Fatigue crack growth in a particulate TiB2 reinforced powder metallurgy iron-based composite

Fatigue crack growth behavior has been examined in a particulate titanium diboride (TiB2)–reinforced iron-based composite that had been produced via a mechanical alloying process. Comparison with equivalent unreinforced material indicated that fatigue crack growth resistance in the composite was superior to monolithic matrix material in the near-threshold regime. The composite exhibited relatively low crack closure levels at threshold, indicative of a high intrinsic (effective) threshold growth resistance compared to the unreinforced iron. The lower closure levels of the composite were consistent with reduced fracture surface asperity sizes, attributable to the reinforcement particles limiting the effective slip distance for stage I–type facet formation. The observed shielding behavior was rationalized in terms of recent finite-element analysis of crack closure in relation to the size of crack wake asperities and the crack-tip plastic zone. The different intrinsic fatigue thresholds of the composite and unreinforced iron were closely consistent with the influences of stiffness and yield strength on cyclic crack-tip opening displacements. Cracks in the composite were generally seen to avoid direct crack-tip–particle interaction

Seasonal facilitative and competitive trade‐offs between shrub seedlings and coastal grasses

Shrub expansion is occurring in grasslands globally and may be impacted by the balance of competition and facilitation with existing grasses. Along the mid‐Atlantic and Gulf coasts, the native shrub Morella cerifera (wax myrtle) is rapidly expanding and displacing other native coastal species. Recent research suggests that much of this expansion is due to warming winter temperatures, as temperatures below −15°C kill M. cerifera. The objective of this project was to understand the importance of species interactions with grasses on the growth and physiology of M. cerifera at the seedling life stage through both field and laboratory experiments. In the field, grasses were removed around seedlings and microclimate and shrub physiology and growth were measured. Seeds and seedlings were experimentally frozen to measure the freeze tolerance at both life stages. We found that grasses provided ~1.3°C insulation to shrubs during winter. A freezing threshold for M. cerifera seedlings was experimentally found between −6°C and −11°C, but seeds remained viable after being frozen to the coldest ecologically relevant temperatures. Seedlings competed for light with grasses during warm months and grew more where grasses were clipped, revealing a trade‐off between winter insulation and summer light competition. Morella cerifera exhibits ecosystem engineering at the seedling stage by significantly reducing summer maximum temperatures. When seedlings are very young (less than one year), grasses appear to improve germination and seedling survival. These phenomena enable rapid expansion of M. cerifera across the landscape and likely inform shrub expansion mechanisms in other systems. Although seedlings are small and relatively vulnerable, this life stage appears to have significant implications for ecosystem trajectory in grasslands undergoing shrub encroachment

Maltreated children in the Looked After System: a comparison of outcomes for those who go home and those who do not

This project focuses on the consequences of decisions to reunify children who had entered the looked-after system for abuse or neglect. It compares the progress and outcomes of a sample of maltreated children who either went home or remained in the looked-after system

Effects of footwear variations on three-dimensional kinematics and tibial accelerations of specific movements in American football

American football is associated with a high rate of non-contact chronic injuries. Players are able to select from both high and low cut footwear. The aim of the current investigation was to examine the influence of high and low cut American football specific footwear on tibial accelerations and three-dimensional (3D) kinematics during three sport specific movements. Twelve male American football players performed three movements, run, cut and vertical jump whilst wearing both low and high cut footwear. 3D kinematics of the lower extremities were measured using an eight-camera motion analysis system alongside tibial acceleration parameters which were obtained using a shank mounted accelerometer. Tibial acceleration and 3D kinematic differences between the different footwear were examined using either repeated measures or Friedman’s ANOVA. Tibial accelerations were significantly greater in the low cut footwear in comparison to the high cut footwear for the run and cut movements. In addition, peak ankle eversion and tibial internal rotation parameters were shown to be significantly greater in the low cut footwear in the running and cutting movement conditions. The current study indicates that the utilization of low cut American football footwear for training/performance may place American footballers at increased risk from chronic injuries

From revelry to alchemy : six lenses for interpreting theatre for young Australian audiences

University of Technology, Sydney. Faculty of Arts and Social Sciences.This thesis analyses theatre for young audiences as an aesthetic artform in and of itself. Focusing specifically on the moment of live performance, it proposes six interpretive lenses as systems of signification that facilitate understandings of how performances created essentially for children offer important multi-layered experiences for their audiences. Reflecting on the dual roles of theatre as both art and communication, the study challenges the polarised notion that such work exists solely as either a teaching tool or light entertainment. The artistic codes proposed as part of this research have been developed over twenty years of personal experience creating theatre for children and may be considered as constituting what could be called a poetics of children’s theatre. The six codes are: 1. Revelry, the code that aims to communicate a raucous sense of euphoric, cathartic energy and unity through audience participation, carnivalesque laughter and fear. 2. Enchantment, the code that communicates a sense of soothing and surrender to a sense of sublime wonder and hope. 3. Instruction, the code that teaches. 4. Identity, the code that aims to connect on a personal level, in which individuals recognise themselves or something of their own lives. . 5. Enlightenment, the code that shows diversity and critical thinking about philosophical and social issues. 6. Alchemy, the code of stimulation that seeks to communicate change; aiming to grow the imagination and inspire a sense of self-belief. Findings show that whilst theatre for young audiences can be both educational and diversionary, it also provides in-depth works that provide complex encounters. Thus theatre for young people is an enriching medium for its audiences of all ages

Quantum repeaters with individual rare-earth ions at telecommunication wavelengths

