Evaluation of passive microwave snow water equivalent algorithms in the depth hoar-dominated snowpack of the Kuparuk River Watershed, Alaska, USA

This research investigates the utility of passive microwave remote sensing instruments to accurately determine snow water equivalent (SWE) over large spatial extents. Three existing Special Sensor Microwave Imager (SSM/I) snow water equivalent algorithms produced by Chang, Tait and Goodison were evaluated for their ability to determine snow water equivalent in a snowpack containing substantial depth hoar, large faceted snow crystals. The Kuparuk River Watershed (8140 km²) test site on the North Slope of Alaska was chosen for its snowpack containing a think depth hoar layer and long history of ground truth data. A new regional snow water equivalent algorithm was developed to determine if it could produce better results than the existing algorithms in an area known to contain significant depth hoar. The four algorithms were tested to see how well they could determine snow water equivalent: (1) on a per pixel basis, (2) across swath-averaged spatial bands of approximately 850 km², and (3) on a watershed scale. The algorithms were evaluated to see if they captured the annual spatial distribution in snow water equivalent over the watershed. Results show that the algorithms developed by Chang and from this research are generally within 3 cm of the spatially averaged snow water equivalents over the entire watershed. The algorithms produced by Chang, Tait, and in this research were able to predict the basin-wide ground measured snow water equivalent value within a percent error range from −32.4% to 24.4% in the years with a typical snowpack. None of the algorithms produce accurate results on a pixel-by-pixel scale, with errors ranging from −26% to 308%.     

Simulated autohydrolysis of aspen milled wood lignin in the presence of aromatic additives: Structural modifications

In a previous article the authors have described changes in molecular weight which occur when aspen milled wood lignin is subjecte to autocatalyzed hydrolysis (autohydrolysis) in the presence of three aromatic additives: 2-naphthol, resorcinol, and p-hydroxybenzoic acid. In the present work, the reactions of these additives have been studied from the viewpoint of their effect on the structure of the lignin. The use of milled wood lignin instead of aspen wood served to distinguish those reactions between the additives and the lignin, without involving the other wood components. The reaction products have been charactrized by elemental analysis and UV and IR spectroscopy. It was concluded that keto groups, generated on the lignin side-chain during autohydrolysis, condense with the additives, which become incorporated into the lignin. This occurs most probably through an aromatic eletrophilic substitution reaction. While 2-naphthol condensed primarily with the β-keto carbonyl groups, resorcinol attacked also the α-keto carbonyl groups. When p-hydroxybenzoic acid was the additive, its incorporation was accompanied by an increase in lignin carboxylic acid groups.     

Studying Formability Limits By Combining Conventional and Incremental Sheet Forming Process

In this work it is assessed the potential of combining conventional and incremental sheet forming processes in a same sheet of metal.This so-called hybrid forming approach is performed through the manufacture of a pre-forming by conventional forming,followed by incremental sheet forming.The main objective is analyzing strain evolution.The pre-forming induced in the conventional forming stage will determine the strain paths,directly influencing the strains produced by the incremental process.To conduct the study,in the conventional processes,strains were imposed in three different ways with distinct true strains.At the incremental stage,the pyramid strategy was adopted with differ-ent wall slopes.From the experiments,the true strains and the final geometries were analyzed.Numerical simulation was also employed for the sake of comparison and correlation with the measured data.It could be observed that single-stretch pre-strain was directly proportional to the maximum incremental strains achieved,whereas samples subjected to biaxial pre-strain influenced the formability according to the degree of pre-strain applied.Pre-strain driven by the prior deep-drawing operation did not result,in this particular geometry,in increased formability.     

Psychological mediators of the effects of opposing expert testimony on juror decisions.

This study examined the effectiveness of the opposing expert safeguard against unreliable expert testimony and whether beliefs about experts as hired guns and general acceptance mediate the effect of opposing expert testimony on juror decisions. We found strong evidence that the presence, but not the content, of opposing expert testimony affected jurors’ trial judgments and that these effects were mediated by mock jurors’ beliefs about general acceptance. The presence of an opposing expert affected jurors’ ratings of the general acceptance of research investigating sexual harassment in the workplace. Jurors’ beliefs about general acceptance then affected jurors’ ratings of plaintiff expert competence and research, which affected juror ratings of the probability that the plaintiff experienced a hostile work environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polymer biomaterials (polyphosphazenes) in the repair of peripheral nervous system

Biodegradable polymers gives interesting perspectives of use in making artificial conduits for peripheral nerve reconstruction. Poliphosphazenes are materials highly biocompatible and have a controllable reabsorption rate. According to the substitutes that are introduced in the molecule, they can also be used as a framework for drug release. Conduits obtained with poli [bis(etilalanate) phosphazene] were evaluated as guides for nerve regeneration in an experimental animal model. In six Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect was then repaired using the conduit. On the controlateral limb the nerve continuity was restored using as an autograft the segment removed from the right. Control were performed at 30, 90, 180 days and consisted in histological and electron microscopy investigations. They showed the gradual degradation of the conduit without signs of local and general toxicity. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different from the one obtained with the autologous grafts. So poliphosphazene conduits may be considered effective as a guide for nerve regeneration, above all for the possibility of use the polymer as a carrier for neurite-promoting factors.     

Estimate of the electric energy generating potential for different sources of biogas in Brazil

The increasing interest in the recuperation of the biogas coming from organic residues, associated with its energetic use is a subject that has been widely discussed. Biogas was merely seen as a sub-product obtained from anaerobic decomposition (without oxygen) of organic residue. In the paper is carried out an evaluation of the quantities of organic residues coming out from the sugar and alcohol industry (vinasse), urban solid and liquid wastes (garbage and sewage) and livestock residues (bovine and swine manure) in Brazil. Finally the electricity generation potential of biogas out of the evaluated sources of organic residues in Brazil is estimated. The results of this study indicate that the potential regarding the production of biogas out of the aforementioned organic residues of electricity production using could meet an energy demand of about 1.05 to 1.13 %. Constraints for biogas energy utilization are identified and discussed.     

Shear modification of polyethylene

Polymers like LDPE can be modified by applying a shearing process for an extended period. As a result the melt elasticity is reduced, as evidenced by the decrease in extrudate (die) swell at the exit of a capillary and onset of melt fracture. Melt viscosity was also slightly reduced; melt flow index (measured in short capillary) is highly increased. At the same time, melt density rises. All these parameters vary mostly for LDPE grades that exhibit the highest degree of long-chain branching. It was confirmed that the intrinsic viscosisty of the polymer samples was essentially unaffected, so that chain scission may be ruled out. Moreover, the process itself is shown to be reversible as the initial parameters were recovered by special treatment, due to heating or solvation. The mechanism of shear modification is believed to consist of disentanglement of temporary couplings betwen long branches. The practical utilization of this process will be pursued, as well as the scientific understanding of structuring entangled branched chains.