Softened C-H modes of adsorbed methyl and their implications for dehydrogenation: An ab initio study

To investigate the softening of CH vibrational frequencies and their implications for dehydrogenation of adsorbed hydrocarbons, an issue of scientific and technological importance, density functional theory calculations have been performed on the chemisorption and dehydrogenation of CH3 on Cu(111) and Pt(111) surfaces. By comparing these results with those of Ni(111) we find that the CH bonds of the adsorbate, when close enough, interact with metal atoms of the surface. It is this interaction and its associated lengthening and weakening of CH bonds that is the physical origin of mode softening. We rule out the possibility of a relationship between the mere presence of mode softening and dehydrogenation. We do show, however, that there is a clear relationship between the extent to which a surface can induce mode softening and the activation energy to dehydrogenation. In addition, periodic trends concerning the extent of mode softening are reproduced. (C) 2001 American Institute of Physics.

Steady-State and Transient Performance of Biodiesel-Fueled Compression-Ignition-Based Electrical Generation

This paper investigates the performance characteristics of rapeseed methyl ester, EN 14214 biodiesel, when used for electrical generation in compression ignition engines. The work was inspired by the need to replace fossil diesel fuel with a sustainable low carbon alternative while maintaining generator performance, power quality, and compliance with ISO 8528-5. A 50-kVA Perkins diesel engine generator was used to assess the impact of biodiesel with particular regard to gen-set fuel consumption, load acceptance, and associated standards. Tests were performed on the diesel gen-set for islanded and grid-connected modes of operation, hence both steady-state and transient performance were fully explored. Performance comparisons were made with conventional fossil diesel fuel, revealing minimal technical barriers for electrical generation from this sustainable, carbon benign fuel. Recommendations for improved transient performance are proposed and validated through tests.

Modes of Griot Inscription in African Cinema

A recurring idea in criticism of African cinema has been that the films frequently deploy the narrative techniques of ‘the griot’, the storyteller of African tradition. In particular, Manthia Diawara (1989) has alerted us to the inscription of the oral narrator within the visual discourse of particular African films, while other critics have considered how the films recall the narrative forms of traditional oral tales. However, these critics’ exclusive attention to the visual track and/or narrative form overlooks another inscription of the griot - an inscription that exists at the level of music. Examining music and image relationships in an aesthetically diverse set of African films, this paper demonstrates how griot inscription emerges as a major variable, modulating between music and image within and between texts. This propels music, and the griot, to a status of primary importance in terms of understanding the ways in which the films engage with, and re-appropriate, notions of ‘African-ness’, while negotiating the tensions of address generated when oral forms of narrative meet the literate, industrial form of cinema.

Binding modes of diketo-acid inhibitors of HIV-1 integrase: A comparative molecular dynamics simulation study

HIV-1 integrase (IN) has become an attractive target since drug resistance against HIV-1 reverse transcriptase (RT) and protease (PR) has appeared. Diketo acid (DKA) inhibitors are potent and selective inhibitors of HIV-1 IN: however the action mechanism is not well understood. Here, to study the inhibition mechanism of DKAs we performed 10 ns comparative molecular dynamics simulations on HIV-1 IN bound with three most representative DMA inhibitors: Shionogi inhibitor, S-1360 and two Merck inhibitors L-731,988 and L-708,906. Our simulations show that the acidic part of S-1360 formed salt bridge and cation-pi interactions with Lys159. In addition, the catalytic Glu152 in S-1360 was pushed away from the active site to form an ion-pair interaction with Arg199. The Merck inhibitors can maintain either one or both of these ion-pair interaction features. The difference in potencies of the DMA inhibitors is thus attributed to the different binding modes at the catalytic site. Such structural information at atomic level, not only demonstrates the action modes of DMA inhibitors but also provides a novel starting point for structural-based design of HIV-1 IN inhibitors.

Down with MNE-centric theories! Market entry and expansion as the bundling of MNE and local assets

Both Anderson and Gatignon and the Uppsala internationalization model see the initial mode of foreign market entry and subsequent modes of operation as unilaterally determined by multinational enterprises (MNEs) arbitraging control and risk and increasing their commitment as they gain experience in the target market. OLI and internalization models do recognize that foreign market entry requires the bundling of MNE and complementary local assets, which they call location or country-specific advantages, but implicitly assume that those assets are freely accessible to MNEs. In contrast to both of these MNE-centric views, I explicitly consider the transactional characteristics of complementary local assets and model foreign market entry as the optimal assignment of equity between their owners and MNEs. By looking at the relative efficiency of the different markets in which MNE and complementary local assets are traded, and at how these two categories of assets match, I am able to predict whether equity will be held by MNEs or by local firms, or shared between them, and whether MNEs will enter through greenfields, brownfields, or acquisitions. The bundling model I propose has interesting implications for the evolution of the MNE footprint in host countries, and for the reasons behind the emergence of Dragon MNEs.

