Search results for "Geology"

Numerical analysis of masonry structures via interface models

2001

The present paper is devoted to the theoretical formulation and numerical implementation of an interface model suitable to simulate the behavior of mortar joints in masonry structures. The interface laws are formulated in the framework of elasto-plasticity for non-standard materials in order to simulate the softening response which occurs along the decohesion process in presence of shear and tension tractions. A variable material dilatancy parameter is introduced together with a further geometrical dilatancy related to the roughness of contact surfaces after joint fracture. An asperity model is adopted with the aim to describe the evolution of the contact surface shape during the loss of co…

Validation of a Shear Model for RC and Hybrid Beams with Two Different Inclinations of Transversal Reinforcement

2016

The validation of an analytical model recently proposed for evaluation of the shear capacity in Reinforced Concrete (RC) beams containing multiple inclination of transverse stirrups is presented. The model is a suitable extension of that currently proposed in Eurocode 2 for the evaluation of the shear resistance, and it is derived by means of the the variable-inclination stress-field theory based on Nielsen’s plastic approach. Experimental and numerical data available in the literature on Hybrid Steel-Trussed Concrete Beams (HSTCBs) are used for model validation and result discussion. Finally, also the comparison with a different analytical approach for the assessment of the shear resistanc…

Welfare, Home Market Effects, and Horizontal Foreign Direct Investment

2005

We investigate the spatial distribution and organization of an imperfectly competitive industry when firms may choose to operate more than a single production unit. Focusing on a short-run setting with a fixed mass of firms, we fully characterize the spatial equilibria analytically. Comparing the equilibrium and the first-best, we show that both organizational and spatial inefficiencies may arise. In particular, when fixed costs are low enough the market outcome may well lead to overinvestment and, therefore, to too many multinationals operating from a social point of view. Furthermore, once multinationals are taken into account, the market outcome may well lead too little agglomeration.

Coupled petrological-geodynamical modeling of a compositionally heterogeneous mantle plume

2018

Abstract Self-consistent geodynamic modeling that includes melting is challenging as the chemistry of the source rocks continuously changes as a result of melt extraction. Here, we describe a new method to study the interaction between physical and chemical processes in an uprising heterogeneous mantle plume by combining a geodynamic code with a thermodynamic modeling approach for magma generation and evolution. We pre-computed hundreds of phase diagrams, each of them for a different chemical system. After melt is extracted, the phase diagram with the closest bulk rock chemistry to the depleted source rock is updated locally. The petrological evolution of rocks is tracked via evolving chemi…

Mapping Sediment Accumulation Rate by using Volume magnetic Susceptibility Core Correlation in a contaminated Bay (Lake Geneva, Switzerland)

2003

The Bay of Vidy is the most contaminated area of Lake Geneva: contamination is caused by the effluent of the sewage treatment plant (STP) of the City of Lausanne. The implementation of a chemical stage in the treatment plant to remove phosphorus using FeC13 in 1971 is indirectly recorded in the lake sediments by a strong and sharp increase in the volume magnetic susceptibility (VMS) signal. A total of 43 sediment cores have been retrieved and measured for VMS. The synchronism of the VMS signal increase and its relation to the implementation of the P-removal stage in the STP has been shown in seven 137Cs-dated sediment cores. The VMS signal has been used to date by stratigraphie correlation …

Cladistic analysis of the Middle Jurassic ammonite radiation

2004

Cladistic analysis of the Middle Jurassic ammonite radiation shows how the Aalenian-age ancestral stock, known variously as the Hammatocerataceae or Hammatoceratinae, gave rise to numerous new groups in Bajocian times. Cladistic analysis shows this ancestral stock is not a single lineage but two: the ‘Erycites group’, which gave rise to the Stephanocerataceae, and the ‘Hammatoceras group’, from which all other Bajocian groups derived.

Age and spatial structure of natural Pinus sylvestris stands in Latvia

2005

Abstract The age and spatial structure of six natural old growth Pinus sylvestris stands in Latvia were investigated, to attempt to identify retrospectively the past features of development. In each stand, one or two plots of size 200–900 m2 were established. Tree locations were mapped, stem diameter was measured, and tree age was determined from cores or by counting branch whorls. Tree distribution was assessed by Ripley's K function. A clumped spatial pattern was shown for P. sylvestris younger than 100 years. The temporal patterns of establishment could be partly linked to favourable climatic periods. The major disturbance affecting pine stands along the coast was windblown sand, which p…

Tree rings and volcanic cooling

2012

Brief Introduction to Probability Distributions

2014

There is a great deal of uncertainty in any project. That is, data is seldom absolutely reliable and exact, since there is never certainty about duration of tasks, price variations, effect on the environment, etc., to say nothing about those aspects which are external to the project and for which the project developer has no control, such as weather conditions, demand, stock fluctuations, inflation, supplier’s delays, etc. It is believed that many projects are not completed in time and finish with cost overrun, because in their preparation, data is taken as unquestionable, and then actual conditions show that it is not precisely the case. For this reason the uncertainty aspect has to be con…

Shareholder Wealth Effects of Women on Boards Promoting Policies: Evidence from Germany

2017

This study discusses differences in the effectiveness of voluntary and mandatory policies promoting women on boards and their potential effects on stock price returns. Furthermore, it classifies the announcements of the policy proposals discussed in Germany and analyzes their impact using event study methodology. The event date identification follows a two-step procedure employing search engine query data from GoogleTrends and traditional search methods using Lexis-Nexis and newspapers. One key event produces negative significant cumulative abnormal stock returns (CAR) of approximately 1.3 percentage points. Further regression analysis of the CAR reveals that the share of women on the super…