Program user's manual for optimizing the design of a liquid or gaseous propellant rocket engine with the automated combustor design code AUTOCOM

This computer program manual describes in two parts the automated combustor design optimization code AUTOCOM. The program code is written in the FORTRAN 4 language. The input data setup and the program outputs are described, and a sample engine case is discussed. The program structure and programming techniques are also described, along with AUTOCOM program analysis

Optimal interlayer hopping and high temperature Bose–Einstein condensation of local pairs in quasi 2D superconductors

Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose–Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose–Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures

High Viscosity Jetting System for 3D Reactive Inkjet Printing

High viscosity ink is a potential solution for the improvement of current 3D ink jetting technology. In this study, experiments are carried out to study a series of inks with differing viscosities jetted with PicoDot™ jet valves under different process parameters of temperature and pressure. Results show that a wide range of ink materials from low viscosity (water like materials) to very high viscosity (thixotropic materials) can be jetted with the piezoelectric actuated jet valves without the need of solvents and surfactants. The jetting volume can be controlled under certain conditions between 2nl and 15nl. The jetting performances for low, medium and high viscosity inks have been recorded by high-speed video photography.Mechanical Engineerin

National interest to global reform: patterns of reasoning in British foreign policy discourse

Discussion of the national interest often focuses on how Britain's influence can be maximized, rather than on the goals that influence serves. Yet what gives content to claims about the national interest is the means-ends reasoning which links interests to deeper goals. In ideal-typical terms, this can take two forms. The first, and more common, approach is conservative: it infers national interests and the goals they advance from existing policies and commitments. The second is reformist: it starts by specifying national goals and then asks how they are best advanced under particular conditions. New Labour's foreign policy discourse is notable for its explicit use of a reformist approach. Indeed, Gordon Brown's vision of a 'new global society' not only identifies global reform as a key means of fulfilling national goals, but also thereby extends the concept of the national interest well beyond a narrow concern with national security

Realization of an Inductance Scale Traceable to the Quantum Hall Effect Using an Automated Synchronous Sampling System

In this paper, the realization of an inductance scale from 1~$\mu$H to 10~H for frequencies ranging between 50~Hz to 20~kHz is presented. The scale is realized directly from a series of resistance standards using a fully automated synchronous sampling system. A careful systematic characterization of the system shows that the lowest uncertainties, around 12~$\mu$H/H, are obtained for inductances in the range from 10~mH to 100~mH at frequencies in the kHz range. This new measurement system which was successfully evaluated during an international comparison, provides a primary realization of the henry, directly traceable to the quantum Hall effect. An additional key feature of this system is its versatility. In addition to resistance-inductance (R-L) comparison, any kind of impedances can be compared: R-R, R-C, L-L or C-C, giving this sampling system a great potential of use in many laboratories around the world

On Active Galactic Nuclei as Sources of Ultra-High Energy Cosmic Rays

We measure the correlation between sky coordinates of the Swift BAT catalogue of active galactic nuclei with the arrival directions of the highest energy cosmic rays detected by the Auger Observatory. The statistically complete, hard X-ray catalogue helps to distinguish between AGN and other source candidates that follow the distribution of local large-scale structure. The positions of the full catalogue are marginally uncorrelated with the cosmic ray arrival directions, but when weighted by their hard X-ray flux, AGN within 100 Mpc are correlated at a significance level of 98 per cent. This correlation sharply decreases for sources beyond ~100 Mpc, suggestive of a GZK suppression. We discuss the implications for determining the mechanism that accelerates particles to these extreme energies in excess of 10^19 eV.Comment: 5 pages, 2 figures. Accepted for publication in MNRA

Same space, different standards : a review of cumulative effects assessment practice for marine mammals

