13,867 research outputs found
On resolving the refractive index and the wave vector
The identification of the refractive index and wave vector for general
(possibly active) linear, isotropic, homogeneous, and non-spatially dispersive
media is discussed. Correct conditions for negative refraction necessarily
include the global properties of the permittivity and permeability functions
and . On the other hand, a
necessary and sufficient condition for left-handedness can be identified at a
single frequency (\re\epsilon/|\epsilon|+\re\mu/|\mu|<0). At oblique
incidence to semi-infinite, active media it is explained that the wave vector
generally loses its usual interpretation for real frequencies
A family of irreducible free divisors in P^2
An infinite family of irreducible homogeneous free divisors in
is constructed. Indeed, we identify sets of monomials such that the general
polynomial supported on is a free divisor.Comment: comments are welcom
A microscopic model of wave-function dephasing and decoherence in the double-slit experiment
The act of measurement on a quantum state is supposed to "collapse" the state
into one of several eigenstates of the operator corresponding to the observable
being measured. This measurement process is sometimes described as outside
standard quantum-mechanical evolution and not calculable from Schr\"odinger's
equation. There are two general approaches to the study of wave-function
collapse: one called the "consistent" or "decoherent" histories approach and
the other, the "environmental decoherence" approach, which studies the effect
of the environment upon the quantum system, to explain wave-function collapse.
In the "environmental decoherence" approach, one usually studies a
Markovian-approximated Master equation to study the time-evolution of reduced
density matrix and obtains the long-term dependence of the off-diagonal
elements of this matrix. We do not make a Markovian assumption and study a
particularly simple and calculable example. We find, the short-time behavior of
a collapsing system, at least the one considered in this paper, is not
exponential, which is a new result (the long-term behavior is, of course, still
exponential). This allows one to connect the Fermi-golden rule
quadratic-in-time behavior of a transition probability to the exponential
long-time behavior of a collapsing wave-function
Implementation of JPEG compression and motion estimation on FPGA hardware
A hardware implementation of JPEG allows for real-time compression in data intensivve applications, such as high speed scanning, medical imaging and satellite image transmission. Implementation options include dedicated DSP or media processors, FPGA boards, and ASICs. Factors that affect the choice of platform selection involve cost, speed, memory, size, power consumption, and case of reconfiguration. The proposed hardware solution is based on a Very high speed integrated circuit Hardware Description Language (VHDL) implememtation of the codec with prefered realization using an FPGA board due to speed, cost and flexibility factors; The VHDL language is commonly used to model hardware impletations from a top down perspective. The VHDL code may be simulated to correct mistakes and subsequently synthesized into hardware using a synthesis tool, such as the xilinx ise suite. The same VHDL code may be synthesized into a number of sifferent hardware architetcures based on constraints given. For example speed was the major constraint when synthesizing the pipeline of jpeg encoding and decoding, while chip area and power consumption were primary constraints when synthesizing the on-die memory because of large area. Thus, there is a trade off between area and speed in logic synthesis
Method of preparing fiber reinforced ceramic material
Alternate layers of mats of specially coated SiC fibers and silicon monotapes are hot pressed in two stages to form a fiber reinforced ceramic material. In the first stage a die is heated to about 600 C in a vacuum furnace and maintained at this temperature for about one-half hour to remove fugitive binder. In the second stage the die temperature is raised to about 1000 C and the layers are pressed at between 35 and 138 MPa. The resulting preform is placed in a reactor tube where a nitriding gas is flowed past the preform at 1100 to 1400 C to nitride the same
REDEVELOPMENT OF INDUSTRIAL LAND IN URBAN AREAS: OPPORTUNITIES AND CONSTRAINTS. A CASE STUDY OF TEXTILE MILL LAND REDEVELOPMENT IN MUMBAI
Urban industrial land is an important and integral part of city land use. Mumbai had been the industrial power house of India since the British were in rule. It was a prime centre for cotton processing that directly fed into the cotton mills that were established in the subsequent phases of history. After led by the textile mills, several other large and medium scale industries were established in the post-independence era and the development plans made provision for the same through earmarking industrial zones for manufacturing, trade and logistics operations. Bombay has shown how to build the enormous potential in industrial production and almost became one of the country’s backbones of industries and economy. However, concentration of industries and industrialization have also left many demands on city’s infrastructure and housing, and pressure began to mount on making the city inhabitable through shifting of industries to the outskirts. In the subsequent periods, what is known as the ‘decongestion’ policies were laid down in the era of first regional master plan proposed both industrial as well as population decongestion, at a time when the population rise and industrialization were on move. These together with other factors laid death knell for manufacturing industry in general and textile industry in particular. As textile mills were closing down their operations, they sought commercial redevelopment of the land, which became an important historical battle between the industry and government. The first proposal of government based on the Charles Correa Committee report sought equal distribution of land between city government, industry and state government, which was later amended to change the fate of declining textile mills through DCR 58. This paper traces these changes in industrial planning and policy in Mumbai that have some important implications to the development of industrial land in cities.industrial location policy, textile mill land, redevelopment, planning and markets
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