Long-term testing and applications of high-stress MV EPR cables

High-stress design 35-kV ethylene propylene rubber (EPR)-insulated cables with 1.14-mm (45-mil) wall reduction have been in service for more than ten years. In the mid 1990s, an extensive cable testing program was initiated to demonstrate that high-stress designs up to 4 kV/mm (101.6 V/mil) exhibit a significant electrical and mechanical safety margin to operate on typical utility network systems. Investigations were also undertaken to demonstrate the suitability of accessories for high-stress designs. This paper will present the results of six-year, long-term wet electrical testing conducted to demonstrate that with proper design, the aging performance of standard wall and high-stress design cables provide satisfactory results and suitable performance for the intended application. Additionally, utility field experience is presented on 35- and 15-kV cables operating at high stress. The experience for these 15-kV medium-voltage EPR cable designs employ the highest recommended stress for cables of this class, as well as taking into account the complete system performance.     

Removal efficiency of subsurface vertical flow constructed wetlands for different organic loads.

Using subsurface vertical flow constructed wetlands (SSVFCWs) with intermittent loading it is possible to fulfil the stringent Austrian effluent standards regarding nitrification. For small plants (less than 500 persons) standards for ammonia nitrogen concentration have to be met at water temperatures higher than 12 degrees C, effluent concentrations and treatment efficiencies for organic matter have to be met the whole year around. According to the Austrian design standards the required surface area for SSVFCWs treating wastewater was 5 m2 per person. Within the first part of an Austrian research project the goal was to optimise, i.e. minimise the surface area requirement of vertical flow beds. Therefore, three SSVFCWs with a surface area of 20 m2 each have been operated in parallel. The organic loads applied were 20, 27 and 40 g COD/m2/d, which corresponds to a specific surface area requirement of 4, 3 and 2 m2 per PE, respectively. The paper compares the effluent concentrations and elimination efficiencies of the three parallel operated beds. It could be shown that a specific area demand of 4 m2 per person is suitable to be included in the revision of the Austrian design standard. Additionally it could be shown that during the warmer seasons (May-October) when the temperature of the effluent is higher than 12 degrees C the specific surface area might be further reduced; even 2 m2 per person has been proven to be adequate.     

The beneficial effects of storage on the quality of wastewater for irrigation: a case study in Sicily.

Although the main function of reservoirs in agriculture is to allow the storage and temporal shifting of large volumes of waters, further benefits emerge from their application in wastewater reuse systems. In fact, as observed in several other studies carried out on such complex natural systems, the storage period, under proper conditions, can lead to a significant improvement of the water quality for irrigation thanks to concurrent physical, chemical and biological processes. In order to investigate the reservoir dynamics, an experimental research was carried out in a farm reservoir (volume of 11,000 m3, maximum depth of 6.3 m and mean depth of about 5 m), receiving treated wastewater and subject to scheduled highly variable input to volume ratios, in order to observe the broadest range of behaviour responses. Specifically, over a monitoring period lasted 4 months, the reservoir was operated as a standard batch reactor in the first and third phases and as a continuous flow reactor in the second one. Based on correlation analysis between the chemical, physical and biological water parameters and operational ones, a new operative index is proposed which integrates the morphological characteristics of the tank and the management ones, and shows a significant correlation with the qualitative characteristics of the stored water.     

The herbicide propachlor--14 C synthesis, toxicologic problems and methodology studies on the determination of residues in corn, potatoes, water and soil

Using the synthesized agent propachlor (N-isopropyl-2-chloroacetanilid) labelled with 14C, methodical investigations revealed an extremely high steam volatility not being assumed before because of the low vapour pressure. The method of steam distillation basing on this fact is of universal application to the processing of maize, potatoes, water, and soil, in which propachlor could be quantitatively determined by gas chromatography with a detection sensitivity of 0.02 ppm. Furthermore, this methods allows a simple purification of the raw product of synthesis containing impurities up to 20%. Propachlor codistilled with steam had a purity of more than 99%. Possibly, the high steam volatility of propachlor could have economic and toxicological consequences as to its application (volatilization in the open air with a high atmospheric humidity along with high temperatures). Therefore, an investigation of the steam volatility in the general screening programme for new agents is to be recommended in addition to the usual investigations of steam pressure.     

