A new base station receiver for increasing diversity order in a CDMA cellular system

A new base station receiver is proposed and analyzed for a code-division multiple-access (CDMA) cellular system. The proposed receiver can achieve remarkable diversity gain by increasing diversity order with reasonable cost and complexity. From the numerical results, it is confirmed that the proposed receiver structure can be a practical solution for enhancing reverse-link capacity and improving performance in CDMA cellular system operations. The result in the letter can find its applications to legacy IS-95/cdma2000 1x base stations with simple modifications.     

Tertiary treatment of biologically treated piggery wastewater using vibratory shear-enhanced RO membrane.

This study presents a good example for the tertiary treatment of biologically treated piggery wastewater using vibratory shear enhanced RO membrane (VSEP RO). Through a simple process combination, utilizing Bioceramic SBR(BCS) and VSEP RO, at Gimhae plant livestock wastewater is treated excellently to meet the strict effluent standards. Application of RO membrane directly to the biologically treated effluent has been successful without any pretreatment to reduce high suspended solids. The combination of VESP UF followed by RO filtration processes produced a higher recovery rate in the 3-week pilot test.     

Synthesis and properties of an ionic polyacetylene with norbornene moieties

New conjugated ionic polymer with the pendent norborene moieties was prepared by the activated polymerization of 2-ethynylpyridine by using 5-[(5-bromopenthoxy)methyl]-2-norborene without any additional initiator or catalyst. This polymerization proceeded well in the mild reaction condition to give a high yield of polymer (polymer yield: 90%). The chemical structure of poly{2-ethynyl-N-[(5-norborenylmethoxy)pentyl]pyridinium bromide} (PENPPB) was characterized by such instrumental methods as NMR (¹H and ¹³C), IR, UV–vis spectroscopies, and elemental analysis to have the conjugated polymer backbone bearing norbornyl moieties. The photoluminescence maximum peak of polymer was located at 519 nm, which corresponds to the photon energy of 2.39 eV. The norbornyl substituents within the polyacetylene-based polymers shifted PL maximum values because substituent size affects the molecule arrangement. The cyclovoltammograms of polymer exhibited the electrochemically stable window at ?1.6 to 2.3 V region. It was found that the kinetics of the redox process of polymer might be mainly controlled by the electron transfer process based on the experiment of the oxidation current density of polymer versus the scan rate.     

Damage detection method for large structures using static and dynamic strain data from distributed fiber optic sensor

A method for damage detection applicable to large slender steel structures such as towers of large-scale wind turbines, long-span bridges, and high-rise buildings is presented. This method is based on continuous strain data obtained by distributed fiber optic sensor (FOS) and neural network (NN) analysis. An analytical model for cracked beam based on an energy balance approach was used to train a NN. The continuous static strains and the natural frequencies obtained from the distributed FOSs were used as the input to the trained NN to estimate the crack depths and locations. An experimental study was carried out on a cracked cantilever beam to verify the present method for damage identification. The cracks were inflicted on the beam, and static and free vibration tests were performed for the intact case and the damage cases. The distributed FOSs were used to measure the continuous strains. The damage estimation was carried out for the 5 damage cases using the NN technique. It has been found that the identified crack depths and locations agree reasonably well with the inflicted cracks on the structure.     

An efficient one-step lookahead A* algorithm for PM-CT scheduling problems

In this paper, we present an improved one-step lookahead A* algorithm for the scheduling problem for parallel-mode cluster tools, where n wafer types are simultaneously processed on a cluster tool with m chambers. Specifically, we suggest a refined cost function, priority-based node selection, N-chamber cycle detection to identify deadlock situations, and a one-step lookahead method to reduce the number of unsafe states generated. Using numerical experiments, we show that the proposed algorithm leads to a significant reduction in the number of explored states and execution time necessary to find an optimal solution.     

Cross-resistance of a chlorpyrifos-methyl resistant strain of Oryzaephilus surinamensis (Coleoptera: Cucujidae) to fumigant toxicity of essential oil extracted from Eucalyptus globulus and its major monoterpene, 1,8-cineole

The fumigant toxicities of eucalyptus essential oil and 1,8-cineole, the major component of eucalyptus oil, were tested against a chlorpyrifos-methyl resistant strain and a reference strain of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.). The resistant strain showed 1.9- and 2.2-fold higher tolerance against essential oil and 1,8-cineole fumigation toxicity, respectively, relative to the susceptible strain. The increased tolerance for the essential oil may be the result of cross-resistance. The resistance mechanisms in the resistant strain are discussed in relation to elevated detoxifying enzymes such as cytochrome P450 and esterases.     

Volatility behavior of oil,industrial commodity and stock markets in a regime-switching environment

This study supplements previous regime-switching studies on WTI crude oil and finds two possible volatility regimes for the strategic commodity prices of Brent oil, WTI oil, copper, gold and silver, and the S&P 500 index, but with varying high-to-low volatility ratios. The dynamic conditional correlations (DCCs) indicate increasing correlations among all the commodities since the 2003 Iraq war but decreasing correlations with the S&P 500 index. The commodities also show different volatility persistence responses to financial and geopolitical crises, while the S&P 500 index responds to both financial and geopolitical crises. Implications are discussed.     

Cycling performance of a lithium-ion polymer cell assembled by in-situ chemical cross-linking with fluorinated phosphorous-based cross-linking agent

Lithium-ion polymer cells composed of a carbon anode and a LiCoO₂ cathode are assembled with a gel polymer electrolyte cured by in-situ chemical cross-linking with novel cross-linking agents. The strong interfacial adhesion between the electrodes and the porous polyethylene membrane by the chemical cross-linking results in the stable capacity retention of the cell. However, a reduction in the ionic mobility in both the electrolyte and the electrodes adversely affects the high rate performance of the cell. These results imply that proper control of the cross-linking density in the cell is imperative for achieving good capacity retention and high rate performance of the cell.     

A quasi-two-dimensional electrochemistry modeling tool for planar solid oxide fuel cell stacks

A quasi-two-dimensional numerical model is presented for the efficient computation of the steady-state current density, species concentration, and temperature distributions in planar solid oxide fuel cell stacks. The model reduction techniques, engineering approximations, and numerical procedures used to simulate the stack physics while maintaining adequate computational speed are discussed. The results of the model for benchmark cases with and without on-cell methane reformation are presented with comparisons to results from other research described in the literature. Simulations results for a multi-cell stack have also been demonstrated to show capability of the model on simulating cell to cell variation. The capabilities, performance, and scalability of the model for the study of large multi-cell stacks are then demonstrated.