200 research outputs found
Influence of pressure on the oxidation resistance of carbon fiber reinforced ZrB2/SiC composites at 2000 and 2200°C
No full textThe influence of pressure on the oxidation resistance of C-ZrB2/SiC composites was studied. Materials were tested in air at 2000-2200 °C at 1-900 mbar. SEM analysis on the tested samples revealed the formation of an outer compact layer of ZrO2 and an intermediate layer of ZrO2-SiO2 as well as a porous interface layer of ZrO2. SiC increase was beneficial up to 1650 °C, then the trend was inverted. At 1 mbar all samples were visibly less damaged and displayed similar performance both at 2000 and 2200 °C, indicating that oxidation resistance is mostly dominated by fiber consumption, which is more severe at ambient pressure
Application of the impedance model of de Levie for the characterization of porous electrodes
No full textFrom the de Levie's theory for a porous electrode, the impedance can be expressed in function of the cylindrical pore characteristics: the pore length, the pore radius and the number of pores. If the pores have a finite length, these parameters can be regressed from the experimental impedance diagrams. In the case of a semi-infinite pore length, only the product r3/2n can be obtained. In this paper, two practical examples of porous electrodes were presented: the corrosion of cast iron in drinking water and the electrodissolution of copper in 1 M hydrochloric acid solution. In each case, the pore parameters were assessed
High-pressure corrosion fatigue experiments employing diverse methodologies for assessing rates of crack propagation
No full textThe new extreme faces strain gauges (XFS) technique, when compared to the direct current potential drop (DCPD) and back face strain gauge (BFS) methods, has shown superior accuracy and reliability in studying corrosion fatigue in high pressure. The XFS method serves a dual purpose by accurately measuring the crack length and acting as a mechanical load transducer. The results indicate that all three techniques can predict the final crack length effectively. However, BFS is unsuitable for high-pressure environments, and the current DCPD method can affect the crack propagation rate. The developed XFS methodology shows excellent performance in accurately evaluating corrosion fatigue studies
Reaction model simulating the role of sulphate and chloride in anodic dissolution of iron
No full textAssociation entre la mortinatalite et lexposition aux produits chimiques pendant la grossesse
No full textThe objective of this research was to study the relationship between stillbirth and chemical exposure of pregnant workers.A case control study was conducted among women working in three sectors: Health, Personal services and Agriculture, and Manufacturing industries. Two hundred and twenty-seven (227) stillbirths aged 20 weeks of gestation or more, were matched to two hundred and twenty-seven (227) livebirths, for mother's age, gravidity and socio-economic status. Chemicals were divided into ten (10) groups. Exposure was assessed by visits to the workplaces, telephone calls or extrapolations. Conditional logistic regression analyses were done.Women working as hairdressers-beauticians (O.R. 0,01 (0,00-0,34)) and those working in the garment industry* (O.R. 0,24 (0,08-0,77)) had significantly less stillbirths while women working in metal-electrical-chemical industries* (O.R. 5,11 (0,99-26,37)) had a significant excess of stillbirth. Exposure to pesticides/germicides, irrespective of the level or frequency (O.R. 2,06 (1,15-3,68)), and occasional exposure to "miscellaneous" chemicals (other chemicals potentially fetotoxic)* (O.R. 12,07 (1,22-119,9)) showed a significant increased risk of stillbirth while exposure to a low level of metals (O.R. 0,28(0,10-0,83)) showed a significantly lower risk of stillbirth.Leatherworkers* (O.R. 2,59 (0,47-14,33)), women working in the textile industry (O.R. 2,55 (0,42-15,41)), agricultural workers* (O.R. 3,88 (0,47-31,88)), women exposed to a moderate (2) level of metals (O.R. 2,32 (0,59-9,10)) and those exposed to a high (3) level of solvents (O.R. 2,49 (0,47-13,30)) had a non significant (P 0,05) increased risk of stillbirth.The author proposes that ergonomic factors could be a confounder of the association between stillbirth and exposure to pesticides/germicides or metals. A study looking more closely at the association between stillbirth and ergonomic factors is therefore suggested. Because exposure of pregnant workers to elevated levels of chemicals is quite rare, further epidemiological studies should include more subjects. ftn: stillbirths aged 20 weeks of gestation or more. ftn*: stillbirths aged 28 weeks of gestation or more
De bereiding van trinatrium-nitrilo-triacetaat
No full textDocument(en) uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science
Right to farm laws
No full textIn the lead up to the 2015 State election it was reported in The Land that the Coalition Government and NSW Farmers had entered into “an unprecedented” memorandum of understanding. Among the “key commitments” entered into were the reform of biodiversity laws and consideration of “proposals for a Right to Farm policy during 2015”.
