A new generation scheduling program at Ontario Hydro

The new daily generation scheduling model for the Ontario Hydro system is presented. The model is capable of considering the thermal and hydraulic systems together with system reserve requirement and transmission losses. The hydraulic system is considered in a detailed formulation that can handle river couplings in a complete manner. Inability to do this was a major weakness in the peak shaving technique used since early 1970s. A special network programming technique has been used to solve the problem. This method has proved to be very efficient from a computational point of view. Test results from application of the new technique are presented and compared to the peak shaving method. The user has estimated 1.4 million dollars per year of savings from the new computer package     

Nuclear Power Plant Control beyond the 1980s

Designers of nuclear power plant control and instrumentation systems are being pushed by an electronics technology that currently passes through several generations of development during the time taken to design and bring a plant into production. Despite the success of existing designs and the pressure to stick to them, the rapidity with which new components become available and others drop from the suppliers' shelves, require that we give attention to system architectures that are more tolerant of this situation. A distributed data base, containing both on-line and archival information, made available to all systems of a nuclear power plant by means of a highly reliable communications medium, could form the basis for such an architecture. It could not only solve this problem of rapid component development but also provide for complete and comprehensive plant control and surveillance. The possibility of implementing such schemes in an operating plant is probably ten years away but development must begin now if the new electronics technology is to have a planned place in the architectures of the future. At the Chalk River Nuclear Laboratories a long range program is underway. It is exploiting extensive additions that were needed in the data acquisition and processing capability associated with engineering experiments in the large research reactors NRU and NRX.     

Differences in preschool children's conceptual strategies when thinking about animate entities and artifacts.

Two-, 3-, and 4-year-old children viewed 10 stimulus sets. Each set contained a sample picture (e.g., a dog), a basic-level taxonomic match (e.g., another dog), a thematic match (e.g., a bone), and an irrelevant match (e.g., a pen). The children were asked to choose a match that "goes with" each sample. Sample pictures were either animate entities or artifacts. The children's choice behavior indicated that a shift occurs between 3 and 4 years of age from a taxonomic bias to a thematic bias and that, at both ages, animate sample stimuli enhance the children's tendency to adopt thematic conceptual strategies. These data are consistent with recent suggestions that thematic thinking presupposes basic-level taxonomic thinking during early conceptual development and that this developmental progression occurs more rapidly in some domains of knowledge than in others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PARSEC-process analysis with recipe support for etcher control

The authors describe PARSEC, a system developed to automate processing, perform endpoint signal analysis, and monitor wafer movement within the plasma area. The system provides automatic downloading of process recipes, detection of defined process problems by the automated analysis of endpoint signals, automatic archiving of these signals, and automated data logging for increased lot-tracking efficiency. The system hardware, software, support tools, implementation, performance and results are described     

Definitions and diagnoses: A brief response to Morey and McNamara.

Morey and McNamara (see record 1987-34626-001) provided a thoughtful discussion of Widiger, Frances, Warner, and Bluhm (1986). The distinctions between definitions and diagnoses, prototypal and classical categories, and artifactual and natural concepts do have important implications for the classification and validation of the personality disorders. In this brief response, we clarify our position with respect to these issues and offer further considerations and discussion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

L^{1}-optimal compensators for continuous-time systems

Previous work has been concerned with minimizing thel^{1}-norm of an error pulse response for discrete-time SISO [1] and MIMO [2] systems. In this paper we study the problem of minimizing the L¹-norm of the error impulse response for SISO continuous-time systems. This problem is quite different from the discrete-time problem in that irrational solutions are obtained even when the problem data are rational. Two methods are suggested for the solution of the continuous-time problem; an exact method which leads to a finite-dimensional nonlinear programming problem, and an approximate method which leads to a linear programming problem.     

The effect of pulsed reverse current on the polarization behaviour of acid copper plating solutions containing organic additives

The polarization behaviour of acid copper solutions containing polyethers, sulphopropyl sulphides and chloride ions was studied using both direct and pulsed reverse current. The effect of these additives on the rest potentials of copper foils immersed in the electrolyte was also studied. Polyethers were found to have an inhibiting effect on the deposition of copper whereas the sulphopropyl sulphides produced a stimulating (i.e. depolarizing) effect. Chloride ion concentration was found to have an influence on the adsorption characteristics of the polyether. The use of pulsed reverse current in solutions containing both polyether and sulphopropyl sulphide was found to inhibit the adsorption/diffusion of the sulphopropyl sulphide at the cathode surface. Thus at higher current densities, above 2 A dm^–2, the inihibiting effect of the polyether produced a shift in the cathodic polarization potential to more negative values as compared with an equivalent current density using direct current. At lower current densities, below 2 A dm^–2, the depolarization effect of the sulphopropyl sulphide was still effective. This effect of pulsed current on additive containing solutions can improve dramatically the metal distribution in low current density areas on plated items. This was illustrated by plating Hull cell panels using both pulsed and direct current.     

Normative three-dimensional patellofemoral and tibiofemoral kinematics: a dynamic, in vivo study.

In order to advance biomechanical modeling, knee joint implant design and clinical treatment of knee joint pathology, accurate in vivo kinematic data of the combined patellofemoral and tibiofemoral joint during volitional activity are critical. For example, one cause of the increased prevalence of anterior knee pain in the female population is hypothesized to be altered tibiofemoral kinematics, resulting in pathological patellofemoral kinematics. Thus, the objectives of this paper were to test the hypothesis that knee joint kinematics vary based on gender and to explore the correlation between the 3-D kinematics of the patellofemoral and tibiofemoral joints. In order to accomplish these goals, a large (n = 34) normative database of combined six degree of freedom patellofemoral and tibiofemoral kinematics, acquired noninvasively during volitional knee extension-flexion using fast-PC (dynamic) magnetic resonance imaging, was established. In this normative database, few correlations between tibiofemoral and patellofemoral kinematics were found. Specifically, tibial external rotation did not predict lateral patellar tilt, as has been stated in previous studies. In general, significant differences could not be found based on gender. Further investigation into these relationships in the presence of pathology is warranted.     

Molecular typing techniques to characterize the development of a lactic acid bacteria community on vacuum-packaged beef

The development of a community of lactic acid bacteria from vacuum-packaged beef was investigated during a 6-week storage trial at 2 degrees C. The lactic acid bacteria population was monitored by using molecular techniques to identify a random sample of isolates at biweekly intervals during the storage trial. The polymerase chain reaction and a randomly amplified polymorphic DNA technique were used to identify and distinguish populations of lactic acid bacteria that developed during the storage trial. At week 0, the population of lactic acid bacteria was 3.5 log cfu/120 cm2 and by week 6, the population reached a maximum of 7.6 log cfu/120 cm2. A sampling from the week 0 population indicated a mixed community of Lactobacillus curvatus, Lactobacillus sakei and Leuconostoc spp. However, the sampling from week 6 indicated the population composition had changed to one where a single Leuconostoc strain predominated. This strain demonstrated antagonism towards the growth of other lactic acid bacteria isolated during the study. Additionally, the strain inhibited the growth of foodborne pathogens Escherichia coli O157:H7 and Listeria monocytogenes. DNA sequence data from the 16S rRNA gene suggested that the isolate may be a Leuconostoc gelidum strain.