Optimum checking request policies

We discuss checking policies, in which an inspector is requested to perform the check, for a ono-unit system. Applying the unique modifications of Markov renewal processes, we analyse the stochastic behaviour of each CR policy (checking request policy) and CRSL policy (checking request and surveillance limit policy), where it is assumed that the failure time for each unit and the inspector's arrival time havo arbitrary distributions. Introducing replacement eosts, the request for the inspector to perform the check, system failure and surveillance, we derive the optimal policies which maximize the cost effectiveness under suitablo conditions for each model. In particular, wo discuss the optimal policies as a non-linear programming problem with two variables.     

Simple evaluation of aortic arch calcification by chest radiography in hemodialysis patients

Vascular calcification is associated with a poor prognosis in dialysis patients. It can be assessed with computed tomography but simple inoffice techniques may provide useful information. We compared the results obtained with a simple noninvasive technique with those obtained using multidetector computed tomography for aortic arch calcification volume (AoACV) in chronic hemodialysis (HD) patients. The enrolled study subjects were 63 (32 men and 31 women) maintenance HD patients. Calcification of the aortic arch was semiquantitatively estimated with a AoAC score (AoACS) on plain chest radiology. The AoACV was increased, with a mean value of 6.6 ranging from 0% to 36.5%. The coefficient of intraobserver variation was less than 2.5%. Aortic arch calcification score was highly correlated with AoACV (r=0.635, P<0.001). Multiple regression analysis showed age (F value=12.62, P<0.001) and pulse pressure (F value=4.54, P=0.037) to be significant independent determinants of AoACS. In conclusion, a simple measurement of AoACS may be useful for inoffice imaging to choose a therapeutic regimen in HD patients.     

Stabilization of a non-linear distributed parameter vibratory system

The feedback stabilization problem for a non-linear elastic distributed parameter system including a destabilizing effect is studied. The model is formulated as an evolution equation in a Hilbert space. Semigroup theory is used to investigate an initial value problem for the equation. Moreover, a control system with a finite dimensional controller is constructed. It is then proved that the state of the overall system converges to zero with a desirable exponential decay rate as time tends to infinity.     

A LRT Control Method Using Sensor Information in Distribution Systems with a Large Amount of PVs and EVs

It is of prime importance to maintain voltage profile within the proper range in distribution systems with a large amount of photovoltaics and electric vehicles (EVs). In particular, there is a possibility that line drop compensation (LDC) logic, which is utilized for the control of load ratio tap transformer (LRT) does not work properly when reverse power flow is included partially. Hence, in this paper, we have developed a new LRT control method based on the sensor information supposing that some section switchgears with sensors are introduced in the future distribution systems. Specifically, the extreme value of voltage profile is estimated by convergence calculation in the section between the section switchgear with sensor and LRT. Moreover, the voltage at the end node can be estimated by LDC method using sensor information of section switchgear. The proposed method was tested using a distribution system model and its effectiveness was shown.     

Flow behaviour and scanning electron microscopy of myosin B, soya protein components and mixtures at varying temperatures

The relationship of shear stress versus shear rate of myosin B, soya protein components and mixtures of them in solution was investigated at varying temperatures. Scanning electron microscopic observations were also made at varying temperatures. Myosin B solution showed thixotropic flow behaviour at room temperature, while the solution of soya protein components and the mixture of myosin B and soya protein components were rheopectic. Upon heating the rheopectic property of soya protein components and the mixture of myosin B and soya protein components became thixotropic. Scanning electron microscopic observations revealed that a three dimensional network was formed prior to gel formation on heating for myosin B and also for soya protein components and the mixture of myosin B and soya protein components. The results suggest that in these systems thixotropic flow behaviour precedes the formation of a protein gel on heating.     

SENSORY AND INSTRUMENTAL TEXTURE ANALYSIS OF CASSAVA (MANIHOT ESCULENTA, CRANTZ) ROOTS

Two cassava varieties, at three harvesting ages, 6, 12 and 24 months, were analyzed for sensory flavor and texture development. Maximum shear force, Texture Profile Analysis (TPA) and water absorption during cooking were determined at various sampling times. Changes during cooking were described by pseudo‐zero order models for water absorption, flavor and texture development for the fast cooking samples. The 24‐month‐old roots had higher variability and never reached optimum texture or flavor development. Significant pseudo first order models could represent hardness, cohesiveness and chewiness of the TPA, while springiness and adhesiveness varied in a non‐linear fashion. Maximum shear force was 111 N for raw samples and 8.1 N for samples that cooked in less than 25 min. Samples that required longer cook time had on the average a maximum shear force of 19 N.     

Gelation Mechanism of Soybean 11S Globulin: Formation of Soluble Aggregates as Transient Intermediates

Thermal association-dissociation behavior of soybean 11S globulin was investigated by sucrose density gradient centrifugation and polyacrylamide gel electrophoresis. Soluble aggregates with a molecular weight of 8 × 10⁶ were formed when 0.5% and 5% protein solutions were heated for 1 min at 100°C. At the lower protein concentration, subsequent heating caused disappearance of the soluble aggregate followed by complete dissociation into acidic and basic subunits. At the higher concentration, however, subsequent heating caused formation of highly polymerized aggregates, and gel was formed after 5 min of heating. The soluble aggregates appear to be transient intermediates in the course of gel formation of 11S globulin.