1,250 research outputs found
Exploiting the Design Freedom of RM
This paper details how Rapid Manufacturing (RM) can overcome the restrictions imposed by the
inherent process limitations of conventional manufacturing techniques and become the enabling
technology in fabricating optimal products. A new design methodology capable of exploiting
RM’s increased design freedom is therefore needed. Inspired by natural world structures of trees
and bones, a multi-objective, genetic algorithm based topology optimisation approach is
presented. This combines multiple unit cell structures and varying volume fractions to create a
heterogeneous part structure which exhibits a uniform stress distribution.Mechanical Engineerin
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Rapid Manufactured Textiles
Rapid Manufacturing (RM) is increasingly becoming a viable manufacturing process due
to dramatic advantages that are achievable in the area of design complexity. Through the
exploration of the design freedom, this paper introduces the concept of manufacturing textiles for
potential smart and high performance textile applications. This paper discusses the current
limitations associated with the manufacture of textiles through RM and presents a novel
methodology for the generation of 3D conformal RM textile articles. The paper concludes that
through RM it is entirely possible to manufacture a structure that incorporates drape and free
movement properties directly comparable to conventional textiles.Mechanical Engineerin
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Analysis of Droplet Train/Moving Substrate Interactions in Ink-Jetting Processes
Ink-jetting technology has been applied to several processes in solid free-form
fabrication (SFF) wherein droplets impinge onto a substrate to deposit the build material.
Droplet impact behaviour on a surface has been the interest of many researchers; however,
few studies have been undertaken to investigate the interaction of droplets with the moving
substrate. This paper reports the impact behaviour of the droplets jetted at different
frequencies onto a substrate moving over a range of velocities. The phenomena associated
with the interaction were classified into three main regimes.Mechanical Engineerin
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Impact Absorbent Rapid Manufactured Structures (IARMS)
Rapid Manufacturing (RM) is increasingly becoming a viable manufacturing process due
to dramatic advantages that it facilitates in the area of design complexity. Through the
exploration of the design freedom afforded by RM, this paper introduces the concept and initial
research surrounding Impact Absorbent Rapid Manufactured Structures (IARMS), with an
application in sports personal protective equipment (PPE). Designs are based on the cellular
structure of foams; the inherent advantages of the cellular structure are used as a basis to create
IARMS that have the potential to be optimised for a specific impact absorbent response. The
paper provides some initial results from compression testingMechanical Engineerin
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
Determining the phonon density of states from specific heat measurements via maximum entropy methods
The maximum entropy and reverse Monte Carlo methods are applied to the computation of the phonon density of states (DOS) from heat capacity data. The approach is introduced and the formalism is described. Simulated data are used to test the method, and its sensitivity to noise. Heat capacity measurements from diamond are used to demonstrate the use of the method with experimental data. Comparison between maximum entropy and reverse Monte Carlo results shows that the form of the entropy used here is correct, and that results are stable and reliable. Major features of the DOS are picked out, and acoustic and optical phonons can be treated with the same approach. The treatment set out in this paper provides a cost-effective and reliable method for studies of the phonon properties of materials
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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
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