102,077 research outputs found
Mathematical Model of \u3cem\u3eChlorella minutissima\u3c/em\u3e UTEX2341 Growth and Lipid Production Under Photoheterotrophic Fermentation Conditions
To reduce the cost of algal biomass production, mathematical model was developed for the first time to describe microalgae growth, lipid production and glycerin consumption under photoheterotrophic conditions based on logistic, LuedekingâPiret and LuedekingâPiret-like equations. All experiments were conducted in a 2 L batch reactor without considering CO2 effect on algaeâs growth and lipid production. Biomass and lipid production increased with glycerin as carbon source and were well described by the logistic and LuedekingâPiret equations respectively. Model predictions were in satisfactory agreement with measured data and the mode of lipid production was growth-associated. Sensitivity analysis was applied to examine the effects of certain important parameters on model performance. Results showed that S0, the initial concentration of glycerin, was the most significant factor for algae growth and lipid production. This model is applicable for prediction of other single cell algal species but model testing is recommended before scaling up the fermentation of process
Six Signs of Scientism
As the English word âscientismâ is currently used, it is a trivial verbal truth that scientismâan inappropriately deferential attitude to scienceâshould be avoided. But it is a substantial question when, and why, deference to the sciences is inappropriate or exaggerated. This paper tries to answer that question by articulating âsix signs of scientismâ: the honorific use of âscienceâ and its cognates; using scientific trappings purely decoratively; preoccupation with demarcation; preoccupation with âscientific methodâ; looking to the sciences for answers beyond their scope; denying the legitimacy or worth of non-scientific (e.g., legal or literary) inquiry, or of writing poetry or making art
Lautman and the Reality of Mathematics
Working in he 1930s, Albert Lautman described with extraordinary clarity the new understanding of mathematics of that time. He delighted in the multiple manifestations of a common idea in different mathematical fields. However, he took the common idea to belong not to mathematics itself, but to an 'ideal reality' sitting above mathematics. I argue in this paper that now that we have a mathematical language which can characterize these common ideas, we need not follow Lautman to adopt his form of Platonism. On the other hand, Lautman should be much better known than he is for pointing philosophy towards this most important feature of mathematics
On F-theory Quiver Models and Kac-Moody Algebras
We discuss quiver gauge models with bi-fundamental and fundamental matter
obtained from F-theory compactified on ALE spaces over a four dimensional base
space. We focus on the base geometry which consists of intersecting F0=CP1xCP1
Hirzebruch complex surfaces arranged as Dynkin graphs classified by three kinds
of Kac-Moody (KM) algebras: ordinary, i.e finite dimensional, affine and
indefinite, in particular hyperbolic. We interpret the equations defining these
three classes of generalized Lie algebras as the anomaly cancelation condition
of the corresponding N =1 F-theory quivers in four dimensions. We analyze in
some detail hyperbolic geometries obtained from the affine A base geometry by
adding a node, and we find that it can be used to incorporate fundamental
fields to a product of SU-type gauge groups and fields.Comment: 13 pages; new equations added in section 3, one reference added and
typos correcte
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Apportionment of primary and secondary organic aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)
Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each of these methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70â90% were observed during midday periods, whereas minimum SOA contributions of ~45% were observed during peak morning traffic periods. These results are contrary to previous estimates of SOA throughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed
Science and Engineering Labor Force
[Excerpt] Like most developed economies, the United States increasingly depends on a technically skilled workforce, including scientists and engineers. Workers for whom knowledge and skill in S&E are central to their jobs have an effect on the economy and the wider society that is disproportionate to their numbers: they contribute to research and development, increased knowledge, technological innovation, and economic growth. Moreover, the knowledge and skills associated with science and engineering have diffused across occupations and become more important in jobs that are not traditionally associated with S&E
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