Quantifying the uncertainty of on-line sensors at WWTPs during field operation

It remains an ongoing task to quantify the uncertainty of continuous measuring systems at WWTPs during field operation. The commonly used methods are based on lab experiments under standardized conditions and are only suitable for characterizing the measuring device itself. For measuring devices under field conditions, a knowledge of the response time, trueness and precision is equally important.

A method is proposed which can be used to characterize newly installed on-line sensors or to evaluate monitoring data which may contain systematic errors. The concept is based on comparative measurements between the sensor and a reference. A linear regression is used to differentiate between trueness and precision. Various statistical tests are conducted to validate the preconditions of linear regression. The information about the trueness and precision of the measuring system under field conditions helps to adapt control strategies more effectively to the relevant processes and permits sophisticated control concepts. Moreover, the concept can help to define guidelines for evaluating the uncertainties of effluent quality monitoring to overcome the concerns about on-line sensors, improve the trust in these systems and to allow the use of continuously measuring systems for legislative purposes.

The approach is discussed in detail in this paper and all statistical tests and formulas are listed in the Appendix.     

A guideline for simulation studies of wastewater treatment plants.

A guideline for simulation studies of wastewater treatment plants is proposed. The aim of the HSG-guideline is to define a reference quality level that helps to make the results of simulation studies comprehensible and comparable and therefore increases the quality and reliability of mathematical modelling in wastewater treatment. The paper gives a summary of the HSG-guideline, written by a group of university members from Germany, Austria and Switzerland.     

Localized Deformation and Fracture in Neutron Irradiated Zircaloy-2

A detailed examination of the deformation bands and the fracture surface morphologies was made with neutron irradiated Zircaloy-2 sheet that had been prepared with similar compositions and microstructures, but with different crystallographic textures. These materials were irradiated at 600 (327°C) to fluences up to 2 x l0²¹ n/cm² (E > 1 MeV). Tests were made in simple tension and in plane strain tension at 523 (250°C) and at a strain rate of 0.05 min^-1. In the material with (0002) poles predominantly parallel to the normal of sheet sample, the specimen tested in simple tension was macroscopically deformed in a manner consistent with the expected slip direction (1120). However, within individual grains, “pencil glide” deformation was noted where the slip direction was shared by more than one slip plane. The slip planes are of the type (10―1l), where the most likely values ofl are 0 and 1. The deformation was in sharply defined bands reminiscent of Lüders bands, to other materials, where (0002) poles were tilted toward the tensile direction, deformation occurred in less localized manner. In plane strain tension, however, the same materials fractured with very little plastic deformation, but with indications that small amounts of shear deformation occurred in a direction not parallel to the basal plane. The fracture morphologies were strongly affected by texture in the simple tension tests, to plane strain, however, the fracture morphologies were determined more by the constraints of the test than by the texture of the material in spite of the large differences in fracture stress that have been observed in materials with different texture.     

Influence of diazepam and phenytoin on penicillin-induced cerebral convulsions (author''s transl)

Abnormal serum aminotransferase activities with dominance of aspartate aminotransferase over alanine aminotransferase activity, and elevated serum adenosine deaminase activity and immunoglobulin. A concentration, were commonly encountered among patients with portal cirrhosis. The full triad was present in 31 of 49 cases (63%). As isolated abnormalities, these features were not uncommon in patients with other diseases of the liver and biliary tree, but the full triad was found only in 11 of 163 such cases (6.8%). The presence of this triad in a patient with unexplained hepatomegaly is indicative of portal cirrhosis.     

Construction and use of a smoke-measuring transducer

A smoke-measuring transducer that can be used in aircraft burn tests was designed, was built, and was demonstrated in a burn test in which it gathered data that had previously been unavailable. The principles of operation of the transducer, its construction, and its use in the burn test are described.     

