The role of adverse weather conditions in acute releases of hazardous substances, Texas, 2000-2001

High winds, flooding, lightning, and other phenomena associated with adverse weather can cause power failures, equipment damage, and process upsets resulting in chemical releases. Of the 5000 events in Texas that were reported to the Hazardous Substances Emergency Events Surveillance (HSEES) system during 2000-2001, adverse weather conditions contributed to 110 (2%) events. Rain was the most frequent adverse weather condition. Most events to which adverse weather conditions contributed occurred during June or September; these months correspond with the high temperature and hurricane season in Texas. Most events occurred in coastal counties with large numbers of industrial facilities. Three industries reported the majority of events: industrial and miscellaneous chemicals manufacturing; petroleum refining; and plastics, synthetics, and resin manufacturing. Power failures were associated more often with adverse weather-related events than with nonweather-related events. Releases occurred most commonly from ancillary process equipment and process vessels. Events associated with adverse weather-related conditions involved nine victims. System and process design improvements, such as improved backup power generation and redesigned secondary containment systems, could be explored to reduce the potential negative effects of severe weather.     

Development of direct ELISA for the determination of 4-nonylphenol and octylphenol

Development of direct competitive enzyme-linked immunoadsorbent assays (ELISAs) based on polyclonal and monoclonal antibodies raised against 4-n-alkylphenol hapten mimics is described. A strong tendency to recognize 4-nonylphenol (NP) and 4-octylphenol (OP) as a total analyte amount was indicated by cross-reactivity pattern established for two polyclonal antibodies. These antibodies were employed for development of class-selective assays exhibiting IC(50) values around 40 microg.L(-1) for technical 4-NP. Specificity of the monoclonal antibody 4H6 and additional two polyclonal antibodies allowed sensitive detection of linear long-chain forms of 4-n-alkylphenols (4-n-AP). The assays incorporating these antibodies offer a potential for detecting the minor fraction of NP/OP isomer spectrum having IC(50) = 11.5 microg.L(-1) for 4-n-NP. No cross-reactivity interference was indicated for linear alkylbenzene sulfonates and phenolic compounds. To interpret the measured data in terms of analytical equivalents, a reliable relationship between the assay responses and AP content of contaminated samples should be verified and validated.     

Security in the wild: user strategies for managing security as an everyday,practical problem

Ubiquitous and mobile technologies create new challenges for system security. Effective security solutions depend not only on the mathematical and technical properties of those solutions, but also on people’s ability to understand them and use them as part of their work. As a step towards solving this problem, we have been examining how people experience security as a facet of their daily life, and how they routinely answer the question, “is this system secure enough for what I want to do?” We present a number of findings concerning the scope of security, attitudes towards security, and the social and organizational contexts within which security concerns arise, and point towards emerging technical solutions.     

The analysis of condensation products of 2,6-xylenol and formaldehyde in the presence of cresols

Methylenebisphenols, commonly used as antioxidants for polyolefines, are prepared by condensation of suitably alkylated phenols and formaldehyde in the presence of acid catalyst. Usually by-products are produced from the impurities in starting raw materials. In this work the condensation of 2,6-dimethylphenol with formaldehyde and the influence of cresols was studied. By-products, namely bisphenols and trisphenols were separated by means of gel chromatography and analyzed by reversed phase liquid chromatography, mass spectrometry and nuclear magnetic resonance.     

Diagnose von Korrosionsfällen an einer Saturationskolonne für Synthesegas

Diagnosis of case histories from a synthesis gas saturation column The saturation column, made of steel type 1Cr18Ni9Ti (wall thickness: 8 mm), in which the gas is cooled down to 240°C by a water jet and, simultaneously saturated with water vapour, failed after only 3000 hours' operation; the failure was attributable to a damaged footing tube. An analysis of the damaged parts suggested, that the main cause of the failure was not the design of the equidistant shells, i. e. the welding connection between the tubes and the two shells, which had originally been assumed to be faulty, but in a first line the material selection which was wrong in view of possible corrosion. The tensile stresses resulting from the rigid connection of the footing pipes are but one of the factors contributing to the development of stress corrosion cracking. This opinion concerning the reason of the first failure was confirmed when another failure occurred after another 1000 hours' operation of the column: a thorough inspection revealed some spots where stress corrosion cracking bad developed.     

Assembly interdependence among the S. cerevisiae bud neck ring proteins Elm1p,Hsl1p and Cdc12p

In Saccharomyces cerevisiae, a complex comprising more than 20 different polypeptides assembles in a ring at the neck between the mother cell and the bud. This complex functions to coordinate cell morphology with cell division. Relatively little is known about this control system, including the physical relationships between the components of the neck ring. This study addressed the assembly interactions of three components of the ring, specifically the protein kinases Elm1p and Hsl1p and the septin Cdc12p. Specific amino acid substitutions in each of these three proteins were identified that either cause or suppress a characteristic phenotype of abnormally elongated cells and delay in the G(2)-M transition. Each protein was fused to green fluorescent protein, and its ability to localize at the neck was monitored in vivo in cells of various genotypes. Localization of Hsl1p to the neck requires Elm1p function. Elm1p localized normally in the absence of Hsl1p, although a specific point mutation in Hsl1p clearly affected Elm1p localization. The cdc12-122 mutation prevented assembly of Elm1p or Hsl1p into the neck ring. Normal assembly of Cdc12p at the neck was dependent upon Elm1p and also, to a smaller extent, on Hsl1p. Ectopic localization of Cdc12p at the bud tip was observed frequently in elm1 mutants and also, to a lesser extent, in hsl1 mutants. Thus, Elm1p is a key factor in the assembly and/or maintenance of Hsl1p, as well as at least one septin, into the bud neck ring.     

Assessment of the mean-value of 17-hydroxypregnenolone in the umbilical blood of newborns by the exploratory analysis of biochemical data

The main aim of data analysis in biochemical metrology is the extraction of relevant information from biochemical data measurements. A system of extended exploratory data analysis (EDA) based on the concept of graphical tools for sample data summarization and exploration is proposed and the original EDA algorithm in S-Plus is available on the Internet at http://www.trilobyte.cz/EDA. To check basic assumptions about biochemical and medical data is to examine the independence of sample elements, sample normality and homogeneity. The exact assessment of the mean-value and the variance of steroid levels in controls is necessary for the correct assessment of the samples from patients. Data examination procedures are illustrated by a determination of the mean-value of 17-hydroxypregnenolone in the umbilical blood of newborns. For an asymmetric, strongly skewed sample distribution corrupted with outliers the best estimate of location seems to be the median. The Box–Cox transformation improves a sample symmetry. The proposed procedure gives reliable estimates of a mean-value for an asymmetric distribution of 17-hydroxypregnenolone when the arithmetic mean can not be used.     

Generalised multi-pattern-based verification of programs with linear linked structures

The paper deals with the problem of automatic verification of programs working with extended linear linked dynamic data structures, in particular, pattern-based verification is considered. In this approach, one can abstract memory configurations by abstracting away the exact number of adjacent occurrences of certain memory patterns. With respect to the previous work on the subject the method presented in the paper has been extended to be able to handle multiple patterns, which allows for verification of programs working with more types of structures and/or with structures with irregular shapes. The experimental results obtained from a prototype implementation of the method show that the method is very competitive and offers a big potential for future extensions.