869 research outputs found
Rocket Propulsion Engineering Company Small Launch Vehicle
Rocket Propulsion Engineering (RPe) is developing the first in a family of two low-cost, two stage, small rocket vehicles suitable for target, suborbital, and small-sat orbital applications. The first of these two launch vehicles, the Prospect LV-1 will have an orbital payload of 300-400 lb. The larger vehicle, the Prospect LV-2, uses about 80% of the components and technology of the LV-1 and will orbit payloads of 1500-1700 lb. Two engines are being developed. A first stage 30,000 lbf class engine (R1-30L) and a second stage engine of approximately 2400 lbf (R1-2H). The engine designs are essentially identical except for size. Propellants are hydrogen peroxide/kerosene. The engines are ablatively cooled with additional film cooling. Chamber pressure is approximately 715 PSIA. Both engines use centrifugal turbopumps driven by an open cycle, bipropellant gas generator. Medium-technology pump-fed rockets have significant advantages over pressure fed alternatives, provided the pump technology remains simple. Among these advantages are: smaller, lighter, more efficient engines; less propellant use; and simpler and smaller ground-handling equipment. Most importantly, propellant tank structure is lighter and much simpler to engineer and manufacture, and high-pressure helium tankage is greatly reduced. RPe therefore decided to put the engineering effort into developing the turbopump rather than pressure-fed vehicle structures. To be practical and cost effective, the turbopump must be simple by modern rocket engine standards. To this end, RPe has been pursuing a very modular, scalable pump design, utilizing as few components as possible – all components being readily available through standard commercial supply and manufacturing processes. The result is a very simple, very low-cost pump design that significantly enhances the overall vehicle design and greatly reduces vehicle structural weight and propellant requirements. Vehicle structure employs weight-saving features such as the use of a common propellant tank bulkhead and the extensive use of modern composites. Storable, ambient temperature propellants eliminate many of the material, embrittlement, and strain-related design problems that typically accompany cryogenic vehicles. The engines for these vehicles, especially the smaller R1-2H, should also be attractive candidates for use as the main propulsion engines on orbital transfer upper stages and as storable spacecraft engines
DNA-Ormocer based biocomposite for fabrication of photonic structures
We report microfabrication of high quality photonicstructures such as two-dimensional photonic crystals and beam splitters from a high DNA load, photosensitive Ormocer nanocomposite. This nanocomposite combines the high dye loading capacity of DNA with the photopatternability and hardness of the Ormocer. The fabrication is performed with the two-photon lithography method. Detailed studies of the deoxyribonucleic acid distribution in the fabricatedstructures are conducted with Raman microscopy. We also demonstrate that the deoxyribonucleic acid based nanocomposite films cast on glass substrates are of high enough quality to support amplified spontaneous emission from dyes intercalated in the deoxyribonucleic acid
High power and ultra-low-noise photodetector for squeezed-light enhanced gravitational wave detectors
Current laser-interferometric gravitational wave detectors employ a self-homodyne
readout scheme where a comparatively large light power (5–50 mW) is detected per photosensitive
element. For best sensitivity to gravitational waves, signal levels as low as the quantum
shot noise have to be measured as accurately as possible. The electronic noise of the detection
circuit can produce a relevant limit to this accuracy, in particular when squeezed states of light
are used to reduce the quantum noise. We present a new electronic circuit design reducing the
electronic noise of the photodetection circuit in the audio band. In the application of this circuit at
the gravitational-wave detector GEO 600 the shot-noise to electronic noise ratio was permanently
improved by a factor of more than 4 above 1 kHz, while the dynamic range was improved by
a factor of 7. The noise equivalent photocurrent of the implemented photodetector and circuit
is about 5 µA/
√\ud
Hz above 1 kHz with a maximum detectable photocurrent of 20 mA. With the
new circuit, the observed squeezing level in GEO 600 increased by 0.2 dB. The new circuit also
creates headroom for higher laser power and more squeezing to be observed in the future in
GEO 600 and is applicable to other optics experiments
DNA Based Electrolyte/Separator for Lithium Battery Application
In this study, we demonstrated the use of DNA-CTMA (DC) in combination with PolyVinylidene Fluoride (PVDF) as a host matrix or separator for Lithium based electrolyte to form solid polymer/gel like electrolyte for potential application in Li-ion batteries.
The addition of DC provided a better thermal stability of the composite electrolyte as shown by the thermos-gravimetric analysis (TGA). The AC conductivity measurements suggest that the addition of DC to the gel electrolyte had no effect on the overall ionic conductivity of the composite. The obtained films are flexible with high mechanical stretch-ability as compared to the gel type electrolytes only
Deoxyribonucleic acid-based photochromic material for fast dynamic holography
The authors report on a biopolymeric material made of deoxyribonucleic acid (DNA) complexed with the cationic surfactant cetyltrimethyl-ammonium (CTMA) and doped with the photochromic disperse red 1 dye (DR1) for dynamic holographic recording. The molar ratio of the DNA-CTMA to the dye is about 5:1. They have found that the photochromic properties of DR1 in the DNA-CTMA matrix are favorably modified in speed of response with respect to conventional polymeric matrices. Dynamic holographic gratings which were inscribed in DR1:DNA-CTMA films are characterized by switching times within a 1–10ms range. An excellent reversibility of the recording process is reported.The authors acknowledge the Australian Research Council
Discovery Project No. DP0556942, the Materials and
Manufacturing Directorate Air Force Office of Scientific Research,
the AOARD Grant No. 05-4010, and the Polish Ministry
of Science and Higher Education Grant No. N50713231/3302 for financial support
First demonstration of 6 dB quantum noise reduction in a kilometer scale gravitational wave observatory
Photon shot noise, arising from the quantum-mechanical nature of the light,
currently limits the sensitivity of all the gravitational wave observatories at
frequencies above one kilohertz. We report a successful application of squeezed
vacuum states of light at the GEO\,600 observatory and demonstrate for the
first time a reduction of quantum noise up to dB in a
kilometer-scale interferometer. This is equivalent at high frequencies to
increasing the laser power circulating in the interferometer by a factor of
four. Achieving this milestone, a key goal for the upgrades of the advanced
detectors, required a better understanding of the noise sources and losses, and
implementation of robust control schemes to mitigate their contributions. In
particular, we address the optical losses from beam propagation, phase noise
from the squeezing ellipse, and backscattered light from the squeezed light
source. The expertise gained from this work carried out at GEO 600 provides
insight towards the implementation of 10 dB of squeezing envisioned for
third-generation gravitational wave detectors
An Experiment for Observing Quantum Gravity Phenomena using Twin Table-Top 3D Interferometers
Theories of quantum gravity based on the holographic principle predict the
existence of quantum fluctuations of distance measurements that accumulate and
exhibit correlations over macroscopic distances. This paper models an expected
signal due to this phenomenology, and details the design and estimated
sensitivity of co-located twin table-top 3D interferometers being built to
measure or constrain it. The experiment is estimated to be sensitive to
displacements in a frequency band between
1 and 250 MHz, surpassing previous experiments and enabling the possible
observation of quantum gravity phenomena. The experiment will also be sensitive
to MHz gravitational waves and various dark matter candidates.Comment: Accepted for publication in Classical and Quantum Gravit
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