An organization of knowledge for problem solving and language comprehension

Plan synthesis and language comprehension, or more generally, the act of discovering how one perception relates to others, are two sides of the same coin, because they both rely on a knowledge of cause and effect—algorithmic knowledge about how to do things and how things work. I will describe a new theory of representation for commonsense algorithmic world knowledge, then show how this knowledge can be organized into larger memory structures, as it has been in a LISP implementation of the theory. The large-scale organization of the memory is based on structures called bypassable causal selection networks. A system of such networks serves to embed thousands of small commonsense algorithm patterns into a larger fabric which is directly usable by both a plan synthesizer and a language comprehender. Because these bypassable networks can adapt to context, so will the plan synthesizer and a language comprehender. I will propose that the model is an approximation to the way humans organize and use algorithmic knowledge, and as such, that it suggests approaches not only to problem solving and language comprehension, but also to learning. I'll describe the commonsense algorithm representation, show how the system synthesizes plans using this knowledge, and trace through the process of language comprehension, illustrating how it threads its way through these algorithmic structures.     

Calibration and validation of an ASM3-based steady-state model for activated sludge systems--part II: Prediction of phosphorus removal

An ASM3-based steady-state model which can be used for estimating the average nitrogen-removal, sludge-production and phosphorus-removal rates of different biological phosphorus-removing systems (AAO, UCT, intermittent processes) is developed. It considers the wastewater composition, the oxygen and nitrate input in the anaerobic compartment and the interaction between biological phosphorus removal and denitrification for different operating conditions. The model is calibrated and validated with data from a number of long-term pilot and full-scale experiments for Swiss municipal wastewater. The steady-state model is adequate for a comparison of different BPR process configurations or for a first estimation of the nutrient-removal efficiency. It allows the plant performance and key parameters to be determined very quickly. Excel spreadsheets of the model for different flow schemes are available from the corresponding author.     

Dissolved natural organic matter (NOM) impacts photosynthetic oxygen production and electron transport in coontail Ceratophyllum demersum

Dissolved natural organic matter (NOM) is dead organic matter exceeding, in freshwater systems, the concentration of organic carbon in all living organisms by far. 80-90% (w/w) of the NOM is made up of humic substances (HS). Although NOM possesses several functional groups, a potential effect on aquatic organisms has not been studied. In this study, direct effects of NOM from various origins on physiological and biochemical functions in the aquatic plant Ceratophyllum demersum are presented. Environmentally relevant concentrations of NOM cause inhibitory effects on the photosynthetic oxygen production of C. demersum. Various NOM sources and the synthetic humic substance HS1500 inhibit the photosynthetic oxygen production of the plant as observed with 1-amino-anthraquinone, a known inhibitor of plant photosynthesis. 1-Aminoanthraquinone may serve as an analogue for the quinoid structures in NOM and HS. Most likely, the effects of NOM may be related to quinoid structures and work downstream of photosynthesis at photosystem (PS) II.     

Feuchtetransport in Bauteilen aus wasserundurchlässigem Beton

Moisture transport through water‐impermeable concrete elements Frequently during planning construction elements made of water‐impermeable concrete it is disregarded that they are a matter of design, not of material. The article comments on different ways of moisture transport in water‐impermeable concrete elements and explains the state of the knowledge. It goes into the German guideline “WU‐Richtlinie” published by the German Committee of Reinforced Concrete (DAfStb) and discusses the consideration of moisture transport for the specification of the guideline requirements. Additional possible measures to be taken in cases of high‐quality classification of design utilization in accordance with the guideline are described.     

Determination of operating characteristics of agitators in tubes

Operating characteristics of an agitator in a tube are necessary for the calculation of its pumping capacity and power consumption in a given configuration. General dimensionless equations for pumping and power characteristics are presented which were derived by inspection analysis of basic equations. Experimental procedure for the determination of these characteristics is put forward. This procedure is based on the measurement of flow rate or pressure rise and power consumption for an agitator in a draft tube, calandria or closed tube. The measurements and their evaluation are illustrated on the example of a three-blade screw agitator.