A process-dependent real-time controller for sequencing batch reactor plants: results of full-scale operation.

This paper presents results of a research project, in which a process-dependent real-time control (RTC) strategy for a sequencing batch reactor plant was realised in full-scale. The cycle controller is based on NH4 analysers, NO3 probes, TSS probes and sludge level probes. With this new RTC strategy it was possible to increase the treatment capacity by 50%. By implementation of the new controller the TN, TP and NH4-N treatment efficiency could be improved significantly, too. The treatment efficiency concerning COD is comparable.     

Data compression in multimedia computing — standards and systems

Note. There are several ways to order the mentioned Standards of ISO. In the US, for example, one may call ANSI (212-642-4900) or Global Engineering Documents, Washington, DC (800-854-7179)     

An intelligent visualisation and decision support system for decentralised wastewater treatment plants.

Current sanitation concepts of decentralised wastewater treatment and reuse raise the issue of monitoring and maintenance of such systems. To guarantee high quality of the recycled water, systems with high requirements concerning process technology are essential. With increasing numbers of decentralised treatment systems spread over far distances it will become more and more impossible and uneconomic to have expert personnel on site. Therefore, new visualisation and intelligent information systems are necessary. The paper describes the structure and 3D-demonstrations as a base for information visualisation. Up-to-date visualisation techniques, facilitating the cognition of context-adapted information, make it possible to maximise the amount of information presented to the user without overwhelming her or him. Concerning diagnosis and decision support systems in the domain of wastewater treatment, several interesting approaches are presented, estimating their applicability for decentralised wastewater treatment systems. The intelligent decision support system presented here consists of a combined ontology- and case-based reasoning system in addition to a process monitoring system. It is responsible for plausibility checks, error diagnosis, solution proposals, and optimisation suggestions.     

Functional imaging in small animals using X-ray computed tomography--study of physiologic measurement reproducibility

X-ray computed tomography (CT) has been traditionally used for morphologic analysis and in the recent past has been used for physiology imaging. This paper seeks to demonstrate functional CT as an effective tool for monitoring changes in tissue physiology associated with disease processes and cellular and molecular level therapeutic processes. We investigated the effect of noise and sampling time on the uncertainty of tissue physiologic parameters. A whole body compartmental model of mouse was formulated to simulate tissue time density curves and study the deviation of tissue physiologic parameters from their true values. These results were then used to determine the appropriate scanning protocols for the experimental studies. Dynamic contrast enhanced CT (DCE-CT) was performed in mice following the injection of hydrophilic iodinated contrast agent (CA) at three different injection rates, namely 0.5 ml/min, 1 ml/min, and 2.0 ml/min. These experiments probed the Nyquist sampling limit for reproducibility of tissue physiologic parameters. Separate experiments were performed with three mice at four different X-ray tube currents corresponding to different image noise values. A two-compartment model (2CM) model was formulated to describe the contrast kinematics in the kidney cortex. Three different 2CMs were implemented namely the 4-parameter (4P), 5-parameter (5P), and the 6-parameter (6P) model. The tissue kinematics is fitted to the models by using the Levenberg-Marquardt algorithm implemented in IDL (RSI Inc.) programming language to minimize the weighted sum of squares. The relevant tissue physiologic parameters extracted from the models are the renal blood flow (RBF), glomerular filtration rate (GFR), fractional plasma volume, fractional tubular volumes and urine formation rates. The experimental results indicate that the deviation of the tissue physiologic parameters is within the limits required for tracking disease physiology in vivo and thus small animal functional X-ray CT would be able to determine changes in tissue physiology in vivo.     

Flow-Sheeting-Programme für die Prozeßsimulation

Flowsheeting systems for process simulation. Simulation of process plants with flowsheeting systems has been state of the art in chemical plant design and in the chemical industry for many years. Modern computers now permit steady state simulation of complex chemical plants with sufficient accuracy. This paper outlines the different approaches to steady state process simulation, names the advantages and disadvantages, and gives an outlook on further developments. Process optimization, process integration, and process synthesis will be discussed. The integration of different programs, e.g. the connection between flowsheeting systems and computer-aided design (CAD) will be described. An advance in user friendliness will be reached by latest developments in the field of personal computers and workstations and by database management systems.     

Phasengleichgewichte des Schnittes FeOn–CaO im Dreistoffsystem FeO–Fe2O3–CaO bei Eisensättigung

Überprüfung der Schmelzgleichgewichte des Dreistoffsystems FeO–Fe₂O₃–CaO auf der wüstitreichen, eisengesättigten Seite des Systems. Angaben über die Ergebnisse der thermischen Analysen, isothermen Halteversuche und mikroskopischen Untersuchungen. Aussagen über den quasibinären Schnitt Eisen-Kalkferrit bei Temperaturen unter 1150 °C sowie über den quasibinären Schnitt Calciowüstit-Kalk über 1150 °C.     

Rumination activity of dairy cows in the 24 hours before and after calving

Monitoring rumination behavior serves multiple purposes in feeding and herd management of dairy cows. The process of calving is a major event for cows, and a detailed understanding of alterations in behavioral patterns of animals in the time around calving is important in calving detection. The objective of this study was to describe the short-term changes in rumination patterns in dairy cows immediately before and after parturition. In total, 17 cows were fitted with rumination sensors that were able to monitor rumination time, number of rumination boli, and number of rumination jaw movements. Rumination time was decreased in the last 4 h antepartum and in the first 8 h postpartum. Cows stopped ruminating 123 ± 58 min (mean ± standard deviation) before calving and resumed ruminating 355 ± 194 min after calving. The number of rumination jaw movements and boli per day were decreased in the 24-h period postpartum. Rumination rate, the number of rumination jaw movements per rumination minute, and the number of boli per rumination minute changed little around calving. The calving event primarily influenced the duration and frequency of various rumination characteristics but not rumination intensity. Among detected characteristics, rumination time showed the greatest potential for monitoring of calving events.     

Zustandsschaubilder und Reduktionsgleichgewichte des Dreistoffsystems Fe-Fe2O3-CaO zwischen 550 und 1070 °C

Darstellung und Erörterung isothermer Zustandsschaubilder des Feststoffsystems Fe–Fe₂O₃–CaO bei elf charakteristischen Temperaturen. Angabe der CO₂/CO- und H₂O/H₂-Verhältnisse sowie der Sauerstoffdrücke der zugehörigen Gasphase. Entwurf von Zusammensetzung-Temperatur-Schaubildern bei der Reduktion von Fe₂O₃-CaO-Mischungen sowie des Zustandsschaubildes ?FeO?–CaO bei Eisensättigung und der Sättigungsflächen des kalkhaltigen Wüstits.     

Zur Verzunderung von unlegiertem Stahl

Kritische Erörterung des Schrifttums über die Verzunderung von Eisen und Stahl. Verzunderungsversuche an unlegierten Stählen mit unterschiedlichen Kohlenstoffgehalten in Sauerstoff. Messung von Kohlenstoffabgabe und Massenveränderung der Probe sowie Ermittlung der Kohlenstoffverteilung an den verzunderten Proben durch chemische Analyse zur Beschreibung der Entkohlung und inneren Oxydation. Ermittlung der Siliciumverteilung in Oberflächennähe mit einer Elektronenstrahlmikrosonde zum Erfassen einer dem Sauerstoffstrom gegenläufigen Siliciumdiffusion.