Spherical solid-propellant rocket motor Patent

Spherical solid propellant rocket engine desig

High-throughput in-situ characterization and modelling of precipitation kinetics in compositionally graded alloys

The development of new engineering alloy chemistries is a time consuming and iterative process. A necessary step is characterization of the nano/microstructure to provide a link between the processing and properties of each alloy chemistry considered. One approach to accelerate the identification of optimal chemistries is to use samples containing a gradient in composition, ie. combinatorial samples, and to investigate many different chemistries at the same time. However, for engineering alloys, the final properties depend not only on chemistry but also on the path of microstructure development which necessitates characterization of microstructure evolution for each chemistry. In this contribution we demonstrate an approach that allows for the in-situ, nanoscale characterization of the precipitate structures in alloys, as a function of aging time, in combinatorial samples containing a composition gradient. The approach uses small angle x-ray scattering (SAXS) at a synchrotron beamline. The Cu-Co system is used for the proof-of-concept and the combinatorial samples prepared contain a gradient in Co from 0% to 2%. These samples are aged at temperatures between 450{\textdegree}C and 550{\textdegree}C and the precipitate structures (precipitate size, volume fraction and number density) all along the composition gradient are simultaneously monitored as a function of time. This large dataset is used to test the applicability and robustness of a conventional class model for precipitation that considers concurrent nucleation, growth and coarsening and the ability of the model to describe such a large dataset.Comment: Published in Acta Materiali

Volumetric Flow Measurement for Irrigation District Turnouts

Technical assistance related to irrigation district turnout flow/volumetric measurement is provided by ITRC on behalf of California Dept. of Water Resources, USBR, and BIA irrigation projects. Throughout that work, it was apparent there was a need to organize well-established information as well as to provide new insights into irrigation flow measurement. The target audiences are irrigation districts and others who want to improve measurement accuracy for irrigation flow rates and volumetric deliveries to meet regulations, improve the efficiency of ditchriders (system operators), and provide equity and transparency to farmers and managers. The focus of this publication is on turnouts (deliveries) to fields or to relatively small groups of fields, rather than flow measurement on large canals. Dozens of excellent publications are available on the topic of flow measurement. This publication is not meant to replace those other references. Rather, it supplements those with two important types of information: 1. An overview of irrigation turnout flow measurement devices and situations for the western US. 2. Practical insights on the installation and operation of various devices

Geodynamic setting and origin of the Oman/UAE ophiolite

The ~500km-long mid-Cretaceous Semail nappe of the Sultanate of Oman and UAE (henceforth referred to as the Oman ophiolite) is the largest and best-preserved ophiolite complex known. It is of particular importance because it is generally believed to have an internal structure and composition closely comparable to that of crust formed at the present-day East Pacific Rise (EPR), making it our only known on-land analogue for ocean lithosphere formed at a fast spreading rate. On the basis of this assumption Oman has long played a pivotal role in guiding our conceptual understanding of fast-spreading ridge processes, as modern fast-spread ocean crust is largely inaccessible

The variation in composition of ultramafic rocks and the effect on their suitability for carbon dioxide sequestration by mineralization following acid leaching

Carbon dioxide capture and storage by mineralization has been proposed as a possible technology to contribute to the reduction of global CO2 levels. A main candidate as a feed material, to supply Mg cations for combination with CO2 to form carbonate, is the family of ultramafi c rocks, Mgrich silicate rocks with a range of naturally occurring mineralogical compositions. A classifi cation scheme is described and a diagram is proposed to display the full range of both fresh and altered ultramafi c rock compositions. This is particularly for the benefi t of technologists to raise the awareness of the variation in possible feedstock materials. A systematic set of acid leaching experiments, in the presence of recyclable ammonium bisulphate, has been carried out covering the range of ultramafi c rock compositions. The results show that lizardite serpentinite releases the most Mg with 78% removed after 1 h, while an olivine rock (dunite) gave 55% and serpentinized peridotites intermediate values. Antigorite serpentinite only released 40% and pyroxene- and amphibole-rich rocks only 25%, showing they are unsuitable for the acid leaching method used. This wide variation in rock compositions highlights the necessity for accurate mineralogical characterization of potential resources and for technologists to be aware of the impact of feed material variations on process effi ciency and development

Medical decision making using knowledge of patient identification as Aboriginal or Torres Strait Islander: what do medical students think?

Objective Best-practices guidelines require Australian health practitioners to ask all patients “are you [is the person] of Aboriginal and/or Torres Strait Islander origin?”. The present study investigated medical student attitudes regarding medical decisions made after asking this standard status question. Methods A hypothetical interaction between a doctor and an Aboriginal patient was presented in a pen-and-paper questionnaire in which: (1) the doctor considered (or did not consider) the patient’s Indigenous status relevant to make a medical diagnosis, and (2) the doctor registered (or did not register) the patient for the Closing the Gap PBS co-payment. Participants were first- and second-year medical students at the Australian National University who evaluated the doctor’s decisions against 20 attributes characterising professionalism and prejudice. Results Students evaluated the doctor more favourably when the doctor registered the patient for the co-payment and when the doctor did not consider Indigenous status relevant to making a medical diagnosis. Conclusions Encouragingly, medical students recognise that withholding registration for the co-payment is unprofessional. At the same time, medical students clearly do not think medical diagnoses should be made using the knowledge a patient identifies as Aboriginal. Implications With the continual development of policy and guidelines (and the prospect of diagnostic guidelines) to improve Aboriginal and Torres Strait Islander health, students and practitioners must understand how to use this knowledge of a patient’s status to benefit health outcomes