Thixotropic behavior of metal-containing coordination polymers: Melt viscosity of neutral aliphatic polyesters with Zn carboxylates

The viscosity behavior of polymer melts containing complexes formed between the neutralized polyester poly(diethylene glycol-co-succinic acid) and Zn acetates is discussed. The melt viscosity of these materials increases with the concentration of metal ions, and shows strong thixotropy and shear thinning. This behavior is attributed to the formation of coordination bonds between the electron donor groups within the polyester chain, and empty coordination sites of the various Zn acetate salts. The coordination complexes were obtained in situ in the polymer melt, which contains well-dispersed ZnO, by adding an equimolar amount of CH3COOH. It is proposed that the shear applied to the polymer melt destroys the polar network of the coordination polymer at a rate that is greater than the rate of reformation of the coordination bonds for the sample returning back to equilibrium, following a shear deformation

An improved Monte Carlo study of coherent scattering effects of low energy charged particle transport in Percus-Yevick liquids

We generalize a simple Monte Carlo (MC) model for dilute gases to consider the transport behavior of positrons and electrons in Percus-Yevick model liquids under highly non-equilibrium conditions, accounting rigorously for coherent scattering processes. The procedure extends an existing technique [Wojcik and Tachiya, Chem. Phys. Lett. 363, 3--4 (1992)], using the static structure factor to account for the altered anisotropy of coherent scattering in structured material. We identify the effects of the approximation used in the original method, and develop a modified method that does not require that approximation. We also present an enhanced MC technique that has been designed to improve the accuracy and flexibility of simulations in spatially-varying electric fields. All of the results are found to be in excellent agreement with an independent multi-term Boltzmann equation solution, providing benchmarks for future transport models in liquids and structured systems.Comment: 27 pages, 6 figure

Workbook for prioritizing petroleum industry exploration and production sites for remediation

The purpose of this Workbook is to provide a screening-level method for prioritizing petroleum exploration and production sites for remediation that is based on readily available information, but which does not require a full characterization of the sites being evaluated. The process draws heavily from the Canadian National Classification System for Contaminated Sites, and fits into the framework for ecological risk assessment provided in guidance from the US Environmental Protection Agency. Using this approach, scoring guidelines are provided for a number of Evaluation Factors relating to: (1) the contaminants present at the site; (2) the potential exposure pathways for these contaminants; and (3) the potential receptors of those contaminants. The process therefore incorporates a risk-based corrective action (RBCA) framework to estimate the relative threat posed by a site to human health and to ecological systems. Physical (non-toxic) disturbance factors have also been incorporated into the process. It should also be noted that the process described in this Workbook has not yet been field tested at petroleum E and P sites. The first logical step in the field testing of this process is to apply the method at a small number of sites to assess the availability of the information that is needed to score each evaluation factor. Following this evaluation, the Workbook process should be applied at a series of sites to determine the effectiveness of the process at ranking sites according to their relative need for remediation. Upon completion of these tests, the Workbook should be revised to reflect the findings of the field tests

Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?

Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus is on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern

Boltzmann's equation at 150: Traditional and modern solution techniques for charged particles in neutral gases

Seminal gas discharge experiments of the late 19th and early 20th centuries laid the foundations of modern physics, and the influence of this "golden era" continues to resonate well into the 21st century through modern technologies, medical applications, and fundamental scientific investigations. Key to this continuing success story has been the kinetic equation formulated by Ludwig Boltzmann in 1872, which provides the theoretical foundations necessary for analyzing such highly non-equilibrium situations. However, as discussed here, the full potential of Boltzmann's equation has been realized only in the past 50 years or so, with modern computing power and analytical techniques facilitating accurate solutions for various types of charged particles (ions, electrons, positrons, and muons) in gases. Our example of thermalization of electrons in xenon gas highlights the need for such accurate methods-the traditional Lorentz approximation is shown to be hopelessly inadequate. We then discuss the emerging role of Boltzmann's equation in determining cross sections by inverting measured swarm experiment transport coefficient data using machine learning with artificial neural networks

On the approximation of transport properties in structured materials using momentum-transfer theory

In this paper, we present a fluid model for electrons and positrons in structured and soft-condensed matter utilizing dilute gas phase cross-sections together with a structure factor for the medium. Generalizations of the Wannier energy and Einstein (Nernst–Townsend) relations to account for coherent scattering effects present in soft-condensed matter are presented along with new expressions directly relating transport properties in the dilute gas and the structured matter phases. The theory is applied to electrons in a benchmark Percus–Yevick model and positrons in liquid argon, and the accuracy is tested against a multi-term solution of Boltzmann's equation (White and Robson 2011 Phys. Rev. E 84 031125)

Characterization of Naturally Occurring Radioactive Material (NORM) in Oil and Gas Industry Equipment and Wastes

This Sampling and Analysis (S and A) Plan was developed for the NORM Characterization Program, and describes the information to be gained through the program, how the required information is to be collected, and the anticipated form and content of the final data. The S and A Plan provides detailed procedures describing the work to be performed, how and why the work will be performed, and who will be responsible for conducting the various aspects of the work. The S and A Plan has been prepared with input from all parties involved with the program. Where appropriate, portions of the procedures described in the S and A Plan will be field tested by personnel of the Idaho National Engineering Laboratory (INEL) and the Grand Junction Project Office (GJPO), as well as representatives of the cosponsor organizations prior to their use in the field

Crossing lines: a multidisciplinary framework for assessing connectivity of hammerhead sharks across jurisdictional boundaries

Conservation and management of migratory species can be complex and challenging. International agreements such as the Convention on Migratory Species (CMS) provide policy frameworks, but assessments and management can be hampered by lack of data and tractable mechanisms to integrate disparate datasets. An assessment of scalloped (Sphyrna lewini) and great (Sphyrna mokarran) hammerhead population structure and connectivity across northern Australia, Indonesia and Papua New Guinea (PNG) was conducted to inform management responses to CMS and Convention on International Trade in Endangered Species listings of these species. An Integrated Assessment Framework (IAF) was devised to systematically incorporate data across jurisdictions and create a regional synopsis, and amalgamated a suite of data from the Australasian region. Scalloped hammerhead populations are segregated by sex and size, with Australian populations dominated by juveniles and small adult males, while Indonesian and PNG populations included large adult females. The IAF process introduced genetic and tagging data to produce conceptual models of stock structure and movement. Several hypotheses were produced to explain stock structure and movement patterns, but more data are needed to identify the most likely hypothesis. This study demonstrates a process for assessing migratory species connectivity and highlights priority areas for hammerhead management and research

Modelling hand gestures to test leap motion controlled applications

Programs that use a Natural User Interface (NUI) are not controlled with a mouse and keyboard, but through input devices that monitor the user’s body movements. Manually testing applications through such interfaces is time-consuming. Generating realistic test data automatically is also challenging, because the input is a complex data structure that represents real body structures and movements. Previously, it has been shown that models learned from user interactions can be used to generate tests for NUI applications controlled by the Microsoft Kinect. In this paper, we study the case of the Leap Motion input device, which allows applications to be controlled with hand movements and finger positions, resulting in substantially more complex input data structures. We present a framework to model human hand data interacting with applications, and generate test data automatically from these models. We also evaluate the influence of the training data, as well as the influence of using a single model of the complete user data vs. multiple models for the different aspects of hand movement (e.g., finger positions, hand positions, hand rotations). Experiments on five applications controlled by the Leap Motion demonstrate that our approach generates effective test data. The quality and quantity of the training data used to derive the models is the main factor that determines their effectiveness. On the other hand, the effects of using multiple (as opposed to single) models are minor and application specific