Frozen Carrots Texture and Pectic Compotients as Affected by Low-Temperature-Blanching and Quick Freezing

Carrots preheated for 2 hr at 60°C and then cooked became firmer than raw or cooked carrots. After preheating, the amount of high methoxyl pectin decreased, and low methoxyl pectin increased. Firmness of carrots decreased through freezing then thawing, but preheated carrots retained firmer texture than those blanched in boiling water. Quick-freezing resulted in better texture than slow-freezing. Loss in texture was accompanied by release of pectin. Slow-freezing accelerated release of pectin as compared to quick-freezing. Preheated carrots were slower in release of pectin. The degree of esterification of pectin substances in raw carrots decreased during preheating, freezing and thawing. Cell damage in quick frozen carrots was slight. Optimum preheating occurred with 30 min at 60°C or 5 min at 70°C. Preheating and then quick freezing were effective in improving texture of frozen carrots.     

Preparation of High-Coercivity BaFe12O19

Particles of BaFe₁₂O₁₂ were prepared by chemical coprecipitation; their magnetic properties were studied. A coercive force of 6000 Oe, one of the highest reported for isotropic BaFe₁₂O₁₉, was obtained. X-ray and Moessbauer studies were conducted to examine the mechanism of formation. Superparamagnetic α-Fe₂O₃ was present during synthesis. Ferrites were sintered from these precipitated powders by both the usual method and a hot-press-forging method. The observed magnetic characteristics result from partial orientation of defect-free single-domain coprecipitated powders.     

PRESENT STATUS OF POWDER TECHNOLOGY EDUCATIONAL PROGRAMS AND RESEARCHES IN JAPAN

Tables to indicate the present status of powder technology educational programs in Japan are presented on the basis of a questionnaire style investigation by the Society of Powder Technology, Japan. Research activities in universities and research institutes are also included in the tables.

The activities of both the Society of Powder Technology and the Association of Powder Process Industry and Engineering in Japan are also introduced by explaining their organizations and annual events.     

Chinese Cabbage Midribs and Leaves Physical Changes as Related to Freeze-processing

Differences were investigated in texture, drip and pectic composition of raw or blanched Chinese cabbage midribs and leaves after conventional (F) or program freezing (PF). Softening of tissues and amount of drip were least to greatest: PF-5°C/min < PF-2°C/min < F-35°C < F-20°C, respectively. Freezing-thawing accelerated release of pectin but the freezing rate did not affect pectin release much. Total pectin in raw midribs was less than in raw leaves. The leaves contained more low methoxyl pectin than midribs, but the high methoxyl pectin was almost the same. Cell damage in frozen-thawed midribs and leaves by light-and electron-microscopy appeared extensive.     

A contour mode resonator with arched interdigital electrodes

A square plate resonator of contour mode is described in a low frequency operation. The resonator has four-part arched interdigital electrodes (IDEs) on one surface of a piezoelectric ceramic plate. The IDEs are used both for the poling treatment and the excitation of the vibration. Three modes are excited according to the combination of polarization for driving the IDEs, which are the antisymmetrical-antisymmetrical (AA) mode, the antisymmetrical-symmetrical mode (AS), and the symmetrical-symmetrical (SS) mode. The AA mode resonator is obtained in a single mode operation around 256 kHz under a condition for mechanical support.     

Robust stability of a class of uncertain nonlinear dynamical systems with time-varying delay

We consider the problem of robust stability of a class of uncertain nonlinear dynamical systems with time-varying delay. Based on the assumption that the nominal system (i.e. the system in the absence of uncertainty and delay) is stable, we derive some sufficient conditions on robust stability of uncertain nonlinear dynamical systems with time-varying delay. Some analytical methods and the Bellman-Gronwall inequality are used to investigate such sufficient conditions. The notable features of the results obtained in this paper are their simplicity in testing the stability of uncertain dynamical systems with delay and their clarity in giving an insight into system analysis. Our results are also applicable to perturbed time-delay dynamical systems without exact knowledge of the delay. In addition, a numerical example is given to demonstrate the validity of our results.     

Histological Changes in High-Pressure-Frozen Carrots

Histological changes in carrots frozen using a computer-programmed high pressure pilot unit for food processing were examined by light microscope. When raw carrots were frozen at 50 MPa, – 15°C; 100 MPa, –15°C; 150 MPa, –25°C; 200 MPa, –28°C, they were extremely damaged due to volume expansion by the formation of ice I. Conversely, carrots pressurized at 100 MPa, – 10°C (between liquid phase and ice I) and 200 MPa at –20°C (liquid phase) were not damaged because they were frozen rapidly during pressure reduction. They were not damaged even after pressurizing-then-immersing in LN₂. Carrots frozen at 240 MPa, –28°C and at 280 MPa, –25°C, were also not damaged, although ice III formed. The structure of carrots frozen at 400 MPa, –20°C (ice V) was comparatively intact. When carrots were preheated at 60°C for 30 min and frozen at 100 MPa, –15°C or at 400 MPa, –20°C, damage was reduced further.     

A non-linear optimization model for water treatment planning of a river basin

The primary objective of this study is to develop a long-range planning model for water treatment management of a river basin.

In order to satisfy environmental standards concerning river water pollution, it is fundamentally necessary to construct area-wide sewerages and sewage treatment plants. Hero, an optimal planning problem to construct these public sewage treatment systems is formulated as a non-linear optimization one. In addition the water supply planning problem is taken into consideration by assuming that waste water treated by public tertiary treatment plants can be roused for industrial purposes. The objective function adopted in this model is the total cost of both construction and operation necessary for public sewage treatment systems, and the optimal solution which minimizes this objective function is determined using the generalized reduced gradient (GRG) algorithm.

Through the study of the Yodo river basin in Japan, it is ascertained that various information necessary for planning can be obtained from the model developed in this study.     

Time optimal control of linear systems with a terminal region

In this paper we formulate a time optimal control problem for a continuous time linear system with a terminal region by the method based on functional analysis and present its solution. The solution is obtained from the results of a minimization of a convex function that is solved by a digital computer. Numerical results of an example system are shown for the two cases of amplitude constraint and energy constraint on control inputs.     

Imperfect debugging models with fault introduction rate for software reliability assessment

In general it is considered to be unrealistic in software reliability modelling to assume that the faults detected by software testing are perfectly removed without introducing new faults. In this paper we propose two software reliability assessment models with imperfect debugging by assuming that new faults are sometimes introduced when the faults originally latent in a software system are corrected and removed during the testing phase. It is assumed that the fault detection rate is proportional to the sum of the numbers of faults remaining originally in the system and faults introduced by imperfect debugging. These two models are described by a nonhomogeneous Poisson process. Several quantitative measures for reliability assessment are derived, and the maximum likelihood estimations of unknown model parameters are presented. Finally, numerical examples of software reliability analysis based on these two models are shown.