Tetramethylsuccinonitrile in polyvinyl chloride products for food and its release into food-simulating solvents

The content of tetramethylsuccinonitrile (TMSN), the main decomposition product of 2,2'-azobis-isobutyronitrile, in polyvinyl chloride (PVC) products used for food packaging, were examined as well as food-simulating solvents. The TMSN concentration in 17 PVC products ranged from below the detection limit, 0.05 mg/kg, up to 523 mg/kg. The release of TMSN from two PVC products into five kinds of food-simulating solvents at 60 degrees C for 30 min was observed, except for 1 +/- 1 micrograms/kg of TMSN in n-heptane from a PVC bottle containing 523 +/- 30.4 mg/kg of TMSN. The detection limit of TMSN in the food-simulating solvents was 1 micrograms/kg. When pieces of the bottle were stored in olive oil at 40 degrees C for 120 days, 5 +/- 1 micrograms/kg of TMSN was detected in the oil. The release of TMSN from the pieces of the bottle into olive oil between 80 and 140 degrees C depended on the formula ln y = 0.08786x-5.696, r = 0.9927, where y is the concentration (microgram/kg) of TMSN in olive oil, x is the temperature (degrees C), and r is the correlation coefficient.     

Physiological and pathological factors influencing bovine alpha-lactalbumin and beta-lactoglobulin concentrations in milk

Bovine alpha-lactalbumin and beta-lactoglobulin concentrations were determined by radial immunodiffusion in 354 milk samples from uninfected and 98 samples from infected quarters from 42 Holstein-Friesian cows taken at 30, 150, and 270 days of lactation. alpha-Lactalbumin and beta-lactoglobulin concentrations were not affected by quarter location. The alpha-lactalbumin decreased at the end of lactation and in samples collected beyond second lactation. The beta-lactoglobulin concentration increased with stage of lactation. There was a positive correlation between alpha-lactalbumin and beta lactoglobulin (r = .12). Milk from uninfected quarters had mean alpha-lactalbumin and beta-lactoglobulin concentrations of 1.47 and 4.6 mg/ml, respectively. Milk from quarters infected by major pathogens or Corynebacterium bovis had less alpha-lactalbumin. Milk from quarters infected by minor pathogens had less beta-lactoglobulin. There was a negative correlation between alpha-lactalbumin concentration and somatic cell count (r = .31), which was amplified by infection status of quarters. No correlation was noted between somatic cell count and beta-lactoglobulin concentration when considered over the whole sampling period, but the correlation became negative in quarters infected by major pathogens.     

StoryGrid [educational computing]

The StoryGrid project undertook studying the role new interface technologies might play in education, particularly at the high school level. Unfortunately, technology often seizes center stage in high school classrooms; i.e., it becomes the topic of instruction. We believe that learning about technology would be most successful when technology is not the topic, but simply a tool used during instruction. StoryGrid, therefore, was designed to support and to enhance existing narrative activity in classrooms by adhering to the following goals: trigger reflection and interpretation, accommodate individual expression and encourage student discourse.     

Optimizing the design of railway tank cars to minimize accident-caused releases

The design of vehicles transporting hazardous materials has important public safety and economic implications. Conventional wisdom among industry and government has held that a thicker tank on railroad tank cars and trucks reduces risk. However, a thicker tank increases vehicle weight and thus leads to an increase in the number of shipments required to transport the same amount of product and consequently greater exposure to accidents. In this research we develop a model that analyzes the tradeoff between increased damage resistance and greater exposure to accidents in which the objective function is minimization of the probability of release. The model accounts for the reduction in tank car release probability as a function of tank thickness, and the increased exposure to accidents that occurs due to the increased number of shipments needed for the heavier car. Three variables affecting this optimal thickness are considered in this paper: the volumetric capacity of the tank, the probability of release from other, non-tank sources, and the weight capacity of the car. Sensitivity analyses using the model indicate that for any particular configuration of tank car there is an optimal thickness. This optimal thickness is affected by several factors and there is no single optimum for all tank cars.     

Verf?rbung grau und wei? pigmentierter Beschichtungen auf Acrylharzbasis auf Tropenh?lzern

Ohne Zusammenfassung     

Some modifications of the classification tree construction algorithm

The paper describes a few modifications of the classification tree construction algorithm that have proved to be useful for solving tasks of noise spectra processing with reference to NPP diagnostics. The article was translated by the authors.