Mesoscale Calculations of the Dynamic Behavior of a Granular Ceramic

Mesoscale calculations have been conducted in order to gain further insight into the dynamic compaction characteristics of granular ceramics. The primary goals of this work are to numerically determine the shock response of granular tungsten carbide and to assess the feasibility of using these results to construct the bulk material Hugoniot. Secondary goals include describing the averaged compaction wave behavior as well as characterizing wave front behavior such as the strain rate versus stress relationship and statistically describing the laterally induced velocity distribution. The mesoscale calculations were able to accurately reproduce the experimentally determined Hugoniot slope but under predicted the zero pressure shock speed by 12%. The averaged compaction wave demonstrated an initial transient stress followed by asymptotic behavior as a function of grain bed distance. The wave front dynamics demonstrate non-Gaussian compaction dynamics in the lateral velocity distribution and a power-law strain rate–stress relationship

INCREASING SELF-INITIATED QUESTION ASKING WITH ADULTS WITH AUTISM USING PIVOTAL RESPONSE TRAINING STRATEGIES AND CONSTANT TIME DELAY

The purpose of this study was to implement pivotal response training (PRT) strategies paired with constant time delay (CTD) to teach an individual with autism spectrum disorder (ASD) and intellectual disability (ID) to self-initiate through question asking. A multiple probe across behaviors design was used to evaluate effectiveness of implementation. Results show that this naturalistic intervention is effective for some questions, while other questions need to be taught in more contrived scenarios

F-106B airplane active control landing gear drop test performance

Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant factors in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteristics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted on series-hydraulic active control nose gear. The experiments involved testing the gear in both passive and active control modes. Results of this investigation show that a series-hydraulic active control gear is feasible and that such a gear is effective in reducing the loads transmitted by the gear to the airframe during ground operations

Linear Forms in Logarithms and Integer Points on Genus-two Curves

We consider a linear form with algebraic coefficients, evaluated at points on the analytic Jacobian of a genus-two curve whose projective coordinates are algebraic. Previous results on the existence of a lower bound of a particular shape are made explicit. We study various properties of Jacobians of genus-two curves, paying particular attention to their embeddings into projective space, and give a method which can be used to find provably all integer points on a genus-two curve. We apply this method to one particular curve by way of example

Soft hands: A mid-career percussion teacher’s professional development journey.

Professional development is an important part of any teaching career. Although it has been investigated within the field of music education, there is limited research on the experiences of mid-career music teachers from a first-person perspective, especially within a conservatory context. In this collaborative self-study, the authors analyze the professional development journey that one of them undertook as she followed a series of snare drum lessons to enhance her practice as a mid-career percussion teacher. Over a period of a year, the first author kept a research journal, working dialogically with a researcher to understand and extend these reflections. Using self-study as a systematic means of inquiry into practice, this article reveals the development of the first author’s practical knowledge and subjective educational theory. Five themes encapsulate the findings: (i) although a learner by nature, going back to basics was a challenge; (ii) reflecting on learning prompted reflection on teaching; (iii) the importance of placing learning in a histori-cal context and wider framework; (iv) taking care of students; and (v) with fresh eyes comes the need to keep focused. In presenting evocative accounts of lived experience, reflective and reflexive commentary, and critical reflection informed by literature, the results and discussion read as a through-composed narrative. This research offers insights to mid-career music teachers and their employers regarding the impact and design of professional development opportunities. It also dem-onstrates an approach to self-study that might be useful to others who want to undertake similar investigations of their practice

Phylogeography of the crown-of-thorns starfish in the Indian Ocean

Background: Understanding the limits and population dynamics of closely related sibling species in the marine realm is particularly relevant in organisms that require management. The crown-of-thorns starfish Acanthaster planci, recently shown to be a species complex of at least four closely related species, is a coral predator infamous for its outbreaks that have devastated reefs throughout much of its Indo-Pacific distribution. Methodology/Principal Findings: In this first Indian Ocean-wide genetic study of a marine organism we investigated the genetic structure and inferred the paleohistory of the two Indian Ocean sister-species of Acanthaster planci using mitochondrial DNA sequence analyses. We suggest that the first of two main diversification events led to the formation of a Southern and Northern Indian Ocean sister-species in the late Pliocene-early Pleistocene. The second led to the formation of two internal clades within each species around the onset of the last interglacial. The subsequent demographic history of the two lineages strongly differed, the Southern Indian Ocean sister-species showing a signature of recent population expansion and hardly any regional structure, whereas the Northern Indian Ocean sister-species apparently maintained a constant size with highly differentiated regional groupings that were asymmetrically connected by gene flow. Conclusions/Significance: Past and present surface circulation patterns in conjunction with ocean primary productivity were identified as the processes most likely to have shaped the genetic structure between and within the two Indian Ocean lineages. This knowledge will help to understand the biological or ecological differences of the two sibling species and therefore aid in developing strategies to manage population outbreaks of this coral predator in the Indian Ocean

