Intellectual Property Topics in Open University Distance-Taught Courses

Patents lie at the heart of engineering as a permanent and ongoing record of invention. We have taught the subject for about 5 years in both UG and PG courses, written from scratch owing to the absence of textbooks aimed specifically at engineers. Most practising engineers develop patent skills on the job rather than through conventional courses. But there is a need to present such courses as early as possible in the engineering curriculum, so that graduates have a flying start in their first employment

Spin-dependent charge recombination along para-phenylene molecular wires

We have used an efficient new quantum mechanical method for radical pair recombination reactions to study the spin-dependent charge recombination along PTZ$^{\bullet+}$--Ph$_n$--PDI$^{\bullet-}$ molecular wires. By comparing our results to the experimental data of E. Weiss {\em et al.} [J. Am. Chem. Soc. {\bf 126}, 5577 (2004)], we are able to extract the spin-dependent (singlet and triplet) charge recombination rate constants for wires with $n=2-5$. These spin-dependent rate constants have not been extracted previously from the experimental data because they require fitting its magnetic field-dependence to the results of quantum spin dynamics simulations. We find that the triplet recombination rate constant decreases exponentially with the length of the wire, consistent with the superexchange mechanism of charge recombination. However, the singlet recombination rate constant is nearly independent of the length of the wire, suggesting that the singlet pathway is dominated by an incoherent hopping mechanism. A simple qualitative explanation for the different behaviours of the two spin-selective charge recombination pathways is provided in terms of Marcus theory. We also find evidence for a magnetic field-independent background contribution to the triplet yield of the charge recombination reaction, and suggest several possible explanations for it. Since none of these explanations is especially compelling given the available experimental evidence, and since the result appears to apply more generally to other molecular wires, we hope that this aspect of our study will stimulate further experimental work.Comment: 12 pages, 10 figure

Interrelationship between atomic species, bias voltage, texture and microstructure of nano-scale multilayers

A matrix of binary and ternary nitrides containing lighter elements (Al, Ti, V and Cr) with atomic mass 89 has been formulated. These have been grown as nano-scale multilayer coatings (bilayer thickness approx. 3.0 nm) on stainless steel substrates using an industrial size multiple-target ABS coater. When lighter elements are incorporated into the multilayer at a lower bias voltage (U-B = -75 V) pronounced {111} or {110}, textures develop which are determined by the dominating species present. A {111} or {110} texture develops when TiAlN or VN and or CrN dominates the matrix, respectively. In contrast when a heavier element is incorporated a {100} texture is observed. Additionally, there is a strong indication that in the case when heavy elements (>89) are involved in the growth process, which evolves by continuous re-nucleation. Conversely, when only light elements (<52) are involved then the coating evolves by competitive growth. This observation is limited only for the lower bias voltage range of U-B -75 to -120 V However, as the bias voltage is increased (up to U-B = -150 V) the texture becomes increasingly sharp and in all cases a {111} texture develops. A lower residual compressive stress (typically -1.8 GPa) is observed when one of the bi-layers is dominated by a heavier element. The stress increases (up to -6.8 GPa) in these coatings when the bias voltage is increased to U-B = -150 V which is always systematically lower than in coatings containing only lighter elements which are typically up to -11.7 GPa at the same bias voltage. In parallel this results in an increase in plastic hardness (80 GPa) and in the sliding wear coefficient by an order of magnitude regardless of the type of lattice growth observed

Asymmetric recombination and electron spin relaxation in the semiclassical theory of radical pair reactions

We describe how the semiclassical theory of radical pair recombination reactions recently introduced by two of us [D. E. Manolopoulos and P. J. Hore, J. Chem. Phys. 139, 124106 (2013)] can be generalised to allow for different singlet and triplet recombination rates. This is a non-trivial generalisation because when the recombination rates are different the recombination process is dynamically coupled to the coherent electron spin dynamics of the radical pair. Furthermore, because the recombination operator is a two-electron operator, it is no longer sufficient simply to consider the two electrons as classical vectors: one has to consider the complete set of 16 two-electron spin operators as independent classical variables. The resulting semiclassical theory is first validated by comparison with exact quantum mechanical results for a model radical pair containing 12 nuclear spins. It is then used to shed light on the spin dynamics of a carotenoid-porphyrin-fullerene (CPF) triad containing considerably more nuclear spins which has recently been used to establish a 'proof of principle' for the operation of a chemical compass [K. Maeda et al., Nature 453, 387 (2008)]. We find in particular that the intriguing biphasic behaviour that has been observed in the effect of an Earth-strength magnetic field on the time-dependent survival probability of the photo-excited C+PF- radical pair arises from a delicate balance between its asymmetric recombination and the relaxation of the electron spin in the carotenoid radical

Vibration limiting of rotors by feedback control

Experimental findings of a three mass rotor with four channels of feedback control are reported. The channels are independently controllable with force being proportional to the velocity and/or instantaneous displacement from equilibrium of the shaft at the noncontacting probe locations (arranged in the vertical and horizontal attitudes near the support bearings). The findings suggest that automatic feedback control of rotors is feasible for limiting certain vibration levels. Control of one end of a rotor does afford some predictable vibration limiting of the rotor at the other end

Preliminary design-lift/cruise fan research and technology airplane flight control system

This report presents the preliminary design of a stability augmentation system for a NASA V/STOL research and technology airplane. This stability augmentation system is postulated as the simplest system that meets handling qualities levels for research and technology missions flown by NASA test pilots. The airplane studied in this report is a T-39 fitted with tilting lift/cruise fan nacelles and a nose fan. The propulsion system features a shaft interconnecting the three variable pitch fans and three power plants. The mathematical modeling is based on pre-wind tunnel test estimated data. The selected stability augmentation system uses variable gains scheduled with airspeed. Failure analysis of the system illustrates the benign effect of engine failure. Airplane rate sensor failure must be solved with redundancy

Continued development of doped-germanium photoconductors for astronomical observations at wavelengths from 30 to 120 micrometers

The development of doped-germanium detectors which have optimized performance in the 30- to 120-mu m wavelength range and are capable of achieving the objectives of the infrared astronomical satellite (IRAS) space mission is discussed. Topics covered include the growth and evaluation of Ge:Ga and Ge:Be crystals, procedures for the fabrication and testing of detectors, irradiance calculations, detector responsivity, and resistance measurements through MOSFET. Test data are presented in graphs and charts

Fluctuations and correlations in population models with age structure

We study the population profile in a simple discrete time model of population dynamics. Our model, which is closely related to certain ``bit-string'' models of evolution, incorporates competition for resources via a population dependent death probability, as well as a variable reproduction probability for each individual as a function of age. We first solve for the steady-state of the model in mean field theory, before developing analytic techniques to compute Gaussian fluctuation corrections around the mean field fixed point. Our computations are found to be in good agreement with Monte-Carlo simulations. Finally we discuss how similar methods may be applied to fluctuations in continuous time population models.Comment: 4 page

Test of sodium boiling in a single tube-in- shell heat exchanger over the range 1720 deg to 1980 deg F /1211 to 1355 K/

Bimetallic heat exchanger tube performance in sodium boiling facilit