Stoichiometric dye-binding procedure for the determination of the reactive lysine content of soya bean protein

A new analytical method has been developed for the determination of the reactive lysine content of soya bean protein. The method is based on the reaction of the free basic groups of the protein with 1-phenylazo-2 naphthol-6,8 disulphonic acid. With regard to the stoichiometry of the procedure, it has been proved, contrary to earlier reports, that the basic amino acids, histidine, arginine and lysine, each combine with one mole of the dye. After acylation with propionic anhydride lysine alone loses its dye reactivity. The usefulness of the proposed method has been demonstrated by the determination of the reactive lysine content of several untreated, heat-treated and acid-treated soya bean samples. The results show that heat damage of about 5% in reactive lysine content can be measured in 1·5 h with good reproducibility.     

Effect of Methionine Supplementation on Nitrogen Balance in Infants Fed a Low-Cost Soy-Oats Formula

A nitrogen balance study, comparing a low-cost soy-oats infant formula with and without supplemental methionine, was carried out with infants of ages 3 - 26 months at a single equivalent level of nitrogen intake (approximately 850 mg/kg/day). Nitrogen retention was found to be unaffected by methionine supplementation. Com- parison of data obtained in this study with previous research re- vealed that a critical value for intake of total L-sulfur amino acids apparently exists in infants 3 - 26 months of age, below which methionine supplementation will increase nitrogen retention, but above which it will not. This value appears to coincide with that of 49 mg/kg/day recommended for infants by the FNB.     

Influence of weld misalignment and weld metal overmatch on the prediction of fracture in pipeline girth welds

$\text{J-}\text{integral}$ estimates using elastic-plastic finite element calculations, are shown to compare well with experimental results from single edge-notch bend (SENB) specimens made of X483 grade line pipe steel.The influence of weld misalignment and weld metal overmatch on fracture of cracked girth welds is predicted, also using elastic-plastic finite element calculations. Weld metal overmatch reduces plastic strain levels in the weld and appears beneficial in reducing $\text{J-}\text{integral}$ magnitudes. Predicted values of $\text{J-}\text{integral}$ are shown to increase with weld misalignment. However, $\text{J-}\text{integral}$ magnitudes near the critical value for crack growth initiation were only attained after considerable plastic straining at or near limit load. This result suggests that limit load calculations may be more appropriate for prediction of failure of cracked girth welds than conventional fracture techniques.     

Interconnection of Subsystem Reduced-Order Models in the Electrothermal Analysis of Large Systems

Heat conduction in an electronic device is commonly modeled as a discretized thermal system (e.g., finite element or finite difference models) that typically uses large matrices for solving complex problems. The large size of electronic-system heat transfer models can be reduced using model reduction methods and the resulting reduced-order models can yield accurate results with far less computational costs. Electronic devices are typically composed of components, like chips, printed circuit boards, and heat sinks that are coupled together. There are two ways of creating reduced-order models for devices that have many coupled components. The first way is to create a single reduced-order model of the entire device. The second way is to interconnect reduced-order models of the components that constitute the device. The second choice (which we call the "reduce then interconnect" approach) allows the heat transfer specialist to perform quick simulations of different architectures of the device by using a library of reduced-order models of the different components that make up the device. However, interconnecting reduced-order models in a straightforward manner can result in unstable behavior. The purpose of this paper is two-fold: creating reduced-order models of the components using a Krylov subspace algorithm and interconnecting the reduced-order models in a stable manner using concepts from control theory. In this paper, we explain the logic behind the "reduce then interconnect" approach, formulate a control-theoretic method for it, and finally exhibit the whole process numerically, by applying it to an example heat conduction problem     

Ochratoxin A in pork kidneys--description of a method

A rapid procedure for the isolation and clean-up on a silica gel column is described for the determination of Ochratoxin A from pork kidneys. The detection limit is 0.3 microgram/kg.