Use of an Online Photo Management and Sharing Application to Create a Searchable Digital Dental Radiograph Repository

Problem: Dental radiographs generally display one or more findings/diagnoses, and are linked to a unique set of patient demographics, medical history and other findings not represented by the image. However, this information is not associated with radiographs in any type of meta format, and images are not searchable based on any clinical criteria (1,2). The purpose of this pilot study is to create an online, searchable data repository of dental radiographs to be used for patient care, teaching and research. [See PDF for complete abstract

TRAIT2D: a Software for Quantitative Analysis of Single Particle Diffusion Data

Single particle tracking (SPT) is one of the most widely used tools in optical microscopy to evaluate particle mobility in a variety of situations, including cellular and model membrane dynamics. Recent technological developments, such as Interferometric Scattering microscopy, have allowed recording of long, uninterrupted single particle trajectories at kilohertz framerates. The resulting data, where particles are continuously detected and do not displace much between observations, thereby do not require complex linking algorithms. Moreover, while these measurements offer more details into the short-term diffusion behaviour of the tracked particles, they are also subject to the influence of localisation uncertainties, which are often underestimated by conventional analysis pipelines. we thus developed a Python library, under the name of TRAIT2D (Tracking Analysis Toolbox – 2D version), in order to track particle diffusion at high sampling rates, and analyse the resulting trajectories with an innovative approach. The data analysis pipeline introduced is more localisation-uncertainty aware, and also selects the most appropriate diffusion model for the data provided on a statistical basis. A trajectory simulation platform also allows the user to handily generate trajectories and even synthetic time-lapses to test alternative tracking algorithms and data analysis approaches. A high degree of customisation for the analysis pipeline, for example with the introduction of different diffusion modes, is possible from the source code. Finally, the presence of graphical user interfaces lowers the access barrier for users with little to no programming experience

Composite Membranes Derived from Cellulose and Lignin Sulfonate for Selective Separations and Antifouling Aspects

Cellulose-based membrane materials allow for separations in both aqueous solutions and organic solvents. The addition of nanocomposites into cellulose structure is facilitated through steric interaction and strong hydrogen bonding with the hydroxy groups present within cellulose. An ionic liquid, 1-ethyl-3-methylimidazolium acetate, was used as a solvent for microcrystalline cellulose to incorporate graphene oxide quantum dots into cellulose membranes. In this work, other composite materials such as, iron oxide nanoparticles, polyacrylic acid, and lignin sulfonate have all been uniformly incorporated into cellulose membranes utilizing ionic liquid cosolvents. Integration of iron into cellulose membranes resulted in high selectivity (\u3e 99%) of neutral red and methylene blue model dyes separation over salts with a high permeability of 17 LMH/bar. With non-aqueous (alcohol) solvent, iron–cellulose composite membranes become less selective and more permeable, suggesting the interaction of iron ions cellulose OH groups plays a major role in pore structure. Polyacrylic acid was integrated into cellulose membranes to add pH responsive behavior and capacity for metal ion capture. Calcium capture of 55 mg Ca2+/g membrane was observed for PAA-cellulose membranes. Lignin sulfonate was also incorporated into cellulose membranes to add strong negative charge and a steric barrier to enhance antifouling behavior. Lignin sulfonate was also functionalized on the commercial DOW NF270 nanofiltration membranes via esterification of hydroxy groups with carboxyl group present on the membrane surface. Antifouling behavior was observed for both lignin-cellulose composite and commercial membranes functionalized with lignin. Up to 90% recovery of water flux after repeated cycles of fouling was observed for both types of lignin functionalized membranes while flux recovery of up to 60% was observed for unmodified membranes