A modular extension of a finite element contact implementation

The structural mechanics module of the OOFEM finite element software has been developed to include various algorithms for solving contact mechanics problems. After developing small strain contact algorithms in the 2D domain and their extension to large strain applications [1, 2], the present contribution extends the existing framework to the 3D domain. After reviewing the current code and comparing existing solutions found in the literature, we identify the common ground between 2D and 3D applications, then propose and implement the necessary changes and additions to smoothly integrate the 3D support into existing code. Tests and example problems are presented to confirm the functionality of the resulting implementation

The 1987 Chesapeake Bay Agreement: A Model of Intergovernmental and Multi-State Cooperation in Estuary/Coastal Resource Management

The 1980s witnessed an increased awareness of the problems of estuary and coastal water pollution. The medical waste problems of 1988 heightened public awareness of this problem and showed that coastal pollution is not just isolated but rather is a regional problem which requires regional solutions. During the 1980x the Environmental Protection Agency (EPA), and the States of Maryland, Virginia, Pennsylvania, and the District of Columbia worked together to forge two agreements, one in 1983, and more significantly a broader agreement in 1987, in which they agreed to work together to develop specific goals and objectives to address and solve the problems confronting Chesapeake Bay. These agreements are significant because the signatories recognized that the Chesapeake Bay\u27s importance and problems transcend regional boundaries and they committed to managing the Chesapeake Bay as an integrated ecosystem. The 1987 Agreement established a framework for governance through the Chesapeake Executive Council and outline 29 specific commitment strategies, and deadlines, to work towards the protection and restoration of the Bay\u27s significant living resources. This landmark agreement established new initiatives and specific goals, deadlines and objectives for addressing key issues such as nutrient and toxic pollution, the decline of the bay\u27s aquatic resources, population growth and land use. All objectives which will set the course of efforts over the next several years

FINITE ELEMENT IMPLEMENTATION OF GEOMETRICALLY NONLINEAR CONTACT

The OOFEM finite element software has been recently updated to include contact algorithms for small strain applications. In this work, we attempt to extend the contact algorithms to large strain problems. Reviewing the current code and comparing it with approaches encountered in literature, we arrive at a specific algorithmic solution and integrate it into the current code base. The current code is explained, the necessary extensions are derived and documented, and the algorithmic changes are described. Tests confirm the functionality and quadratic rate of convergence of the proposed implementation

Thermal analysis of grapevine shoot tips during dehydration and vitrification

The wider use of cryopreservation methods for conservation of plant genetic resources is limited by a sensitivity of different genotypes to specific procedures. Thermal analysis can improve routine use of these methods, by means of determination of melting point and proportion of freezable water after dehydration at each step of the cryoprotocol. Changes in these characteristics during explants dehydration were compared with changes in their viability in three grapevine varieties ('Blussard modry', 'Portugal modry' and 'Kerner'). The highest sensitivity to dehydration was found in the variety 'Kerner'. The proportion of freezable water during dehydration was affected mostly by cryoprotective solutions and partly by genotype. Tested protocol could allow using the cryopreservation procedure for preservation of grapevine variety with different sensitivity to dehydration. It was demonstrated that thermal analysis was a useful tool to validate cryoprotective solutions used for grapevine cryoconservation

Methods of Thermal Analysis as a Tool to Develop Cryopreservation Protocols of Vegetatively Propagated Crops

Cryopreservation is considered to be a reliable biotechnological tool for the long-term conservation of vegetatively propagated plant germplasm. The technique is based on freezing plant tissues at an ultralow temperature. However, high water content in plant tissue can result in injury during the cooling and thawing processes. Water behavior in the process of cryopreservation can be assessed by the use of thermal analysis method. This chapter demonstrates how the use of heat flux-type differential scanning calorimetry (DSC) thermal analysis methods such as standard DSC, temperature-modulated DSC (TMDSC), and quasi-isothermal temperature-modulated DSC (QITMDSC) can be used to assess the amount of freezable water and verify if the tissue being used has reached glass transition as well as analyzing the thermal events during cooling and freezing to reduce crystallization and damage by frost. Here, you can find a guide on how these thermal analysis methods can be applied, through concrete examples of each method and their use in the development of a more reliable and precise cryopreservation protocol for vegetatively propagated plant species