3,683 research outputs found
Cellulase production by Trichoderma sp. on apple pomace under solid state fermentation
The feasibility of using apple pomace for cellulase production by Trichoderma sp. under solid state fermentation was evaluated in this study. Our results indicated that initial moisture level of the medium, incubation temperature and inoculum size influenced the cellulase production greatly. The optimuminitial moisture level, incubation temperature and inoculum size were 70%, 32 and 2×108 spores/flask, respectively. The supplement of lactose and corn-steep solid to the apple pomace favored the enzyme formation markedly
Maintenance optimization for a Markovian deteriorating system with population heterogeneity
We develop a partially observable Markov decision process model to incorporate population heterogeneity when scheduling replacements for a deteriorating system. The single-component system deteriorates over a finite set of condition states according to a Markov chain. The population of spare components that is available for replacements is composed of multiple component types that cannot be distinguished by their exterior appearance but deteriorate according to different transition probability matrices. This situation may arise, for example, because of variations in the production process of components. We provide a set of conditions for which we characterize the structure of the optimal policy that minimizes the total expected discounted operating and replacement cost over an infinite horizon. In a numerical experiment, we benchmark the optimal policy against a heuristic policy that neglects population heterogeneity
Invisible surfaces enabled by the coalescence of anti-reflection and wavefront controllability in ultrathin metasurfaces
Though existing metamaterial antireflection coatings have been optimized in terms of thickness and functionality, these coatings do not provide phase control in the deep subwavelength scale. Here, the authors report multi-layered metasurfaces that provide both antireflection and phase control
The mineralogy of newly formed dust in active galactic nuclei
The tori around active galactic nuclei (AGN) are potential formation sites
for large amounts of dust, and they may help resolve the so-called dust budget
crisis at high redshift. We investigate the dust composition in 53 of the 87
Palomar Green (PG) quasars showing the 9.7 micron silicate feature in emission.
By simultaneously fitting the mid-infrared spectroscopic features and the
underlying continuum, we estimate the mass fraction in various amorphous and
crystalline dust species. We find that the dust consists predominantly of
alumina and amorphous silicates, with a small fraction in crystalline form. The
mean crystallinity is 8 +/- 6%, with more than half of the crystallinities
greater than 5%, well above the upper limit determined for the Galaxy. Higher
values of crystallinity are found for higher oxide fractions and for more
luminous sources.Comment: 24 pages, 9 figures, accepted for publication in Planetary and Space
Scienc
Microscopic magnetic dipole radiation in neutron stars
There is neutron superfluid region in NS (neutron star) interior.
For a rotating NS, the superfluid region is like a system of rotating
magnetic dipoles. It will give out electromagnetic radiation, which may
provides a new heating mechanism of NSs. This heating mechanism plus some
cooling agent may give sound explanation to NS glitches.Comment: To be published by ChJA
Testing the Bell Inequality at Experiments of High Energy Physics
Besides using the laser beam, it is very tempting to directly testify the
Bell inequality at high energy experiments where the spin correlation is
exactly what the original Bell inequality investigates. In this work, we follow
the proposal raised in literature and use the successive decays
to testify
the Bell inequality. Our goal is twofold, namely, we first make a Monte-Carlo
simulation of the processes based on the quantum field theory (QFT). Since the
underlying theory is QFT, it implies that we pre-admit the validity of quantum
picture. Even though the QFT is true, we need to find how big the database
should be, so that we can clearly show deviations of the correlation from the
Bell inequality determined by the local hidden variable theory. There have been
some critiques on the proposed method, so in the second part, we suggest some
improvements which may help to remedy the ambiguities indicated by the
critiques. It may be realized at an updated facility of high energy physics,
such as BES III.Comment: 16 pages, 5 figure
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