Polyimide–silica hybrids containing novel phenylethynyl imide silanes as coupling agents for surface-treated titanium alloy

Polyimide–silica hybrids composed of an organic precursor containing a novel phenylethynyl imide silane and an inorganic precursor were evaluated as an adhesion-promoting interphase between surface-treated titanium alloy and a phenylethynyl-containing imide adhesive. The phenylethynyl groups present in the organic precursor, either as a pendent or end group, can bond chemically with a phenylethynyl-containing imide adhesive during processing, while the silane groups of the organic precursor would react chemically with the inorganic precursor. In addition, the inorganic precursor is able to react with the titanium alloy to form a stable bond with the metal oxide. Bond strength and durability were evaluated by single lap shear tests at various conditions. Lap shear specimens exhibited predominantly cohesive failure after a 3-d water boil with 92% retention of the initial room temperature strength. Morphology and chemical composition of the hybrid interphase were investigated with scanning electron microscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy, which revealed development of a silicon-gradient, hybrid structure between the metal substrate and the adhesive.     

Basic sites on mixed nitrided galloaluminophosphates “AlGaPON”: infrared studies of SO2 and CDCl3 adsorption

The basic properties of nitrided galloaluminophosphate “AlGaPON” are documented by FTIR of sulphur dioxide and deuterated chloroform. To evidence the increase in the number of basic sites with nitrogen enrichment, we compared the spectra recorded after adsorption of CDCl₃ on the phosphate precursor “AlGaPO” and on four oxynitrides with increasing nitrogen contents. On the oxide, adsorption arises from CDCl₃ interacting with surface hydroxyl groups, on the oxynitrides basic sites are shown to be M–NH₂ groups. This interpretation is confirmed by FTIR of adsorbed SO₂. This revised version was published online in July 2006 with corrections to the Cover Date.     

Zur Rolle von EDA-Komplexen bei kationischen Polymerisationen. VIII. Zur Charge-Transfer-Wechselwirkung von bπ-Donatoren mit organischen Kationen in Lösung

On the Role of EDA-complexes in Cationic Polymerization. VIII. The Charge-Transfer-Interaction of bπ-Donors with Organic Cations in Solution The interaction of 25 aromatic bπ-donors with organic cations of the type (RC₆H₄)₃ C^⊕X^⊖ (R =  CH₃,  C(CH₃)₃,  OCH₃,  H,  Cl,  I,  NO₂; X = BF₄^⊖, AsF₆^⊖, SbCl₆^⊖, FeCl₄^⊖) is investigated by means of u.v.-spectroscopy. The influence of the dissociation on the charge transfer energy will be discussed. With the decreasing concentration of the salt the charge transfer band is hardly shifted at longer wave length. The charge transfer energy can be described as a linear function of structural parameters (i.e. σ_p of R; I_p of the donor and reciprocal radius of the anions, respectively). The influence of the solvent is dependent on both the donicity and dielectric factors.     

Overview of R&D at TLK for process and analytical issues on tritium management in breeder blankets of ITER and DEMO

Safe, reliable, and efficient tritium management in the breeder blanket will have to face unprecedented technological challenges. Beside the efficiency for tritium recovery from the breeder blanket (Tritium Extraction (TES) and Coolant Purification Systems (CPS)), the accuracy for tritium tracking between the inner and the outer fuel cycle must also be demonstrated. This paper focuses on the recent R&D carried out at the Tritium Laboratory Karlsruhe to tackle these issues. For ITER, the recently consolidated TES and CPS designs comprise adsorption columns and getter beds operated in semi-continuous mode. Different approaches for the tritium accountancy stage (TAS) have been evaluated. Balancing static (batch-wise gas collection at the TBM outlets and the tritium plant) or dynamic (in/on-line) approaches with respect to the expected analytical performances and integration issues, the first conceptual design of the TAS for EU TBMs is presented. For DEMO, the overall strategy for tritium recovery and tracking has been revisited. The necessity for on-line real-time tritium accountancy and improved process efficiency suggest the use of continuous processes such as permeator and catalytic membrane reactor. The main benefits combining the PERMCAT process with advanced membranes is discussed with respect to process improvements and facilitated accountancy using spectroscopic methods.     

Zur Prüfung und Bewertung der Umweltverträglichkeit von Holzschutzmitteln

Wood preservation can be made more environmentally compatible (1) by confining the use of wood preservative chemicals to the necessary minimum, and (2) by the use of effective and at the same time environmentally compatible wood preservatives. The aims and main points of testing and evaluating the environmental compatibility of wood preservatives are described. Crucial in this concern is the emission rate of the active ingredients of the wood preservatives (which leave the impregnated wood by leaching or evaporation), and this rate should be as low as possible for reasons of both long-term efficacy and low environmental load. The main pathways of possible environmental input of the active ingredients are leaching and evaporation during storage, transport and use of the impregnated wood and the input of their components or decomposition products during waste management. Looking at the leaching of non-fixing, not yet fixed as well as fixed wood preservative salts and organic active substances some problems arising in the practice of wood preservation and in the evaluation of the environmental compatibility of wood preservatives are dealt with and possible solutions are demonstrated.     

