8 research outputs found
Orientation effects and figures of merit in advanced 2-2-type composites based on [011]-poled domain-engineered single crystals
Get PDFThe paper reports new results that compare the group of performance figures of merit of piezo-active 2-2-type composites based on [011]-poled domain-engineered (1 - x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 single crystals, where the main crystallographic axes in the crystal layers are rotated to tailor effective electromechanical properties and related parameters. Examples of the orientation and volume-fraction dependences of the figures of merit are analysed for the first time for the system of 2-2 single crystal/polymer composites and 2-0-2 single crystal/corundum ceramic/polymer composites at x = 0.0475-0.09. The connections between the piezoelectric coefficients, energy-harvesting figures of merit and modified figures of merit (j = 1, 2 and 3) are highlighted during rotation of the main X and Y crystallographic axes around the Z axis of the crystal layers. A similar orientation behaviour of, and and their large anisotropy are studied at specific volume fractions of the single-crystal component and for a variety of microgeometric architectures of a corundum ceramic/polymer layer with 0-3 connectivity. Maxima of the longitudinal parameters, and at x = 0.0475-0.09 and constant volume fraction of the single-crystal component of the 2-2-type composites are observed in a relatively narrow orientation range. A new performance diagram is built to show regions of a large anisotropy of and in a 2-0-2 composite and, as a result of the large piezoelectric coefficients and figures of merit, the composites show significant potential in the field of piezoelectric energy-harvesting and sensor applications. This journal is </p
Piezoelectric Performance and Hydrostatic Parameters of Novel 2&#x2013;2-Type Composites
Get PDFThis paper provides a detailed study of the structure - piezoelectric property relationships and the hydrostatic response of 2&#x2013;2-type composites based on relaxor-ferroelectric 0.72Pb(Mg1/3Nb2/3)O3&#x2013;0.28PbTiO3 single crystal material. Type I layers in the composite system are represented by a single-domain &#x005B;111&#x005D;-poled single crystal. Changes in the orientation of the crystallographic axes in the Type I layer are undertaken to determine the maximum values of the hydrostatic piezoelectric coefficients dh&#x002A;, gh&#x002A;, and eh&#x002A;, and squared figure of merit dh&#x002A; gh&#x002A; of the composite. The Type II layers are a 0&#x2013;3 composite whereby inclusions of modified PbTiO3 ceramic are distributed in a polymer matrix. A new effect is described for the first time due to the impact of anisotropic elastic properties of the Type II layers on the hydrostatic piezoelectric response that is coupled with the polarization orientation effect in the Type I layers. Large hydrostatic parameters gh&#x002A;&#x2248;300&#x2013;400 mV&#x02D9;m/N, eh&#x002A;&#x2248;40&#x2013;45C/m2, and dh&#x002A; gh&#x002A;&#x007E; 10&#x2212;11 Pa&#x2212;1 are achieved in the composite based on the 0.72Pb(Mg1/3Nb2/3)O3&#x2013;0.28PbTiO3 single crystal. Examples of the large piezoelectric anisotropy (&#x007C; d33&#x002A; / d3f&#x002A; &#x007C;&#x2265;5 or &#x007C; g33&#x002A; / g3f&#x002A; &#x007C;&#x2265;5) are discussed. The hydrostatic parameters of this novel composite system are compared to those of conventional 2&#x2013;2 piezocomposites.</p
Oil spill problems and sustainable response strategies through new technologies
Get PDFCrude oil and petroleum products are widespread water and soil pollutants resulting from marine and terrestrial spillages. International statistics of oil spill sizes for all incidents indicate that the majority of oil spills are small (less than 7 tonnes). The major accidents that happen in the oil industry contribute only a small fraction of the total oil which enters the environment. However, the nature of accidental releases is that they highly pollute small areas and have the potential to devastate the biota locally. There are several routes by which oil can get back to humans from accidental spills, e.g. through accumulation in fish and shellfish, through consumption of contaminated groundwater. Although advances have been made in the prevention of accidents, this does not apply in all countries, and by the random nature of oil spill events, total prevention is not feasible. Therefore, considerable world-wide effort has gone into strategies for minimising accidental spills and the design of new remedial technologies. This paper summarizes new knowledge as well as research and technology gaps essential for developing appropriate decision-making tools in actual spill scenarios. Since oil exploration is being driven into deeper waters and more remote, fragile environments, the risk of future accidents becomes much higher. The innovative safety and accident prevention approaches summarized in this paper are currently important for a range of stakeholders, including the oil industry, the scientific community and the public. Ultimately an integrated approach to prevention and remediation that accelerates an early warning protocol in the event of a spill would get the most appropriate technology selected and implemented as early as possible-the first few hours after a spill are crucial to the outcome of the remedial effort. A particular focus is made on bioremediation as environmentally harmless, cost-effective and relatively inexpensive technology. Greater penetration into the remedial technologies market depends on the harmonization of environment legislation and the application of modern laboratory techniques, e.g. ecogenomics, to improve the predictability of bioremediation
