Influence Of External Pressure Research Articles

Influence of pressure on magnetization and magnetostriction jumps in the manganite (Eu1−xGdx)0.6Sr0.4MnO3(x=0,0.1)

We have demonstrated the influence of external pressure on magnetization jump in Gd substituted Eu0.58Sr0.42MnO3. The collapse of magnetization jump of the Eu based manganite caused by the applied pressure up to 1.2 GPa is explained by a suppression of the metastable blocked state, which is inherent to the phase separated manganite system exhibiting the magnetic avalanche. On the other hand, the magnetization jump of the Gd substituted sample is enhanced under the same pressure. To further examine the nature of the magnetization jump, the influence of pressure on the isothermal magnetostriction of the parent manganite is carried out. These findings indicate the crucial role on the abrupt transition played by the frozen phase separated phase.

Large variations in the magnetic ordering behavior of EuCu2As2 with the application of external pressure and magnetic field

The influence of external pressure on the electrical transport and magnetic properties of EuCu2As2, crystallizing in a ThCr2Si2-type structure, is reported. The system is known to be an antiferromagnet below TN ≈ 15 K in the absence of external magnetic fields. We find that there is a gradual reduction of TN with the application of a magnetic field with an extrapolated value of the critical field of around 18 kOe which can drive TN to zero. Electrical resistivity under pressure (<11 GPa) reveals that the magnetic ordering temperature is pushed up dramatically to higher temperatures which is quite interesting if compared with the behavior in isostructural FeAs-based systems containing Eu. Above 7 GPa, the pressure-induced state appears to be ferromagnetic. The results thus reveal interesting changes in the magnetic ordering behavior of this compound with increasing pressure and magnetic fields.

Australian English: Its Evolution and Current State

&lt;strong&gt;&lt;strong&gt;&lt;/strong&gt;&lt;/strong&gt;&lt;p align="LEFT"&gt;T&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;his paper provides a critical overview of research on Australian English (‘AusE’), &lt;/span&gt;&lt;/span&gt;and of the vexing questions that the research has grappled with. These include: What is the historical explanation for the homogeneity of the Australian accent? Was it formed by the fi rst generation of native-born Australians in the ‘Sydney mixing bowl’, its spread subsequently facilitated by high population &lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;mobility? Or &lt;/span&gt;&lt;/span&gt;is the answer to be found in sociolinguistic reconstructions of the early colony suggesting that a uniform London English was transplanted to Australia in 1788 and that speakers of other dialects quickly adapted to it? How is Australia’s national identity embodied in its lexicon, and to what extent is it currently under the infl uence of external pressure from American English? What are the most distinctive structural features of AusE phonology, morphosyntax and discourse? To what extent do allegedly unique Australian features such as sentence-final &lt;em&gt;&lt;span style="font-family: DejaVuSerifCondensed-Italic; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed-Italic; font-size: small;"&gt;but &lt;/span&gt;&lt;/span&gt;&lt;/em&gt;and &lt;em&gt;&lt;span style="font-family: DejaVuSerifCondensed-Italic; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed-Italic; font-size: small;"&gt;yeah-no &lt;/span&gt;&lt;/span&gt;&lt;/em&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;in discourse serve the social role of indexing &lt;/span&gt;&lt;/span&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;‘Australianness’? What is &lt;/span&gt;&lt;/span&gt;the nature and extent of variation – regional, social and ethnic – in contemporary AusE? Are such regional phonological &lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;differences as /æ/~/a/ variation increasing &lt;/span&gt;&lt;/span&gt;or &lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;&lt;span style="font-family: DejaVuSerifCondensed; font-size: small;"&gt;diminishing? Does there exist a pan-ethnic variety of AusE that is particularly &lt;/span&gt;&lt;/span&gt;associated with younger Australians of second generation Middle Eastern and Mediterranean background? Has contemporary AusE consolidated its own norms as an independent national standard?&lt;/p&gt;

Modeling and imaging of biomechanical properties of breast using microwave pulses

