Thermodynamic phase-field model for microstructure with multiple components and phases: the possibility of metastable phases

A diffuse-interface model for microstructure with an arbitrary number of components and phases was developed from basic thermodynamic and kinetic principles and formalized within a variational framework. The model includes a composition gradient energy to capture solute trapping, and is therefore suited for studying phenomena where the width of the interface plays an important role. Derivation of the inhomogeneous free energy functional from a Taylor expansion of homogeneous free energy reveals how the interfacial properties of each component and phase may be specified under a mass constraint. A diffusion potential for components was defined away from the dilute solution limit, and a multi-obstacle barrier function was used to constrain phase fractions. The model was used to simulate solidification via nucleation, premelting at phase boundaries and triple junctions, the intrinsic instability of small particles, and solutal melting resulting from differing diffusivities in solid and liquid. The shape of metastable free energy surfaces is found to play an important role in microstructure evolution and may explain why some systems premelt at phase boundaries and phase triple junctions while others do not.Comment: 14 pages, 8 figure

Pine Needle Abortion Among Cows Grazing Foothill Ranges

The frequent occurrence of pine needle abortion in cattle grazing foothill ranges having tree stands of ponderosa pine (Pinus ponderosa) causes management problems for many ranchers in South Dakota, Wyoming, Colorado, Idaho, and California as well as many areas in Canada. Surveys (1973-75) covering eight counties in western South Dakota and eastern Wyoming indicate the area loss to be approximately 700 calves annually even with good management to prevent pregnant cows from consuming pine needles. Loss of the cow as well from infection of a retained placenta is not unusual. In 1975, for example, one rancher lost 38 calves from pine needle abortion and 12 of the cows thereafter from infection resulting fram retained placentas. Investigations are in progress to isolate and identify the causative factor in pine needles. Ranchers assumed the factor to be present in needles only during late winter and early spring since this was the period when abortions were noted with cattle

Resource applications of Geographic Information Systems: the development of the roads layer for the Siuslaw National Forest

The U.S. Forest Service has been actively using new information technologies since the formation of the agency. Currently forests are using Geographic Information Systems (GIS) for mapping, data storage, modeling, and spatial analysis. The Siuslaw National Forest has an active GIS with many data layers. A project to correct the errors in the roads layer began in 1996 and involved linking the Transportation Management System Oracle database to the Arclnfo GIS roads layer using a dynamic segmentation process. The updated roads layer is more accurate and has more variables for mapping and analysis. As the Siuslaw has changed from a timber management forest to an ecosystem management forest following the implementation of the President's Northwest Forest Plan, the roads layer has been used for watershed analysis, restoration projects, and for other management purposes. The impacts of roads on forest ecosystems has been widely studied, and restoration activities on the Siuslaw are proving to be successful. The results of these activities and other forest characteristics are stored in the GIS

Estimated dietary phytoestrogen intake and major food sources among women during the year before pregnancy

<p>Abstract</p> <p>Background</p> <p>Phytoestrogens may be associated with a variety of different health outcomes, including outcomes related to reproductive health. Recently published data on phytoestrogen content of a wide range of foods provide an opportunity to improve estimation of dietary phytoestrogen intake.</p> <p>Methods</p> <p>Using the recently published data, we estimated intake among a representative sample of 6,584 women of reproductive age from a multi-site, population-based case-control study, the National Birth Defects Prevention Study (NBDPS). The NBDPS uses a shortened version of the Willett food frequency questionnaire to estimate dietary intake during the year before pregnancy. We estimated intake among NBDPS control mothers.</p> <p>Results</p> <p>Lignans contributed 65% of total phytoestrogen intake; isoflavones, 29%; and coumestrol, 5%. Top contributors to total phytoestrogen intake were vegetables (31%) and fruit (29%); for isoflavones, dairy (33%) and fruit (21%); for lignans, vegetables (40%) and fruit (29%); and for coumestans, fruit (55%) and dairy (18%). Hispanic women had higher phytoestrogen intake than non-Hispanic white or black women. Associations with maternal age and folic acid-containing supplements were more modest but indicated that older mothers and mothers taking supplements had higher intake.</p> <p>Conclusions</p> <p>The advantage of the approach used for the current analysis lies in its utilization of phytoestrogen values derived from a single laboratory that used state-of-the-art measurement techniques. The database we developed can be applied directly to other studies using food frequency questionnaires, especially the Willett questionnaire. The database, combined with consistent dietary intake assessment, provides an opportunity to improve our ability to understand potential associations of phytoestrogen intake with health outcomes.</p

Guidance for Materials 4.0 to interact with a digital twin

The rapid development of new infrastructure programmes requires an accelerated deployment of new materials in new environments. Materials 4.0 is crucial to achieve these goals. The application of digital to the field of materials has been at the forefront of research for many years, but there does not exist a unified means to describe a framework for this area creating pockets of development. This is confounded by the broader expectations of a digital twin (DT) as the possible answer to all these problems. The issue being that there is no accepted definition of a component DT, and what information it should contain and how it can be implemented across the product lifecycle exist. Within this position paper, a clear distinction is made between the “manufacturing DT” and the “component DT”; the former being the starting boundary conditions of the latter. In order to achieve this, we also discuss the introduction of a digital thread as a key concept in passing data through manufacturing and into service. The stages of how to define a framework around the development of DTs from a materials perspective is given, which acknowledges the difference between creating new understanding within academia and the application of this knowledge on a per-component basis in industry. A number of challenges are identified to the broad application of a component DT; all lead to uncertainty in properties and locations, resolving these requires judgments to be made in the provision of safety-dependent materials property data

Review of material modeling and digitalization in industry: barriers and perspectives

Materials modeling technologies are fundamental to explore, understand, and ultimately predict materials behavior. They are essential to solve challenges posed by the need to reduce human impact on the environment. Modeling and simulation of materials behavior have been recognized over the years as fundamental as an asset in industrial R & D, guiding the decision-making process regarding the design or optimization of new products and manufacturing processes. At the same time, it reduces product cost and development time. However, highlighting the revenue brought by using such tools is not trivial, especially because they mainly affect the complex activities such as the innovation process, whose return only becomes available in the long run and it is difficult to measure. This means that the materials modeling field is often overlooked in an industry setting, where it is not integrated in the company workflow. In some cases, modeling provides the potential to capture tacit knowledge preventing the loss of capability in an aging specialist community, that why its industrial integration is important. This paper explores the reason behind this dichotomy, presenting first what it is intended for the modeling process, and the main types used in materials application. The current industrial adoption is reviewed by outlining success stories, economic impact, business uptake, and barriers. Past and current approaches and strategies are also presented and discussed. In prospective, materials modeling plays a key role in developing material-centric industry for sustainable economy, providing physical understating (physics-based models) and fast approaches (data-driven solutions). Digitalization is the mean for the green economy and it needs to push for a more integration at the core of the business of materials modeling