13,487 research outputs found

    Degradation of road tested automotive connectors

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    The automotive environment is particularly demanding on connector performance, and is characterized by large temperature changes, high humidity and corrosive atmospheres. This paper presents an initial study of connector performance in terms of temperature profiles taken from road vehicles. The temperature profiles are then simulated using empirical relationships to allow prediction of connector performance. Wire harnesses have been investigated to seek evidence of the connector degradation predicted from the temperature data. Initial indications are that the wire harness shows the type of fretting behavior associated with the temperature changes. Evidence of fretting corrosion was found at the contact interface on tin plated terminals from sealed and unsealed connectors

    Dynamic conversion of solar generated heat to electricity

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    The effort undertaken during this program led to the selection of the water-superheated steam (850 psig/900 F) crescent central receiver as the preferred concept from among 11 candidate systems across the technological spectrum of the dynamic conversion of solar generated heat to electricity. The solar power plant designs were investigated in the range of plant capacities from 100 to 1000 Mw(e). The investigations considered the impacts of plant size, collector design, feed-water temperature ratio, heat rejection equipment, ground cover, and location on solar power technical and economic feasibility. For the distributed receiver systems, the optimization studies showed that plant capacities less than 100 Mw(e) may be best. Although the size of central receiver concepts was not parametrically investigated, all indications are that the optimal plant capacity for central receiver systems will be in the range from 50 to 200 Mw(e). Solar thermal power plant site selection criteria and methodology were also established and used to evaluate potentially suitable sites. The result of this effort was to identify a site south of Inyokern, California, as typically suitable for a solar thermal power plant. The criteria used in the selection process included insolation and climatological characteristics, topography, and seismic history as well as water availability

    Supermonads: one notion to bind them all

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    Several popular generalizations of monads have been implemented in Haskell. Unfortunately, because the shape of the associated type constructors do not match the standard Haskell monad interface, each such implementation provides its own type class and versions of associated library functions. Furthermore, simultaneous use of different monadic notions can be cumbersome as it in general is necessary to be explicit about which notion is used where. In this paper we introduce supermonads: an encoding of monadic notions that captures several different generalizations along with a version of the standard library of monadic functions that work uniformly with all of them. As standard Haskell type inference does not work for supermonads due to their generality, our supermonad implementation is accompanied with a language extension, in the form of a plugin for the Glasgow Haskell Compiler (GHC), that allows type inference for supermonads, obviating the need for manual annotations

    Coagulation and fragmentation processes with evolving size and shape profiles : a semigroup approach

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    We investigate a class of bivariate coagulation-fragmentation equations. These equations describe the evolution of a system of particles that are characterised not only by a discrete size variable but also by a shape variable which can be either discrete or continuous. Existence and uniqueness of strong solutions to the associated abstract Cauchy problems are established by using the theory of substochastic semigroups of operators

    Comparing perceived clarity of information on overdiagnosis used for breast and prostate cancer screening in England: an experimental survey.

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    OBJECTIVES: 'Overdiagnosis', detection of disease that would never have caused symptoms or death, is a public health concern due to possible psychological and physical harm but little is known about how best to explain it. This study evaluated public perceptions of widely used information on the concept to identify scope for improving communication methods. DESIGN: Experimental survey carried out by a market research company via face-to-face computer-assisted interviews. SETTING: Interviews took place in participants' homes. PARTICIPANTS: 2111 members of the general public in England aged 18-70 years began the survey; 1616 were eligible for analysis. National representativeness was sought via demographic quota sampling. INTERVENTIONS: Participants were allocated at random to receive a brief description of overdiagnosis derived from written information used by either the NHS Breast Screening Programme or the prostate cancer screening equivalent. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was how clear the information was perceived to be (extremely/very clear vs less clear). Other measures included previous exposure to screening information, decision-making styles and demographic characteristics (eg, education). Binary logistic regression was used to assess predictors of perceived clarity. RESULTS: Overdiagnosis information from the BSP was more likely to be rated as more clear compared with the prostate screening equivalent (adjusted OR: 1.43, 95% CI 1.17 to 1.75; p=0.001). Participants were more likely to perceive the information as more clear if they had previously encountered similar information (OR: 1.77, 1.40 to 2.23; p<0.0005) or a screening leaflet (OR: 1.35, 1.04 to 1.74; p=0.024) or had a more 'rational' decision-making style (OR: 1.06, 1.02 to 1.11; p=0.009). CONCLUSIONS: Overdiagnosis information from breast screening may be a useful template for communicating the concept more generally (eg, via organised campaigns). However, this information may be less well-suited to individuals who are less inclined to consider risks and benefits during decision-making

