Shape deformation in continuous map generalization

Given a collection of regions on a map, we seek a method of continuously altering the regions as the scale is varied. This is formalized and brought to rigor as well-defined problems in homotopic deformation. We ask the regions to preserve topology, area-ratios, and relative position as they change over time. A solution is presented using differential methods and computational geometric techniques. Most notably, an application of this method is used to provide an algorithm to obtain cartograms.

Combined effects of alcohol and distraction on driving performance

Although alcohol and distraction are often cited as significant risk factors for traffic crashes, most research has considered them in isolation. It is therefore necessary to consider the interactions between alcohol and distraction impairment sources, especially when examining the relationship between behavior and crash risk. In a driving simulator, the primary goal was to maintain a safe headway to a lead vehicle and the secondary goal was to maintain stable lane position. All participants engaged in distractions that represented different levels of resource competition and half of the participants consumed alcohol (target BAC 0.08 g/dl). Specific comparisons were made between sober driving while distracted and driving intoxicated without distraction. Distraction tasks produced more changes in driving behavior than did alcohol for both longitudinal (primary) and lateral (secondary) driving goals. Alcohol impairment was evident only in relation to lateral driving performance, however there was an amplification of impairment when alcohol and distraction conditions were combined. Distraction resulted in a general level of impairment across all driving goals, whereas participants with alcohol appeared to shed secondary driving goals to “protect” primary driving goals. Drivers’ strategies to cope with alcohol (and distraction) may not be sufficient to offset the increased crash risk.     

A double-torsion study of the fracture of polyethersulphone

Fracture studies of polyethersulphone have been undertaken using the double torsion geometry, in particular to establish the effects of ageing and crack speed on fracture toughness. The stability of crack growth was found in all cases to be very dependent on initial notching. If by suitable techniques, e.g. fatigue, a craze was formed at the notch root the subsequent crack growth was found to be stable, with a craze ahead of the growing crack. Under these conditions only a slight dependence of fracture toughness on crack speed was observed, with no significant differences between material aged for 5 years at room temperature and freshly moulded samples. The dimensions of the observed craze were found to be very similar to those of crazes observed in a parallel study using compact tension geometry and lead to comparable values for craze stress and crack opening displacement. In many instances unstable crack growth was observed, often described as “stick-slip”. This was often associated with the absence of a craze at the crack tip, perhaps due to a damage zone created during razor notching. The initiation load and load for crack arrest were determined and used to calculate initiation and arrest values for the fracture toughness as a function of the applied deformation rate. It was found that these values converged at high crosshead speeds to a value independent of ageing, although for the freshly moulded material the initiation values were significantly higher, and the arrest values lower. Electrically conducting grids were used to establish that crack speeds up to 400 m sec⁻¹ occur during stick-slip crack growth. A detailed discussion is presented of conditions required for stable and unstable crack growth in polyethersulphone.     

Electromagnetic field and ac power loss enhancements at the edges of adjacent strips in a superconducting cable

In most flexible superconducting cables the current is carried by a series of strips laid along the length of the cable with small gaps between their edges to accommodate bending. One consequence of dividing the conductor into strips is an enhancement of the electromagnetic fields in the vicinity of the gaps. The ac losses in the superconductor are thereby also enhanced. Data are presented which enable the effects of these field and loss enhancements on cable performance to be assessed. In particular it is found that there is an optimum corner radius for the strips to achieve a minimum increase in loss compared to a smooth tube and that this increase need not be large for a suitably rounded corner. A non-uniform distribution of the strips around the cross-section of the cable can be deleterious while any radial displacements are likely to increase the losses considerably.     

