Residual mode filters and H ∞ control for a class of infinite-dimensional discrete-time systems

An H _∞, control problem with measurement feedback.for infinite-dimensional discrete-time (IDDT) systems whose homogeneous parts are described by Riesz-spectra operators is considered. The aim is to construct a finite-dimensional stabilizing controller for the IDDT system that makes the H _∞ norm of the closed-loop transfer function less than a given positive number δ. For that purpose, we first formulate the IDDT system as an IDDT system in l² and derive a finite-dimensional reduced-order system for the IDDT system in l². A stabilizing controller that makes the H _∞ norm of the closed-loop transfer function less than another positive number is then constructed for the reduced-order model. The finite-dimensional controller together with a residual mode Jilter plays a role of a finite-dimensional stabilizing controller that makes the H _∞ norm of the closed-loop transfer function less than δ for the original IDDT system, if the order of the residual mode filter is chosen suficiently large.     

Impact of the Coulomb interaction on nano-scale silicon device characteristics

Monte Carlo simulations coupled self-consistently with the three-dimensional Poisson equation are carried out under the double-gate MOSFET structures. The Coulomb force experienced by an electron inside the device is directly evaluated by performing the Monte Carlo simulations with or without the full Coulomb interaction and the Coulomb force on the channel electron corresponding to plasmon excitations is clarified. It is pointed out that the consistency of the boundary condition is achieved only if the long-range Coulomb interaction is properly taken into account, and this is crucial for predicting reliable device characteristics in ultra-small devices. The drain current and transconductance are greatly reduced if the self-consistent potential fluctuations are taken into account.     

A 4-wavelength optical multi/demultiplexer for WDM subscriber loop systems using analog baseband video transmission

This paper describes the design principles and performance of optical multi/demultiplexers (MUX/DEMUX's) in wavelength-division multiplexing (WDM) subscriber-loop systems over a 50- μm core diameter, graded-index (GI), multimode fiber, which employ analog baseband video transmission using laser diodes (LD's). In this WDM arrangement, requirements for MUX/DEMUX's are: 1) low insertion loss; 2) no signal degradation caused by optical interchannel crosstalk; 3) only a small amount of analog baseband signal degradation caused by the use of MUX/DEMUX; 4) a small size and simple structure capable of multiplexing three or four wavelengths; and 5) good stability. The newly developed 4-wavelength MUX/DEMUX satisfies the preceding requirements and is suitable for application to WDM subscriber-loop systems using analog baseband signals along with digital signals.     

Estimation of forest area near deserts — production of Global Bio-Methanol from solar energy

This paper proposes a new synthesis method for methanol as a future alternative fuel, by the combination of carbon supplied from wood and hydrogen supplied from the electrolysis of water using a solar power generation system in the desert. In the developed countries, more than half of the potential forest area has already been converted into other land uses, while existing forests are well organized and available for wood production. In the developing countries, potential forest sites are expected to be available for wood production, even though they are presently grasslands or secondary forests, while natural tropical forests will not be allowed to be converted into artificial forests. The area available for plantations within 500 km distant from deserts was estimated to be 65 Mha in the world, except for the mountain areas. Biomass production from these sites will be converted annually into 980 Mt methanol with hydrogen from the deserts. This amount is equal to 34% of the world's fuel consumption by vehicles.     

Single-step synthesis and characterization of single-walled carbon nanohorns hybridized with Pd nanoparticles using N2 gas-injected arc-in-water method

Single-walled carbon nanohorns (SWCNHs) hybridized with palladium (Pd) nanoparticles were synthesized by a single-step gas-injected arc-in-water method (GI-AIW) with a Pd wire inserted inside the anode hole. In the arc zone, carbon and Pd were vaporized simultaneously, leading to the formation of hybrid material of SWCNHs and Pd nanoparticles due to effective quenching. Based on TEM and CO chemisorption analyses, Pd nanoparticles were found to be embedded inside SWCNH aggregates. The size of Pd nanoparticles, determined by X-ray diffraction, was in the range of 3–6 nm when Pd wires with diameters of 0.1 and 0.3 mm were used. Using a Pd wire with a diameter larger than 0.5 mm results in larger Pd nanoparticles which tend to be exposed to the outer surface of the hybrid material. According to thermogravimetric analyses, the weight fraction of Pd nanoparticles is increased by increasing the Pd wire diameter although the yield of Pd nanoparticles decreased. SWCNHs hybridized with dispersed Pd nanoparticles, synthesized with 0.1 mm Pd wire, exhibited strong anti-oxidation resistance with a highly graphitic structure.     

