THE CONTROVERSY OF BULGE PACKS

Examines the question of what height packs are best suited for fresh fruit and vegetables bulge, flat or slack.Agribusiness,

On the computation of the term w21z2zˉw_{21}z^2\bar{z} of the series defining the center manifold for a scalar delay differential equation

In computing the third order terms of the series of powers of the center manifold at an equilibrium point of a scalar delay differential equation, with a single constant delay $r>0,$ some problems occur at the term $w_{21}z^2\bar{z}.$ More precisely, in order to determine the values at 0, respectively $-r$ of the function $w_{21}(\,.\,),$ an algebraic system of equations must be solved. We show that the two equations are dependent, hence the system has an infinity of solutions. Then we show how we can overcome this lack of uniqueness and provide a formula for $w_{21}(0).$Comment: Presented at the Conference on Applied and Industrial Mathematics- CAIM 2011, Iasi, Romania, 22-25 September, 2011. Preprin

Conformal Maps to Multiply-Slit Domains and Applications

By exploiting conformal maps to vertically slit regions in the complex plane, a recently developed rational spectral method [Tee and Trefethen, 2006] is able to solve PDEs with interior layer-like behaviour using significantly fewer collocation points than traditional spectral methods. The conformal maps are chosen to 'enlarge the region of analyticity' in the solution: an idea which can be extended to other numerical methods based upon global polynomial interpolation. Here we show how such maps can be rapidly computed in both periodic and nonperiodic geometries, and apply them to some challenging differential equations

Compensation for nonlinear effects due to high heat flux in thin-film thermometry

Compensation for nonlinear effects due to high heat flux in thin-film thermometr

Convection and heat transfer in layered sloping warm-water\ud aquifers

What convective flow is induced if a geologically-tratified groundwater aquifer is subject to a vertical temperature gradient? How strong is the flow? What is the nett heat transfer? Is the flow stable? How does the convection affect the subsequent species distribution if a pollutant finds its way into the aquifer? This paper begins to address such questions. Quantitative models for buoyancy-driven fluid flow in long, sloping warm-water aquifers with both smoothly- and discretely-layered structures are formulated. The steady-state profiles are calculated for the temperature and for the fluid specific volume flux (Darcy velocity) parallel to the boundaries in a sloping system subjected to a perpendicular temperature gradient, at low Rayleigh numbers. The conducted and advected heat fluxes are compared and it is shown that the system acts somewhat like a heat pipe. The maximum possible ratio of naturally advected-to-conducted heat transfer is determined, together with the corresponding permeability and thermal conductivity profiles

Annular honeycomb seals: Test results for leakage and rotordynamic coefficients; comparisons to labyrinth and smooth configurations

Test results are presented for leakage and rotordynamic coefficients for seven honeycomb seals. All seals have the same radius, length, and clearance; however, the cell depths and diameters are varied. Rotordynamic data, which are presented, consist of the direct and cross-coupled stiffness coefficients and the direct damping coefficients. The rotordynamic-coefficient data show a considerable sensitivity to changes in cell dimensions; however, no clear trends are identifiable. Comparisons of test data for the honeycomb seals with labyrinth and smooth annular seals show the honeycomb seal had the best sealing (minimum leakage) performance, followed in order by the labyrinth and smooth seals. For prerotated fluid entering the seal, in the direction of shaft rotation, the honeycomb seal has the best rotordynamic stability followed in order by the labyrinth and smooth. For no prerotation, or fluid prerotation against shaft rotation, the labyrinth seal has the best rotordynamic stability followed in order by the smooth and honeycomb seals

Concurrent processing simulation of the space station

The development of a new capability for the time-domain simulation of multibody dynamic systems and its application to the study of a large angle rotational maneuvers of the Space Station is described. The effort was divided into three sequential tasks, which required significant advancements of the state-of-the art to accomplish. These were: (1) the development of an explicit mathematical model via symbol manipulation of a flexible, multibody dynamic system; (2) the development of a methodology for balancing the computational load of an explicit mathematical model for concurrent processing; and (3) the implementation and successful simulation of the above on a prototype Custom Architectured Parallel Processing System (CAPPS) containing eight processors. The throughput rate achieved by the CAPPS operating at only 70 percent efficiency, was 3.9 times greater than that obtained sequentially by the IBM 3090 supercomputer simulating the same problem. More significantly, analysis of the results leads to the conclusion that the relative cost effectiveness of concurrent vs. sequential digital computation will grow substantially as the computational load is increased. This is a welcomed development in an era when very complex and cumbersome mathematical models of large space vehicles must be used as substitutes for full scale testing which has become impractical

Commencement Address

Commencement address given by Frank W. Hale, Jr., Special Assistant to the President, Vice Provost for Minority Affairs, and Professor of Communication at The Ohio State University, to the Summer 1988 graduating class of The Ohio State University, St. John Arena, Columbus, Ohio, September 1, 1988

Evaluation of excavation cave-in accidents before and after the 1990 revisions to the OSHA excavation regulations/

Excavation cave-ins in the construction industry have historically injured and killed workers throughout the nation. In 1990 the Occupational Safety and Health Administration (OSHA) excavation standards were completely revised in response to years of controversy over the ambiguities in the earlier standards. The primary purpose for this study was to evaluate the historical data for excavation cave-in accidents over the period from 1985 through 1994 and determine if there is evidence that the 1990 revisions to the regulations have had a positive impact on reducing accidents. OSHA data from the Integrated Management Information System (IMIS) were utilized to obtain 540 reports on excavation cave-ins for a ten-year period from 1985 through 1994. These data were evaluated against various criteria to identify factors that influenced any trends in the data. A review of various other resources on cave-in accidents, training, and inspections were consulted to obtain a broader perspective on the causes and prevention of cave-ins. Most cave-in accidents continued to occur in small companies, usually in relatively shallow trenches while installing pipelines. The primary cause of cave-in accidents continued to be the lack of employing any type of protective system. The incident rate of excavation cave-ins decreased over the ten-year period. The five-year period since the revisions to the regulations in 1990 showed a notable decrease in accident rates compared to the previous five years. Penalties for citations during the latter five years were significantly higher than for the prior five years