Iron,Neuroinflammation and Neurodegeneration

Disturbance of the brain homeostasis, either directly via the formation of abnormal proteins or cerebral hypo-perfusion, or indirectly via peripheral inflammation, will activate microglia to synthesise a variety of pro-inflammatory agents which may lead to inflammation and cell death. The pro-inflammatory cytokines will induce changes in the iron proteins responsible for maintaining iron homeostasis, such that increased amounts of iron will be deposited in cells in the brain. The generation of reactive oxygen and nitrogen species, which is directly involved in the inflammatory process, can significantly affect iron metabolism via their interaction with iron-regulatory proteins (IRPs). This underlies the importance of ensuring that iron is maintained in a form that can be kept under control; hence, the elegant mechanisms which have become increasingly well understood for regulating iron homeostasis. Therapeutic approaches to minimise the toxicity of iron include N-acetyl cysteine, non-steroidal anti-inflammatory compounds and iron chelation.     

Identification of unbalance forces by metaheuristic search algorithms

This paper discusses the identification of parameters in rotary systems, namely, the unbalance magnitude, phase and position in the rotor system. These parameters can be identified using the measured orbits in the hydrodynamic bearings. The oil film forces are evaluated in the different positions of the orbit of the journal and are applied to the model of the shaft. The model, integrated in time domain, allows with an assumed unbalance, to simulate the orbits. The objective function is basically the difference between measured and simulated orbits, and its minimum corresponds to the identified unbalance amount, phase and position along the shaft. With respect to traditional model based identification procedures, this approach using oil film forces instead of oil film linearized stiffness and damping coefficients, and unfiltered orbits instead of 1X vibration components is suitable to deal with non-linear behaviour of the system.     

Nitrate and chloride concentrations in the high plains aquifer,Texas

Groundwater nitrate and chloride concentrations were compiled for 122 wells in a rural, three‐county area of northwest Texas. The counties are located on the High Plains aquifer, a major source of groundwater in the region. Cropland/pasture is the predominant land use in the study area. The area also contains numerous cattle feedlots. Fertilizer and manure associated with those land uses are potential sources of ground‐water contamination. Although locally elevated above background levels, none of the chemical concentrations exceeded the primary drinking water standard of 44.27 mg/L for nitrate (10mg/L for NO₃ — N) or secondary standard of 250mg/L for chloride. Rank correlations between nitrate and chloride were statistically significant in two of the three counties, where the solutes may have originated from a common surface source. Denitrification and scant precipitation recharge may account for an absence of nitrate levels above the drinking water standard.     

Cities as planning models

A key feature of modern planning history has been the identification of cities admired for their ‘good planning’. In varying degrees, they have stimulated emulation, selective or partial borrowing, or even direct copying of their admired planning features. Model cities at different phases of planning history include Paris, Frankfurt, Vienna, Moscow, London, Stockholm, Barcelona, Chicago, New York, Portland and Vancouver. In recent years, new models have emerged, such as Singapore or Curitiba. The article considers how such cities became or are becoming models. It examines the methods by which the knowledge and reputation of the ‘model’ are promoted and disseminated. The importance of key actors, and visits, conferences and exhibitions focused on planning issues are considered. So too are less specific factors which help draw the gaze of a wider world. The article also considers whether such cities were/are places where new planning approaches have been invented or where they were implemented on a larger scale. Overall the paper discusses a key and strengthening feature in the circulation of contemporary planning knowledge. It does not answer all the surrounding questions in any definitive sense but opens up new debates about planning and the processes behind its historical evolution.     

Developing toughened aromatic polybenzoxazines using thermoplastic oligomers and telechelics,part 1: Preparation and characterization of the functionalized oligomers

The preparation and characterization of three families of thermoplastic oligomers (M_n = 2918–13263 g mol^?1) based on polyarylsulfone (PSU) differing in both molecular weight and terminal functionality and one series of polyarylethersulfone (PES) of different molecular weights is reported. Infrared and nuclear magnetic resonance spectroscopy data support the formation of both the hydroxyl terminated oligomers and conversion (67–89% depending on molecular weight) to the telechelic PSU oligomer bearing reactive benzoxazine groups. Differential scanning calorimetry reveals that the onset of homopolymerization in the telechelic PSU oligomer occurs at around 100°C (peak maximum 125°C at 10 K/min) and rescans show values of the glass transition (for the homopolymers) ranging from 124 to 167°C depending on molecular weight. The influence on the oligomer backbone and terminal functionality is examined using thermal analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40875.