A computational method for the LU decomposition of rectangularmatrices and its implications to the realization of 2-D digital filters

The realization of 2-D digital filters based on the lower-upper triangular decomposition of the coefficient matrix is investigated. A numerical method based on the QA decomposition, which has some important characteristics, is proposed for reaching the LU structure. The coefficients in the final LU structure have values favorable to fixed-point arithmetic implementation. Furthermore, the QR structure can be used for the realization and possesses good numerical characteristics in terms of the approximate decomposition scheme. The symmetry in the impulse response coefficient matrix of an octagonally symmetric 2-D FIR filter is utilized to reduce the computational effort spent in the decomposition and the total number of multipliers in the final realization structure     

An asymmetric Y-branching circuit using total reflectionfor semiconductor integrated optical circuits

A new structure for a compact optical branching circuit is proposed. An asymmetric Y-branching circuit using total reflection is fabricated on an AlGaAs/GaAs wafer. Good branching operation is observed in a single-mode branching circuit with a branching angle of 45°. The exact origins of loss in the branching circuit are also clarified     

Large scale space diversity in a widely spaced network of meteorscatter communication systems and its application to mobilecommunications

A model is developed for predicting the inherent spatial multiplexing or diversity in a widely dispersed network of meteor scatter receivers. The primary measure, network diversity, is defined as the ratio of the arrival rate of useful trails observed by the entire network to the arrival rate at an average node and is less than the number of receivers in the network. Network diversity is calculated from the ground illumination footprint of individual meteor trails and weighted by the spatial arrival pattern of trails. Predictions using the model are compared to an experiment conducted in the western US. Ramifications on the design of meteor scatter communication systems for very large network applications such as automatic vehicle location and tracking are discussed     

Experimental study on a quasi-optical mode converter for transforming the whispering-gallery mode into a circularly polarized hollow radiation beam

An experiment was carried out for transforming the 120 GHz-TE_12.2 whispering-gallery mode (WGM) into a circularly polarized hollow radiation beam. A hollow beam was formed by reflecting the WGM, which was radiated from a 16 mm radius circular waveguide cut, with an annular mirror having suitable local normal vectors. The experimentally observed field intensity profiles of the reflected wave were in good agreement with calculated results.     

Research on paraffin removal and prevention by Bacillus spp. in high-salinity reservoirs

Problems in paraffin deposition occur frequently in oil exploitation. Considering the problem that some paraffin removal and prevention strains cannot grow in high-salinity reservoirs, we domesticated four salt-tolerant laboratory bacterial strains. Crude oil emulsification effect, paraffin removal rate, and paraffin prevention rate of the strains were evaluated. KB and JH-A strains exhibited good paraffin removal and prevention effects, with paraffin removal rates of 51.82% and 81.56%; and 51.82% and 80.90%, respectively. Gas chromatography mass spectrometry analysis of paraffin components before and after biodegradation was performed on KB and JH-A strains. Results showed that relative contents of n-alkanes between C15–C23 and C27–C30 evidently decreased, indicating their good biodegradation. This technique provides a new method for practical application of paraffin removal and prevention in high-salinity reservoirs.     

Distribution of vanadium and vanadyl porphyrins during fractionation of resins of heavy sulfurous oils

Features of the content and distribution of vanadium and vanadyl porphyrins in the fractions of resins, which were obtained by separation using column chromatography on silica, have been studied on heavy sulfurous oils of various deposits of the Volga–Ural basin (Russia). The difference of the vanadium and vanadyl porphyrin contents in the fractions of oils of various production complexes has been shown. Features of structural–group composition and predominant types of vanadyl porphyrins in the fractions of resins have been determined.     

Dearomatization of Diesel by Solvent Extraction: Influence of the Solvent Ratio and Temperature on Diesel Raffinate Properties

To comply with the stringent environmental regulations concerning the quality of fuels the production of ultra low sulfur fuels is obligatory. Consequently, the removal of aromatics from fuels has turned to be a serious issue. This is due to the fact that the presence of aromatics in fuel deters the ultra-low sulfur fuel production. Therefore the researcher’s interest has involved the dearomatization of fuels. As a result of the dearomatization, the quality of fuels improves tremendously. Here, solvent extraction was performed to dearomatize a feedstock sample with 20.1% aromatic and 166 ppm sulfur using acetonitrile. The extraction was performed at low temperature and ambient atmospheric pressure. The aromatic contents were determined via HPLC, while the ASTM methods were employed in other parameters determination. The results showed 72% minimum yield, 8.6% aromatic content, 58–64 cetane index, 73.2 ppm sulfur content, 5.4 viscosity, RI 1.4535, aniline point 82.15, specific gravity 0.824–0.812 with API 40.32–42.88 and flash point 70–78°C. The boiling range of the produced diesel fraction raffinate (172–373°C) that corresponds to C₈–C₂₄ cuts render it a potential candidate for other petrochemical applications.     

Petrophysical evaluation and volumetric estimation within Central swamp depobelt,Niger Delta,using 3-D seismic and well logs

Estimation of hydrocarbon volume is a critical issue for the economic aspect of the petroleum industry. It is very key in production to estimate reserves and after considerable production, to determine the efficiency of recovery and also as a basis for advanced studies such as reservoir simulations. The petrophysical parameters and hydrocarbon volume within the Central swamp depobelt in the Niger Delta has been evaluated from seismic and well logs data. Two reservoirs, GA and GB were delineated from the logs. The lithologies are sand and shale sequences. The trapping system were interpreted from seismic sections as anticlinal and fault closures. Two horizons and several faults were mapped from the seismic sections. The faults mapped are mainly synthetic and antithetic, characteristic of the Niger Delta. The seismic to well tie shows a fairly good match. The average porosity and permeability estimated for reservoir GA are 20% and 1338 md respectively. Similarly, the estimated average porosity and permeability for reservoir GB are 21% and 1392 md respectively. The results show that the oil bearing zones in the reservoirs are porous and highly permeable. There was no gas present in either of the reservoirs. The estimated initial hydrocarbon in place for reservoirs GA and GB are 57.84 MMSTB and 48.43 MMSTB respectively. The results of the research shows that the field has a decent hydrocarbon potential and can be economically produced from.     

A novel on-chip electrostatic discharge (ESD) protection withcommon discharge line for high-speed CMOS LSIs

A novel on-chip electrostatic discharge (ESD) protection for high-speed CMOS LSI's that operate at higher than 500 MHz has been developed. Introduction of a newly developed common discharge line (CDL) can completely eliminate the protection device influence on the inner circuit operation. This enables minimization of the I/O capacitance by shrinking the dimension of the output transistor, which also serves as a protection device in conventional devices. This new protection (CDL protection) was applied to a high-speed DRAM of which I/O pin capacitance specification is 2 pF. As a result, the ESD tolerance of 4 kV for the charged device model test, 4 kV for the human body model test, and 700 V for the machine model test were obtained. In addition, the DRAM data rate higher than 660 MHz at room temperature was achieved. The results show significant improvement for both ESD and the I/O capacitance, compared with the conventional structure     

Implementation of media processors

Conventional standard processors do not correspond well to the characteristics of multimedia signal processor algorithms. Therefore, special architectural approaches are necessary for multimedia processors to deliver the required high processing power with efficient use of hardware resources. Programmable approaches offer a high degree of flexibility. In order to attain multimedia signal processor performance, architectural strategies for programmable processors are based on parallelization and adaptation principles. The future multimedia signal processor implementation hinges upon an optimal trade-off between the two design spaces, which can be effectively addressed by a codesign approach