10,981 research outputs found
Simple method for forming thin-wall pressure vessels
Application of internal hydrostatic pressure to seam-welded circular cylindrical tanks having corner-welded, flat, circular ends forms large thin-walled high quality tanks. Form limits expansion of cylindrical portion of final tank while hemispherical ends develop freely; no external form or restraint is required to fabricate spherical tanks
Evaluation of half wave induction motor drive for use in passenger vehicles
Research performed at the University of Missouri-Columbia to devise and design a lower cost inverter induction motor drive for electrical propulsion of passenger vehicles is described. A two phase inverter motor system is recommended. The new design is predicted to provide comparable vehicle performance, improved reliability and a cost advantage for a high production vehicle, decreased total rating of the power semiconductor switches, and a somewhat simpler control hardware compared to the conventional three phase bridge inverter motor drive system. The major disadvantages of the two phase inverter motor drive are that it is larger and more expensive than a three phase machine, the design of snubbers for the power leakage inductances produce higher transient voltages, and the torque pulsations are relatively large because of the necessity to limit the inverter switching frequency to achieve high efficiency
SOFIA: A Stratospheric Observatory for Infrared Astronomy
SOFIA is described as it was originally (May 1988) for the Space and Earth Sciences Advisory Committee (SESAC). The format and questions were provided by SESAC as a standard for judging the merit of potential U.S. space science projects. This version deletes Section IIF, which addressed development costs of the SOFIA facility. SOFIA's unique astronomical potential is described and it is shown how it complements and supports existing and planned facilities
Evidence for nodal superconductivity in LaFePO
In several iron-arsenide superconductors there is strong evidence for a fully
gapped superconducting state consistent with either a conventional s-wave
symmetry or an unusual state where there the gap changes sign between
the electron and hole Fermi surface sheets. Here we report measurements of the
penetration depth in very clean samples of the related
iron-phosphide superconductor, LaFePO, at temperatures down to 100 mK.
We find that varies almost perfectly linearly with strongly
suggesting the presence of gap nodes in this compound. Taken together with
other data, this suggests the gap function may not be generic to all pnictide
superconductors
Protein Feeds for the War Period
The shortage of high-protein feeds and protein supplements for livestock is becoming more acute every day. Supplies of animal protein are not large enough to meet present needs mainly because of the increased demand for them due to (1) greater use of protein feeds by livestock producers in order to provide more milk, meat, and eggs, and (2) the need for larger amounts of casein and other animal proteins, as well as certain vegetable proteins, in war industries. It has been estimated that the shortage of protein concentrates in the United States will exceed 1,810,000 tons for 1943.\u27 Because of this shortage it is very important to the war effort that every livestock producer-farmer, rancher, and livestock feeder-do everything within his power to use existing supplies efficiently and to produce more protein feeds. He can use them best by avoiding overfeeding and other waste of feed, culling out low-producing animals and selling them, and using methods approved by authorities to control diseases and maintain sanitation
A neutron scattering study of the interplay between structure and magnetism in Ba(FeCo)As
Single crystal neutron diffraction is used to investigate the magnetic and
structural phase diagram of the electron doped superconductor
Ba(FeCo)As. Heat capacity and resistivity measurements have
demonstrated that Co doping this system splits the combined antiferromagnetic
and structural transition present in BaFeAs into two distinct
transitions. For =0.025, we find that the upper transition is between the
high-temperature tetragonal and low-temperature orthorhombic structures with
( K) and the antiferromagnetic transition occurs at
K. We find that doping rapidly suppresses the
antiferromagnetism, with antiferromagnetic order disappearing at . However, there is a region of co-existence of antiferromagnetism and
superconductivity. The effect of the antiferromagnetic transition can be seen
in the temperature dependence of the structural Bragg peaks from both neutron
scattering and x-ray diffraction. We infer from this that there is strong
coupling between the antiferromagnetism and the crystal lattice
Experimental research on the effects of water application on greenhouse gas emissions from beef cattle feedlots
The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg mâ2 hâ1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg mâ2 hâ1 for N2O, CH4, and CO2, respectively.The effect of water application (e.g., through rainfall or sprinkler system) on emissions of greenhouse gases (GHGs), such as nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from pen surfaces of open-lot beef cattle feedlots was evaluated under controlled laboratory conditions. Soil/manure samples were collected from several randomly selected pens from two beef cattle feedlots in Kansas and were used as simulated pen surfaces. Three treatments (i.e., dry and loose, moist and loose, and moist and compacted pen surface conditions) were considered, simulating surface conditions in the field after a typical rainfall event or water application with a sprinkler system. Soil/manure and water were mixed within glass containers and analyzed for GHG emission using a photo-acoustic infrared multi-gas analyzer; emission rates were calculated from measured concentrations. GHG emissions from the dry soil/manure samples were low, with mean values of 0.02, 0.00, and 45 mg mâ2 hâ1 for N2O, CH4, and CO2, respectively, compared to moist soil/manure samples. Water application on the dry manure samples resulted in large peaks of GHG fluxes, with peak values of 99.2, 28.6, and 15,443 mg mâ2 hâ1 for N2O, CH4, and CO2, respectively
Research Project as Boundary Object: negotiating the conceptual design of a tool for International Development
This paper reflects on the relationship between who one designs for and what one designs in the unstructured space of designing for political change; in particular, for supporting âInternational Developmentâ with ICT. We look at an interdisciplinary research project with goals and funding, but no clearly defined beneficiary group at start, and how amorphousness contributed to impact. The reported project researched a bridging tool to connect producers with consumers across global contexts and show players in the
supply chain and their circumstances. We explore how both the nature of the research and the toolâs function became contested as work progressed. To tell this tale, we invoke
the idea of boundary objects and the value of tacking back and forth between elastic meanings of the projectâs artefacts and processes. We examine the projectâs role in India, Chile and other arenas to draw out ways that it functioned as a catalyst and how absence of committed design choices acted as an unexpected strength in reaching its goals
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