The lead author is a PhD student, whose stipend during the undertaking of this work was provided by a James Watt scholarship (Heriot-Watt University). Financial support enabling the open access publication of this research was provided by Natural England - the government’s adviser for the natural environment in England.Marine mammals are vulnerable to a variety of acute and chronic anthropogenic stressors, potentially experiencing these in isolation, successively and/or simultaneously. Formal assessment of the likely impact(s) of the cumulative effects of multiple stressors on a defined population is carried out through a Cumulative Effects Assessment (CEA), which is a mandatory component of the Environmental Impact Assessment (EIA) process in many countries. However, for marine mammals, the information required to feed into CEA, such as thresholds for disturbance, frequency of multiple (and simultaneous) exposures, interactions between stressors, and individual variation in response, is extremely limited, though our understanding is slowly improving. The gaps in knowledge make it challenging to effectively quantify and subsequently assess the risk of individual and population consequences of multiple disturbances in the form of a CEA. To assess the current state of practice for assessing cumulative effects on marine mammals within UK waters, 93 CEAs were reviewed across eleven maritime industries. An objective framework of thirteen evaluative criteria was used to score each assessment on a scale of 13-52 (weak - strong). Scores varied significantly by industry. On average, the aquaculture industry produced the lowest scoring CEAs, whilst the large offshore windfarm industry (≥ 20 turbines) scored highest, according to the scoring criteria used. There was a significant increase in scores over the sample period (2009-2019), though this was mostly attributed to five industries (cable, large and small offshore wind farms, tidal and wave energy). There was inconsistency in the language used to define and describe cumulative effects and a lack of routinely applied methodology. We use the findings presented here, along with a wider review of the literature, to provide recommendations and discussion points aimed at supporting the standardisation and improvement of CEA practice. Although this research focused on how marine mammals were considered within UK CEAs, recommendations made are broadly applicable to assessments conducted for other receptors, countries and/or environments. Adoption of these proposals would help to ensure a more consistent approach, and would aid decision-makers and practitioners in mitigating any potential impacts, to ensure conservation objectives of marine mammal populations are not compromised.Publisher PDFPeer reviewe

A Three-Point Cosmic Ray Anisotropy Method

The two-point angular correlation function is a traditional method used to search for deviations from expectations of isotropy. In this paper we develop and explore a statistically descriptive three-point method with the intended application being the search for deviations from isotropy in the highest energy cosmic rays. We compare the sensitivity of a two-point method and a "shape-strength" method for a variety of Monte-Carlo simulated anisotropic signals. Studies are done with anisotropic source signals diluted by an isotropic background. Type I and II errors for rejecting the hypothesis of isotropic cosmic ray arrival directions are evaluated for four different event sample sizes: 27, 40, 60 and 80 events, consistent with near term data expectations from the Pierre Auger Observatory. In all cases the ability to reject the isotropic hypothesis improves with event size and with the fraction of anisotropic signal. While ~40 event data sets should be sufficient for reliable identification of anisotropy in cases of rather extreme (highly anisotropic) data, much larger data sets are suggested for reliable identification of more subtle anisotropies. The shape-strength method consistently performs better than the two point method and can be easily adapted to an arbitrary experimental exposure on the celestial sphere.Comment: Fixed PDF erro

Suppression of Mott–Hubbard states and metal–insulator transitions in the two-band Hubbard model

I investigate band and Mott insulating states in a two-band Hubbard model, with the aim of understanding the differences between the idealized one-orbital model and the more realistic multi-band case. Using a projection ansatz I show that additional orbitals suppress the metal–insulator transition, leading to a critical coupling of approximately eight times the bare bandwidth. I also demonstrate the effects of orbital ordering, which hinder Mott–Hubbard states and open a bandgap. Since multi-band correlations are common in real materials, this work suggests that very strongly correlated band insulators may be more common than Mott–Hubbard insulators

High broad-band photoresponsivity of mechanically formed InSe-graphene van der Waals heterostructures

We exploit the broad-band transparency of graphene and the favorable band line up of graphene with van der Waals InSe crystals to create new functional heterostructures and high-performance photodetectors. The InSe-graphene heterostructure exhibits a high photoresponsivity, which exceeds that for other two-dimensional van der Waals crystals, and a spectral response that extends from the near-infrared to the visible spectrum. The highest photoresponsivity is achieved in device architectures where the InSe and graphene layers are vertically stacked, thus enabling effective extraction of photogenerated carriers from the InSe to the graphene electrodes