Economic and Environmental Impacts of Cellulosic Feedstock Production in Minnesota

Crop Production/Industries, Environmental Economics and Policy, Production Economics,

Electrogenic transport and K(+) ion channel expression by the human endolymphatic sac epithelium.

The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid

Estimating Crown Height for Unthinned Planted Pines in East Texas

Stand-level models were derived to predict crown height or the distance from ground to the first live branch of unthinned planted loblolly (Pinus taeda L.) and slash (Pinus elliottii Eng elm.) pine trees in East Texas. Average height of the tallest trees was the principal predictor in the models. In addition, the influence of number of planted trees per acre, nonplanted basal area and fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f.sp. fusiforme ) was considered. The models quantify the plantation ages when the butt log and successive lower stem logs are clear of live branches. This information may assist with merchandising the planted pines

Influence of Planting Density on Diameter and Height in East Texas Pine Plantations

The response of diameter and height of unthinned planted stands ofloblolly (Pinus taeda L.) and slash (Pinus elliottii Eng elm.)pine in East Texas to different classes of planting densities were analyzed. After tracking the development ofdiameterand heightfor 15yron a setofpennanentplots representing a broad range of plantation parameters, average diameter and average height trends were observed. For both species, average diameter values were significantly larger with lower planting densities. 1n contrast, average height growth is insensitive to planting density at younger age classes for loblolly and at older age classes for slash pine plantations

Hybrid carbon fibre–carbon nanotube composite interfaces

Both low and high modulus carbon fibres are coated with carboxylated single wall carbon nanotubes (SWNTs). It is shown that it is then possible to follow, for the first time, the local deformation of low modulus carbon fibres and composite interfaces using Raman spectroscopy. By deforming coated single carbon fibre filaments in tension, and following the shift in the position of a band located at ∼2660 cm−1 (2D band) it is possible to calibrate the local stress state of a fibre embedded in an epoxy resin. To follow the interface between the fibres and the epoxy resin, a thin film model composite is used. Point-to-point variation of stress along a single fibre, both inside and outside the resin, is recorded and stress transfer models are used to determine the interfacial shear stress (ISS). Values of the ISS (∼20 MPa) are obtained for the thin film model composites for untreated high modulus fibres. A beneficial interfacial effect of the presence of SWNTs on the surface of the high modulus carbon fibre samples is demonstrated resulting in an increase in the maximum ISS (>30 MPa) compared to uncoated samples. Similarly coated low modulus fibres exhibit a very high ISS (>50 MPa). These increases are attributed to an enhanced contact between the resin and the fibres due to an increased surface area as a result of the nanotubes and additional bonding caused due to the presence of carboxylate groups

Controlling and mapping interfacial stress transfer in fragmented hybrid carbon fibre-carbon nanotube composites

Copyright © 2014 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Composites Science and Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Composites Science and Technology Vol. 100 (2014), DOI: 10.1016/j.compscitech.2014.05.034Raman spectroscopy was used to map the stress transfer at the interface between high and low modulus carbon fibres in model composites when undergoing fragmentation. Both fibre surfaces were coated with two types of single wall carbon nanotubes (HiPCO and carboxylated nanotubes) in order to enhance the interfacial shear strength with an epoxy resin. For the low modulus carbon fibre this coating also enabled stress mapping at the interface. In both cases single fibres embedded in a dumbbell shaped model composite were deformed to cause fragmentation. When no further fragmentation took place the critical fibre length was calculated and converted to interfacial shear stress using classical Kelly–Tyson theory. These values were compared to data obtained using a Raman spectroscopic approach where the rate of change of stress with respect to distance along the fibre was measured directly. These data were then shown to fit a shear lag model. Two forms of single-wall carbon nanotubes were compared; namely unmodified and COOH modified. It was shown that only the COOH modified single wall carbon nanotubes increase the maximum interfacial shear stress significantly. Evidence of matrix yielding at the fibre ends is also presented and the possibility of the enhancement of the shear yield stress of the resin by the presence of the nanotubes is also discussed

Improved electron injection in polymer light-emitting diodes using anionic conjugated polyelectrolyte

We report improved performance in polymer light-emitting diodes incorporating conjugated polyelectrolytes as an electron injection layer (EIL). When we introduce water soluble conjugated polymers, poly[9,9'-bis(4-sulfonatobutyl)fluorene-co-alt-1,4-phenylene] (anionic PFP), between the aluminum (Al) cathode and emissive layer, the devices show an increased electroluminescence efficiency with a lowered turn-on voltage. We believe the mobile Na(+) ions in the EIL layer directly influences the device efficiency by forming a low work function layer at the interface between the EIL and Al cathode, thereby facilitating the electron injection into the emissive layer.open141

Photochemical Organonitrate Formation in Wet Aerosols

Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal and OH &ndash; containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). During the 3 hour irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids) were formed in both ammonium sulfate (AS) aerosols and sulfuric acid (SA) aerosols. However, the major products were organonitrogens (CHNO), organosulfates (CHOS), and organonitrogen-sulfates (CHNOS). These were also the dominant products formed in the dark chamber indicating non-radical formation. In the humid chamber (> 70 % RH), two main products for both AS and SA aerosols were organonitrates, which appeared at m/z&minus; 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.</html