise temperature sensing and control units with the objective of using them for the fabrication of far infrared active cavity radiometers. The sensing unit, first characterized at 300 K using industrial platinium resistance thermometers, has a noise level of ⌠25 â 30 ”Keff for a 3 hours measuring time and in a 1 Hz bandwidth. Using YBCO superconducting thermometers, the noise level goes down to 2.5 ”Keff, which is strongly limited by excess 1/f noise in the YBCO film at the superconducting transition. The sample holder used in the 90 K experiments is built with an auxiliary heating resistor, which enables an easy and accurate identification of the electrothermal model, even in the closed loop operation. Based on a design previously published by NIST, we estimate from these experimental results that the overall noise limitations of radiometers could be lowered by one order of magnitude. PACS numbers: 07.20.Dt, 07.50.Hp, 07.57.-c 1