AbstractA closed‐form theoretical model for the biomechanical properties of breast tissues under the influence of external pressure is derived and validated. That model is employed in a microwave imaging method that aims at extracting the three‐dimensional biomechanical properties of breast. The high contrast in the biomechanical properties between healthy and malignant tissues represents the basis of the presented imaging method. In this method, the breast is inserted in an enclosure that has an array of ultrawideband (UWB) antennas embedded in the upper movable plate of the enclosure. Each of those antennas transmits an UWB pulse towards the breast and measure the backscattered pulse before and after compressing the breast by a controlled force applied at the top of the movable plate. A sliding‐window cross‐correlation is used to get a three‐dimensional strain image of the breast. As lesion tissue is much stiffer than the normal breast tissues the regions of zero strain indicate areas of suspected tumor. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2761–2765, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26440

Transport and magnetic behavior under pressure and high-resolution photoemission studies of Ce2Rh0.7Co0.3Si3, an alloy on the verge of quantum critical point

We report the influence of external pressure on the temperature dependence of magnetization and electrical resistivity as well as high-resolution photoemission studies for an alloy, Ce2Rh0.7Co0.3Si3, ordering magnetically below 3 K. It is found that external pressure has the same effect as that induced by (further) Co substitution for Rh in the series, Ce2Rh1-xCoxSi3, resulting in qualitative changes in the features in the magnetic and transport data, with a suppression of magnetic ordering followed by quantum critical point effect. The high-resolution photo-emission spectra reveal signature of Kondo feature even at ambient pressure. These findings support the validity of spin-density-wave picture in this series.

Strain Imaging of the Breast by Compression Microwave Imaging

A method that uses microwave pulses to achieve strain imaging of the breast is presented. In the proposed method, the breast is inserted in an enclosure that defines the boundary conditions for the breast deformation under the influence of external pressure. The upper plate of the enclosure, which also includes an antenna array, is attached to a compression tool, whereas the lower and the front plates are fixed. The breast is allowed to extend in the lateral direction when pressed by the top plate. Each of the antennas at the top plate is used to send an ultrawideband pulse to penetrate the breast and measure the backscattered pulse. Two sets of measurements are taken: one pre- and another post-compression of the breast. A sliding window of cross correlation is then performed on the two sets of data to establish the time delay of each segment of the scattered pulse due to compression. That time delay is then employed to get a three-dimensional strain image of the breast. As lesion tissue is typically much stiffer than normal breast tissue, then regions of low or zero strain indicate areas in need of further diagnostic checks. Full-wave simulations are used to validate the presented imaging method.

Coordination of innovation policies in the catching-up context: a historical perspective on Estonia and Brazil

This paper highlights some of the crucial weaknesses of innovation- policy-research that limit the relevance of this research for policy-making practices in catching-up countries. The paper proposes a framework that takes a multi-level and dynamic approach towards studying innovation-policy-making processes. This framework is applied herein to examine the evolution of innovation policy and governance trajectories of Estonia and Brazil and how this has affected the capacities for technological accumulation and development. The paper argues that crucial aspects of these contextual trajectories are being overlooked by standard innovation policy and governance analyses. In terms of policy implications, the paper concludes that the increasing influence of external pressures on innovation policy trajectories of catching-up countries is only reinforcing the use of narrow analytical perspectives and threatens to further de-contextualise innovation-policy-making in these countries. The spread of 'participatory' or 'networked' innovation policy models is presented as an example of these tendencies. Reference to this paper should be made as follows: Karo, E. and Kattel, R. (2010) 'Coordination of innovation policies in the catching-up context: a historical perspective on Estonia and Brazil', Int. J. Technological Learning, Innovation and Development, Vol. 3, No. 4, pp.293-329.

