Unified model of hyperthermia via hysteresis heating in systems of interacting magnetic nanoparticles

We present a general study of frequency and magnetic field dependence of the specific heat power produced during field-driven hysteresis cycles in magnetic nanoparticles with relevance to hyperthermia applications in biomedicine. Employing a kinetic Monte-Carlo method with natural time scales allows us to go beyond the assumptions of small driving field amplitudes and negligible inter-particle interactions, which are fundamental to applicability of the standard approach based on linear response theory. The method captures the superparamagnetic and fully hysteretic regimes and the transition between them. Our results reveal unexpected dipolar interaction-induced enhancement or suppression of the specific heat power, dependent on the intrinsic statistical properties of particles, which cannot be accounted for by the standard theory. Although the actual heating power is difficult to predict because of the effects of interactions, optimum heating is in the transition region between the superparamagnetic and fully hysteretic regimes

Frio brine sequestration pilot in the Texas Gulf Coast

A field experiment to pioneer CO2 injection for sequestration in a brine-bearing sandstone-shale sequence in the Texas Gulf Coast, USA, is in the preinjection modeling and planning phase. Innovations in this experiment include (1) CO2 injection into high-volume highpermeability rocks that have storage capacity sufficient to impact greenhouse gas emissions, (2) injection into a setting lacking the complications introduced by hydrocarbons and perturbations resulting from production and secondary recovery, and (3) intensive pre-, syn-, and post-injection monitoring and modeling for validation of the effectiveness of sequestration. The experiment is designed to provide a rapid increase in information from a small-volume and short-duration injection.Bureau of Economic Geolog

Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments

Thermally activated magnetization decay is studied in ensembles of clusters of interacting dipolar moments by applying the master-equation formalism, as a model of thermal relaxation in systems of interacting single-domain ferromagnetic particles. Solving the associated master-equation reveals a breakdown of the energy barrier picture depending on the geometrical symmetry of structures. Deviations are most pronounced for reduced symmetry and result in a strong interaction dependence of relaxation rates on the memory of system initialization. A simple two-state system description of an ensemble of clusters is developed which accounts for the observed anomalies. These results follow from a semi-analytical treatment, and are fully supported by kinetic Monte-Carlo simulations.Comment: 9 pages, 6 figure

Continuous subcutaneous insulin infusion therapy and multiple daily insulin injections in type 1 diabetes mellitus: a comparative overview and future horizons.

INTRODUCTION: Continuous subcutaneous insulin infusion (CSII) therapy is currently accepted as a treatment strategy for type 1 diabetes. Transition from multiple daily injection therapy (MDI; including basal-bolus regimens) to CSII is based on expectations of better metabolic control and fewer hypoglycaemic events. Evidence to date has not been always conclusive. AREAS COVERED: Evidence for CSII and MDI in terms of glycaemic control, hypoglycaemia and psychosocial outcomes is reviewed in the adult and paediatric population with type 1 diabetes. Findings from studies on threshold-based insulin pump suspension and predictive low glucose management (PLGM) are outlined. Limitations of current CSII application and future technological developments are discussed. EXPERT OPINION: Glycaemic control and quality of life (QOL) may be improved by CSII compared to MDI depending on baseline HbA1c and hypoglycaemia rates. Future studies are expected to provide evidence on clinical and cost effectiveness in those who will benefit the most. Training, structured education and support are important to benefit from CSII. Novel technological approaches linking continuous glucose monitoring (CGM) and CSII may help mitigate against frequent hypoglycaemia in those at risk. Development of glucose-responsive automated closed-loop insulin delivery systems may reduce the burden of disease management and improve outcomes in type 1 diabetes.Support for the research work by JDRF, Seventh Framework Programme of the European Union, Diabetes UK, National Institute for Health Research Cambridge Biomedical Research Centre

Sociomateriality and IS Identity

Challenges to identifying the information systems (IS) field originate within the community, from external institutional forces, from the change in technology, from the emergence of new phenomena, and finally, from the changing understanding of what a “field” or “discipline” entails. In this study we trace the historiography of the IS field to illustrate sources of confusion arising from deeply held assumptions regarding the formation and legitimacy of IS identity. By introducing the identity of IS as a “human science” as opposed to that of a natural science, we illuminate an interstitial gap in knowledge which IS inhabits. To address this gap, we posit sociomateriality as a perspective that offers IS a distinct identity as an academically and socially relevant field by uncovering and enabling research into the entanglement of humans, information, and technologies

Capacity investigation of brine-bearing sands of the Frio Formation for geologic sequestration of CO2

The capacity of fluvial brine-bearing formations to sequester CO2 is investigated using numerical simulations of CO2 injection and storage. Capacity is defined as the volume fraction of the subsurface available for CO2 storage and is conceptualized as a product of factors that account for two-phase flow and transport processes, formation geometry, formation heterogeneity, and formation porosity. The space and time domains used to define capacity must be chosen with care to obtain meaningful results, especially when comparing different authors’ work. Physical factors that impact capacity include permeability anisotropy and relative permeability to CO2, brine/CO2 density and viscosity ratios, the shape of the trapping structure, formation porosity and the presence of low permeability layering.National Energy Technology LaboratoryBureau of Economic Geolog

Frio pilot in CO2 sequestration in brine-bearing sandstones: The University of Texas at Austin, Bureau of Economic Geology, report to the Texas Commission on Environmental Quality to accompany a class V application for an experimental technology pilot injection well.

GEOSEQ project (LBNL, LLNL, ORNL), NETL, Schlumberger–Doll Research Center, Transpetco, Sandia TechnologiesJackson School of Geoscience

Continued evaluation of potential for geologic storage of carbon dioxide in the southeastern United States

Southern States Energy Board Duke Energy Santee Cooper Power Southern CompanyBureau of Economic Geolog

Potential Sinks for Geologic Storage of CO2 Generated in the Carolinas

This document summarizes a scoping study of the current state of knowledge of carbon storage options for our geographic area. The focus is on one aspect of carbon capture and storage—identification of deep saline aquifers in which carbon dioxide (CO2 ) generated in the Carolinas might be stored. The study does not address other aspects of CO2 storage projects, such as capture and compression of the gas, well construction and development, or injection. Transport of CO2 is touched upon in this study but has not been fully addressed. The information contained in this document is primarily from review of published geologic literature and unpublished data. No field data collection has been completed as part of this study. Further work will be necessary to increase confidence in the suitability of the potential CO2 storage sites identified in this report. This study does not address the regulatory, environmental, or public policy issues associated with carbon storage, which are under development at this time.Duke Energy, Progress Energy, Santee Cooper Power, South Carolina Electric and Gas, Electric Power Research Institute (EPRI), Southern States Energy Board (SSEB)Bureau of Economic Geolog