Lehigh University

About: Lehigh University is a education organization based out in Bethlehem, Pennsylvania, United States. It is known for research contribution in the topics: Catalysis & Fracture mechanics. The organization has 12684 authors who have published 26550 publications receiving 770061 citations.

Present state of global wetland extent and wetland methane modelling: methodology of a model inter-comparison project (WETCHIMP)

Abstract: The Wetland and Wetland CH4 Intercomparison of Models Project (WETCHIMP) was created to evaluate our present ability to simulate large-scale wetland characteristics and corresponding methane (CH4) emissions. A multi-model comparison is essential to evaluate the key uncertainties in the mechanisms and parameters leading to methane emissions. Ten modelling groups joined WETCHIMP to run eight global and two regional models with a common experimental protocol using the same climate and atmospheric carbon dioxide (CO2) forcing datasets. We reported the main conclusions from the intercomparison effort in a companion paper (Melton et al., 2013). Here we provide technical details for the six experiments, which included an equilibrium, a transient, and an optimized run plus three sensitivity experiments (temperature, precipitation, and atmospheric CO2 concentration). The diversity of approaches used by the models is summarized through a series of conceptual figures, and is used to evaluate the wide range of wetland extent and CH4 fluxes predicted by the models in the equilibrium run. We discuss relationships among the various approaches and patterns in consistencies of these model predictions. Within this group of models, there are three broad classes of methods used to estimate wetland extent: prescribed based on wetland distribution maps, prognostic relationships between hydrological states based on satellite observations, and explicit hydrological mass balances. A larger variety of approaches was used to estimate the net CH4 fluxes from wetland systems. Even though modelling of wetland extent and CH4 emissions has progressed significantly over recent decades, large uncertainties still exist when estimating CH4 emissions: there is little consensus on model structure or complexity due to knowledge gaps, different aims of the models, and the range of temporal and spatial resolutions of the models.

A revision of the Fe-Ni phase diagram at low temperatures (<400 °C)

Abstract: The low-temperature Fe-Ni phase diagram was assessed experimentally by investigating Fe-Ni regions of meteorites using high resolution analytical electron microscopy techniques. The present phase diagram differs from the available experimental phase diagram based on observations of meteorite structure, but it is consistent with the available theoretical diagram in that α/Ni3Fe equilibrium was found at low temperatures. The a phase containing 3.6 wt.% Ni is in local equilibrium with the γ′ (Ni3Fe) phase containing 65.5 wt.% Ni, while the γ′' (FeNi) phase is present as a metastable phase. The new phase diagram incorporates a monotectoid reaction (γ1 → α + γ2, where (γ1 is a paramagnetic fcc austenite, a is a bcc ferrite, and γ2 is a ferromagnetic fcc austenite) at about 400 °C, a eutectoid reaction (γ2 → α + γ′) at about 345 °C, and a miscibility gap associated with a spinodal region at low temperatures. The miscibility gap is located between 9.0 and 51.5 wt. % Ni at ∼200 °C. The new low-temperature Fe-Ni phase diagram is consistent with all the phases observed in the metallic regions of meteorites.

Violations of Implicit Theories and the Sense of Prediction and Control: Implications for Motivated Person Perception

Abstract: Beginning with the assumption that implicit theories of personality are crucial tools for understanding social behavior, the authors tested the hypothesis that perceivers would process person information that violated their predominant theory in a biased manner. Using an attentional probe paradigm (Experiment 1) and a recognition memory paradigm (Experiment 2), the authors presented entity theorists (who believe that human attributes are fixed) and incremental theorists (who believe that human attributes are malleable) with stereotype-relevant information about a target person that supported or violated their respective theory. Both groups of participants showed evidence of motivated, selective processing only with respect to theory-violating information. In Experiment 3, the authors found that after exposure to theory-violating information, participants felt greater anxiety and worked harder to reestablish their sense of prediction and control mastery. The authors discuss the epistemic functions of implicit theories of personality and the impact of violated assumptions.

Aqueous two-phase systems for biomolecule separation

Abstract: Over the past-thirty years, aqueous polymer two-phase technology has evolved, both experimentally and theoretically, into a separation science with many useful applications in biomolecule purification and bioconversion. This paper summarizes the developments in the applications of aqueous two-phase systems to biotechnology. The main topics to be considered are the phase diagram and its characteristics, fundamentals of biomolecule partition, large-scale and multi-stage aqueous two-phase biomolecule purification, and extractive bioconversions. The first topic involves a discussion of the thermodynamics of aqueous polymer two-phase formation and how it is influenced by such factors as polymer molecular weight and concentration, temperature, and salt type and concentration. Next, the theoretical and experimental aspects of biomolecule partition in aqueous two-phase systems will be discussed in light of the factors which influence biomolecule partition: polymer concentration and molecular weight; temperature; salt type and concentration; the addition of charged, hydrophobic and affinity derivatives. Having reviewed the fundamentals of phase diagram formation and biomolecule partition, the next two topics are applications of aqueous two-phase technology. The first set of applications involve the large-scale extraction of proteins using one to three equilibrium stages and multi-stage purifications using countercurrent distribution, liquid-liquid partition chromatography and continuous countercurrent chromatography. The second application, and very promising area for future aqueous two-phase technology, is the extractive bioconversion which permits the simultaneous production and purification of a biomolecule.