Clemson University

About: Clemson University is a education organization based out in Clemson, South Carolina, United States. It is known for research contribution in the topics: Population & Control theory. The organization has 20556 authors who have published 42518 publications receiving 1170779 citations. The organization is also known as: Clemson Agricultural College of South Carolina.

Dormancy-associated MADS genes from the EVG locus of peach [Prunus persica (L.) Batsch] have distinct seasonal and photoperiodic expression patterns

Abstract: Mapping and sequencing of the non-dormant evg mutant in peach [Prunus persica (L.) Batsch] identified six tandem-arrayed DAM (dormancy-associated MADS-box) genes as candidates for regulating growth cessation and terminal bud formation. To narrow the list of candidate genes, an attempt was made to associate bud phenology with the seasonal and environmental patterns of expression of the candidates in wild-type trees. The expression of the six peach DAM genes at the EVG locus of peach was characterized throughout an annual growing cycle in the field, and under controlled conditions in response to a long day-short day photoperiod transition. DAM1, 2, 4, 5, and 6 were responsive to a reduction in photoperiod in controlled conditions and the direction of response correlated with the seasonal timing of expression in field-grown trees. DAM3 did not respond to photoperiod and may be regulated by chilling temperatures. The DAM genes in peach appear to have at least four distinct patterns of expression. DAM1, 2, and 4 are temporally associated with seasonal elongation cessation and bud formation and are the most likely candidates for control of the evg phenotype.

Free Volume as the Basis of Gas Solubility and Selectivity in Imidazolium-Based Ionic Liquids

Abstract: While molar volume-based models for gas solubility in ionic liquids (ILs) have been proposed, free volume within the IL can be shown to be the underlying property driving gas solubility and selecitivity. Previously published observations as to the distinct differences in solubility trends for gases such as CH4 and N2 relative to CO2 in systematically varied ILs can be attributed to positive and negative effects arising from increasing free volume with increasing alkyl chain length. Through the use of COSMOtherm as a powerful and rapid tool to calculate free volumes in 165 existing and theoretical 1-n-alkyl-3-methylimidazolium ([Cnmim][X]) ILs, a previously unreported, yet speculated, critical underlying relationship between gas solubility in ILs is herein described. These results build upon previous assertions that Regular Solution Theory is applicable to imidazolium-based ILs, which appeared to indicate that a global maximum had already been observed for CO2 solubility in imidazolium-based ILs. However, ...

How Important Are Capital and Total Factor Productivity for Economic Growth

Abstract: We examine the relative importance of the growth of physical and human capital and the growth of total factor productivity (TFP) using newly organized data on 145 countries that spans more than 100 years for 23 of these countries. For all countries, only 14% of average output growth per worker is associated with TFP growth. We use priors from theories to construct estimates of the relative importance of the variances of aggregate input growth and TFP growth across countries. Much of the importance of the variance of TFP growth across countries is associated with negative TFP growth. (JEL O47, O50, O57, O30, N10) How much of growth in output per worker is associated with growth in physical and human capital per worker, and how much is due to technology, institutional change, and other factors? An economy’s output is a positive function of physical and human capital given the technology. Assumptions of constant returns to scale and competitive factor markets make it possible to calculate the growth rate of output implied by the growth of physical and human capital; deviations of actual output from this implied growth rate are due to changes in technology, institutional change, failure of the twin assumptions of constant returns to scale and competitive factor markets, and other factors. These deviations are called growth in total factor productivity (TFP), although these deviations include much more than what is suggested by the word productivity and probably are more fairly called the ‘‘residual’’ or ‘‘Solow residual’’ in growth. This type of analysis, called growth accounting, preceded the theoretical contributions to growth theory by Solow (1956) and Swan (1956), but many more publications succeeded them. Abramovitz (1956) found that only 10% of output growth per person in the United States from 1869–78 to 1944–53 is associated with growth of factors of production, and 90% of output growth is associated with growth of TFP. Solow (1957) found that the accumulation of physical capital accounts for roughly 12% of output growth per hour worked in the United States from 1900 to 1949 with the remaining 88% attributed to growth of TFP. Although later work has reduced this unexplained residual, it is

Advances in modeling the effects of selected parameters on the SLS process

Abstract: Selective laser sintering (SLS) is a leading process for developing rapid prototype objects by selectively fusing layers of powder according to numerically defined cross‐sectional geometry. The process has the potential to become an indispensable industrial tool. However, continuous process improvement is necessary. Improved understanding of the parameter effects on the process response is expected to lead to process advances. In this work the analytical problem describing the energy delivery, heat transfer and sintering process along with other pertinent phenomena is studied. Physical experiments and implementation of a numerical simulation are conducted using Bisphenol‐A polycarbonate. The effects of selected parameters on the SLS process response are examined. The primary parameters of interest are the laser power, laser beam velocity, hatch spacing, laser beam spot size and scan line length. This work shows that the secondary process parameters, delay period and number of effective exposures have a significant influence on the process response.