Psychic Distance, its Business Impact and Modes of Coping: A Study of British and Indian Partner SMEs

This paper reports one of the first investigations to analyze inter-partner perceptions of psychic distance between two countries. Its empirical focus is British and Indian SMEs engaged in business with each other. It examines different dimensions of psychic distance, their impact and modes of coping with them. Potential firm-level and individual influences are also taken into account. The paper aims to transcend some of the conceptual and methodological limitations of previous research on the subject and to identify the theoretical and practical implications that arise. A ‘mirror’ approach is applied, accessing both partners’ perceptions. These are assessed through a ‘mixed’ method combining quantitative measurement with qualitative interpretations. Psychic distance dimensions are found to vary in their impact on doing business with the other country, and there is also variation according to the firm’s sector. There is considerable asymmetry in British and Indian partners’ perceptions of psychic distance but the degree of difference between their psychic distance evaluations lacks predictive power. Culturally embedded psychic distance dimensions tend to have less impact and to be easier to cope with than institutionally embedded dimensions. Four categories of coping are identified. The principal theoretical implication of this study is that a contingency perspective needs to be adopted in the field of ‘distance’ research, taking account of factors such as a firm’s sector, and that this will require a more complex analytical framework that hitherto.

Extracting statistically dominant modes of a steel truss bridge from vehicle-induced vibrations

This study is intended to investigate the validity of the stability diagram (SD) aided multivariate autoregressive (MAR) analysis for identifying modal parameters of a real truss bridge. The MAR models are adopted to fit the time series of the dynamic accelerations recorded from a number of observation points on the bridge; then the modal parameters are extracted from the MAR model coefficient matrix. The SD is adopted to determine statistically dominant modes. In plotting the SD, a number of stability criteria are further adopted for filtering out those modes with unstable modal parameters. By the present method, the first five modal frequencies and mode shapes are identified with very high precision, while the damping ratios are identified with high precision for the 1st mode but with poorer precision for higher modes. Moreover, the ability of the SD in selecting structural modes without getting involved in any model-order optimization problem is highlighted through a comparison study.

Control over the Self-Assembly Modes of PtII Complexes by Alkyl Chain Variation: From Slipped to Parallel π-Stacks

We report the self-assembly of a new family of hydrophobic,bis(pyridyl) PtII complexes featuring an extendedoligophenyleneethynylene-derived π-surface appended withsix long (dodecyloxy (2)) or short (methoxy (3)) side groups.Complex 2, containing dodecyloxy chains, forms fibrous assemblies with a slipped arrangement of the monomer units (dPt···Pt… =14 Å) in both nonpolar solvents and the solid state.Dispersion-corrected PM6 calculations suggest that this organizationis driven by cooperative π–π, C-H···Cl and π–Pt interactions, which is supported by EXAFS and 2D NMR spectroscopic analysis. In contrast, nearly parallel π-stacks (dPt···Pt… = 4.4 Å) stabilized by multiple π–π and C-H···Cl contact sare obtained in the crystalline state for 3 lacking longside chains, as shown by X-ray analysis and PM6 calculations.Our results reveal not only the key role of alkyl chain lengthin controlling self-assembly modes but also show the relevanceof Pt-bound chlorine ligands as new supramolecular synthons.

Creating New Design-Build-Test Experiences as Outputs of Undergraduate Design-Build-Test Projects

This paper describes a methodology of using individual engineering undergraduate student projects as a means of effectively and efficiently developing new Design-Build-Test (DBT) learning experiences and challenges.
A key aspect of the rationale for this approach is that it benefits all parties. The student undertaking the individual project gets an authentic experience of producing a functional artefact, which has been the result of a design process that addresses conception, design, implementation and operation. The supervising faculty member benefits from live prototyping of new curriculum content and resources with a student who is at a similar level of knowledge and experience as the intended end users of the DBT outputs. The multiple students who ultimately undertake the DBT experiences / challenges benefit from the enhanced nature of a learning experience which has been “road tested” and optimised.
To demonstrate the methodology the paper will describe a case study example of an individual project completed in 2015. This resulted in a DBT design challenge with a theme of designing a catapult for throwing table tennis balls, the device being made from components laser cut from medium density fibreboard (MDF). Further three different modes of operation will be described which use the same resource materials but operate over different timescales and with different learning outcomes, from an icebreaker exercise focused on developing team dynamics through to full DBT where students get an opportunity to experience the full impact of their design decisions by competing against other students with a catapult they have designed and built themselves.