Piezoelectric Performance and Hydrostatic Parameters of Novel 2&#x2013;2-Type Composites
Get PDFThis paper provides a detailed study of the structure - piezoelectric property relationships and the hydrostatic response of 2&#x2013;2-type composites based on relaxor-ferroelectric 0.72Pb(Mg1/3Nb2/3)O3&#x2013;0.28PbTiO3 single crystal material. Type I layers in the composite system are represented by a single-domain &#x005B;111&#x005D;-poled single crystal. Changes in the orientation of the crystallographic axes in the Type I layer are undertaken to determine the maximum values of the hydrostatic piezoelectric coefficients dh&#x002A;, gh&#x002A;, and eh&#x002A;, and squared figure of merit dh&#x002A; gh&#x002A; of the composite. The Type II layers are a 0&#x2013;3 composite whereby inclusions of modified PbTiO3 ceramic are distributed in a polymer matrix. A new effect is described for the first time due to the impact of anisotropic elastic properties of the Type II layers on the hydrostatic piezoelectric response that is coupled with the polarization orientation effect in the Type I layers. Large hydrostatic parameters gh&#x002A;&#x2248;300&#x2013;400 mV&#x02D9;m/N, eh&#x002A;&#x2248;40&#x2013;45C/m2, and dh&#x002A; gh&#x002A;&#x007E; 10&#x2212;11 Pa&#x2212;1 are achieved in the composite based on the 0.72Pb(Mg1/3Nb2/3)O3&#x2013;0.28PbTiO3 single crystal. Examples of the large piezoelectric anisotropy (&#x007C; d33&#x002A; / d3f&#x002A; &#x007C;&#x2265;5 or &#x007C; g33&#x002A; / g3f&#x002A; &#x007C;&#x2265;5) are discussed. The hydrostatic parameters of this novel composite system are compared to those of conventional 2&#x2013;2 piezocomposites.</p
Orientation effects and figures of merit in advanced 2-2-type composites based on [011]-poled domain-engineered single crystals
Get PDFThe paper reports new results that compare the group of performance figures of merit of piezo-active 2-2-type composites based on [011]-poled domain-engineered (1 - x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 single crystals, where the main crystallographic axes in the crystal layers are rotated to tailor effective electromechanical properties and related parameters. Examples of the orientation and volume-fraction dependences of the figures of merit are analysed for the first time for the system of 2-2 single crystal/polymer composites and 2-0-2 single crystal/corundum ceramic/polymer composites at x = 0.0475-0.09. The connections between the piezoelectric coefficients, energy-harvesting figures of merit and modified figures of merit (j = 1, 2 and 3) are highlighted during rotation of the main X and Y crystallographic axes around the Z axis of the crystal layers. A similar orientation behaviour of, and and their large anisotropy are studied at specific volume fractions of the single-crystal component and for a variety of microgeometric architectures of a corundum ceramic/polymer layer with 0-3 connectivity. Maxima of the longitudinal parameters, and at x = 0.0475-0.09 and constant volume fraction of the single-crystal component of the 2-2-type composites are observed in a relatively narrow orientation range. A new performance diagram is built to show regions of a large anisotropy of and in a 2-0-2 composite and, as a result of the large piezoelectric coefficients and figures of merit, the composites show significant potential in the field of piezoelectric energy-harvesting and sensor applications. This journal is </p
Structure, Physicochemical Properties and Biological Activity of Lipopolysaccharide from the Rhizospheric Bacterium <i>Ochrobactrum quorumnocens</i> T1Kr02, Containing <span style="font-variant: small-caps">d</span>-Fucose Residues
No full textLipopolysaccharides (LPSs) are major components of the outer membranes of Gram-negative bacteria. In this work, the structure of the O-polysaccharide of Ochrobactrum quorumnocens T1Kr02 was identified by nuclear magnetic resonance (NMR), and the physical–chemical properties and biological activity of LPS were also investigated. The NMR analysis showed that the O-polysaccharide has the following structure: →2)-β-d-Fucf-(1→3)-β-d-Fucp-(1→. The structure of the periplasmic glucan coextracted with LPS was established by NMR spectroscopy and chemical methods: →2)-β-d-Glcp-(1→. Non-stoichiometric modifications were identified in both polysaccharides: 50% of d-fucofuranose residues at position 3 were O-acetylated, and 15% of d-Glcp residues at position 6 were linked with succinate. This is the first report of a polysaccharide containing both d-fucopyranose and d-fucofuranose residues. The fatty acid analysis of the LPS showed the prevalence of 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, lactobacillic, and 27-hydroxyoctacosanoic acids. The dynamic light scattering demonstrated that LPS (in an aqueous solution) formed supramolecular particles with a size of 72.2 nm and a zeta-potential of –21.5 mV. The LPS solution (10 mkg/mL) promoted the growth of potato microplants under in vitro conditions. Thus, LPS of O. quorumnocens T1Kr02 can be recommended as a promoter for plants and as a source of biotechnological production of d-fucose
