Certification of Highly Complex Safety-Related Systems

The BIA has now 15 years of experience with the certification of complex electronic systems for safety-related applications in the machinery sector. Using the example of machining centres, this presentation will show the systematic procedure for verifying and validating control systems using Application Specific Integrated Circuits (ASICs) and microcomputers for safety functions.

One section will describe the control structure of machining centres with control systems using “ integrated safety.” A diverse redundant architecture combined with crossmonitoring and forced dynamisation is explained. In the main section the steps of the systematic certification procedure are explained showing some results of the certification of drilling machines. Specification reviews, design reviews with test case specification, statistical analysis, and walk-throughs are the analytical measures in the testing process. Systematic tests based on the test case specification, Electro Magnetic Interference (EMI) and environmental testing, and site acceptance tests on the machines are the testing measures for validation.

A complex software driven system is always undergoing modification. Most of the changes are not safety-relevant but this has to be proven. A systematic procedure for certifying software modifications is presented in the last section of the paper.     

Repertoire sharing and song-post distance in nightingales (Luscinia megarhynchos B.)

Summary The relationship was studied between song-post distances and the extent of vocal repertoire sharing in 34 territorial nightingales settling in six homogeneously structured habitats. Repertoires were compared on the basis of shared song types and distances were measured between nocturnal song posts of first-order and higher-order neighbours. Our results showed that male nightingales shared fewer song types with very close and more distant neighbours than with neighbours at intermediate distances. This distribution is explained by the interaction betwee repelling and attracting components, which depends on the distance between song posts.     

Toxic oxide deposits from the combustion of landfill gas and biogas

Oxide deposits found in combustion systems of landfill gas fired power stations contain relatively high concentrations of elements which form volatile species such as P, As, Sb and Sn. These deposits should be handled with care because of their potential toxicity. By contrast, deposits in biogas system engines were found to contain much lower levels of such elements. The enrichment of these elements can be attributed to a hypothetical multistage process. The elements form volatile species in the landfill body. They are selectively transported as part of the landfill gas into the gas-burning devices. Inside the burners, they are immobilized as nonvolatile oxides.     

Cycling of volatile organic sulfur compounds in anaerobically digested biosolids and its implications for odors.

The objectives of this research were to elucidate the mechanisms for production and degradation of volatile organic sulfur compounds (VOSCs), key odor causing compounds produced by biosolids. These compounds included methanethiol (MT), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS). A series of experiments were used to probe various pathways hypothesized to produce and degrade these VOSCs. The production of MT was found to mainly occur from degradation of methionine and the methylation of hydrogen sulfide. DMS was formed through the methylation of MT. DMDS was formed by MT oxidation. All three of the VOSCs were readily degraded by methanogens and a cyclic pathway was proposed to describe the production and degradation of VOSCs. The research demonstrated that the main source of VOSCs was the biodegradation of protein within the biosolids and the results provided a framework for understanding the production of odor from anaerobically digested sludges before and after dewatering.     

The trophic position of dead autochthonous organic material and its treatment in trophic analyses

1. The importance of the recycling of organic matter for the overall carbon and nutrient flow in a food web, e.g., by the microbial loop has been recognized for pelagic and other ecosystems during the last decade. In contrast, analyses of the trophic food web structure conducted, e.g., by network analysis based on mass‐balanced flow diagrams (i.e., computation of, e.g., trophic positions and transfer efficiencies, organismal composition of trophic levels) which greatly contribute to our understanding of the flow and cycling of matter in food webs, have not yet responded adequately to this fact by developing coherent techniques with which dead organic matter and its consumers could be considered in the models. 2. At present, dead organic matter (measured in units of carbon or nutrients) is either allocated to a fixed trophic position (between zero and one), or the trophic position of dead autochthonous material depends on the trophic position of the organisms which released it. This causes partially ambiguous and inconsistent interpretations of key measures like trophic transfer efficiences and trophic positions and greatly hampers cross‐system comparisons. 3. The present paper describes and compares four different definitions of the trophic position of dead autochthonous organic material which have either been newly invented or already used. Their impact on the resulting trophic positions of individual groups is illustrated using a food web model from the pelagic zone of Lake Constance. The present analysis evaluates the partially far reaching consequences of the definition chosen, and suggests to allocate all dead organic material to the ‘zeroth’ trophic level irrespectively of its origin (allochthonous or autochthonous), chemical composition and the commodity used to quantify the food web model (e.g., units of carbon or nutrients). By this means trophic positions and trophic transfer efficiencies get a clear and consistent ecological interpretation, while inconsistencies between analyses conducted in units of carbon or nutrients and some operational problems can be overcome and cross‐system comparisons and empirical verification are facilitated.     