Influence of pressure on the magnetic behavior and the anomalous magnetoresistance inTb5Si3

The compound, Tb5Si3, crystallizing in Mn5Si3-type hexagonal structure, was recently reported by us to exhibit a sudden and huge enhancement in electrical resistivity (rho) at a critical magnetic field (H_cr) in the magnetically ordered state (<70 K) tracking isothermal magnetization (M) behavior. We have investigated the influence of external pressure (<15 kbar) and negative chemical pressure induced by Ge substitution for Si on M and rho as a function of temperature (5-300 K) and magnetic field (<120 kOe), with the primary aim of understanding the field-induced anomalies. Focussing on isothermal M and magnetoresistance (MR) at two temperatures, 5 and 20K, we find that this rho anomaly persists under external as well as negative chemical pressures, however with a large change in the H_cr. The pressure-derivative of H_cr is negative and this trend and the MR behavior at the H_cr are comparable to that observed in some Laves phase itinerant magnetic systems. On the basis of this observation, we speculate that the magnetic fluctuations induced at this critical field could be responsible for the MR anomal.ies

Effect of pressure on the electric transport properties of carbon-doped

We report about the influence of external pressure on the electrical resistivity of EuB5.99C0.01, the compound believed to be intrinsically inhomogeneous due to fluctuations of carbon content. Our results show that the low-temperature resistivity maximum shifts to a lower temperature with applied pressure, opposite to the behavior reported for stoichiometric EuB6. The origin of such a qualitative difference we associate with the increasing volume fraction of the phase that is not compatible with ferromagnetic ordering (originating in regions with relatively higher carbon concentration) with increasing pressure. Our results support a recent proposition of Batkova et al. (2008) [12] that carbon-rich regions strongly influence magnetotransport properties of carbon-doped EuB6, such as they play a role of “spacers”, which prevent the percolation of a ferromagnetic phase.

Stellar feedback and triggered star formation

AbstractYoung, massive stars influence their ambient medium through winds and radiation. The outcome of this feedback depends on the number of massive stars in a star cluster and on the density of the ambient medium. This contribution is based on a comparison of observations to the results of numerical simulations. We discuss the gravitational fragmentation of feedback-driven shells expanding from young stellar clusters. The thin-shell approximation is compared to 3D hydrodynamical simulations with smoothed-particle hydrodynamics and adaptive-mesh refinement codes. We explore the influence of external pressure and propose a thick-shell dispersion relation, where the pressure of the external medium is included. The mass spectrum of the shell fragments is constructed and we speculate about the origin of the deficit of low-mass objects.

A Kinetic Study on the Nitric Oxide Trapping by the Fe(III)-Dithiocarbamate-Nitroxyl Complex: Influence of the Ligand Structure and External Pressure on the Trapping Rate

Abstract The Fe(III)-dithiocarbamate-nitroxyl (Fe-dtc-nitroxyl) complex, where nitroxyl represents nitroxyl free radical (R-N(O)-R’), has been shown to trap nitric oxide (NO) in aqueous solution, replacing the nitroxyl ligand. As a result, non-complexed nitroxyl radical was released to the solution. Fe(III)-dithiocarbamate (Fe-dtc) complexes without the nitroxyl ligand also traps NO, producing NO-Fe-dtc complex. These two reactions have been used for the purpose of NO detection. We investigated how the ligand structure and external pressure influence NO trapping rates in these complexes. The ratios of NO trapping rates (k 1/k 2) between various Fe-dtc-nitroxyl complexes and the Fe-dtc complex were determined by using a competitive NO trapping method. The ratio k 1/k 2 was 29.8±2.8 for Fe-dtc-nitroxyl and Fe-dtc, where dtc = N-(dithiocarboxy) sarcosine (DTCS) and nitroxyl = 2,2,6,6-tetramethyl- piperidine-1-oxyl (TEMPO). For another combination, dtc = N-methyl-D-glucamine dithiocarbamate (MGD)/nitroxyl = TEMPO, k 1/k 2 was 7.19±0.25. Overall, NO trapping rate of the Fe-dtc-nitroxyl complex was faster than that of the Fe-dtc complex, and k 1/k 2 for Fe-MGD complex was dependent on the electron-withdrawing or -repelling nature of the functional group in the ligand. Based on pressure dependence experiments for the competitive reaction, we obtained large negative activation volumes for NO trapping of the Fe-dtc-nitroxyl complex as well as the difference in activation volumes (–45 to –26 cm3 mol–1) between the NO trapping reactions by the two Fe complexes. These data sets with different nature allowed us to speculate the reaction mechanism for NO trapping of the Fe-dtc-nitroxyl complex.