We present a quantum repeater scheme that is based on individual erbium and europium ions. Erbium ions are attractive because they emit photons at telecommunication wavelength, while europium ions offer exceptional spin coherence for long-term storage. Entanglement between distant erbium ions is created by photon detection. The photon emission rate of each erbium ion is enhanced by a microcavity with high Purcell factor, as has recently been demonstrated. Entanglement is then transferred to nearby europium ions for storage. Gate operations between nearby ions are performed using dynamically controlled electric-dipole coupling. These gate operations allow entanglement swapping to be employed in order to extend the distance over which entanglement is distributed. The deterministic character of the gate operations allows improved entanglement distribution rates in comparison to atomic ensemble-based protocols. We also propose an approach that utilizes multiplexing in order to enhance the entanglement distribution rate.Comment: 13 pages, 4 figure

Simulation of the channelling of ions from MeV C60 in crystalline solids

Simulations were performed describing the motion and breakup of energetic C60 ions interacting with crystalline targets. A hybrid algorithm was used that employs a binary collision model for the scattering of the carbon ions by the atoms of the solid, and molecular dynamics for the Coulomb interactions of the 60 carbon ions with one another. For the case of yttrium iron garnet (YIG), directions such as [1 1 0], [1 0 0], [0 1 0] and [0 0 1] demonstrate channelling for a large fraction of the C ions. For directions such as [1 1 1], [2 1 1] and [7 5 3] the trajectories show no more channelling than for random directions. The effects of tilt, shielding and wake-field interactions were investigated for YIG and α-quartz

Tripartite Entanglement versus Tripartite Nonlocality in Three-Qubit Greenberger-Horne-Zeilinger-Class States

We analyze the relationship between tripartite entanglement and genuine tripartite nonlocality for three-qubit pure states in the Greenberger-Horne-Zeilinger class. We consider a family of states known as the generalized Greenberger-Horne-Zeilinger states and derive an analytical expression relating the three-tangle, which quantifies tripartite entanglement, to the Svetlichny inequality, which is a Bell-type inequality that is violated only when all three qubits are nonlocally correlated. We show that states with three-tangle less than 1/2 do not violate the Svetlichny inequality. On the other hand, a set of states known as the maximal slice states does violate the Svetlichny inequality, and exactly analogous to the two-qubit case, the amount of violation is directly related to the degree of tripartite entanglement.We discuss further interesting properties of the generalized Greenberger-Horne-Zeilinger and maximal slice states

Evidence for O(2) universality at the finite temperature transition for lattice QCD with 2 flavours of massless staggered quarks

We simulate lattice QCD with 2 flavours of massless quarks on lattices of temporal extent N_t=8, to study the finite temperature transition from hadronic matter to a quark-gluon plasma. A modified action which incorporates an irrelevant chiral 4-fermion interaction is used, which allows simulations at zero quark mass. We obtain excellent fits of the chiral condensates to the magnetizations of a 3-dimensional O(2) spin model on lattices small enough to model the finite size effects. This gives predictions for correlation lengths and chiral susceptibilities from the corresponding spin-model quantities. These are in good agreement with our measurements over the relevant range of parameters. Binder cumulants are measured, but the errors are too large to draw definite conclusions. From the properties of the O(2) spin model on the relatively small lattices with which we fit our `data', we can see why earlier attempts to fit staggered lattice data to leading-order infinite-volume scaling functions, as well as finite size scaling studies, failed and led to erroneous conclusions.Comment: 27 pages, Latex with 10 postscript figures. Some of the discussions have been expanded to satisfy a referee. Typographical errors were correcte

United States Pharmacopeia (USP) \u3c800\u3e Standards: Increasing Compliance of Safe Handling and Proper Administration of USP General Chapter \u3c800\u3e Drugs

Problem: United States Pharmacopeia (USP) developed a set of standards to minimize exposure risks to patients, healthcare workers, and the environment when preparing, handling, and administering hazardous drugs (HDs) known as USP \u3c800\u3e HDs. The guidelines became effective December 1, 2019, but additional information is needed to ensure healthcare personnel are complying with the standards. Context: Two medical surgical units from Hospital A were included in this project. Currently mandatory online modules about USP \u3c800\u3e standards are provided annually to every healthcare worker, but it is unknown if the policies and procedures are being followed appropriately. Interventions: Active and passive observations as well as inspections were used to compile data regarding the compliance of USP \u3c800\u3e standards of both healthcare workers and within the hospital setting. Surveys were conducted through informal ‘elbow-to-elbow’ interviews with hospital employees, primarily nurses, to collect subjective evidence. Measures: The measures can be divided into two categories: personnel and atmosphere compliance. Measures to determine personnel compliance include determining a current level of knowledge and comfortability, collecting self-reported compliance to the standards, and observing personal protective equipment (PPE) donning and doffing techniques. Atmosphere compliances are measured by calculating the total number of patients taking USP \u3c800\u3e HDs, evaluating the accuracy and efficiency of notifications in the electronic health record (EHR), documenting the frequency of correctly displayed signage on patient doors, and assessing supplies located on USP \u3c800\u3e carts. Results: Nurses self-reported a high level of knowledge and comfortability regarding safe handling and administration practices of USP \u3c800\u3e HDs. However, despite over a quarter of the patients being on at least one USP \u3c800\u3e drug, compliance with proper PPE recommendations, signage, and accessibility of supplies was low. Conclusions: This project determined that healthcare employees at Hospital A are not consistently following the recommended USP \u3c800\u3e standards. It also provided a baseline knowledge for future education to ensure safety of patients, healthcare employees, and the environment