Rods Near Curved Surfaces and in Curved Boxes

We consider an ideal gas of infinitely rigid rods near a perfectly repulsive wall, and show that the interfacial tension of a surface with rods on one side is lower when the surface bends towards the rods. Surprisingly we find that rods on both sides of surfaces also lower the energy when the surface bends. We compute the partition functions of rods confined to spherical and cylindrical open shells, and conclude that spherical shells repel rods, whereas cylindrical shells (for thickness of the shell on the order of the rod-length) attract them. The role of flexibility is investigated by considering chains composed of two rigid segments.Comment: 39 pages including figures and tables. 12 eps figures. LaTeX with REVTe

A practice-based approach to developing creativity in higher education

There is increasing demand for professional level creativity. In order to facilitate such professionally orientated creativity development through tertiary education we suggest that students need learning experiences different from those conventionally provided in Higher Education degree programmes today. This paper reports on an ongoing project which aims to introduce professionally orientated creativity development in the undergraduate planning degree course at Cardiff University’s School of City and Regional Planning. The project represents a response to calls for education providers to equip planning graduates with creative problem solving and visioning abilities. Considering the professional profile of planners, creativity development focuses specifically on ‘Creative Leadership’ and ‘Creative Urban Planning Intelligence’. The authors’ efforts and experiences of introducing creativity development led to the creation of a forward looking curriculum model that combines old and new pedagogies and content. Progress toward implementing this model in Cardiff is traced and critically evaluated by sharing lessons from the first three years of experimentation, discussing different variations of intervention and their effects. Introducing changes in established programmes and curricula is difficult. Our experience demonstrates that the (nonconformist) collaboration between a lecturer and an expert creativity consultant employed in this project has been useful and stimulating in facilitating such changes

A New Edge Micro Data Center and its Passive Thermosyphon Cooling System at TUe:Cooling System Thermal Performance Tests

A new innovative Edge Micro Data Centre and its new passive two-phase cooling system are presented here. EMDC's are hyperconverged heterogenous hardware capacities ranging from 1.8kW up to 500kW. HIRO, providing Powerfull Edge as a Service (PEaaS) is seeking very high cooling energy efficiency (PUE approaching 1.0) and solutions to re-use waste heat from their locally installed EMDC's and edge services that are supporting the big data processing and AI of their customers (smart hospitals, Industry 4.0, 5G/6G MEC, smart cities, smart energy grids). The smallest EMDC with 11 nodes (8 processing and acceleration, 1 ethernet switch, 1 PCIe switch and DC power) is used in the test setup. The gravity-driven loop thermosyphon cooling system is composed of a compact monoblock for insertion and cooling of 11 EDMC nodes, a riser and downcomer and a compact aircoil condenser cooled by several fans (or by natural convection). The heat of the EDMC nodes is removed by 11 thermal bridges in the monoblock evaporator. In demonstration “stress” tests run at TUe in The Netherlands, monitoring all individual node temperatures and energy consumptions, the cooling system achieved very high cooling performance during all the tests. Defining the PUE here to be equal to the total energy consumption including fans divided by that of only the computer itself, at maximum heat load the PUE was only 1.034 while at medium heat loads using lower fan speeds values as low as 1.007 were recorded and at heat loads of 186 W and below, the fans could be turned off for completely passive cooling operation

Membranes in rod solutions: a system with spontaneously broken symmetry

We consider a dilute solution of infinitely rigid rods near a curved, perfectly repulsive surface and study the contribution of the rod depletion layer to the bending elastic constants of membranes. We find that a spontaneous curvature state can be induced by exposure of BOTH sides of the membrane to a rod solution. A similar result applies for rigid disks with a diameter equal to the rod's length. We also study the confinement of rods in spherical and cylindrical repulsive shells. This helps elucidate a recent discussion on curvature effects in confined quantum mechanical and polymer systems.Comment: 10 pages, 2 figures, 1 table; submitted to PR

Critical adsorption on curved objects

A systematic fieldtheoretic description of critical adsorption on curved objects such as spherical or rodlike colloidal particles immersed in a fluid near criticality is presented. The temperature dependence of the corresponding order parameter profiles and of the excess adsorption are calculated explicitly. Critical adsorption on elongated rods is substantially more pronounced than on spherical particles. It turns out that, within the context of critical phenomena in confined geometries, critical adsorption on a microscopically thin `needle' represents a distinct universality class of its own. Under favorable conditions the results are relevant for the flocculation of colloidal particles.Comment: 52 pages, 10 figure

Predicting phase equilibria in polydisperse systems

Many materials containing colloids or polymers are polydisperse: They comprise particles with properties (such as particle diameter, charge, or polymer chain length) that depend continuously on one or several parameters. This review focusses on the theoretical prediction of phase equilibria in polydisperse systems; the presence of an effectively infinite number of distinguishable particle species makes this a highly nontrivial task. I first describe qualitatively some of the novel features of polydisperse phase behaviour, and outline a theoretical framework within which they can be explored. Current techniques for predicting polydisperse phase equilibria are then reviewed. I also discuss applications to some simple model systems including homopolymers and random copolymers, spherical colloids and colloid-polymer mixtures, and liquid crystals formed from rod- and plate-like colloidal particles; the results surveyed give an idea of the rich phenomenology of polydisperse phase behaviour. Extensions to the study of polydispersity effects on interfacial behaviour and phase separation kinetics are outlined briefly.Comment: 48 pages, invited topical review for Journal of Physics: Condensed Matter; uses Institute of Physics style file iopart.cls (included

Rapid and simultaneous detection of human hepatitis B virus and hepatitis C virus antibodies based on a protein chip assay using nano-gold immunological amplification and silver staining method

BACKGROUND: Viral hepatitis due to hepatitis B virus and hepatitis C virus are major public health problems all over the world. Traditional detection methods including polymerase chain reaction (PCR)-based assays and enzyme-linked immunosorbent assays (ELISA) are expensive and time-consuming. In our assay, a protein chip assay using Nano-gold Immunological Amplification and Silver Staining (NIASS) method was applied to detect HBV and HCV antibodies rapidly and simultaneously. METHODS: Chemically modified glass slides were used as solid supports (named chip), on which several antigens, including HBsAg, HBeAg, HBcAg and HCVAg (a mixture of NS3, NS5 and core antigens) were immobilized respectively. Colloidal nano-gold labelled staphylococcal protein A (SPA) was used as an indicator and immunogold silver staining enhancement technique was applied to amplify the detection signals, producing black image on array spots, which were visible with naked eyes. To determine the detection limit of the protein chip assay, a set of model arrays in which human IgG was spotted were structured and the model arrays were incubated with different concentrations of anti-IgG. A total of 305 serum samples previously characterized with commercial ELISA were divided into 4 groups and tested in this assay. RESULTS: We prepared mono-dispersed, spherical nano-gold particles with an average diameter of 15 ± 2 nm. Colloidal nano-gold-SPA particles observed by TEM were well-distributed, maintaining uniform and stable. The optimum silver enhancement time ranged from 8 to 12 minutes. In our assay, the protein chips could detect serum antibodies against HBsAg, HBeAg, HBcAg and HCVAg with the absence of the cross reaction. In the model arrays, the anti-IgG as low as 3 ng/ml could be detected. The data for comparing the protein chip assay with ELISA indicated that no distinct difference (P > 0.05) existed between the results determined by our assay and ELISA respectively. CONCLUSION: Results showed that our assay can be applied with serology for the detection of HBV and HCV antibodies rapidly and simultaneously in clinical detection