East Carolina University : Research and Creative Achievement Week 2011
Stine Haskell Research Center, Newark, DE 19711 In industry, spectroscopy is used to monitor batch chemical reactions and to maximize production of a material for a minimum cost. However, there are many challenges involved in using spectroscopic methods to characterize reaction systems that undergo crystallization. For instance, the crystallization of a product in solution creates a slurry mixture for which it is hard to measure light absorption due to the nature of the mixture. Some of these problems are less prominent when using attenuated total reflectance (ATR) techniques (provided the enhancement of solid particles is low), due to its ability to circumvent the problems of separating light absorption from light scattering encountered in diffuse reflectance measurements [1]. The aim of this work is to formulate a kinetic model [2] for the reaction of salicylic acid with acetic anhydride that leads to the formation of acetylsalicylic acid and to its subsequent crystallization.The experiment involves a solid addition of salicylic acid into acetic anhydride, followed by an addition of water to consume the excess reactant, and finally a cooling step to initiate nucleation and crystal growth. The kinetic model will be constructed based on changes in light absorption measured by attenuated total reflectance ultraviolet-visible (ATR UV-vis) spectroscopy. In addition, near infrared (NIR) diffuse reflectance spectroscopy will be used to determine the onset of nucleation and the degree of supersaturation which is the driving force for a power law based model describing the crystallization of the product. References [1] Falconet et al, Applied Optics 47 (2008) 1734-1739 [2] Gemperline P., Practical Guide to Chemometrics, 2nd Edition (2006), Boca Raton, Taylor & Francis
Spatial And Temporal Variability Of Surface Shelf Sediments On The Waipaoa River Margin, New Zealand, Joseph Kiker, J.P. Walsh, D. Reide Corbett The Waipaoa River Margin, located off the northeast coast of the North Island of New Zealand, affords the opportunity to assess the fidelity of the stratigraphic record and sediment dynamics in a coastal setting characterized by a narrow shelf (~20 km) and ample sediment supply (15 Mt y-1). Sediments are delivered to this margin via the Waipaoa River which drains a small mountainous catchment (2205 km2) comprised of highly erodible lithologies. As part of an NSF-funded project, time-series analysis of surface seabed properties is being used as a foundation to evaluate spatial and temporal changes in strata formation and sediment dynamics on the adjacent margin. Samples were collected on three cruises taking place in 2010 (January, May, and September) with a fourth scheduled for mid-February 2011. Preliminary results show that both erodibility measurements of the seabed and radioisotope inventories vary in a complex manner through space and time. Erodibility measurements (n=14) of mid-shelf depocenter muds, determined using a Gust microcosm, had a mean value (AVG) of 0.42 kg m-2, with a standard deviation (Ăƒ) of 0.10 in comparison to measurements (n=12) made at 160
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