Exact finite elements for conduction and convection

An approach for developing exact one dimensional conduction-convection finite elements is presented. Exact interpolation functions are derived based on solutions to the governing differential equations by employing a nodeless parameter. Exact interpolation functions are presented for combined heat transfer in several solids of different shapes, and for combined heat transfer in a flow passage. Numerical results demonstrate that exact one dimensional elements offer advantages over elements based on approximate interpolation functions

Decision Support for Grassland Systems in Developing Countries

Key points 1. Information flows in complex systems are often themselves highly complex, and decision support approaches based on linear input-output processes may have only limited impact. 2. How decisions are made, and how they can be appropriately supported, is often incompletely understood, in part because of inadequate understanding of the objectives and attitudes of all the decision makers involved. 3. Much of the developing world faces daunting problems in the coming 30 years, and appropriate information could play a critical role in dealing with these. 4. System complexity, household variability, and institutional intricacies have to be embraced rather than avoided, and so decision support might best be orientated towards identifying ‘hotspot’ areas of the highly disadvantaged and targeting appropriate activities in pursuit of the Millennium Development Goals. 5. Effective decision support could be served by more coordinated efforts to develop and maintain key baseline databases in developing countries, and by innovative, participatory approaches to the processing, adaptation and use of information

Finite element thermal-structural analysis of cable-stiffened space structues

Finite element thermal-structural analyses of large, cable-stiffened space structures are presented. A computational scheme for the calculation of prestresses in the cable-stiffened structures is also described. The determination of thermal loads on orbiting space structures due to environment heating is discussed briefly. Three finite element structural analysis techniques are presented for the analysis of prestressed structures. Linear, stress stiffening, and large displacement analysis techniques were investigated. These three techniques were employed for analysis of prestressed cable structures at different prestress levels. The analyses produced similar results at small prestress, but at higher prestress, differences between the results became significant. For the cable-stiffened structures studied, the linear analysis technique may not provide acceptable results. The stress stiffening analysis technique may yield results of acceptable accuracy depending upon the level of prestress. The large displacement analysis technique produced accurate results over a wide range of prestress and is recommended as a general analysis technique for thermal-structural analysis of cable-stiffened space structures

Integrated transient thermal-structural finite element analysis

An integrated thermal structural finite element approach for efficient coupling of transient thermal and structural analysis is presented. Integrated thermal structural rod and one dimensional axisymmetric elements considering conduction and convection are developed and used in transient thermal structural applications. The improved accuracy of the integrated approach is illustrated by comparisons with exact transient heat conduction elasticity solutions and conventional finite element thermal finite element structural analyses

Origin of broad luminescence from site‐controlled InGaN nanodots fabricated by selective‐area epitaxy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106777/1/pssa201330362.pd

Planted Forage Legumes in West Africa

Planted forage legumes were introduced into West Africa circa 1950. Since then, a range of species and strategies for their introduction into farming have been evaluated. Approaches to both evaluation and use have changed considerably, especially in the past 15 years. Much of the early research was on-station and focused on using mainly Stylosanthes species as introduced pastures. The Stylosanthes fodder bank concept followed this, but with a fairly stringent recipe for farmers to manage and use the legume bank for strategic ruminant supplementation in the dry season. Later evaluation included more legume species, more participatory approaches, and identification of potential domains in relation to farmers\u27 social, economic and biophysical situations. It also included a holistic view of the potential multiple roles of legumes in West Africa, especially in relation to the major mixed crop-livestock system, on which up to 80% of the population may depend. In the context of intensifying mixed crop livestock systems, dual purpose varieties of annual (food-feed) legumes (mainly cowpea and groundnut) are gaining popularity, especially in areas where farmers have good market access and pressure on land is high. [Dual purpose legumes are not considered in the assessment of adoption and potential in this manuscript]. Farmers in areas with poor market access and lower land pressure have adopted non-food legumes to a limited extent, especially Centrosema pascuorum (used as cut-and-carry from a 1-year planted sole plot), and to a lesser extent, Aeschynomene histrix (grazed in situ from a 1-2 year planted fallow) planted for forage and soil fertility restoration

Dual Purpose Cowpea for West Africa

Cowpea (Vigna unguiculata (L.) Walp. ) is grown as an intercrop with cereals in some 9M ha of West Africa, mostly in the dry savanna. Though grain yields are low (circa 500 kg/ha), it is a nutritious food and dry season fodder. The haulms (leaves and stems) are cut and stored after grain harvest. It aids soil fertility by fixing soil N and returning N via manure from ruminants fed with haulms. Up to the early 1990s, research had focused on developing high grain yielding varieties. Recognition of farmers\u27 appreciation of multiple uses, in particular the fodder value and the increasing importance of crop residues as feed resources in much of West Africa where expansion of agricultural land and intensification mean reduced availability of land for planted forages, led to joint research by ILRI and IITA from 1994 onwards, resulting in identification of dual purpose varieties - with the potential to provide both good grain yields and quality fodder under farmer conditions

Timing analysis techniques at large core distances for multi-TeV gamma ray astronomy

We present an analysis technique that uses the timing information of Cherenkov images from extensive air showers (EAS). Our emphasis is on distant, or large core distance gamma-ray induced showers at multi-TeV energies. Specifically, combining pixel timing information with an improved direction reconstruction algorithm, leads to improvements in angular and core resolution as large as ~40% and ~30%, respectively, when compared with the same algorithm without the use of timing. Above 10 TeV, this results in an angular resolution approaching 0.05 degrees, together with a core resolution better than ~15 m. The off-axis post-cut gamma-ray acceptance is energy dependent and its full width at half maximum ranges from 4 degrees to 8 degrees. For shower directions that are up to ~6 degrees off-axis, the angular resolution achieved by using timing information is comparable, around 100 TeV, to the on-axis angular resolution. The telescope specifications and layout we describe here are geared towards energies above 10 TeV. However, the methods can in principle be applied to other energies, given suitable telescope parameters. The 5-telescope cell investigated in this study could initially pave the way for a larger array of sparsely spaced telescopes in an effort to push the collection area to >10 km2. These results highlight the potential of a `sparse array' approach in effectively opening up the energy range above 10 TeV.Comment: Published in Astroparticle Physic

Pediatric endocrine society survey of diabetes practices in the United States: What is the current state?

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144633/1/pedi12677.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144633/2/pedi12677_am.pd