Hydrogen storage: the major technological barrier to the development of hydrogen fuel cell cars

In this paper, we review the current technology for the storage of hydrogen on board a fuel cell-propelled vehicle. Having outlined the technical specifications necessary to match the performance of hydrocarbon. fue1, we first outline the inherent difficulties with gas pressure and liquid hydrogen storage. We then outline the history of transition metal hydride storage, leading to the development of metal hydride batteries. A viable system, however, must involve lighter elements and be vacuum-tight. The first new system to get serious consideration is titanium-activated sodium alanate, followed by the lithium amide and borohydride systems that potentially overcome several of the disadvantages of alanates. Borohydrides can alternatively produce hydrogen by reaction with water in the presence of a catalyst but the product would have to be recycled via a chemical plant. Finally various possible ways of making magnesium hydride decompose and reform more readily are discussed. The alternative to lighter hydrides is the development of physisorption of molecular hydrogen on high surface area materials such as carbons, metal oxide frameworks, zeolites. Here the problem is that the surface binding energy is too low to work at anything above liquid nitrogen temperature. Recent investigations of the interaction mechanism are discussed which show that systems with stronger interactions will inevitably require a surface interaction that increases the molecular hydrogen–hydrogen distance

Identification and purification of an endogenous receptor for the lectin pallidin from Polysphondylium pallidum.

We report the identification and purification of an endogenous carbohydrate-containing receptor of pallidin, the cell surface lectin implicated in mediating cell-cell adhesion in the cellular slime mold Polysphondylium pallidum. The receptor is identified in an aqueous extract of crude P. pallidum membranes as a potent inhibitor of the hemagglutination activity of pallidin. The inhibitor is purified to apparent homogeneity by affinity precipitation with pallidin followed by fractionation of the solubilized precipitate on Sepharose 4B. The hemagglutination inhibitor (HAI) is metabolically radiolabeled, indicating that it is a biosynthetic product of the amoebae and not an ingested food substance. The HAI is released into the extracellular medium by living, differentiated amoebae. This release is markedly facilitated by the addition of D-galactose, a specific saccharide that binds to pallidin. Hence, the HAI appears to have an in situ association with pallidin at the cell surface. Exogenously added HAI promotes the agglutination of differentiated amoebae in a gyrated suspension at very low concentrations. The results are consistent with a model of cell-cell adhesion in which the HAI is a multivalent, extracellular aggregation factor that is recognized by pallidin molecules on adjacent cells. The HAI would then be analogues to the aggregation factors identified in marine sponges

Progressive surface modeling scheme from unorganised curves

This paper presents a novel surface modelling scheme to construct a freeform surface progressively from unorganised curves representing the boundary and interior characteristic curves. The approach can construct a base surface model from four ordinary or composite boundary curves and support incremental surface updating from interior characteristic curves, some of which may not be on the final surface. The base surface is first constructed as a regular Coons surface and upon receiving an interior curve sketch, it is then updated. With this progressive modelling scheme, a final surface with multiple sub-surfaces can be obtained from a set of unorganised curves and transferred to commercial surface modelling software for detailed modification. The approach has been tested with examples based on 3D motion sketches; it is capable of dealing with unorganised design curves for surface modelling in conceptual design. Its limitations have been discussed

Cigarette consumption in The Netherlands 1970-1995 - Does tax policy encourage the use of hand-rolling tobacco?

Background: Tax rises to reduce cigarette consumption are a major feature of European tobacco control policies. In many countries, hand-rolling tobacco is much cheaper than manufactured cigarettes. We Investigated whether changes in price differentials between manufactured and hand-rolled cigarettes influenced cigarette consumption in The Netherlands. Method: We developed regression models to explain changes in the consumption of the two cigarette types. Price elasticities, the percentage changes in consumption for a 1% change in price, are calculated from Netherlands data for 1970-1980 and 1985-1995. Results: The ratio of manufactured to hand-rolled cigarette prices changed little during 1970-1980 but varied subsequently. On multivariate analysis, manufactured cigarette consumption in 1970-1980 decreased as its price rose (elasticity = -0.74). In 1985-1995, manufactured cigarette consumption fell with increases in both its own price (elasticity = -0.54) and in the price differential between manufactured and hand-rolled cigarettes (elasticity = -0.60). During 1985-1995, roll-your-own consumption fell as the price ratio of manufactured to hand rolled cigarettes fell (elasticity = +1.0). Conclusion: When the price rise for hand-rolling tobacco is greater than the price rise for manufactured cigarettes, the fall in manufactured cigarette consumption is accompanied by a fall in roll-your-own use. Cigarette smokers are deterred from switching to hand rolled cigarettes instead of stopping smoking. This increases the health benefits of raising taxes on manufactured cigarettes, discourages the use of even more harmful forms of tobacco and may reduce inequalities in health