Teil II: L?sungsans?tze für den landwirtschaftlichen Betrieb bei der Implementierung eines Umweltmanagementsystems

Zusammenfassung  Die Erfassung der Ist-Situation im Rahmen der Umweltprüfung bildet die Grundlage für effiziente Schritte im Rahmen der Implementierung von Umweltmanagementsystemen (UMS). Diese Basis-analyse stützt sich auf die Elemente Wirkungsaudit, Management-audit und Rechtsaudit. Durch die optimale Ausgestaltung einer Umweltprüfung wird bei der Implementierung eines UMS auch in der Landwirtschaft die Basis für einen maximalen Nutzen des Anwenders geschaffen. Dieser Nutzen ist etwa für den Betrieb in seinen Innenbeziehungen, die Transparenz der Betriebsabl?ufe, ?konomische Gesichtspunkte, wie z.B. Einsparpotentiale, Informationsgewinnung sowie Effizienzgesichtspunkte durch die Dokumentation der Ablauforganisation. Darüber hinaus nutzt ein UMS bei externen Anforderungen, wie z.B. beim Umgang mit der ?ffentlichkeit, Marktpartnern, der Stellung gegenüber Beh?rden, Deregulierung oder Haftungsminimierung.      

Bacteria Degrading PCBs and CBs Isolated from Long-Term PCB Contaminated Soil

Bacteria able to degrade polychlorinated biphenyls (PCBs) and chlorobenzoic acids (CBs) were isolated from soil that had been contaminated with PCBs for 15–30 years. Contaminated soil in which PCB content ranged between 10–470 mg/kg was naturally vegetated with different plants including ash (Fraxinus excelsior), birch (Betula pendula), black locust (Robinia pseudoacacia), Austrian pine (Pinus nigra) and goat willow (Salix caprea) trees as well as a variety of grasses and forbs. Bacteria able to use biphenyl as a sole source of carbon and energy were found in the root zone of all plants, but occurred in the largest numbers beneath pine and black locust. Bacteria able to degrade chlorobenzoic acids were isolated from the same location contaminated with PCBs. Strains that were taxonomically identified by 16S rDNA as Pandoraea were able to use 2-CB, 3-CB, 2,3-CB, 2,5-CB as sole carbon sources, and the strain Arthrobacter utilised 4-CB.     

Variationen der Nährstoff-und Schwermetallgehalte in Böden

This article investigates the variations of nutrient (phosphorus (P) and potassium (K)) and heavy metal contents in soils. Therefore, selected regions in Eifel and Hunsrueck (region around Trier) were examined. The data base consists of more than 100.000 existing measurements plus own investigations on the main land use classes —field, grassland, vinicultural areas and forest—with regard to their intensities (conventional und biological). The evaluation of the nutrient contents for P and K was made using the manual adequate fertilization for field and grassland. The creation of heavy metal distribution maps is based on the Kriging method. In the past, soils in the region of Trier received a too large amount of P and K—especially in vinicultural areas. Mineral and organic fertilization has a great influence on the heavy metal contents on farmland. The immission of dust contaminated with heavy met|als is important on forest and grassland locations. On vineyards the use of cupreous plant protection agents is critical. The land use classes have had a substantial influence on the nutrient and heavy metal contents of the soil. In contrast to this, the intensities showed less differences. In order to reduce the anthropogenic impact on heavy metals in soils, it is necessary to create specific reduction strategies for each land use class. For example the fertilization has to be limited to the need of the plant, contaminated secondary raw material fertilizer has to be avoid the comparability of analytical methods has to be ensured.