The civic survey of Greater London: social mapping, planners and urban space in the early twentieth century

This paper examines work conducted between 1915 and 1919 by a group of architects and planners based at the Royal Institute of British Architects. The project, called the Civic Survey of Greater London, and the substantial collection of maps and diagrams that resulted from it are currently unknown in histories of mapping and planning, thus this paper offers a preliminary account and analysis of the work. The paper begins by assessing the development of surveying and mapping techniques in the nineteenth century with the aim of situating the Survey within broader historical trajectories. The following section of the paper examines the immediate context for the Survey, in particular the place of Patrick Geddes and his ideas. The third part of the paper focuses on the work of the Survey itself. The fourth part draws out key analytical threads in dialogue with a number of the maps of the Survey. The emphasis placed here is on exploring lines of continuity between the Civic Survey of Greater London and earlier techniques of representation and governmentality. The concluding section reflects briefly on the reasons for the Survey's subsequent relative obscurity and the importance of the project for later traditions of surveying

Modeling of the solid rotor induction motor

Conventionally the rotors of cage type induction motors are laminated. There is also the possibility of using a solid rotor made from magnetic steel. This option offers advantages associated with ease of construction and reduced material costs. There are two main versions of solid rotor construction. The simpler version is essentially a steel cylinder without a cage or end-rings. A solid steel rotor with an embedded aluminum or copper cage constitutes the other version. There has been very little published work on the first version and, to the author's knowledge, there has not been anything reported on the second version. In this paper an equivalent circuit model is developed for the solid rotor induction motor. The model allows analysis of both rotor versions. It highlights the operational advantages and disadvantages of solid rotor construction

Curvature-related eddy-current losses in laminated axial flux machine cores

In this paper we present an axiperiodic quasi-static model to evaluate the magnetic flux density distribution and power loss due to curvature related radial flux in the laminated core of axial flux machines. It is shown that the relatively low effective permeability in the radial direction and the shielding effect of induced eddy currents result in negligible radial flux density compared to the peak flux densities in the axial and circumferential directions. This justifies the assumption of zero radial flux which simplifies electromagnetic modelling of axial flux machine cores. The model predicts that power loss due to curvature related radial flux is insignificant compared to normal eddy current loss if the core permeability, core conductivity and number of poles are sufficiently high. A laboratory technique is proposed for the practical detection of power loss due to curvature related radial flux

The prevalence of Type 2 diabetes and its associated health problems in a community-dwelling elderly population.

AIMS: Prevalence estimates of Type 2 diabetes and its associated health problems in elderly populations are rare, especially in the very elderly. METHODS: A sample of 15 095 community-dwelling older people aged > or = 75 years were assessed. Type 2 diabetes and associated health problems were identified using self-reporting, general practitioner records, drug histories, and blood and urine measurements. RESULTS: There were 1177 people identified as having Type 2 diabetes mellitus, giving an overall prevalence of 7.8% (95% confidence interval 7.1, 8.5), 9.4% (8.4, 10.5) for men and 6.8% (6.1, 7.6) for women. The age, sex and smoking adjusted odds ratios for various health problems, comparing people with and without diabetes were: low vision 1.6 (1.3, 1.9), proteinuria 1.7 (1.4, 2.1), chronic kidney disease stage 4 or 5 1.5 (1.0, 2.1), angina 1.3 (1.1, 1.6), myocardial infarction 1.5 (1.2, 1.8), cerebrovascular event 2.0 (1.8, 2.1) and foot ulceration 1.7 (1.2, 2.4). CONCLUSIONS: The prevalence of Type 2 diabetes is not high in community-dwelling older people, but diabetes was a contributory factor to a number of health problems

Assessing the impacts of nonindigenous marine macroalgae: an update of current knowledge

Nonindigenous marine species continue to be one of the foremost threats to marine biodiversity. As an update to a 2007 review of the impacts of introduced macroalgae, we assessed 142 additional publications to describe species’ impacts as well as to appraise information on the mechanisms of impact. Only 10% of the currently known nonindigenous macroalgal species were subjects of ecological impact studies, with changed community composition as the most commonly reported effect. Economic impacts were rarely published. Recent research has focused on the impacts of introduced macroalgal assemblages: red algal introductions to the Hawaiian Islands and turf algae in the Mediterranean. Several general issues were apparent. First, many publications included nonsignificant results of statistical analyses but did not report associated power. As many of the studies also had low effect and sample size, the potential for type II errors is considerable. Second, there was no widely accepted framework to categorize and compare impacts between studies. Information in this updated review was still too sparse to identify general patterns and mechanisms of impact. This is a critical knowledge gap as rates of introductions and hence impacts of nonindigenous macroalgae are expected to accelerate with climate change and increasing global trade connectivity