8,231 research outputs found
International Activities of the OSU College of Agriculture, School of Home Economics and School of Natural Resources Faculty: Past Experiences and Future Preferences
Exact date of working paper unknown
Intellectual Life in Antebellum Charleston
https://trace.tennessee.edu/utk_early-american/1013/thumbnail.jp
Fox Factory Bearing Assembly Rundown and Torque Automation Project
A machine design was created to partially automate the rundown and torque of a Fox Factory shock bearing housing. This machine is needed at the factory to keep line associates safe by reducing ergonomic strains associated with this stage in the shock assembly process. Due to the lack of applicable torque drivers for this operation, an open ended, geared drivetrain was designed to allow for engagement of the bearing housing while allowing clearance for the shock shaft that the bearing rides on. This open drivetrain is held by a structure of linear rails and bearings to allow the line associate to guide the open gear into place on the bearing. A pneumatic cylinder and several rail brakes will be used to press the bearing housing into the shock body tube while beginning the rundown process. A control system consisting of a PLC, HMI, and torque driver controller was designed in terms of wiring & programming to control torque and pneumatic outputs. At each stage in the design process, safety and ergonomics were considered so the machine would satisfy the first and second design principle for the Fox manufacturing engineering department: safety and quality, respectively. Basic analysis for component strength and stiffness was performed where any concerns were present, and a maintenance schedule was created for any potential wear items. While the original intent was to manufacture and assemble nearly all machine components in house, parts were instead outsourced by Fox due to various factors stemming from the COVID-19 pandemic
A Spectral Method for Elliptic Equations: The Neumann Problem
Let be an open, simply connected, and bounded region in
, , and assume its boundary is smooth.
Consider solving an elliptic partial differential equation over with a Neumann boundary condition. The problem is converted
to an equivalent elliptic problem over the unit ball , and then a spectral
Galerkin method is used to create a convergent sequence of multivariate
polynomials of degree that is convergent to . The
transformation from to requires a special analytical calculation
for its implementation. With sufficiently smooth problem parameters, the method
is shown to be rapidly convergent. For
and assuming is a boundary, the convergence of
to zero is faster than any power of .
Numerical examples in and show experimentally
an exponential rate of convergence.Comment: 23 pages, 11 figure
A spectral method for elliptic equations: the Dirichlet problem
An elliptic partial differential equation Lu=f with a zero Dirichlet boundary
condition is converted to an equivalent elliptic equation on the unit ball. A
spectral Galerkin method is applied to the reformulated problem, using
multivariate polynomials as the approximants. For a smooth boundary and smooth
problem parameter functions, the method is proven to converge faster than any
power of 1/n with n the degree of the approximate Galerkin solution. Examples
in two and three variables are given as numerical illustrations. Empirically,
the condition number of the associated linear system increases like O(N), with
N the order of the linear system.Comment: This is latex with the standard article style, produced using
Scientific Workplace in a portable format. The paper is 22 pages in length
with 8 figure
Evidence of Augmented Intrarenal Angiotensinogen Associated with Glomerular Swelling in Gestational Hypertension and Preeclampsia:Clinical Implications
Background-—AGT (angiotensinogen) synthesis occurs in renal proximal tubular epithelial cells, independent from systemic AGT, as a component of the intrarenal renin–angiotensin system. We investigated urinary AGT, as a biomarker for renin–angiotensin system activation, and electrolyte concentrations, in relation to glomerular volume, as a proxy for glomerular endotheliosis in renal biopsy tissue from pregnant normotensive control and hypertensive women. Methods and Results-—Urine samples were collected from normotensive control (n=10), gestational hypertensive (n=6), and preeclamptic (n=16) women at the time a renal biopsy was obtained. Samples were collected from Lund University Hospital between November 1999 and June 2001. Urinary AGT, potassium, and sodium were measured, normalized to urinary creatinine. Mean glomerular volume was estimated from biopsy sections. AGT protein expression and localization were assessed in renal biopsies by immunohistochemistry. Urinary AGT concentrations were higher in hypertensive pregnancies (median, gestational hypertension: 11.3 ng/mmol [interquartile range: 2.8–13.6]; preeclampsia: 8.4 ng/mmol [interquartile range: 4.2–29.1]; normotensive control: 0.6 ng/mmol [interquartile range: 0.4–0.8]; P [less than] 0.0001) and showed a positive relationship with estimated mean glomerular volume. Urinary potassium strongly correlated with urinary AGT (P [less than] 0.0001). Although numbers were small, AGT protein was found in both glomeruli and proximal tubules in normotensive control but was present only in proximal tubules in women with hypertensive pregnancy.Conclusions-—This study shows that pregnant women with gestational hypertension or preeclampsia have increased urinary AGT and potassium excretion associated with signs of glomerular swelling. Our data suggest that the kidneys of women with hypertensive pregnancies and endotheliosis have inappropriate intrarenal renin–angiotensin system activation, which may contribute toward the pathogenesis of hypertension and renal injury
INTROGRESSION OF COYOTE MITOCHONDRIAL DNA INTO SYMPATRIC NORTH AMERICAN GRAY WOLF POPULATIONS
Mitochondrial DNA (mtDNA) genotypes of gray wolves and coyotes from localities throughout North America were determined using restriction fragment length polymorphisms. Of the 13 genotypes found among the wolves, 7 are clearly of coyote origin, indicating that genetic transfer of coyote mtDNA into wolf populations has occurred through hybridization. The transfer of mtDNA appears unidirectional from coyotes into wolves because no coyotes sampled have a wolf-derived mtDNA genotype. Wolves possessing coyote-derived genotypes are confined to a contiguous geographic region in Minnesota, Ontario, and Quebec, and the frequency of coyote- type mtDNA in these wolf populations is high (\u3e 500%). The ecological history of the hybrid zone suggests that hybridization is taking place in regions where coyotes have only recently become abundant following conversion of forests to farmlands. Dispersing male wolves unable to find conspecific mates may be pairing with female coyotes in deforested areas bordering wolf territories. Our results demonstrate that closely related species of mobile terrestrial vertebrates have the potential for extensive genetic exchange when ecological conditions change suddenly
Reductions of Hidden Information Sources
In all but special circumstances, measurements of time-dependent processes
reflect internal structures and correlations only indirectly. Building
predictive models of such hidden information sources requires discovering, in
some way, the internal states and mechanisms. Unfortunately, there are often
many possible models that are observationally equivalent. Here we show that the
situation is not as arbitrary as one would think. We show that generators of
hidden stochastic processes can be reduced to a minimal form and compare this
reduced representation to that provided by computational mechanics--the
epsilon-machine. On the way to developing deeper, measure-theoretic foundations
for the latter, we introduce a new two-step reduction process. The first step
(internal-event reduction) produces the smallest observationally equivalent
sigma-algebra and the second (internal-state reduction) removes sigma-algebra
components that are redundant for optimal prediction. For several classes of
stochastic dynamical systems these reductions produce representations that are
equivalent to epsilon-machines.Comment: 12 pages, 4 figures; 30 citations; Updates at
http://www.santafe.edu/~cm
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