Nonlinear Racking Analysis of Nailed Walls

An energy formation of nonlinear analysis of racking resistance of nailed walls is presented. The analysis is dependent on the nonlinear load-slip relationship of nailed connections. The method permits the calculation of the racking force associated with a given horizontal displacement and uses as input data panel geometry, number and spacing of nails, and load distortion relationship of a single connection.Two 4 ft x 8 ft panels with two thicknesses of 1/2 in. and 5/8 in. plywood are analyzed using linear and nonlinear methods, and results of horizontal displacement versus racking force are displayed graphically. It is shown that while the two methods converge at ultimate loads, true representation of wall behavior at low levels of displacement is best described through nonlinear analysis. Good comparison is obtained with a finite element approach

Intervention

Nicaragua’s cases brought a great contribution to the law on intervention. They clarified some of its characteristics, the most important of which relating to the statutory nature of intervention: thus, the admissibility of these proceedings is not dependent upon the consent of the Parties, but on the fulfilment of the conditions established by the Statute. Though the Court took many years to acknowledge this fundamental aspect, its case-law seems now stabilized—at least as a matter of principle. The same cannot be said about the substantive conditions for admissibility of intervention: absent any real attempt from the Court to define the concept of ‘interest of a legal nature which may be affected’, the admission of intervention under Article 62 is still highly circumstantial. These ambiguities also durably impacted the consequences of intervention. The Court firmly maintains a peremptory distinction between intervention as a party and intervention as a non-party, but it also deprives it of any prospect of clarification, since it has never admitted intervention as a party. This emphatic insistence does not help clarifying the status of the intervener, nor does it stimulate the reflection upon its procedural rights and obligations

Acausality in Gowdy spacetimes

We present a parametrization of $T^3$ and $S^1\times S^2$ Gowdy cosmological models which allows us to study both types of topologies simultaneously. We show that there exists a coordinate system in which the general solution of the linear polarized special case (with both topologies) has exactly the same functional dependence. This unified parametrization is used to investigate the existence of Cauchy horizons at the cosmological singularities, leading to a violation of the strong cosmic censorship conjecture. Our results indicate that the only acausal spacetimes are described by the Kantowski-Sachs and the Kerr-Gowdy metrics.Comment: Typos corrected, 10 pages. Dedicated to Michael P. Ryan on the occasion of his 60-th birthda

Generating Gowdy cosmological models

Using the analogy with stationary axisymmetric solutions, we present a method to generate new analytic cosmological solutions of Einstein's equation belonging to the class of $T^3$ Gowdy cosmological models. We show that the solutions can be generated from their data at the initial singularity and present the formal general solution for arbitrary initial data. We exemplify the method by constructing the Kantowski-Sachs cosmological model and a generalization of it that corresponds to an unpolarized $T^3$ Gowdy model.Comment: Latex, 15 pages, no figure

(Non) singular Kantowski-Sachs Universe from quantum spherically reduced matter

Using s-wave and large N approximation the one-loop effective action for 2d dilaton coupled scalars and spinors which are obtained by spherical reduction of 4d minimal matter is found. Quantum effective equations for reduced Einstein gravity are written. Their analytical solutions corresponding to 4d Kantowski-Sachs (KS) Universe are presented. For quantum-corrected Einstein gravity we get non-singular KS cosmology which represents 1) quantum-corrected KS cosmology which existed on classical level or 2)purely quantum solution which had no classical limit. The analogy with Nariai BH is briefly mentioned. For purely induced gravity (no Einstein term) we found general analytical solution but all KS cosmologies under discussion are singular. The corresponding equations of motion are reformulated as classical mechanics problem of motion of unit mass particle in some potential V.Comment: LaTeX file, 16 pages, a few misprints are correcte

MTT-30

Abstract -Only approximate relations are so far available for the pufling figure of an oscillator. An exact derivation of the pnlling figure is presented here, tafdng fufly into account the nonlinearity of the oscillator admittance. Effect of the oscillator nonlinearity on the asymmetry of the pulling range is presented

Minisuperspace Examples of Quantization Using Canonical Variables of the Ashtekar Type: Structure and Solutions

The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real) of the basic Hamiltonian variables of general relativity. We are able to present several new solutions in the minisuperspace (quantum cosmology) sector. The meaning of these solutions is then discussed.Comment: 23 pages, latex, 3 figures (uuencoded, separate file

Isotopic δ\u3csup\u3e15\u3c/sup\u3eN Signature of Grass-Alone and Grass-Legume Tropical Pastures to Estimate Sources of Nitrogen to Grasses in Farmer Managed Pastures

Vast areas of tropical forest have been converted into pastures sown with introduced grasses (Urochloa spp.). The majority of pastures exist in some stage of degradation, which has dramatic ecological and economic consequences. Our objective was to determine isotopic 15N signature of grass alone and grass-legume pastures to estimate sources of nitrogen (N) to grasses in farmer managed pastures. This work contributes to enhancing the sustainability of tropical pastures in forest margins through the integration of legumes. The overarching hypothesis tested was that legumes associated with grasses will improve nutrient supply via symbiotic fixation and mobilization of soil phosphorus (P) reserves increasing belowground inputs and recycling of carbon (C), N and P. We have done preliminary research in ten paired plots of productive grass-alone vs. grass-legume pastures on farms located in the Caquetá region of Colombia. Pasture productivity and sources of plant N uptake using 15N isotope natural abundance methods have been analysed. The integration of legumes increased biomass production by about 74%, and N and P uptake by two-fold. The legumes derived about 80% of their N via symbiotic fixation, showing the significance of this process to N nutrition despite the acidic soil conditions. The isotopic 15N signature of grasses in grass-alone vs. grass-legume pastures suggested that sources of grass N are affected by pasture composition. Furthermore, low δ15N found in some grass-alone pastures, indicate that other N sources apart from soil mineral N are being exploited. The role of different processes like symbiosis with arbuscular mycorrhiza fungi, biological nitrification inhibition or associative N fixation need to be further studied to provide a more comprehensive interpretation of N exploitation in grass-alone pastures