Digital filter design with state space method for 1‐bit signal processing based on delta‐sigma modulation

One‐bit signal processing based on delta‐sigma modulation has been studied for hardware implementation of signal processing systems. In the 1‐bit signal processing, finite word‐length problems such as overflow and coefficient quantization error occur. To solve the problems, a new design method with state space is proposed in this paper. Digital filters are designed to show the feasibility of the method. First, the L₁/L₂‐sensitivity is shown to evaluate coefficient quantization error and L₂ scaling constraints to prevent overflow. Second, a state space equation is presented and the L₁/L₂‐sensitivity and L₂‐scaling constraints are extended to take the filter structure and oversampling effects into account. Finally, the proposed method is shown to attain a higher SNR than conventional ones. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 48–56, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21075     

Speed estimation method for ultrahigh‐speed induction machine utilizing rotor slot harmonics appearing in neutral point voltage

Recently the development of power electronics technology has made it possible to realize ultrahigh‐speed drives, and ultrahigh‐speed drives promise to be useful in various applications. This research aims at sensorless control drive of an induction machine in the ultrahigh‐speed region by utilizing rotor slot harmonics, which occur due to the structure of the induction machine. In this paper, we focus on the slot harmonics which appear in the neutral point voltage, and we propose a method for detection of the slot harmonics voltage and a speed estimation method utilizing the FFT with limitation of the detection band. The effectiveness of the proposed method and the possibility of speed sensorless control with the proposed method are illustrated through speed estimation results obtained both offline and online. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(3): 59–68, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21120     

Single-molecule DNA patterning and detection by padlock probing and rolling circle amplification in microchannels for analysis of small sample volumes

The rolling circle amplification (RCA) is a versatile DNA amplification method in which a DNA molecule is amplified using a single DNA primer, allowing the product to be counted as a single dot. Circular templates for RCA can arise from padlock probes in highly specific DNA target-mediated ligation reactions. However, improvement of detection efficiency represents an important challenge. In homogeneous assays, the detection efficiency is generally only under 0.1%, mainly because the sample volume is too large compared with the detection volume. Here, we used microchannel surfaces in a glass microchip for DNA detection in small volume samples. First, DNA patterning on glass surfaces in microchannels was demonstrated using chemical surface patterning by UV light. By using a photochemical reaction, we realized DNA patterning in a closed space. Second, RCA was demonstrated using dilutions of target molecules, and a calibration curve was obtained. The highest detection efficiency was 22.5% by virtue of the reduced sample volumes from several hundred microliters to 5.0 nL. Accordingly, a countable number of DNA molecules was successfully detected. This method is suitable for analysis of very small volume samples such as single cells, especially by using extended-nanochannels with dimensions of 10-1000 nm.     

Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon devices with a separated double-gate saddle-type structure

Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon flash memory devices based on a separated double-gate (SDG) saddle structure with a recess channel region had two different doping regions in silicon-fin channel to operate two-bit per cell. A simulation results showed that the short channel effect, the cross-talk problem between cells, and the increase in threshold voltage distribution were minimized, resulting in the enhancement of the scaling-down characteristics and the program/erase speed.     

Physical and sensory aspects of maltodextrin gel addition used as fat replacers in confectionery filling systems

Confectionery fillings are products used in confectionery and baking industry containing approximately 30–40 g fat/100 g product. Due to the high fat content, they have considerable high caloric value. Therefore, there is a trend to decrease fat content in confectionery filling formulations. The objective of this study was to investigate the feasibility of using two types of maltodextrin gels as potential fat replacers in confectionery fillings.     

Comparison of aroma characteristics of 16 fish species by sensory evaluation and gas chromatographic analysis

The aroma properties of fish broths prepared from 16 fish species (10 saltwater, three freshwater, two anadromous and one brackish water species) were described quantitatively by reference to 10 sensory attributes. Principal component analysis (PCA) and cluster analysis of sensory attributes classified the fish into four groups. Group 1, characterised by a strong ‘green’ odour, comprised all three freshwater species (loach, pond smelt and carp), two saltwater whitefish species (snapper and conger) and eel. Group 2 included migratory coastal species (sardine, banded blue‐sprat and mackerel) and was distinguished by strong ‘fish oil’ and ‘grilled fish’ notes. Group 3 consisted of swordfish, sablefish and salmon, which exhibited a strong ‘fried chicken’ note. Group 4 included flounder, cod, tuna and goby, which were scored high for ‘cooked fish’, ‘roasted soy sauce’, ‘canned tuna’ and ‘sweet’ aromas. Partial least squares regression (PLSR) models derived from selected influential peaks in the gas chromatograms of the volatile components in the broths for each attribute were highly predictive (R² ≥ 0.936). The selected peaks corresponded well to each sensory attribute. © 2003 Society of Chemical Industry     

Atmospheric pressure solvothermal synthesis of ceria–zirconia solid solutions and their large oxygen storage capacity

