Absence Of External Pressure Research Articles

Tolerance of focal species to forest management intensity as a guide in the development of conservation targets

Although forest managers are trained to optimize timber production, they should be encouraged to integrate biodiversity conservation as an element of sustainable forest management. To do so, coarse-filter approaches should be complemented with an assessment of the response of carefully selected focal species to forest management intensity. Once conservation objectives have been defined, researchers should determine the shape of focal species’ responses to descriptors of management intensity. Sharp transitions (thresholds) in species responses can yield insight for the development of quantitative conservation targets, with the understanding that critical resources (e.g., specific stand structures; amount of habitat in the landscape) should be maintained well above the threshold values observed. Conservation targets should be determined by land managers and policy-makers on the basis of objective, empirical evidence obtained by researchers to ensure that scientific investigation is conducted in the absence of external pressure.

Guided self-organization

Typically, self-organization is defined as the evolution of a system into an organized form in the absence of external pressures. A broad definition of self-organization is given by Haken (2006).

Eurocodes and REACH: Differences and Similarities

The developments of the new European construction standard (Eurocodes) and the new European chemical legislation (REACH) have taken place in parallel, and they are now both in their final stages. Both consist in European harmonization of safety regulations that concern major industries. In this paper, we compare Eurocodes and REACH in terms of purpose, intended level of harmonization, the science-policy interface and controversies about the costs of the regulations. We have found that the science-policy interface of REACH is characterized by public controversy and by attempts to keep risk assessment and risk management apart while the science-policy interface of Eurocodes is characterized by trust in experts, limited public involvement and organizational confluence of risk assessment and risk management. Furthermore, the costs of REACH have been a major issue in discussions between the Commission and the chemical industry while, in contrast, the costs of Eurocodes have not even been calculated either by the Commission or by the construction industry. A major reason for this is that construction industry does not seem to regard possible cost increases due to Eurocodes as a threat to their business interests. Regulators seem to have treated the cost issue as a business interest, not as an aspect of the decision that they should be concerned with even in the absence of external pressure.

Political Trust and the Success of Fiscal Consolidations

The paper examines the effects of political trust on fiscal consolidations. Building on the works of Easton (1965) and Gamson (1968) a theoretical framework is derived on the main channels through which the success of fiscal consolidation can be affected by the level of political trust in the system. The predictions of the theory are tested quantitatively based on evidence from the Economic and Monetary Union and qualitatively through a most-likely - least-likely case comparison between Hungary and Sweden. The results provide strong support for the hypotheses and indicate that in the absence of external pressures lasting fiscal consolidations can take place only in a high-trust regime. In a low-trust regime even if an external crisis triggers adjustment, the incentive to buy support through short-term promises ultimately erodes the commitment to restraint and imbalances reemerge.

Ab initio simulation of high pressure influence on He–H interaction in silicon

To explain the high-pressure influence on He–H interaction in silicon we used the density functional theory and ab initio pseudopotentials. To simulate the pressure we reduced a silicon lattice constant by 1–5% that corresponds to the pressure of 1–5 GPa. Divacancies were used as models of voids in silicon. Calculations show that single He atoms accumulate in divacancies in the absence of external pressure. The 5 GPa pressure reduces the divacancy formation energy by about 1 eV in the absence of He. The presence of two He atoms in a divacancy reduces this value additionally by 0.3 eV. Thus, He stimulates formation of voids in silicon and fills them simultaneously. Leaving silicon interstitial sites for divacancies, H 2 molecules dissociate up and passivate silicon dangling bonds with the energy profit of 1.6 eV. The presence of two He atoms per divacancy reduces this profit by 0.1 eV. The 5 GPa pressure decreases this energy additionally by 0.3 eV and makes H in silicon less bonded and more mobile in accordance with experimental data.

Pressure effect on radial breathing modes of multiwall carbon nanotubes

This paper studies the pressure effect on radial breathing modes (RBMs) of multiwall carbon nanotubes (MWNTs). The analysis is based on a multiple-elastic shell model which assumes that each of the concentric tubes of a MWNT is an individual elastic shell and coupled with adjacent tubes through van der Waals interaction. The pressure effect on RBMs of MWNTs is mainly attributed to the pressure-induced reduction of interlayer spacing and the increase of the interlayer vdW interaction coefficient defined by the second derivative of the energy-interlayer spacing relation of MWNTs. In the absence of external pressure, the RBM frequencies and vibration modes predicted by the present shell model are found to agree very well with the available experimental and molecular-dynamics simulation results. In the presence of an external pressure, our results show that high external pressure considerably raises the vdW interaction coefficients especially between the outermost few layers of MWNTs. As a result, some of the RBM frequencies of MWNTs increase significantly with increasing external pressure. The most significant pressure effect occurs for the highest-frequency mode of large-diameter MWNTs (with the innermost diameter greater than 2nm) or an intermediate-frequency mode of small-diameter MWNTs (with the innermost diameter less than 2nm), and is always associated with those RBMs in which adjacent outermost layers vibrate in opposite directions with significant change in interlayer spacing.

Stress-strain state of bilayer vessels. Report 1. Case of external winkler medium

The stress-strain state of bilayer vessels in the case of an external Winkler medium is investigated. Bilayer cylindrical and spherical vessels are addressed; in this case, their material may be elastic, elasto ideally plastic, elasto-brittle with limited compressibility, and rigidly ideally plastic. Expressions are derived for the stresses that develop in pipes tested under internal pressure. For monolayer vessels, the solution obtained agrees with Andzhaparidze and Shapiro's solution, and in the absence of external pressure, the equations yield Lame's classical solutions for a cylinder and sphere.

Formation and Initial Growth of Single-Asperity Solid-State Bonds

A gold needle point in contact with a gold flat has been used to study the formation and initial growth of single-asperity solid-state bonds. In the absence of external pressure, the growth of the bonded area can be expressed analytically by a diffusion-controlled rate equation. Values for the coefficient of self-diffusion determined from these experiments are in reasonable agreement with those given in the recent literature.