Influence of High Pressure and Magnetic Fields on the Magnetic and Transport Anomalies in Nd7Rh3

The compound, Nd 7 Rh 3 , has been recently shown by us to exhibit exceptional magnetic and transport behavior. There are at least two antiferromagnetic transitions as a function of temperature (10 and 32 K) with the 10 K-transition being first-order-like at low fields; in addition, there is a field-induced first-order (metamagnetic) transition at temperatures well below 10 K. We have investigated the influence of external pressure (<15 kbar) on the magnetic and transport anomalies for this compound. We find that the two transition temperatures interestingly vary in opposite directions with increasing pressure and that the external pressure suppresses the critical field required to induce the metamagnetic magnetism. External pressure, while retaining (magnetic) phase co-existence phenomenon and percolative electrical conduction after field cycling (similar to the behavior known for by-now well-known manganites), suppresses the magnitude of magnetoresistance at high fields. We also report heat-capacity data in the presence of magnetic fields and it appears that the linear term decreases in the presence of a magnetic field as though there is a band splitting effect.

Pressure-induced changes in the energetic structure of the 3d 3 ions in solid matrices

The results of high-pressure spectroscopy of Cr 3+ and Mn 4+ ions in solids are revised. We discuss the influence of external pressure on compression of ion–ligands systems, pressure-induced 4T 2– 2E level crossover, R-lines pressure shift and influence of pressure on the R-lines emission lifetime. The model of energetic structure of the octahedrally coordinated 3d 3 ion that includes electron–phonon and spin–orbit interaction is considered and used for interpretation of the results of high-pressure spectroscopy, especially for quantitative analysis of lattice disorder and crystal field distribution in crystal.

Can near infrared spectroscopy measure the effect of pressure on oxygenation of sacral soft tissue?

To test whether near infrared spectroscopy (NIRS) is applicable for the examination of the influence of external pressure on oxygenation of the soft tissues in the sacral area. Tissue oxygenation was measured in 33 healthy volunteers in the prone position. A NIRS probe was positioned over the sacrum and external pressure was applied in 10 mmHg increments, from 20 mmHg to 200 mmHg and then decreased. At each level, tissue oxygen saturation (StO2) was measured. To test reproducibility, the protocol was repeated in six volunteers, in whom the thickness of the soft-tissue envelope at different levels of external pressure was assessed using ultrasound. There was wide variability in StO2 courses between the 33 subjects, with a non-linear relationship between pressure and StO2. The only consistent finding was that the StO2 was significantly higher after decreasing pressure than at the initial pressure of 20 mmHg, which is indicative of reactive hyperaemia. Despite the application of high external pressures, reasonable tissue oxygenation was maintained in 19 of 33 subjects. Reproducibility of the measurements was poor. Comparison of soft-tissue thickness with corresponding StO2 values showed that, with increasing pressure, the percentage decrease in tissue thickness was higher than the decrease in tissue oxygenation. This study confirms that NIRS is not useful for assessing tissue oxygenation in pressure ulcer research due to unacceptable inter-individual variability and poor reproducibility of measurements.