Forenames and Surnames in Spain in 2004

This paper quantifies the corpus of forenames and surnames in Spain in 2004 using the telephone directory. It describes their frequency patterns, major measurable characteristics, and gives some geographical distributions, international comparisons, and historical explanations. The research presented here is set in a context of a broader study of the quantitative properties of the corpus of personal names in several countries undertaken by Tucker. Amongst the most significant findings are a much more highly skewed distribution towards the most popular surnames than in other countries, the permanence of language regions since the Middle Ages, and important differences in top Hispanic names frequencies between five countries across the Atlantic. It is also suggested that the innovative techniques presented here, combining geographical and statistical analysis of names and their language of origin, opens up enormous possibilities for multidisciplinary work on onomastics

Incremental simulation modelling for Internet collaborative design

In order to support Web-based collaborative design in terms of transferring or updating models dynamically and efficiently, new incremental modelling and local updating strategies have been developed for simulation modelling application since simulation is more focused on visualisation effects than on geometry details. Based on an assembly connection concept, a drag-and-drop assembly method has also been proposed in simulation assembly. An assembly connection is defined as a group of assembly constraints and it makes assembly easier. A case study example is given to show the content of the proposed research

Novel method of capturing static and dynamic anthropometric data for home design

This paper presents a novel method for capturing and measuring both static and dynamic anthropometric data of people. These data can be then used for barrier-free home design based on a concept of ergonomic design with motion. This new approach utilized a 3D motion capture system as a tool to simultaneously obtain anthropometric information based on body motion analyses. This paper reports the experimental system design, data collection and analysis techniques on body motions

Applying scenarios in user-centred design to develop a sketching interface for human modelling and animation

This paper presents our user and usability studies for applying scenarios in user-centred design to develop a sketching interface for virtual human modelling and animation. In this approach, we utilise the User Centred System Design (UCSD) strategy and spiral lifecycles to ensure system usability and functionalities. A series of usability techniques were employed. After the initial conceptual design, a preliminary user study (including questionnaires and sketching observations) was undertaken to establish the formal interface design. Second, an informal user test was conducted on the first prototype: a “sketch-based 3D stick figure animation interface”. Finally, a formal user evaluation (including performance tests, sketching observations, and interviews) was carried out on the latest version: a “sketch-based virtual human builder”. During this iterative process, various paper-based and electronic-based sketching scenarios were created, which were acted-out by users to help designers evoke and verify design ideas, identify users’ needs, and test the prototype interfaces in real contexts. Benefiting from applying the UCSD strategy and scenario-based design to develop a natural and supportive sketching interface, our investigation can be a useful instantiation for the design of other sketching interfaces where these techniques have not been widely acknowledged and utilised in the past

A sketch-based gesture interface for rough 3D stick figure animation

This paper introduces a novel gesture interface for sketching out rough 3D stick figure animation. This interface can allow users to draw stick figures with the system automatic assistance in figure proportion control. Given a 2D hand-drawn stick figure under a parallel view, there is a challenge to reconstruct a unique 3D pose from a set of candidates. Our system utilizes figure perspective rendering, and introduces the concept of ‘thickness contrast’ as a sketch gesture combined with some other constraints/assumptions for pose recovery. The resulting pose can be further corrected, based on physical constraints of human body. Once obtaining a series of 3D stick figure poses, user can easily sketch out motion paths and timing, and add their preferable sound/background. The resulting 3D animation can be automatically synthesized in VRML. This system has been tested on a variety of input devices: electric whiteboard, tablet PC, as well as a standard mouse

From on-line sketching to 2D and 3D geometry: A fuzzy knowledge based system

The paper describes the development of a fuzzy knowledge based prototype system for conceptual design. This real time system is designed to infer user’s sketching intentions, to segment sketched input and generate corresponding geometric primitives: straight lines, circles, arcs, ellipses, elliptical arcs, and B-spline curves. Topology information (connectivity, unitary constraints and pairwise constraints) is received dynamically from 2D sketched input and primitives. From the 2D topology information, a more accurate 2D geometry can be built up by applying a 2D geometric constraint solver. Subsequently, 3D geometry can be received feature by feature incrementally. Each feature can be recognised by inference knowledge in terms of matching its 2D primitive configurations and connection relationships. The system accepts not only sketched input, working as an automatic design tools, but also accepts user’s interactive input of both 2D primitives and special positional 3D primitives. This makes it easy and friendly to use. The system has been tested with a number of sketched inputs of 2D and 3D geometry