6 resultados para pitting
em Queensland University of Technology - ePrints Archive
Resumo:
Rupestris stem pitting (rSP), a graft-transmissible grapevine disease, can be identified only by its reaction (pitted wood) on inoculated Vitis rupestris ‘St. George.’ DsRNA was extracted from grapevines from California and Canada that indexed positive for rSP on St. George. Two distinct dsRNA species (B and C) (Mr = 5.3 × 106 and 4.4 × 106, respectively) were detected from the stem tissue of rSP-positive samples. Although similar dsRNA species (B and C) were detected in extracts of grapevines from New York, the association of dsRNA B and C with rSP in New York samples was not consistent. Also, eight different dsRNAs, known to be associated with the powdery mildew fungus, Uncinula necator, were detected in leaves of New York samples. In New York, the dsRNAs were not observed in leaves or stem samples collected from June through late August during the 1988 and 1989 growing seasons, suggesting that dsRNA detection in the grape tissue is variable throughout the season. We suggest that dsRNA species B and C are associated with rSP disease. The inconsistent results with New York samples are discussed.
Resumo:
This paper merges the analysis of a case history and the simplified theoretical model related to a rather singular phenomenon that may happen in rotating machinery. Starting from the first, a small industrial steam turbine experienced a very strange behavior during megawatt load. When the unit was approaching the maximum allowed power, the temperature of the babbitt metal of the pads of the thrust bearing showed constant increase with an unrecoverable drift. Bearing inspection showed that pad trailing edge had the typical aspect of electrical pitting. This kind of damage was not reparable and bearing pads had to replaced. This problem occurred several times in sequence and was solved only by adding further ground brushes to the shaft-line. Failure analysis indicated electrodischarge machining as the root fault. A specific model, able to take into consideration the effect of electrical pitting and loading capacity decreasing as a consequence of the damage of the babbitt metal, is proposed in the paper and shows that the phenomenon causes the irretrievable failure of the thrust bearing.
Resumo:
Double-stranded RNA species ranging in molecular weight from 0.95 to 6.3 × 106 were detected in grapevines in New York. We recently showed that two of the species (Mr = 5.3 and 4.4 × 106) are associated with rupestris stem pitting disease. In this report, we show that the other eight detectable dsRNA species are associated with the powdery mildew fungus, Uncinula necator. These dsRNAs associated with the powdery mildew fungus were previously detected in leaves and epidermal stem tissue of grapevines infected with powdery mildew. The same dsRNA species were also detected from extracts of isolated cleistothecia and conidia of U. necator devoid of plant tissue. Isometric and rigid rodlike particles were observed in single cleistothecia preparations when examined under transmission electron microscopy.
Resumo:
In the United States, there has been fierce debate over state, federal and international efforts to engage in genetically modified food labelling (GM food labelling). A grassroots coalition of consumers, environmentalists, organic farmers, and the food movement has pushed for law reform in respect of GM food labelling. The Just Label It campaign has encouraged United States consumers to send comments to the United States Food and Drug Administration to label genetically modified foods. This Chapter explores the various justifications made in respect of genetically modified food labelling. There has been a considerable effort to portray the issue of GM food labelling as one of consumer rights as part of ‘the right to know’. There has been a significant battle amongst farmers over GM food labelling – with organic farmers and biotechnology companies, fighting for precedence. There has also been a significant discussion about the use of GM food labelling as a form of environmental legislation. The prescriptions in GM food labelling regulations may serve to promote eco-labelling, and deter greenwashing. There has been a significant debate over whether GM food labelling may serve to regulate corporations – particularly from the food, agriculture, and biotechnology industries. There are significant issues about the interaction between intellectual property laws – particularly in respect of trade mark law and consumer protection – and regulatory proposals focused upon biotechnology. There has been a lack of international harmonization in respect of GM food labelling. As such, there has been a major use of comparative arguments about regulator models in respect of food labelling. There has also been a discussion about international law, particularly with the emergence of sweeping regional trade proposals, such as the Trans-Pacific Partnership, and the Trans-Atlantic Trade and Investment Partnership. This Chapter considers the United States debates over genetically modified food labelling – at state, federal, and international levels. The battles often involved the use of citizen-initiated referenda. The policy conflicts have been policy-centric disputes – pitting organic farmers, consumers, and environmentalists against the food industry and biotechnology industry. Such battles have raised questions about consumer rights, public health, freedom of speech, and corporate rights. The disputes highlighted larger issues about lobbying, fund-raising, and political influence. The role of money in United States has been a prominent concern of Lawrence Lessig in his recent academic and policy work with the group, Rootstrikers. Part 1 considers the debate in California over Proposition 37. Part 2 explores other key state initiatives in respect of GM food labelling. Part 3 examines the Federal debate in the United States over GM food labelling. Part 4 explores whether regional trade agreements – such as the Trans-Pacific Partnership (TPP) and the Trans-Atlantic Trade and Investment Partnership (TTIP) – will impact upon
Resumo:
The influence of fluid flow, surface roughness and immersion time on the electrochemical behaviour of carbon steel in coal seam gas produced water under static and hydrodynamic conditions has been studied. The disc electrode surface morphology before and after the corrosion test was characterized using scanning electron microscopy (SEM). The corrosion product was examined using X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD).The results show that the anodic current density increased with increasing surface roughness and consequently a decrease in corrosion surface resistance. Under dynamic flow conditions, the corrosion rate increased with increasing rotating speed due to the high mass transfer coefficient and formation of non-protective akaganeite β- FeO(OH) and goethite α- FeO(OH) corrosion scale at the electrode surface.The corrosion rate was lowest at 0 rpm.The corrosion rate decreased in both static and dynamic conditions with increasing immersion time. The decrease in corrosion rate is attributed to the deposition of corrosion products on the electrode surface. SEM results revealed that the rougher surface exhibited a great tendency toward pitting corrosion.