Ceria–zirconia solid solution has a function as an oxygen storage material, which keeps air to fuel ratio (A/F) on a stoichiometric composition at the surface of three-way catalyst (TWC) for automotive exhaust. When A/F could be kept stoichiometric, TWC shows good catalytic activity. At first, ceria which dissolves 20 mol% of zirconia was developed by Ozawa et al. in 1987. After that, the ceria–zirconia solid solution was improved to achieve a complete solubility in the solid state at nano-level by surfactant modified homogeneous coprecipitation (J catal 169:490, 1997). Nano-level solid solution of ceria and zirconia could have been made by various methods. Those materials have similar amount of oxygen storage capacity (OSC). The improvement of OSC comes from the larger amount of bulk oxygen that can contributes OSC by the larger amount of zirconia dissolving into ceria (Catal Lett 33(1–2):193–200 1995). Solvothermal synthesis is usually done in a higher temperature than that can be reached under atmospheric pressure. The higher temperature accelerates generation of precipitation; however, a pressure vessel is necessary, and such a hermetically closed system is unsuitable to the material synthesis of the low-value-added product. Atmospheric pressure solvothermal (APS) synthesis was applied to ceria-zirconia solid solutions in this study. The APS ceria-zirconia showed larger amount of OSC. The excellent OSC performance was presumed to come from further uniformity of zirconium ions in the ceria lattice.     

Lead and cadmium contents in cereals and pulses in north-eastern China

It is known that, unlike Japanese, Koreans or southern Chinese who depend on rice as a major source of energy for daily life, people in north-eastern China rely not only on rice, but on wheat and other cereals and to a lesser extent also on pulses. Cereal and pulse samples were collected from open markets in north-eastern China, and analyzed by inductively-coupled plasma spectrometry (ICP-MS) for two potentially hazardous heavy metals — lead (Pb) and cadmium (Cd). The average Pb level in cereals (31.3 ng Pb/g as a geometric mean) and that of pulses (25.7 ng Pb/g) were similar to each other with no significant difference. Among the cereals, Pb contents were higher in foxtail millet (54.3 ng/g) and lower in maize (35.4 ng Pb/g; grain and flour in combination), wheat flour (28.8 ng Pb/g) and rice flour (22.7 ng Pb/g). Lead levels in two important types of pulses, kidney bean and soybean (24.6 and 30.8 ng Pb/g, respectively), were comparable to the levels in rice and wheat. In contrast, Cd levels were substantially higher in pulses (55.7 ng Cd/g) than in cereals (9.2 ng Cd/g), and among the pulses, Cd in soybean (55.7 ng Cd/g) was significantly higher than that in kidney bean (23.8 ng Cd/g). The possible public health implication of the Pb and Cd levels, especially the high Pb level in foxtail millet (54.3 ng Pb/g) and the high Cd level in soybean (73.5 ng Cd/g), is discussed.     

Estimating the relationship between measured wind speed and overturning truck crashes using a binary logit model

This paper develops a quantitative model that correlates overturning freight vehicle crash records in Wyoming to measured wind speeds at nearby weather stations. The database consists of 14,700 truck crashes from 1994 to 2003 and wind speed and gust information from 21 weather stations. A binary logit model was estimated from the data to determine if there was significant correlation between weather station wind data and the likelihood that the crash was of the overturning type. While it is reasonably known that local wind speeds at the crash location are critical in predicting overturning truck crash likelihood, it was not known if distant weather station data were an adequate predictor of these crash types. The results from this work indicate that weather station data can be used as a predictor of overturning crashes. This work provides the necessary first step for the development of operational rules for roadway sections that run high risk of overturning truck crashes in high wind conditions.     

Influence of oil phase concentration on droplet size distribution and stability of oil‐in‐water emulsions

The objective of this study was to investigate the effect of oil phase concentration, at different emulsification conditions concerning homogenization time and emulsifier content, on droplet size distribution and stability of corn oil‐in‐water emulsions. Emulsions were prepared with 3, 5, 10, and 20% w/w triethanolamine oleate (calculated on oil amount), 0.53% w/w carboxymethylcellulose (calculated on water amount), and 5, 10, 20, 30, or 40% w/w oil, and homogenized 5, 10, 20, and 60 min. It was found that increase in oil phase concentration led to decrease in specific surface area and increase in polydispersity of emulsion at lower emulsifier concentration and less intense homogenization. At emulsifier concentrations ≤10% and homogenization time ranges of 20–60 min the non‐monotonous variation in droplet size parameters with oil concentration was observed, as a result of the interaction between triethanolamine oleate and carboxymethylcellulose, which were confirmed by viscosity measurements. However, at emulsifier concentration of 20% an increase in specific surface area and decrease in polydispersity with the increase in oil concentration occurred due to an increase in equilibrium concentration of emulsifier in the continuous phase. Further, influence of oil concentration on emulsion creaming stability was found to be independent on emulsifier concentration and homogenization time. Therefore, a decrease in creaming with increase in oil concentration was observed in all the examined triethanolamine oleate (TEAO) concentration and homogenization time ranges. Practical applications: Emulsions are colloidal systems which can be encountered in different industrial sectors, such as food, pharmaceutical, cosmetics, oil industry, etc. Determination of the droplet size of emulsion is probably the most important way of their characterization, since it influences the properties of emulsion such as rheology, texture, shelf life stability, appearance, taste, etc. The size of the droplets depends on a wide range of parameters. One of them is certainly the concentration of the oil phase. However, since the impact of one parameter is often influenced with the intensity of the other variable involved in the emulsion generation, the aim of the present work was to examine the effect of corn oil concentration on droplet size parameters and stability of oil‐in‐water emulsions at different emulsification conditions. Therefore a step toward creation of emulsions with desired final properties was made.