993 resultados para Corrosion protection


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In this letter, we show how a 2.4-GHz retrodirective array operating in a multipath rich environment can be utilized in order to spatially encrypt digital data. For the first time, we give experimental evidence that digital data that has no mathematical encryption applied to it can be successfully recovered only when it is detected with a receiver that is polarization-matched to that of a reference continuous-wave (CW) pilot tone signal. In addition, we show that successful detection with low bit error rate (BER) will only occur within a highly constrained spatial region colocated close to the position of the CW reference signal. These effects mean that the signal cannot be intercepted and its modulated data recovered at locations other than the constrained spatial region around the position from which the retrodirective communication was initiated.

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This paper describes an experimental investigation of the behaviour of corroded reinforced concrete beams. These have been stored in a chloride environment for a period of 26 years under service loading so as to be representative of real structural and environmental conditions. The configuration and the widths of the cracks in the two seriously corroded short-span beams were depicted carefully, and then the beams were tested until failure by a three-point loading system. Another two beams of the same age but without corrosion were also tested as control specimens. A short span arrangement was chosen to investigate any effect of a reduction in the area and bond strength of the reinforcement on shear capacity. The relationship of load and deflection was recorded so as to better understand the mechanical behaviour of the corroded beams, together with the slip of the tensile bars. The corrosion maps and the loss of area of the tensile bars were also described after having extracted the corroded bars from the concrete beams. Tensile tests of the main longitudinal bars were also carried out. The residual mechanical behaviour of the beams is discussed in terms of the experimental results and the cracking maps. The results show that the corrosion of the reinforcement in the beams induced by chloride has a very important effect on the mechanical behaviour of the short-span beams, as loss of cross-sectional area and bond strength have a very significant effect on the bending capacity.

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The use of social pedagogy as a paradigm for critically appraising developments within child and family social work has been largely neglected. This paper outlines the work of Augusto Boal and his adoption of social pedagogy as a method for empowering oppres-sed social groups in Brazil. It is argued that Boal’s approach can be adapted by using action research techniques to analyse and effect change in situations where child care professionals face daily contradictions in their attempts to both protect children and support families. To demonstrate its relevance to child care practice, a description is provided of how the approach was used with two groups of social work students – one undertaking qualifying training, the other post-qualifying training. The results of this application suggest a new theoretical framework for practice which aims to establish communicative consensus around the needs of children and a mutual appreciation of roles and responsibilities.

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This paper argues that a critical analysis of the ideologies that inform contemporary child care has been missing from the ‘re-focusing debate’. Such an analysis points up the necessity of reasserting a critical social work position in order to provide a basis for reconstructing practice and engaging with other social actors and their ideologies in an open and creative fashion compatible with Habermas’ aspiration of ‘communicative reason’.

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Secretory leukocyte protease inhibitor (SLPI) is an endogenous serine protease inhibitor that protects the lungs from excessive tissue damage caused by leukocyte proteases released during inflammation. Recombinant SLPI (rSLPI) has shown potential as a treatment for inflammatory lung conditions. To date, its clinical application has been limited by rapid enzymatic cleavage by cathepsins and rapid clearance from the lungs after inhalation. In this study, rSLPI was encapsulated in 1,2-Dioleoyl-sn-Glycero-3-[Phospho-L-Serine] : Cholesterol (DOPS : Chol) liposomes for inhalation. Incubation of rSLPI with cathepsin L leads to complete loss of activity while encapsulation of rSLPI in DOPS : Chol liposomes retained 92.6 of its activity after challenge with cathepsin L. rSLPI-loaded liposomes were aerosolized efficiently using a standard nebulizer with a minimal loss of activity and stability. This formulation was biocompatible and encapsulation did not appear to diminish access to intracellular sites of action in in vitro cell culture studies. Liposome encapsulation of rSLPI therefore improves stability and potentially reduces the level and frequency of dosing required for therapeutic effect after inhalation.

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We introduce a protocol for steady-state entanglement generation and protection based on detuning modulation in the dissipative interaction between a two-qubit system and a bosonic mode. The protocol is a global-addressing scheme which only requires control over the system as a whole. We describe a postselection procedure to project the register state onto a subspace of maximally entangled states. We also outline how our proposal can be implemented in a circuit-quantum electrodynamics setup.

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This paper reports the results of the most recent in a series of EHSRE workshops designed to synthesize the current state of the field in Andrology and provide recommendations for future work (ESHRE 1998; 1996). Its focus is on methods for detecting sperm DNA damage and potential application of new knowledge about sperm chromatin organization, vulnerability and repair to improve the diagnosis and treatment of clinical infertility associated with that damage. Equally important is the use and reliability of these tests to identify the extent to which environmental contaminants or pharmaceutical agents may contribute to the incidence of sperm DNA damage and male fertility problems. A working group# under the auspices of ESHRE met in May 2009 to assess the current knowledgebase and suggest future basic and clinical research directions. This document presents a synthesis of the working group’s understanding of the recent literature and collective discussions on the current state of knowledge of sperm chromatin structure and function during fertilization. It highlights the biological, assay and clinical uncertainties that require further research and ends with a series of recommendations.

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Hayes and Houston's positive review of Habermas's contribution to discourse in family group conferences (in this journal) has been challenged by Garrett. In this paper, one of the authors replies to Garrett but extends the analysis through a more considered, developed and detailed examination of Habermas's thoughts on power in social life. This leads to a conceptual framework that enables the participants in the conference to exercise power in a positive manner. In developing this earlier analysis, the paper also acknowledges Garrett's argument that Bourdieu helps us to understand the nature of constraining social structures in child protection. However, Bourdieu's ideas are subsequently challenged on the grounds that they lack a competent formulation on human agency - a faculty that Habermas cogently elucidates. This enlarged understanding of agency, it is argued, offers a theoretical resource that fits better with the ethos of emancipatory social work.