In July 2014, at its annual conference, NSW Farmers passed a motion calling for “right to farm” legislation. Based on an article by Graham Brown, a NSW Farmers’ executive councillor, that argument seems to have two main aspects:
primarily, granting immunity to farmers from litigation involving nuisance complaints, in particular those arising from the interface between the “smelly, sometimes noisy” realities of farming and “expanding urban centres”; and
secondarily, providing protection from regulatory imposition by governments, State and local, referred to as “hindrances” to land use, including the placing by local councils of e-zones over agricultural property.
The article by Graham Brown concluded:
"In the face of extractive issues, expanding urban centres and red and green tape on-farm, protecting and promoting our farmers’ ability to conduct business, manage the landscape, provide environmental stewardship and grow food, must be supported in legislation."
The case was expressly adopted on 23 June 2015 by Robert Brown MLC of the Shooters and Fishers Party. He spoke in favour of “right to farm” policy and, calling for a parliamentary inquiry into the issue, Mr Brown argued that:
"The increasing trend of urban sprawl has presented some grim implications when the interests of agriculture clash with the lifestyle expectations of semi-rural property owners on the fringes of urban areas, or indeed in whole regions of New South Wales."
This e-brief discusses the history and purpose of “right to farm” laws and their application in the US and Canada. The position in Australia is also discussed, as is the question of the place of such laws in the broader context of the system of planning legislation. 
The Representation of Nature in Zola's Ia Faute de l'Abbé Mouret
No full textA study of the representation of nature on Zola's la Faute de l'Abbé Mouret, showing that Zola's depiction of nature rather than establishing a mere décor for the action of the novel, constitution a personal myth by means of which the author exorcizes his innermost obsessions with sexuality and death.Master of Arts (MA
Embedding machine learning into passivity theory: A port-Hamiltonian approach.
No full textPassivity-based control (PBC) is a control methodology that achieves its control objective by rendering a system passive with respect to a desired storage function. A key feature of PBC is that it exploits structural properties of the system. In this thesis, the PBC of systems endowed with a special structure, called port-Hamiltonian (PH) systems, has been investigated. The geometric structure of PH systems allows reformulating the PBC problem in terms of solving a generally complex partial differential equation (PDE). Reinforcement learning (RL), on the other hand, is a learning control method that can solve complex nonlinear (stochastic) control problems without the need for a process model or explicitly solving a set of equations. In RL the controller receives an immediate numerical reward as a function of the process state and possibly control action. The goal is to find an optimal control policy that maximizes the cumulative long-term rewards, which corresponds to maximizing a value function. In this thesis, actor-critic techniques have been used, which are a class of RL methods in which a separate actor (the control law) and critic (a "memory") function are learned. A disadvantage of RL is that without having a process model it can be slow at learning and computationally expensive. In this thesis, the goal was to design a theoretical framework using PBC techniques subject to control saturation that incorporates knowledge about the PH system and learns (optimal) control policies using actor-critic reinforcement learning. Therefore, actor-critic reinforcement learning methods have been combined with different types of PBC, e.g. EB-PBC and IDA-PBC. The combination of EB-PBC with an actor-critic method, energy-balancing actor-critic (EBAC), showed its effectiveness in the pendulum swing-up problem, which was used as a benchmark test. The advantages of the method from a PBC perspective are that no PDE has to be explicitly solved, control saturation can be incorporated, the geometric structure of the PH system is preserved, (numerical) stability can be assessed using passivity theory and the learned controllers can be interpreted in terms of energy-shaping strategies. From a RL perspective, the learning is speeded up because model knowledge is available.Delft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
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