138,735 research outputs found
Slurry Ice as a Cooling System on 30 GT Fishing Vessel
Indonesia is the largest archipelago country in the world that has a sea area that is very spacious. Indonesian sea area is 5.8 million square kilometers and a coastline of 95 181 km has huge potential in the fisheries sector. In line with the need to further improve on the quality of the fish catch. One way to preserve fish is to use a slurry of ice. Slurry ice proved more effective preserving fishery products instead of using ice cubes. Ice slurry cooling system was designed and applied to the fishing vessel 30 GT. The cooling system uses a simple vapor compression system consists of five major components consisting of evaporator, condenser, compressor, and two pumps.In designing this system determined the type of refrigerant used in advance which type of refrigerant R-507a. Then do the design or selection of its main components. The design is only done on the evaporator. As for the other major components such as condensers, compressors, and pumps election in accordance with the specification of the power needed. After that dialakukan depiction of each system component. Then subsequently designing the laying of ice slurry cooling system components on a fishing vessel 30 GT.           Through calculations using simple thermodynamic equations obtained cooling load on this system amounted to 32.06 kW. Condenser with a power of 40 kW. Compressor with power 12 kW. Pump with capacity 10 m3 / h. With memepertimbangkan space left on the ship in the ice slurry system design on the main deck of the ship to the efficient use of space on board. The power requirements of the generator vessel increases due to the addition of ice slurry system components therefore do replacement generator into the generator with a power of 100 kW and penambahn fuel tank to 6,000 L
Approximation of L\"owdin Orthogonalization to a Spectrally Efficient Orthogonal Overlapping PPM Design for UWB Impulse Radio
In this paper we consider the design of spectrally efficient time-limited
pulses for ultrawideband (UWB) systems using an overlapping pulse position
modulation scheme. For this we investigate an orthogonalization method, which
was developed in 1950 by Per-Olov L\"owdin. Our objective is to obtain a set of
N orthogonal (L\"owdin) pulses, which remain time-limited and spectrally
efficient for UWB systems, from a set of N equidistant translates of a
time-limited optimal spectral designed UWB pulse. We derive an approximate
L\"owdin orthogonalization (ALO) by using circulant approximations for the Gram
matrix to obtain a practical filter implementation. We show that the centered
ALO and L\"owdin pulses converge pointwise to the same Nyquist pulse as N tends
to infinity. The set of translates of the Nyquist pulse forms an orthonormal
basis or the shift-invariant space generated by the initial spectral optimal
pulse. The ALO transform provides a closed-form approximation of the L\"owdin
transform, which can be implemented in an analog fashion without the need of
analog to digital conversions. Furthermore, we investigate the interplay
between the optimization and the orthogonalization procedure by using methods
from the theory of shift-invariant spaces. Finally we develop a connection
between our results and wavelet and frame theory.Comment: 33 pages, 11 figures. Accepted for publication 9 Sep 201
Returns on Resilience: The Business Case
Real estate projects designed to withstand the effects of climate change can provide substantial returns on investment and an array of other benefits, according to this new report. Case studies from 10 leading resilience projects are highlighted, ranging from a Boston hospital built to withstand coastal storms to a residential community in San Antonio built to withstand the effects of intense heat and drought. Other communities with highlighted case studies include Queens, N.Y.; Miami, FL; Grand Cayman, Cayman Islands; Nashville, TN; Tucson, AZ and Lancaster, CA.The study found an array of benefits from the climate-smart designs in addition to their strength against climate unpredictability. They include:Better energy efficiency. For example, multilayered impact-resistant windows save energy and reduce utility bills.Greater marketing, sales and leasing success driven by buyers' desires for well-built structures that will withstand harsh conditions and keep their value longer.Better financing options and lower insurance rates based on the reduced risk from resilient and hardened structures
Guaranteeing the diversity of number generators
A major problem in using iterative number generators of the form
x_i=f(x_{i-1}) is that they can enter unexpectedly short cycles. This is hard
to analyze when the generator is designed, hard to detect in real time when the
generator is used, and can have devastating cryptanalytic implications. In this
paper we define a measure of security, called_sequence_diversity_, which
generalizes the notion of cycle-length for non-iterative generators. We then
introduce the class of counter assisted generators, and show how to turn any
iterative generator (even a bad one designed or seeded by an adversary) into a
counter assisted generator with a provably high diversity, without reducing the
quality of generators which are already cryptographically strong.Comment: Small update
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