Synthesis of input signals in parameter identification in static systems

This paper considers the syntheses of optimal input signals for parameter identification in static systems for two types of criteria, i.e. Fisher's information and the mean-square error (MSE). A sufficient condition under which the optimal input signals are comparatively easy to obtain in the form of periodic sequence is derived, particularly for the information criterion. For the MSE criterion, a lower bound on the optimal MSE is obtained in order that information can be given for the construction of desirable sequences. As illustrative examples, unimodal and multimodal Gauss- and Cauchy-type functions are considered, and the effectiveness of the conditions is shown.     

ɛ-POLYLYSINE IMPROVES THE QUALITY OF SURIMI PRODUCTS

To apply ɛ-polylysine (PL) as a natural food preservative for the preparation of surimi products, effects of added PL on the textural properties and shelf-life of kamaboko gels were investigated. Kamaboko gels were prepared by setting at 30C for 1 h, then heating at 80C for 20 min. Breaking force and breaking strain of kamaboko gels increased slightly with increasing PL concentration up to 0.2% and decreased at 0.4%. However, the protein subunit component composition of kamaboko gels did not vary with the amount of PL added, indicating that PL did not promote the polymerization of myosin heavy chain. The increased pH value of surimi to around 7.6 as the result of the incorporation of 0.2% PL was found to be attributable to the increased textural properties of kamaboko gels. The shelf-life of kamaboko gels was significantly extended by the addition of 0.2% PL in surimi, especially at 5C and 10C storage.     

EVALUATION OF THE TEXTURAL PROPERTIES OF JAPANESE PEAR

The texture of Japanese pear (Pyrus serotina Rehder var. culta 'Housui') during fruit enlargement and ripening was evaluated. From the plate compression test, only the deformation ratio, modulus of elasticity, and relaxation were the interpretable textural indices for the Japanese pear. From the puncture test, interpretable textural indices were the rupture force, deformation at the rupture point, toughness, average firmness, initial firmness, apparent modulus of elasticity, bioyield force, penetrating force and penetrating energy in the flesh. The skin of the Japanese pear contributed 70–80% of the firmness of the fruit. As the fruits enlarged, the strain decreased, the elasticity increased, the fruit skin was more prone to mechanical damage, the fruit flesh became softer, and firmness and rigidity of the whole fruit was reduced.     

Pilot-Plant Study of a New Wastewater Treatment System

Because of severe space limitations for the reconstruction of its sewage-treatment system, the city of Nagoya has evaluated a space-saving wastewater treatment system comprising a solid-liquid separator (SLS) and biological aerated filter (BAF). The SLS is filled with plastic media forming a 2 m thick layer, and influent suspended solids are removed through the media packed zone. The BAF plant has a 2 m thick layer packed with porous ceramic media and air is diffused from the bottom of the tank.
The paper outlines the new treatment system and the ongoing study of the demonstration plant since 1992. It discusses the respective SS and BOD removal rates and concludes by showing that the new system can reduce retention period and plant area compared with the conventional activated-sludge process.     

Thermal Activation of Actomyosin Mg2+-ATPases from Flying Fish and Black Marlin Muscles

The effects of heat treatment (25°, 30°, 35°, 37°, and 40°C) on acto-myosin Mg²⁺-ATPase activity from flying fish and black marlin were studied with respect to setting of their meat pastes. The setting ability of flying fish had very high values but black marlin was low. Flying fish actomyosin Mg²⁺ATPase was activated more than three times by heating at 35°C, while the activation of black marlin was about two-thirds at 37°C. For acto-HMM ATPase, however, no appreciable difference in activation was observed between flying fish and black marlin. For both fishes, the acto-S-1 ATPase activities were not enhanced by the heat treatment. A possible role of myosin fragments in this activation is discussed.     

Development of a high energy resolution electron energy-loss spectroscopy microscope

We have developed a high energy resolution electron energy-loss spectroscopy (EELS) microscope, which can take spectra from specified small specimen areas and specified small reciprocal space areas to investigate detailed electronic structures. The EELS microscope is equipped with retarding Wien filters as the monochromator and the analyser. The filters are designed to achieve a stigmatic focus. The energy resolutions are 12 meV and 25 meV for cases without and with a specimen, respectively. Spatial and momentum resolutions are 30–110 nm in diameter and 1.1 nm⁻¹ in angular diameter, respectively. EELS spectra are presented to show the performance of this instrument.     

Preparation of Cerium-Activated Silica Glasses: Phosphorus and Aluminum Codoping Effects on Absorption and Fluorescence Properties

Cerium-activated silica (SiO₂) glasses were prepared by plasma torch chemical vapor deposition (CVD). In Ce-doped SiO₂ glasses, most Ce exists as Ce⁴⁺ ions; the remaining small amount of Ce³⁺ ions exhibits a broad fluorescence spectrum with a large Stokes shift, ∼9600 cm^-1, from the excitation spectrum peak of 324 nm. Aluminum and phosphorus codoping considerably increases the Ce³⁺ ratio and shifts the peaks of both spectra to shorter wavelengths. P codoping is the more effective way to achieve this result and in some cases produces an absorption spectrum similar to that of a Ce-doped phosphate glass. These findings are consistent with the solvatiorn shell model for codoping, as previously proposed. To codope P, a soot remelting method was devised to deal with the highly volatile P₂O₅.     

CHITOSAN AFFECTS TRANSGLUTAMINASE-INDUCED SURIMI GELATION

Effect of chitosan on barred garfish (Hemiramphus far) surimi gel was studied in the presence of EDTA and microbial transglutaminase (MTGase). An increase in breaking force of surimi gels added with 1.0% prawn shell chitosan indicated the gel enhancing effect of chitosan on the heat‐induced gelation of fish myofibrillar proteins. However, gel‐forming ability of surimi containing chitosan was inhibited in the presence of EDTA, especially at higher concentration. Therefore, the enhancing effect of chitosan was possibly mediated through the action of endogenous transglutaminase (TGase) during setting, resulting in the formation of protein‐protein and protein‐chitosan conjugates. In general, addition of MTGase remarkably increased both breaking force and deformation of surimi gel (P<0.05). However, enhancing effect of MTGase was retarded in the presence of chitosan, resulting in lower magnitude of breaking force and deformation (P<0.05). Scanning electron microscopy showed that chitosan particles were uniformly dispersed in the gel matrix. A tightly associated gel network was formed in surimi containing MTGase, whereas a large number of voids were noted in gels with EDTA. These results suggest that chitosan acted as a surimi gel enhancer in combination with endogenous TGase in fish muscle, but hindered gel formation in the presence of MTGase.     

Effects of Varying Levels of Chloride Salts on Clostridium Botulinum Toxin Production in Turkey Frankfurters

Inhibitory effects of sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl₂) on C. botulinum inoculated turkey frankfurter emulsions were determined. Ionic strengths (I.S.) of 0.42, 0.55, and 0.68 were compared (equivalent to 2.5%, 3.25%, and 4.0% NaCl). Sodium nitrite levels were constant at 150 ppm. Inoculated emulsions (10³ spores/g) were incubated and maintained at 27°C. In-creasing NaCl from I.S. 0.42 to 0.68 delayed toxin production from 4 days to at least 40 days. KCl was almost as effective as NaCl at I.S. 0.42, but inferior at higher levels. MgCl₂ did not demonstrate any inhibitory effect. Fifty percent substitution of 2.5% NaCl with KCl or MgCl₂ generally reduced time for toxin production to occur.