Dynamic insulation in transmission-line design

The evolution of the dynamic insulation concept from the integration of two existing technologies is presented. Separate solutions proposed in the recent literature for the reduction of voltage stresses due to nonuniform electric fields and to transient overvoltages in EHV and UHV transmission line insulation are discussed and then integrated into one. The resulting combination, i.e. dynamic insulation, has the potential of providing a superior alternative for the abatement of these two problems and others. Dynamic insulation is a new concept which provides a systems approach to the electrical and mechanical design for tranmission-like insulation. Because of its multifunction capability, dynamic insulation offers various technical and economical advantages, including the mitigation of the effects of contamination on insulation and also the control of fault initiation overvoltages as indicated by transmission-like simulations. Further theoretical studies and experimental work applying known technology is suggested to verify the ideas proposed.     

Natural fermentation of lentils Influence of time, concentration and temperature on protein content, trypsin inhibitor activity and phenolic compound content

Lentil (Lens culinaris var. vulgaris) flour was naturally fermented for 4 days at different temperatures (28°C, 35°C and 42°C) and concentrations (79 g/1, 150 g/1 and 221 g/1). Samples were analysed to establish the changes of total protein content and in vitro protein digestibility, trypsin inhibitor activity (TIA) and phenolic compound content during natural fermentation of lentils. The preparation of lentil flour suspensions to be fermented caused a slight increase in total protein and in vitro protein digestibility content, a decrease of TIA and a sharp decrease the tannin/catechin ratio. During the whole fermentation procedure, the minimum initial lentil concentration and temperature used (79 g/1, 28°C) achieved the maximum protein content and the lowest tannin/catechin ratio. The TIA was more affected by temperature than by concentration, and a 62.5% reduction was observed at 42°C and 79 g/1.     

Levels of chlorinated hydrocarbons in sediments from the central mediterranean

Levels of PCBs, DDTs and BHCs were measured in sediments taken from the central Mediterranean. BHC was usually < 1 ng g^?1; ΣDDT (sum of DDT, DDE and DDD) ranged from < 1 ng g^?1 to 27.5 ng g^?1; ΣPCBs generally ranged from ca. 1 ng g^?1 to > 80 ng g^?1, but exceptionally high values (130–457 ng g^?1) were observed from stations within Augusta Harbor.     

Estimating solar irradiation sums from sunshine and cloudiness observations

A method is presented that offers the possibility of estimating solar irradiation sums on the basis of sunshine and cloudiness observations only. Its application requires the knowledge of the local hourly sums of global and diffuse solar irradiation by clear weather as well as the hourly sums of diffuse solar irradiation due to clouds. These quantities were determined for the actual radiation climate in Lisbon. Effective daily amount of sunshine and cloudiness are defined and compared with the usual daily sunshine and cloudiness concepts; the relationship between daily relative amount of sunshine and cloudiness is established for Lisbon.     

Ti3Ga and αTi interdiffusion between 660° and 860°C

Diffusion experiments were conducted in vacuum with bimetallic couples of the Ti₃Ga (α₂) composition and unalloyed α titanium. The gallium-composition profiles after various timetemperature exposures were determined by microprobe analyzer transverses and evaluated by established techniques. Results from this evaluation include the definition of the α to α +α₂ and the α + α₂ to α₂ phase boundaries for the Ti?Ga system and the determination of the interdiffusion coefficients for gallium in the α Ti and Ti₃Ga (α₂) phases. The interdiffusion coefficients were found to conform to the relationships: $$\tilde D_{\alpha Ti} = 4.4 \times 10^{ - 4} \exp [ - (43.4 \pm 4.7)10^3 /RT]cm^2 /\sec $$ $$\tilde D_{\alpha Ti_3 Ga} = 7.4 \times 10^{ - 5} \exp [ - (43.8 \pm 10.7)10^3 /RT]cm^2 /\sec $$      

Correlation of microhardness and morphology of poly(ether-ether-ketone) films

We have applied microindentation to a series poly(ether-ether-ketone) films crystallized at different temperatures from the melt and from the glass to measure their microhardness. The morphology of the samples was characterized by X-ray diffraction, density measurements and differential scanning calorimetry. The results show that a relationship between microhardness, density and degree of crystallinity can be established for samples crystallized at various temperatures from both the glass and the melt. The values of the microhardness of the crystalline component of the samples can be correlated with the lamellar thickness of the polymer crystals.     

High-power performance of single-mode fiber-optic connectors

We measured the continuous wave (CW) laser-induced damage threshold of single-mode fiber-optic connectors at 1550 nm. Clean standard physical contact and angled physical contact connectors did not show any evidence of damage for 10 min exposures of 1 W or 3 W. Defective connectors with scratched or undercut endfaces showed identical high-power tolerance as clean connectors without defects. Samples contaminated with carbon black-doped acrylate showed drastic optical failure signatures at approximately 50 mW. Contaminated connectors with expanded mode field diameters ranging from 20 to 62 /spl mu/m showed higher failure thresholds than standard connectors with 10-/spl mu/m spot sizes. We observed that the optical failure threshold power level (P/sub failure/) increased linearly with spot size for the highly contaminated connectors used in this study.     

An Economic Model for Water Allocation in North Eastern Spain

The aim of this paper is to construct and apply a model for the allocation of water between two competing users, namely irrigation and hydropower. The model is applied in a case study of a specific water system located in North Eastern Spain. Starting with an irrigation-hydropower joint income function, we develop a constrained maximization process that takes into account the environmental, institutional and actual priority of the water rights. The resulting solution can be useful as a guide for potential bargains between users. Furthermore, we evaluate the results for different supply (precipitation) and water allotments (increase in irrigated land). The results show that there are sufficient incentives so as to reach agreements that lead to improvements in a Pareto sense without side payments.     

Carbon diffusion in Mo2C as determined from carburization of Mo

A diffusion coefficient of C in nonstoichiometric α-Mo2C has been determined from the growth kinetics of the carbide layer. The results conform to the relationship:Dc (in cm²/s) = 68.86 ± 1.51 exp [(-294.77 ± 4.98)/RT] for the temperature range of 1273 to 1673 K, with the activation energy in kJ/mole. The growth rate,Kp, of the carbide thickness can be expressed as:Kp (in cm²/s) = 32.63 ± 1.52 exp [(-319.06 ± 5.12)/RT].