190 research outputs found
Measuring Scaling Effects in Small Two-Stroke Internal Combustion Engines
As internal combustion (IC) engines decrease in displacement, their cylinder surface area to swept volume ratio increases. Examining power output of IC engines with respect to cylinder surface area to swept volume ratio shows that there is a dramatic change in power scaling trends at approximately 1.5 cm-1. At this size, thermal quenching and friction losses are expected to dominate , so power production and efficiency characteristics suffer. Furthermore, small IC engines (100cc displacement) have limited technical performance data compared to IC engines in larger size classes. Therefore, it is critical to establish accurate performance figures for a family of geometrically similar engines in the size class of approximately 1.5 cm-1 in order to better predict the phenomena that contribute to lower efficiencies in small ICEs. A series of three two stroke, single cylinder, spark ignited, air cooled, and carbureted IC engines were tested in this study. They had a displacement of 28cc, 55cc and 85cc corresponding to cylinder surface area to swept volume ratios of 1.81 cm-1, 1.46 cm-1, and 1.28 cm-1 respectively. The engines share design features like compression ratio, gas exchange port design, and scavenging metho
Assessing the Spatial Accuracy of Applanix DSS\u3csup\u3eTM\u3c/sup\u3e Model-301 Sensor Stereo Imagery using a Survey GPS Ground Control Network
During the past decade, Geographic Information Systems (GISs) have become widely used in many disciplines and that has created demands for accurate high-resolution digital data, especially digital imagery. Photogrammetry has emerged as one of the most important disciplines employed in the collection of spatially related information for use in GIS databases, especially for terrestrial landscapes. This study assessed the horizontal and vertical accuracy of the Applanix Digital Sensor System (DSS ) 301 orthophotographs. The study area was located on the University of Arkansas at Monticello campus and included 950 acres. To assess the spatial accuracy of the DSS, 56 Ground Control Points (GCPs) were collected prior to image acquisition using Trimble Surveying grade 4700 Global Positioning Systems (GPS). The 28 stereo aerial photographs used to create the orthorectified mosaic were taken with the DSSâ„¢ 30I, with approximately a 15.24 cm pixel spatial resolution. The average horizontal Root Mean Square Error (RMSE) for the DSS\u27 mosaic was 0.212m using the GPS-aided Inertial Measurement Unit (IMU) and 0.194 m from the mosaic created using one GCP per photo with the IMU. The vertical RMSE was 0.371 m for the 2-meter DEM created from stereo imagery using only the IMU
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Pathological role of double-stranded DNA antibodies in multiple sclerosis.
Multiple sclerosis is a complex disease and one for which the aetiology remains largely unanswered. Anti-dsDNA antibodies have been found intrathecally and bordering lesions in multiple sclerosis patients and in view of their known pathogenity in lupus nephritis the aim of this project was to further investigate their role in multiple sclerosis. Using the acute experimental allergic encephalomyelitis (EAE) model in the Lewis rat, the inflammatory phase of disease was profiled using immunohistological and ELISA methods and was related to clinical sign severity. The parameters of interest were central nervous system deposits of IgM, IgG, B cells and C3 and anti-DNA antibodies in sera, cerebrospinal fluid and in situ. In situ evaluation of anti-dsDNA antibodies was also performed in tissue taken from Biozzi (AH) mice (relapsing/remitting EAE model) and from a multiple sclerosis patient. Inflammatory deposits specifically at sites of perivascular cuffing were found to increase with increasing clinical sign severity. At the time clinical signs had plateaued in the Lewis rat, intrathecal anti-dsDNA antibodies were at their highest level and anti-ssDNA antibodies at their lowest. The latter possibly due to their involvement in the `clearing-up¿ process following tissue damage. Using novel DNA probes fluorescence suggestive of the presence of anti-dsDNA
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antibodies was seen in both animal and human tissue. Within human tissue the antibodies appeared to accumulate around active lesions and within vessels, raising the question of these antibodies having differing location dependent functions. EAE models have the potential to investigate these findings further and to evaluate new therapies.Covance Laboratories Ltd
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A Precision Angular Correlation Table and Calculation of Geometrical Correction Factors
In recent years y-y angular correlations have been very useful in confirming the spins of excited nuclear states. Angular correlation techniques have also been employed to study the electric and magnetic character of excited nuclear states. With these things in mind, it was decided to design, construct, and test a precision angular correlation table
Evaluation of juvenile hormone analogues as rodent feed-through insecticides for control of immature phlebotomine sandflies
The juvenile hormone analogues methoprene and pyriproxyfen were evaluated as rodent feed-through insecticides for control of immature stages of the sandfly Phlebotomus papatasi Scopoli (Diptera: Psychodidae). The development and survival of P. papatasi second-instar larvae fed faeces from Syrian hamsters, Mesocricetus auratus, that had been fed a diet containing methoprene (0, 9.788, 97.88 or 978.8 p.p.m.) or pyriproxyfen (0, 9.82, 98.2 or 982 p.p.m.) were evaluated. The faeces of methoprene-treated hamsters greatly reduced the percentage of larvae that pupated at all concentrations tested and prevented adult emergence at all but the lowest concentration (9.788 p.p.m.). Pyriproxyfen prevented both pupation and adult emergence at all concentrations tested. The results of this study suggest that a control strategy using rodent baits containing juvenile hormone analogues to control phlebotomine sandflies that live in rodent burrows and feed on rodent faeces may be possible. As rodent reservoirs and vectors of Leishmania major live in close association in many parts of the Middle East, control of the transmission of the agent of zoonotic cutaneous leishmaniasis may also be possible. © 2010 The Authors. Medical and Veterinary Entomology © 2010 The Royal Entomological Society
Experimental evidence of a natural parity state in Mg and its impact to the production of neutrons for the s process
We have studied natural parity states in Mg via the
Ne(Li,d)Mg reaction. Our method significantly improves the
energy resolution of previous experiments and, as a result, we report the
observation of a natural parity state in Mg. Possible spin-parity
assignments are suggested on the basis of published -ray decay
experiments. The stellar rate of the Ne(,)Mg
reaction is reduced and may give rise to an increase in the production of
s-process neutrons via the Ne(,n)Mg reaction.Comment: Published in PR
Canine Visceral Leishmaniasis, United States and Canada, 2000–2003
Foxhounds infected with Leishmania spp. were found in 18 states and 2 Canadian provinces
Smoke, curtains and mirrors: the production of race through time and title registration
This article analyses the temporal effects of title registration and their relationship to race. It traces the move away from the retrospection of pre-registry common law conveyancing and toward the dynamic, future-oriented Torrens title registration system. The Torrens system, developed in early colonial Australia, enabled the production of ‘clean’, fresh titles that were independent of their predecessors. Through a process praised by legal commentators for ‘curing’ titles of their pasts, this system produces indefeasible titles behind its distinctive ‘curtain’ and ‘mirror’, which function similarly to magicians’ smoke and mirrors by blocking particular realities from view. In the case of title registries, those realities are particular histories of and relationships with land, which will not be protected by property law and are thus made precarious. Building on interdisciplinary work which theorises time as a social tool, I argue that Torrens title registration produces a temporal order which enables land market coordination by rendering some relationships with land temporary and making others indefeasible. This ordering of relationships with land in turn has consequences for the human subjects who have those relationships, cutting futures short for some and guaranteeing permanence to others. Engaging with Renisa Mawani and other critical race theorists, I argue that the categories produced by Torrens title registration systems materialise as race
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