Process for the preparation of fluorine containing crosslinked elastomeric polytriazine and product so produced

Crosslinking elastomeric polytriazines are prepared by a 4 step procedure which consists of (1) forming a poly(imidoylamidine) by the reaction, under reflux conditions, of anhydrous ammonia with certain perfluorinated alkyl or alkylether dinitriles; (2) forming a linear polytriazine by cyclizing the imidoylamidine linkages by reaction with certain perfluorinated alkyl or alkylether acid anhydrides or halides; (3) extending the linear polytriazine chain by further refluxing in anhydrous ammonia; and (4) heating to cyclize the new imidoylamidine and thereby crosslink the polymer

Mathematical modelling and analysis of aspects of bacterial motility

The motile behaviour of bacteria underlies many important aspects of their actions, including pathogenicity, foraging efficiency, and ability to form biofilms. In this thesis, we apply mathematical modelling and analysis to various aspects of the planktonic motility of flagellated bacteria, guided by experimental observations. We use data obtained by tracking free-swimming Rhodobacter sphaeroides under a microscope, taking advantage of the availability of a large dataset acquired using a recently developed, high-throughput protocol. A novel analysis method using a hidden Markov model for the identification of reorientation phases in the tracks is described. This is assessed and compared with an established method using a computational simulation study, which shows that the new method has a reduced error rate and less systematic bias. We proceed to apply the novel analysis method to experimental tracks, demonstrating that we are able to successfully identify reorientations and record the angle changes of each reorientation phase. The analysis pipeline developed here is an important proof of concept, demonstrating a rapid and cost-effective protocol for the investigation of myriad aspects of the motility of microorganisms. In addition, we use mathematical modelling and computational simulations to investigate the effect that the microscope sampling rate has on the observed tracking data. This is an important, but often overlooked aspect of experimental design, which affects the observed data in a complex manner. Finally, we examine the role of rotational diffusion in bacterial motility, testing various models against the analysed data. This provides strong evidence that R. sphaeroides undergoes some form of active reorientation, in contrast to the mainstream belief that the process is passive

Advanced supersonic technology fuel tank sealants

Status of the fuel tank simulation and YF-12A flight tests utilizing a fluorosilicone sealant is described. New elastomer sealant development is detailed, and comparisons of high and low temperature characteristics are made to baseline fluorosilicone sealants

Fiber-modified polyurethane foam for ballistic protection

Closed-cell, semirigid, fiber-loaded, self-extinguishing polyurethane foam material fills voids around fuel cells in aircraft. Material prevents leakage of fuel and spreading of fire in case of ballistic incendiary impact. It also protects fuel cell in case of exterior fire

Polyimide fiber-glass composite resists high temperatures

Composites synthesized from bismaleimide have superior strength and oxidation resistance at elevated temperatures when compared with similar composites prepared with epoxy or silicon polymers of similar cost. Polyimide synthesis technique and processing method yield essentially void-free fiber-glass reinforced composites

An investigation of the spring and summer diet of feral mink (Mustela Vison Schreber) in Riparian and coastal habitats

A total of 375 mink scats were collected from two riparian areas in Northumberland and a coastal site in Galloway during the period from April to July in order to investigate the composition of spring and summer feeding of mink. In the riparian habitat, the initial order of importance was:- fish, mammal, bird and amphibian; during the summer, though, the mammal group doubled in importance. At Galloway, a temporal variation in the diet was indicated with lagomorph increasing in importance whilst fish and crab decreased. It was postulated that whilst the riparian diet was largely determined by prey availability coupled to some extent with preference for particular species the variation in the coastal diet may have been due to the varying requirements of a female and kits. The radio-tracking of a juvenile male highlighted the unreliability of using scats and tracks as indicators of mink activity. The tagged animal exhibited a mainly diurnal activity pattern with much exploratory behaviour^ and it was suggested that the former may have been the result of maternal influence whilst the latter indicated attempts at territory establishment or the initiation of dispersion. There was apparently no competition between mink and otter in the riparian habitat; but it is a distinct possibility in the coastal habitat and merits further investigation

Conference on the Development of Fire-Resistant Aircraft Passenger Seats

Papers are presented dealing with the development of aircraft seats with the minimum fire risk. Criteria examined include: flame spread, heat release, and smoke and/or toxic fumes. Materials and performance specifications of all seat material options are provided

Economic orthodoxy and the East Asian crisis

It is now clear that the economic crisis that struck East Asia so suddenly and violently at the end of 1997 has irrevocably altered the political and economic landscape of the region. Major Asian companies have gone bankrupt, anxious domestic and foreign investors have relocated vast amounts of capital abroad, interest rates have skyrocketed, and inflation and unemployment have soared. At the same time, the economic crisis has also led to the collapse of several governments within the region. In South Korea, an opposition party led ..

Electrons in the Earth's Outer Radiation Zone

Electrons in the earths outer radiation bel

Rapid metabolic pathway assembly and modification using serine integrase site-specific recombination

Synthetic biology requires effective methods to assemble DNA parts into devices and to modify these devices once made. Here we demonstrate a convenient rapid procedure for DNA fragment assembly using site-specific recombination by ϕC31 integrase. Using six orthogonal attP/attB recombination site pairs with different overlap sequences, we can assemble up to five DNA fragments in a defined order and insert them into a plasmid vector in a single recombination reaction. ϕC31 integrase-mediated assembly is highly efficient, allowing production of large libraries suitable for combinatorial gene assembly strategies. The resultant assemblies contain arrays of DNA cassettes separated by recombination sites, which can be used to manipulate the assembly by further recombination. We illustrate the utility of these procedures to (i) assemble functional metabolic pathways containing three, four or five genes; (ii) optimize productivity of two model metabolic pathways by combinatorial assembly with randomization of gene order or ribosome binding site strength; and (iii) modify an assembled metabolic pathway by gene replacement or addition