Decremental oscillation curve fitting of heart rate response following face immersion into cold water

Sociodemographic differences between rural and urban clients with severe mental illness (SMI) are explored using approaches which extend research in this area beyond limitations found in the few existing studies. Sixteen hundred adult clients from 18 Wisconsin counties are classified according to the degree of rurality of their counties of residence, using two definitions: a dichotomous metropolitan-non-metropolitan grouping and population density. There are significant differences between rural and urban clients for age, gender, and marital status, but not education or income. Young (18-35 years), unmarried males are more likely to live in more densely populated counties. Older (65 and older) women who are currently or previously married are more likely to live in less densely populated counties.     

An efficient treatment technique for TMAH wastewater by catalyticoxidation

Developers used in photolithography contain toxic tetramethylammoniumhydroxide (TMAH) and this creates a problem of how to properly treat developer wastewater. We have developed a TMAH wastewater treatment technique that consists of a combination of two novel decomposition processes: pyrolyzing TMAH to TMA and decomposing TMA to N ₂, H₂O, and CO₂ by means of a selective oxidation catalyst for nitrogenous compounds. We have tested a system using this technique in long-term treatment of the actual wastewater and have found it to be sufficiently practical. The running cost of a treatment system using our technique would be about one-ninth that of disposing of the wastewater as industrial waste but about 2.3 times that of biological treatment. Compared with biological treatment, however, our system is tolerant to many treatment conditions and operation management is much easier. Furthermore, it occupies only about one-sixth the area of a biological treatment system     

Processing of ethanol fermentation broths by Candida krusei to separate bioethanol by pervaporation using silicone rubber‐coated silicalite membranes

BACKGROUND: Pervaporation employing ethanol‐permselective silicalite membranes as an alternative to distillation is a promising approach for refining low‐concentration bioethanol solutions. However, to make the separation process practicable, it is extremely important to avoid the problems caused by the adsorption of succinate on the membrane during the separation process. In this work, the pervaporation of an ethanol fermentation broth without succinate was investigated, as well as the influence of several fermentation broth nutrient components. RESULTS: Candida krusei IA‐1 produces an extremely low level of succinate. The decrease in permeate ethanol concentration through a silicone rubber‐coated silicalite membrane during the separation of low‐succinate C. krusei IA‐1 fermentation broth was significantly improved when compared with that obtained using Saccharomyces cerevisiae broth. By treating the fermentation broth with activated carbon, bioethanol was concentrated as efficiently as with binary mixtures of ethanol/water. The total flux was improved upto 56% of that obtained from the separation of binary mixtures, compared with 43% before the addition of activated carbon. Nutrients such as peptone, yeast extract and corn steep liquor had a negative effect on pervaporation, but this response was distinct from that caused by succinate. CONCLUSION: For consistent separation of bioethanol from C. krusei IA‐1 fermentation broth by pervaporation, it is useful to treat the low nutrient broth with activated carbon. To further improve pervaporation performance, it will be necessary to suppress the accumulation of glycerol. Copyright © 2009 Society of Chemical Industry     

Genomics of industrial Aspergilli and comparison with toxigenic relatives

Aspergillus oryzae has been used in Japanese fermentation industries for more than a thousand years. The species produces large amounts of various hydrolytic enzymes and has been successfully applied to modern biotechnology. The size of the A. oryzae genome (37.5 Mb) is very close to that of A. flavus and A. niger, and 20-30% larger than that of either A. nidulans or A. fumigatus. A. oryzae and A. flavus have exactly the same number of aspartic proteinase genes, of which each orthologous pair shares highly conserved amino acid sequences. Synteny analysis with A. fumigatus and A. nidulans showed that the A. oryzae genome has a mosaic structure consisting of syntenic and non-syntenic blocks. In the microorganisms to be compared, the density of the genes having homologs was obviously higher on the syntenic than on the non-syntenic blocks. Expression analysis by the DNA microarray supported the significantly lower expression of genes on the non-syntenic than on the syntenic blocks.