214 resultados para paints
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Nanoclay-based pigments are promising colorants. They enhance the colorimetric properties of the dye giving more intense and saturated colours. In addition, they act as reinforce additive when they are dispersed into polymers. They can be applied in a wide variety of substrates: printing inks, textiles, acrylic paints and concrete; and more applications are being developed. One important advantage of the nanoclay-based pigments is the fact that they can be considered an ecological alternative to contaminant colorants, in contrast to some traditional inorganic pigments that contend heavy metal in their structure.
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Relatório de estágio apresentado para a obtenção do grau de Mestre em Ensino pré-escolar e 1º ciclo do ensino básico
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Federal Highway Administration, Implementation Division, Washington, D.C.
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Federal Highway Administration, Washington, D.C.
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Federal Highway Administration, Washington, D.C.
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Includes index.
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Some of the vols. Issued in pts.
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Federal Highway Administration, Office of Research and Development, Washington, D.C.
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"Members": v. 28, p. 365-463.
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The IEPA is proud to sponsor these worthwhile programs around the state to help citizens safely rid their homes of unwanted pesticides, paints, automotive fluids and other household items that could pose a threat to our landfills, homes or environment, if disposed in a an unsafe environment.
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Hearings held: July 25-Aug. 10, 1921. (Pt.1)
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Maria McCann paints a dark picture of masculinity and its effects in her novel As Meat Loves Salt (2001). The violent Jacob Cullen struggles with his masculinity as he faces the intricacies of religion, sexuality and politics in the midst of the English Civil War where he falls in love with fellow soldier Christopher Ferris. By using R.W. Connell and James Messerschmidt’s framework for the hierarchy of masculinities, I explore masculinities on local, regional and global levels and emphasized femininity in a close reading of McCann’s novel. My aim is not only to analyse the masculinities of the novel but also to use the framework to redefine toxic masculinity in order to make it a useable concept when analysing masculinities in literature. I redefine toxic masculinity because it lacks a clear definition anchored in an established framework used to study masculinity that does not see masculinity as inherently toxic. I believe that anchoring it to Connell and Messerschmidt’s framework will make it a useable concept. Due to the novel’s relationship to the Bible, I will use masculinity studies done on David and Jesus from the Bible to compare and reveal similarities with the masculinities in the novel, how they appear on the local, regional and global levels in the novel and its effects. I draw parallels between the love story in As Meat Loves Salt to the love story of David and Jonathan in the Bible by using queer readings of David and Jonathan in order to explore how masculinity affects the relationships and how the novel uses these two love stories as a study of toxic masculinity and how it relates it to hegemonic masculinity.
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Recent reports of contamination of the Great Barrier Reef Marine Park by herbicides used in antifouling paints and in agriculture have caused concern over the possible effects on corals in nearshore areas. Pulse-Amplitude Modulated (PAM) chlorophyll fluorescence techniques were used to examine changes in the maximum effective quantum yield (ΔF/Fm′) of symbiotic dinoflagellates within the host tissues (in hospite) of the coral Seriatopora hystrix exposed to a number of Photosystem II (PSII) inhibiting herbicides in short-term toxicity tests. The concentration of herbicide required to reduce ΔF/Fm′ by 50% (median effective concentration [EC50]) differed by over 2 orders of magnitude: Irgarol 1051 (0.7 μg l-1) > ametryn (1.7 μg l-1) > diuron (2.3 μg l-1) > hexazinone (8.8 μg l -1) > atrazine (45 μg l-1) > simazine (150 μg l-1) > tebuthiuron (175 μg l-1) > ionynil (> 1 mg l-1). Similar absolute and relative toxicities were observed with colonies of the coral Acropora formosa (Irgarol 1051 EC50: 1.3 μg l-1, diuron EC50: 2.8 μg l-1), Time-course experiments indicated that ΔF/Fm′ was rapidly reduced (i.e. within minutes) in S. hystrix exposed to Irgarol 1051 and diuron. On return to fresh running seawater, ΔF/Fm′ recovered quickly in diuron-exposed corals (i.e. in minutes to hours), but slowly in corals exposed to Irgarol 1051 (i.e. hours to days). Time-course experiments indicated that the effects of diuron (3 μg l-1) on S. hystrix were inversely related to temperature over the range 20 to 30 °C, although initially the effects were less at the lower temperatures. Repeated exposure to pulses of Irgarol 1051 (daily 2 h exposure to 30 μg l -1 over 4 d) resulted in a 30% decrease in the density of symbiotic dinoflagellates in the tissues of S. hystrix.
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The RAFT-CLD-T methodology is demonstrated to be not only applicable to 1-substituted monomers such as styrene and acrylates, but also to 1,1-disubstituted monomers such as MMA. The chain length of the terminating macromolecules is controlled by CPDB in MMA bulk free radical polymerization at 80 degrees C. The evolution of the chain length dependent termination rate coefficient, k(t)(i,i), was constructed in a step-wise fashion, since the MMA/CPDB system displays hybrid behavior (between conventional and living free radical polymerization) resulting in initial high molecular weight polymers formed at low RAFT agent concentrations. The obtained CLD of k(t) in MMA polymerizations is compatible with the composite model for chain length dependent termination. For the initial chain-length regime, up to a degree of polymerization of 100, k(t) decreases with alpha (in the expression k(t)(i,i) = k(t)(0) . i(-alpha)) being close to 0.65 at 80 degrees C. At chain lengths exceeding 100, the decrease is less pronounced (affording an alpha of 0.15 at 80 degrees C). However, the data are best represented by a continuously decreasing nonlinear functionality implying a chain length dependent alpha.
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Block copolymers have become an integral part of the preparation of complex architectures through self-assembly. The use of reversible addition-fragmentation chain transfer (RAFT) allows blocks ranging from functional to nonfunctional polymers to be made with predictable molecular weight distributions. This article models block formation by varying many of the kinetic parameters. The simulations provide insight into the overall polydispersities (PDIs) that will be obtained when the chain-transfer constants in the main equilibrium steps are varied from 100 to 0.5. When the first dormant block [polymer-S-C(Z)=S] has a PDI of 1 and the second propagating radical has a low reactivity to the RAFT moiety, the overall PDI will be greater than 1 and dependent on the weight fraction of each block. When the first block has a PDI of 2 and the second propagating radical has a low reactivity to the RAFT moiety, the PDI will decrease to around 1.5 because of random coupling of two broad distributions. It is also shown how we can in principle use only one RAFT agent to obtain block copolymers with any desired molecular weight distribution. We can accomplish this by maintaining the monomer concentration at a constant level in the reactor over the course of the reaction. (c) 2005 Wiley Periodicals, Inc.