An experimental investigation of drop deformation and breakup in steady, two-dimensional linear flows

We consider the deformation and burst of small fluid droplets in steady linear, two-dimensional motions of a second immiscible fluid. Experiments using a computer-controlled, four-roll mill to investigate the effect of flow type are described, and the results compared with predictions of several available asymptotic deformation and burst theories, as well as numerical calculations. The comparison clarifies the range of validity of the theories, and demonstrates that they provide quite adequate predictions over a wide range of viscosity ratio, capillary number, and flow type

A computer-controlled four-roll mill for investigations of particle and drop dynamics in two-dimensional linear shear flows

In this paper we describe the design and operating characteristics of a computer-controlled four-roll mill for investigations of particle and drop dynamics in two-dimensional linear flows. The control system is based upon the use of: a video camera to visualize the instantaneous position of the drop or particle; a PDP 11/23 computer, with a pipeline processor acting as an interface between the camera and computer, to calculate the position and implement a control strategy, and d.c. stepping motors to convert an electronic signal to angular velocities of the four rollers. The control objective is to keep the centre of mass of the drop/particle at the centre of the region between the rollers where there is a stagnation point in the undisturbed flow, while maintaining the shear-rate and the ratio of vorticity to strain rate in the flow at fixed values. The resulting system is suitable for studies of: the rotational motions of single solid particles; the deformation and burst of single droplets; or the hydrodynamic interactions of two particles or drops, one of which is held with its centre-of-mass fixed at the stagnation point of the undisturbed flow. In all cases, the flow can be varied from pure rotation to pure strain, and the shear rate can be either steady or changing as a prescribed function of time

A 10-year literature review of family caregiving for motor neurone disease: Moving from caregiver burden studies to palliative care interventions

Background: There is growing awareness that different terminal diseases translate into different family caregiver experiences, and the palliative and supportive care needs of these families are both similar and unique. Family members caring for people with motor neurone disease may experience exceptional strain due to the usually rapid and progressive nature of this terminal illness. Aim: The purpose of this review is to synthesize contemporary research and provide a comprehensive summary of findings relevant to motor neurone disease family caregivers, as well as highlight some of the suggested interventions to alleviate burden and improve quality of life for this group. Design: We conducted a comprehensive review of empirical research on family caregiving for people with motor neurone disease in peer-reviewed journals published in English, January 2000–April 2011. Fifty-nine studies met the inclusion criteria. Results: This comprehensive literature review was consistent with previous research documenting the substantial burden and distress experienced by motor neurone disease family caregivers and revealed important points in the trajectory of care that have the potential for negative effects. The diagnosis experience, assisted ventilation, cognitive changes and end-of-life decision making create challenges within a short time. This review has also implicated the need for improvements in access to palliative care services and highlighted the absence of interventions to improve care. Conclusions: Caregiver burden and quality-of-life studies on motor neurone disease family caregivers have so far dominated the research landscape .The focus needs to be on developing interventions that provide direct practical and psychosocial supports for motor neurone disease family caregivers

Investigating linkage rates among probabilistically linked birth and hospitalization records

BACKGROUND: With the increasing use of probabilistically linked administrative data in health research, it is important to understand whether systematic differences occur between the populations with linked and unlinked records. While probabilistic linkage involves combining records for individuals, population perinatal health research requires a combination of information from both the mother and her infant(s). The aims of this study were to (i) describe probabilistic linkage for perinatal records in New South Wales (NSW) Australia, (ii) determine linkage proportions for these perinatal records, and (iii) assess records with linked mother and infant hospital-birth record, and unlinked records for systematic differences. METHODS: This is a population-based study of probabilistically linked statutory birth and hospital records from New South Wales, Australia, 2001-2008. Linkage groups were created where the birth record had complete linkage with hospital admission records for both the mother and infant(s), partial linkage (the mother only or the infant(s) only) or neither. Unlinked hospital records for mothers and infants were also examined. Rates of linkage as a percentage of birth records and descriptive statistics for maternal and infant characteristics by linkage groups were determined. RESULTS: Complete linkage (mother hospital record – birth record – infant hospital record) was available for 95.9% of birth records, partial linkage for 3.6%, and 0.5% with no linked hospital records (unlinked). Among live born singletons (complete linkage = 96.5%) the mothers without linked infant records (1.6%) had slightly higher proportions of young, non-Australian born, socially disadvantaged women with adverse pregnancy outcomes. The unlinked birth records (0.4%) had slightly higher proportions of nulliparous, older, Australian born women giving birth in private hospitals by caesarean section. Stillbirths had the highest rate of unlinked records (3-4%). CONCLUSIONS: This study shows that probabilistic linkage of perinatal records can achieve high, representative levels of complete linkage. Records for mother’s that did not link to infant records and unlinked records had slightly different characteristics to fully linked records. However, these groups were small and unlikely to bias results and conclusions in a substantive way. Stillbirths present additional challenges to the linkage process due to lower rates of linkage for lower gestational ages, where most stillbirths occur

The footprint of cometary dust analogs: I. Laboratory experiments of low-velocity impacts and comparison with Rosetta data

Cometary dust provides a unique window on dust growth mechanisms during the onset of planet formation. Measurements by the Rosetta spacecraft show that the dust in the coma of comet 67P/Churyumov-Gerasimenko has a granular structure at size scales from sub-um up to several hundreds of um, indicating hierarchical growth took place across these size scales. However, these dust particles may have been modified during their collection by the spacecraft instruments. Here we present the results of laboratory experiments that simulate the impact of dust on the collection surfaces of COSIMA and MIDAS, instruments onboard the Rosetta spacecraft. We map the size and structure of the footprints left by the dust particles as a function of their initial size (up to several hundred um) and velocity (up to 6 m/s). We find that in most collisions, only part of the dust particle is left on the target; velocity is the main driver of the appearance of these deposits. A boundary between sticking/bouncing and fragmentation as an outcome of the particle-target collision is found at v ~ 2 m/s. For velocities below this value, particles either stick and leave a single deposit on the target plate, or bounce, leaving a shallow footprint of monomers. At velocities > 2 m/s and sizes > 80 um, particles fragment upon collision, transferring up to 50 per cent of their mass in a rubble-pile-like deposit on the target plate. The amount of mass transferred increases with the impact velocity. The morphologies of the deposits are qualitatively similar to those found by the COSIMA instrument.Comment: 14 pages, 12 figures, accepted for publication in MNRA

Urban PDS Partnership: Preparing Teachers for Social Justice

We believe that for urban schools to meet their goals and mission — in the way the DECA is modeling — takes a partnership among many stakeholders. One such partnership that supports DECA, and might buttress other schools and students — and simultaneously help to enact a social justice ideal — is a school-university connection. DECA was founded as a Professional Development School (PDS), with the school and university developing a reciprocal relationship with a shared focus on the preparation of new teachers, the enhancement of high school students\u27 achievement, school and university faculty members\u27 professional development, and collaborative inquiries aimed at improving instructional practices for all of the educators involved. In this chapter, we will describe our Midwestern university\u27s response to two social justice issues: the lack of support for urban students to be ready for college; and the issue of teacher quality in urban schools. DECA explicitly endeavors to respond to the dearth of educational opportunities for city youth. As well, as a PDS, DECA serves the university and our profession as a site for preparing the next generation of urban teachers. Our partnership relies on a PDS framework and a social justice approach to impact students\u27 access to learning and to develop quality educators through learning communities. Using the lenses of the Marianist Catholic tradition and the PDS mission, here we will frame our social justice stance. We will specifically describe the revamping of two critical courses in the teacher education program with the goal of enacting social justice through developing effective teachers for urban settings