309 research outputs found
Distributed pressure matching strategy using diffusion adaptation
Personal sound zone (PSZ) systems, which aim to create listening (bright) and
silent (dark) zones in neighboring regions of space, are often based on
time-varying acoustics. Conventional adaptive-based methods for handling PSZ
tasks suffer from the collection and processing of acoustic transfer
functions~(ATFs) between all the matching microphones and all the loudspeakers
in a centralized manner, resulting in high calculation complexity and costly
accuracy requirements. This paper presents a distributed pressure-matching (PM)
method relying on diffusion adaptation (DPM-D) to spread the computational load
amongst nodes in order to overcome these issues. The global PM problem is
defined as a sum of local costs, and the diffusion adaption approach is then
used to create a distributed solution that just needs local information
exchanges. Simulations over multi-frequency bins and a computational complexity
analysis are conducted to evaluate the properties of the algorithm and to
compare it with centralized counterparts
Ultra-broadband Optical Switching Plasmons Waveguide in Ge Nanowires
Plasmonic devices, with their ultra-high integration density and
data-carrying capacity comparable to optical devices, are currently a hot topic
in the field of nanophotonic devices. Photodetectors, non-volatile memories,
and ultra-compact lasers based on plasmons in low-dimensional materials are
emerging at a rapid pace. However, the narrow optical response band and limited
of convenient tunable methods currently available have hindered the development
of these plasmonic materials. Here, we report a ultrabroadband non-equilibrium
plasmonic responses based on Ge nanowires tuned by optical method. We tracked
the blue shift of the plasmonic response of Ge nanowires due to photo-induced
carriers over an ultra-broad spectral range of 800-2000 . For the
first time, we have achieved the imaging of propagating surface plasmon
polaritons (SPPs) in semiconductor nanowires, which were tuned by photo-induced
carriers. The ultrafast and ultrabroadband response of semiconductor nanowire
plasmons is of great significance for future ultrafast all-optical devices
Chandra X-ray Measurement of Gas-phase Heavy Element Abundances in the Central Parsec of the Galaxy
Elemental abundances are key to our understanding of star formation and
evolution in the Galactic center. Previous work on this topic has been based on
infrared (IR) observations, but X-ray observations have the potential of
constraining the abundance of heavy elements, mainly through their K-shell
emission lines. Using 5.7 Ms Chandra observations, we provide the first
abundance measurement of Si, S, Ar, Ca and Fe, in four prominent diffuse X-ray
features located in the central parsec of the Galaxy, which are the
manifestation of shock-heated hot gas. A two-temperature, non-equilibrium
ionization spectral model is employed to derive the abundances of these five
elements. In this procedure, a degeneracy is introduced due to uncertainties in
the composition of light elements, in particular, H, C and N. Assuming that the
hot gas is H-depleted but C- and N-enriched, as would be expected for a
standard scenario in which the hot gas is dominated by Wolf-Rayet star winds,
the spectral fit finds a generally subsolar abundance for the heavy elements.
If, instead, the light elements had a solar-like abundance, the heavy elements
have a fitted abundance of 1--2 solar. The /Fe abundance ratio,
on the other hand, is mostly supersolar and insensitive to the exact
composition of the light elements. These results are robust against potential
biases due to either a moderate spectral S/N or the presence of non-thermal
components. Implications of the measured abundances for the Galactic center
environment are addressed.Comment: 13 pages, 6 figures, Accepted for publication in MNRA
The Production and Characteristics Test of Synthetic Rice Made of Maize Flour
Synthetic rice made of maize flour has a great opportunity to be developed as a staple food. Peopleused to consume synthetic rice, but only limited studies reported about the preferred characteristic of synthetic rice. The purpose of this study is 1) to produce and examine the characteristic of synthetic rice including moisture content, particle size, storage time and steam duration, and 2) toobtaine the preferred sensory level of synthetic rice based on aroma, texture, flavor and color.The procedure was startedbymakingthe maize flourto produce synthetic rice using a granulator machine. The granules was then steamed and dried under the sun light. Seventype of synthetic rice was used in this research, namely pure maize rice (100% maize flour), three mixed synthetic rice of maize flour and wheat flour, and three mixed synthetic riceofmaize flour and tapioca flour withthree different ratio 95:5, 85:75, and 75:25.). The results showed that the water content of synthetic rice was measured between 10.37 to 13.79%. While the steaming timewas reached around 46 to 68 minutes. The rice wasable to be stored about 24-26 hour. The organoleptic testsshowed that the most favorite synthetic rice was a mixture maize rice of 95% maize flour and 5% of tapioca flour for all level preference of the sensory test
Historical development and novel concepts on electrolytes for aqueous rechargeable batteries
In battery systems, aqueous electrolytes are superior in ionic conductivity, interfacial wettability, safety and environmentally benign compared to organic liquids, polymers, inorganic solid-state and ionic liquid electrolytes
Electrooxidation of ammonia on A-site deficient perovskite oxide La0.9Ni0.6Cu0.35Fe0.05O3-δ for wastewater treatment
Wastewater can contain high amounts of ammonia which can pose as a great safety threat if released into natural waters. The electrochemical oxidation of ammonia offers a viable strategy to remove high concentrations and provides an attractive method for wastewater treatment. However, finding a highly efficient and low-cost catalyst is imperative for overcoming the sluggish nature of ammonia oxidation reaction. Herein, a modified A- and B-site perovskite is proposed as a catalyst for the oxidation of ammonia, making it suitable as an anode in an ammonia electrolyser. A series of La1-yNi0.6Cu0.4-xFexO3-δ (x = 0, 0.05 and 0.10; y = 0, 0.05 and 0.10) perovskite materials were synthesised by a conventional sol–gel method. Amongst those tested oxides, La0.9Ni0.6Cu0.35Fe0.05O3-δ was found to have superior activity towards the electrooxidation of ammonia due to an optimised amount of Fe doping and the presence of oxygen vacancies introduced by an A-site deficiency. Subsequently, La0.9Ni0.6Cu0.35Fe0.05O3-δ was employed as an anode in an ammonia electrolyser where the ammonia removal efficiency reached 95.4 % in simulated wastewater after 80 hr and a substantial reduction in real wastewater was also observed. These results demonstrate that the A-site deficient perovskite materials are a viable electrode for the removal of ammonia in a practical energy setting and paves way for future applications
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