Energy expenditure of a noncontact boxing training session compared with submaximal treadmill running

The aim of this study was to determine the energy expenditure of a 1-h noncontact boxing training session and to compare these results with the energy expenditure of a more conventional recreational activity such as running. Eight healthy males, accustomed to noncontact boxing training, were recruited for the study. Subjects underwent three tests: (i) a boxing training session in the laboratory during which energy expenditure was measured continuously using indirect calorimetry (BOXL), (ii) a boxing training session in a boxing studio during which heart rate was measured continuously (BOXS), and (iii) an incremental running test on the treadmill during which energy expenditure was measured continuously. The energy expenditure during 60 min of BOXL ranged between 2519 and 3079 kJ (2821 +/- 190 kJ). Seven of the 8 subjects had higher heart rates during BOXL compared with those during BOXS, suggesting that the subjects exercised at a slightly higher intensity during BOXL, possibly because of the "one on one" supervision. A typical boxing training session lasting 60 min causes a person to expend 2821 +/- 190 kJ x h(-1), the same amount of energy as someone running about 9 km in 60 min on the treadmill.     

Spiral Tunneling Cracks Induced by Environmental Stress Cracking in LaRC™-TPI Adhesives

Some currently-available formulations of LaRC?-TPI, a thermoplastic polyimide originally developed at NASA-Langley, were found to be highly susceptible to environmental stress cracking when exposed to solvents such as acetone, toluene, diglyme and methyl ethyl ketone. The combination of stress and solvent led to rapid cracking in films and adhesive layers of this material system. Residual cool-down stresses induced when the LaRC-TPI is used as an adhesive or coating led, in the presence of a solvent, to dense “mud crack” patterns which relieve a portion of the stored energy. Because these through-the-thickness cracks are not able to relieve the stored energy in the vicinity of the adherends, additional fractures in the form of curious spiral tunnel cracks initiated and grew inward within each adhesive fragment. Micrographs of the spiral fractures are given, along with a qualitative explanation for the failure process as observed in adhesives and coatings.     

Synthesis of ‘ready-to-adsorb’ polymeric nanoshells for magnetic iron oxide nanoparticles via atom transfer radical polymerization

Polymer-magnetite nanoparticle complexes that respond to both magnetic fields and to temperature have been demonstrated. Novel alkyl halide-functional bis(diethylphosphonate) esters were prepared and utilized as initiators for polymerizing N-isopropylacrylamide by controlled atom transfer radical polymerization. The phosphonate esters were removed after polymerization to afford poly(N-isopropylacrylamide) with a bis(phosphonic acid) moiety precisely placed at one terminus. The bis(phosphonic acid) endgroups were adsorbed onto magnetite nanoparticles to yield nanoscale complexes that were stable against any polymer desorption and that were colloidally-stable in physiological media. Thus, the bis(phosphonate) endgroup provides a robust anchoring moiety onto the magnetite. Hydrodynamic sizes of the complexes were predicted with a density distribution model and using the measured sizes of the magnetite cores. Good agreement between the measured and predicted hydrodynamic sizes suggested that the complexes were primarily discrete, non-agglomerated nanoparticles. The complexes exhibited thermosensitive aggregation behavior near the lower critical solution temperature of the poly(N-isopropylacrylamide) component.     

Investigation of γ-Linolenic Acid and Stearidonic Acid Biosynthesis During a Life Cycle of <Emphasis Type="Italic">Borago officinalis</Emphasis> L.

This study investigated the levels of γ-linolenic (GLA, 18:3n-6) and stearidonic acid (SDA, 18:4n-3) in various parts of the borage plant (Borago officinalis L.) to elucidate Δ6-desaturase activity. Lipid class and fatty acid (FA) composition during germination of the seeds and FA composition of various borage parts were determined as well as FA compositions of neutral lipids (NL), polar lipids (PL), glycolipids (GL) and monogalactosyl diacylglycerols (MGDG) of borage leaves. When seeds were germinated for 12 days in the dark then exposed to light for 8 h, an overall decrease in oil content was seen with a significant increase in PL from 0.2 to 39.1%. An increase in SDA (from 0.2 to 0.6 g/100 g oil) indicated minor FA synthesis during germination and therefore, Δ6-desaturase activity with the most marked increase after light exposure. The FA compositions of developing and mature seeds were similar, suggesting oil/FA synthesis takes place at the initial stage of seed development. Among all the borage parts, the leaves had the highest amounts of α-linolenic acid (ALA, 18:3n-3) (36.2%), indicating Δ15-desaturase activity, and SDA (25.2%), indicating Δ6-desaturase activity. In leaves, the GL and especially, MGDG fractions had the highest amounts of SDA (31.8 and 39.8%, respectively), indicating that Δ6-desaturase is most active in chloroplasts. Leaves and developing seeds appear to be the major sources of Δ6-desaturase in borage, associated with different organelles in the different tissues.