Temperature and pressure dependences of tunneling rate constant: Density-functional theory potential-energy surface for H-atom transfer in the fluorene-acridine system

Temperature and pressure dependences of rate constants for solid phase tunneling reactions are analytically considered within the framework of modified theory of radiationless transitions, taking into account the intermolecular and soft intramolecular promotive vibrations of reagents. This treatment allows us to describe theoretically the process of atomic tunneling and the effect of temperature on the potential barrier and reorganization of the reagents. The influence of external pressure appears in our treatment as a static reduction of widths and heights of the potential barrier with hydrostatic compression of the matrix, and also as an increase of frequencies of promotive vibrational modes owing to anharmonicity. The theoretical results are used to interpret experimental data concerning the effect of temperature and pressure on the hydrogen-atom tunneling in the fluorene-acridine reaction system. It has been shown that by taking into account the contributions from reorganization of the reagents, which statically reduce the tunneling barrier and are related to four types of promotive vibrations (translational, librational, and two low-frequency intramolecular modes at 95 and 238 cm(-1)), one can reproduce the experimental data available in the literature. The parameters of the reaction system required for this analysis are calculated from two-dimensional potential-energy surfaces generated at the DFT-B3LYP/6-31G* level.

Crystallization under external pressure

The influence of external pressure on the dynamics of crystallization is examined by considering a solid–liquid two-phase system in a cylinder closed by a piston. The dynamic equations are derived using three methods, namely, Rational Thermodynamics (Liu’s procedure), the Matrix Model, and the general equation for the nonequilibrium reversible-irreversible coupling (GENERIC) formalism. The constitutive relation for the multiphase pressure on the piston is identical for all three methods, whereas some aspects of the result for the phase change dynamics differ. The rational thermodynamics treatment constrains the phase change dynamics of only those structural variables that enter into the dissipation inequality, whereas the other two formalisms make statements about the phase change of all structural variables. Nevertheless, all three methods show, first, that the phase change happens instantaneously at constant volume and, second, where morphological detail can be built into the model without violating thermodynamic principles. It is discussed how an appropriate choice of the morphological variables allows one to incorporate impingement of crystals and depletion zone effects, as well as to distinguish crystal shapes.

Microscopic Aspects of Pressure Influence on Order-Disorder Type Ferroelectrics

Within the developed microscopic models we analyze the role of different mechanisms of external pressure influence on phase transitions in deuterated crystals of the KD 2 PO 4 family; crystals of DMAGaS type, and H-bonded ferroelectrics of the Me 3 H(XO 4 ) 2 family.

Thermo-elastic buckling of layered shell segments

The buckling behavior of multilayer shells is studied for composite structures subjected to combinations of uniform temperature change, applied external pressure, and applied and reactive circumferential edge loads. A stability criterion is established for the class of structures of interest and a transverse loading parameter is identified. Critical parameters are identified, and closed form analytical solutions are obtained for the associated non-linear problems. Numerical simulations, based on these solutions, are performed and the stability criterion is applied, revealing characteristic behavior of the structures of interest. Such behavior includes “sling-shot” buckling, whereby the structure slings from deflections in one direction to deflections in the opposite sense, in an unstable manner, at critical temperatures. The influence of external pressure on the critical temperature change of thermally loaded composite structures is elucidated, as is the influence of temperature change on the buckling behavior of pressure loaded multilayer shells.

Managing Public Impressions: Environmental Disclosures in Annual Reports

Through the juxtaposition of theory and a meso-level empirical illustration of the environmental disclosures included in the annual reports of Canadian public companies operating in the mineral extraction, forestry, oil and gas, and chemical industries over the 1982 to 1991 period, the current study attempts to increase our understanding of the role and functioning of environmental disclosures. Our analyses focus on three concerns: the influence of external pressure on environmental disclosures in annual reports, including the amount and types of strategies used in disclosure; the characteristics of environmental disclosure vis-á-vis other “social” disclosures; and the association between environmental disclosures and actual performance. We question whether such disclosures highlight positive environmental actions, obfuscate negative environmental effects or both.

The Volume Diffusion of Interstitial Atoms in Ordered Magnetic Alloys Under Pressure

ABSTRACTTheoretical investigation of interstitial atom diffusion in a binary alloy A-B with crystal lattice of CsCl type with atomic and magnetic (ferromagnetic or antiferromagnetic) order has been performed. The influence of external pressure on diffusion of hydrogen atoms has been defined. Calculations has been carried out by methods of statistical physics with application of thermodynamic functions.