A multivariable screening procedure adaptable to electronic computers for the empirical exploration of response surfaces

M.S.Harrison M. Wadswort

Predicting primary productivity in Westhampton Lake, Richmond, Virginia.

Several predictive photosynthetic models were tested using light, temperature, nutrient, chlorophyll, and primary productivity data collected from Westhampton Lake, Richmond, Virginia from February-September, 1972. A simple linear model, the Kendall rank correlation coefficient, was used to relate photosynthesis to individual meteorological, physical, chemical, and biological factors. iii Of the parameters measured, only the daily maximum photosynthetic efficiency ((P/chl) max ) was significantly correlated with photosynthesis. Five multiple factor (non-linear) models were tested. In the best fitting model, primary productivity was a function of the maximum observed ratio of photosynthesis/chlorophyll concentration, light intensity, temperature, nutrient concentrations, and chlorophyll concentration. The Pearson (r) correlation coefficient between predicted and observed values of photosynthesis for this model was .58, indicating that only 34% of the variability between predicted and observed values was accounted for by the model

Dielectrowetting Driven Spreading of Droplets

The wetting of solid surfaces can be modified by altering the surface free energy balance between the solid, liquid, and vapor phases. Here we show that liquid dielectrophoresis induced by nonuniform electric fields can be used to enhance and control the wetting of dielectric liquids. In the limit of thick droplets, we show theoretically that the cosine of the contact angle follows a simple voltage squared relationship analogous to that found for electrowetting on dielectric. Experimental observations confirm this predicted dielectrowetting behavior and show that the induced wetting is reversible. Our findings provide a noncontact electrical actuation process for meniscus and droplet control

Education and Taiwan’s Changing Employment and Earnings Structure

[Excerpt] Between 1980 and 1992, the enormous changes in economic development in Taiwan had significant impacts on the island\u27s labour market. Examples of these changes include the island\u27s almost legendary and meteoric economic growth, the maintenance of essentially full employment, an increase of around 116 per cent in real labour earnings, considerable upgrading of the educational qualifications of the labour force as a whole, a sustained and systematic shift in the composition of the labour force from agriculture into manufacturing and services and occupational upgrading (defined as the expansion of the share of the labour force in the better occupations, at the expense of the lesser occupations). The main purpose of this chapter is to provide in-depth analysis of these and other underlying changes in the Taiwanese labour market, with the main focal point being, on the one hand, the linkages between the employment and earnings structures, whilst on the other, the changes in the education and qualification levels and the new occupational structure of the island\u27s labour force. Our econometric analysis is based upon a dataset taken from the Manpower Utilization Surveys (MUS) produced by the Directorate-General of Budget, Accounting and Statistics (DGBAS) in Taiwan, covering the years 1980 to 1992. The data for 1993 is not used in this chapter, despite being available to us, essentially because the occupation codes adopted after 1992 were incompatible with those of the earlier years

Avoidance of the left lateral decubitus position during sleep in patients with heart failure: relationship to cardiac size and function

AbstractObjectivesWe sought to determine whether patients with congestive heart failure (CHF) avoid the left lateral decubitus (LLD) position during sleep and, if so, whether this avoidance would be more pronounced in those with greater degrees of cardiomegaly.BackgroundAnecdotal reports suggest that, in patients with CHF, the LLD position is associated with discomfort due to the enlarged apical heart beat and greater degree of dyspnea (trepopnea) than other positions. It has also been suggested that the LLD position is associated with increased sympathetic nervous activity.MethodsA total of 75 patients with CHF and 75 control subjects underwent nocturnal polysomnography with monitoring of body position. Echocardiography was performed in all patients with CHF to determine left ventricular end-diastolic diameter (LVEDD). A total of 40 patients underwent cardiac catheterization from which pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were obtained.ResultsPatients with CHF spent significantly less time in the LLD position than in the right lateral decubitus position. No such difference was observed among control subjects. Among patients with CHF, those with larger LVEDD, higher PCWP, and lower CO spent less time in the LLD position.ConclusionsPatients with CHF avoid the LLD position spontaneously during sleep. This may be a protective strategy to avoid discomfort from the enlarged apical heart beat or further hemodynamic or autonomic compromise

Capillary interaction and self-assembly of tilted magnetic ellipsoidal particles at liquid interfaces

Copyright © 2018 American Chemical Society. Magnetic ellipsoidal particles adsorbed at a liquid interface provide exciting opportunities for creating switchable functional materials, where self-assembly can be switched on and off using an external field [Davies et al., Adv. Mater., 2014, 26, 6715]. In order to gain a deeper understanding of this novel system in the presence of an external field, we study the capillary interaction and self-assembly of tilted ellipsoids using analytical theory and finite element simulations. We derive an analytical expression for the dipolar capillary interaction between tilted ellipsoids in elliptical polar coordinates, which exhibits a 1/r2 power law dependence in the far field (i.e., large particle separations r) and correctly captures the orientational dependence of the capillary interactions in the near field. Using this dipole potential and finite element simulations, we further analyze the energy landscape of particle clusters consisting of up to eight tilted ellipsoids in contact. For clusters of two particles, we find that the side-to-side configuration is stable, whereas the tip-to-tip configuration is unstable. However, for clusters of more than three particles, we find that circular loops of side-to-side particles become globally stable, whereas linear chains of side-to-side particles become metastable. Furthermore, the energy barrier for the linear-to-loop transition decreases with increasing particle number. Our results explain both thermodynamically and kinetically why tilted ellipsoids assemble side-to-side locally but have a strong tendency to form loops on larger length scales

Correction to: Capillary Interaction and Self-Assembly of Tilted Magnetic Ellipsoidal Particles at Liquid Interfaces ((2018) 3:11 (14962?14972) DOI: 10.1021/acsomega.8b01818)

© 2019 American Chemical Society. We would like to correct the following minor errors in the paper: Figure 3 legend: Blue data points should be ss sims, red data points should be tt sims, blue line should be ss elliptical, and red line should be tt elliptical. Figure 3 caption, lines 4 and 5 should read, ...for the side-to-side configuration (blue) and the tip-to-tip configuration (red). p 14965, column 2, paragraph 2, lines 8-10 should read, ...has a higher energy compared to the 1/r12 2 power law, whereas the tip-to-tip configuration has a lower energy... The above corrections do not change any of the conclusions of the paper

Controlling the breakup of toroidal liquid films on solid surfaces

The breakup of a slender filament of liquid driven by surface tension is a classical fluid dynamics stability problem that is important in many situations where fine droplets are required. When the filament is resting on a flat solid surface which imposes wetting conditions the subtle interplay with the fluid dynamics makes the instability pathways and mode selection difficult to predict. Here, we show how controlling the static and dynamic wetting of a surface can lead to repeatable switching between a toroidal film of an electrically insulating liquid and patterns of droplets of well-defined dimensions confined to a ring geometry. Mode selection between instability pathways to these different final states is achieved by dielectrophoresis forces selectively polarising the dipoles at the solid-liquid interface and so changing both the mobility of the contact line and the partial wetting of the topologically distinct liquid domains. Our results provide insights into the wetting and stability of shaped liquid filaments in simple and complex geometries relevant to applications ranging from printing to digital microfluidic devices