    Annual cycle of Southeast Asia - Maritime Continent rainfall and the asymmetric monsoon transition

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    J. Climate, 18, 287-301.(Manuscript)In general the Bay of Bengal, Indochina Peninsula and Philippines are in the Asian summer monsoon regime while the Maritime Continent experiences a wet monsoon during boreal winter and a dry season during boreal summer. However, the complex distribution of land, sea and terrain results in significant local variations of the annual cycle. This work uses historical station rainfall data to classify the annual cycles of rainfall over land areas, the TRMM rainfall measurements to identify the monsoon regimes of the four seasons in the entire Southeast Asia, and the QuikSCAT winds to study the causes of the variations. The annual cycle is dominated largely by interactions between the complex terrain and a simple annual reversal of the surface monsoonal winds throughout all monsoon regions from the Indian Ocean to the South China Sea and the equatorial western Pacific The semiannual cycle is comparable in magnitude to the annual cycle over parts of the equatorial landmasses, but only a very small region reflects the twice-yearly crossing of the sun. Most of the semiannual cycle appears to be due to the influence of both the summer and the winter monsoon in the western part of the Maritime Continent where the annual cycle maximum occurs in fall. Analysis of the TRMM data reveals a structure whereby the boreal summer and winter monsoon rainfall regimes intertwine across the equator and both are strongly affected by the wind-terrain interaction. In particular the boreal winter regime extends far northward along the eastern flanks of the major island groups and landmasses. A hypothesis is presented to explain the asymmetric seasonal march in which the maximum convection follows a gradual southeastward progression path from the Asian 2 summer monsoon to the Asian winter monsoon but a sudden transition in the reverse. The hypothesis is based on the redistribution of mass between land and ocean areas during spring and fall that results from different land-ocean thermal memories. This mass redistribution between the two transition seasons produces sea- level patterns leading to asymmetric wind-terrain interactions throughout the region, and a low- level divergence asymmetry in the region that promote the southward march of maximum convection during boreal fall but opposes the northward march during boreal spring.In general the Bay of Bengal, Indochina Peninsula and Philippines are in the Asian summer monsoon regime while the Maritime Continent experiences a wet monsoon during boreal winter and a dry season during boreal summer. However, the complex distribution of land, sea and terrain results in significant local variations of the annual cycle. This work uses historical station rainfall data to classify the annual cycles of rainfall over land areas, the TRMM rainfall measurements to identify the monsoon regimes of the four seasons in the entire Southeast Asia, and the QuikSCAT winds to study the causes of the variations. The annual cycle is dominated largely by interactions between the complex terrain and a simple annual reversal of the surface monsoonal winds throughout all monsoon regions from the Indian Ocean to the South China Sea and the equatorial western Pacific The semiannual cycle is comparable in magnitude to the annual cycle over parts of the equatorial landmasses, but only a very small region reflects the twice-yearly crossing of the sun. Most of the semiannual cycle appears to be due to the influence of both the summer and the winter monsoon in the western part of the Maritime Continent where the annual cycle maximum occurs in fall. Analysis of the TRMM data reveals a structure whereby the boreal summer and winter monsoon rainfall regimes intertwine across the equator and both are strongly affected by the wind-terrain interaction. In particular the boreal winter regime extends far northward along the eastern flanks of the major island groups and landmasses. A hypothesis is presented to explain the asymmetric seasonal march in which the maximum convection follows a gradual southeastward progression path from the Asian 2 summer monsoon to the Asian winter monsoon but a sudden transition in the reverse. The hypothesis is based on the redistribution of mass between land and ocean areas during spring and fall that results from different land-ocean thermal memories. This mass redistribution between the two transition seasons produces sea- level patterns leading to asymmetric wind-terrain interactions throughout the region, and a low- level divergence asymmetry in the region that promote the southward march of maximum convection during boreal fall but opposes the northward march during boreal spring

    Constructing applicative functors

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    Applicative functors define an interface to computation that is more general, and correspondingly weaker, than that of monads. First used in parser libraries, they are now seeing a wide range of applications. This paper sets out to explore the space of non-monadic applicative functors useful in programming. We work with a generalization, lax monoidal functors, and consider several methods of constructing useful functors of this type, just as transformers are used to construct computational monads. For example, coends, familiar to functional programmers as existential types, yield a range of useful applicative functors, including left Kan extensions. Other constructions are final fixed points, a limited sum construction, and a generalization of the semi-direct product of monoids. Implementations in Haskell are included where possible
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