71 research outputs found
Implementing Lanier's patents for stable, safe and economical ultra-short wing vacu- and para-planes
Backyard Technology are interested in aspects of aircraft design described by Edward H Lanier in a series of six patents obtained from 1930 to 1933. Lanier's overall aim was to provide an exceptionally stable aeroplane that would both fly normally and recover from undesirable attitudes without pilot aid. Backyard Technology were specifically interested in Lanier's idea of creating a vacuum cavity in the wing by replacing a section of the upper skin of the wing with a series of angled slats, believing that this wing design would give superior lift and stability compared to typical wing designs
Utilizing bifurcations to separate particles in spiral inertial microfluidics
Particles suspended in fluid flow through a closed duct can focus to specific
stable locations in the duct cross-section due to hydrodynamic forces arising
from the inertia of the disturbed fluid. Such particle focusing is exploited in
biomedical and industrial technologies to separate particles by size. In curved
ducts, the particle focusing is a result of balance between two dominant forces
on the particle: (i) inertial lift arising from small inertia of the fluid, and
(ii) drag arising from cross-sectional vortices induced by the centrifugal
force on the fluid. Bifurcations of particle equilibria take place as the bend
radius of the curved duct varies. By using the mathematical model of Harding,
Stokes, and Bertozzi [1], we illustrate via numerical simulations that these
bifurcations can be leveraged in a spiral duct to achieve large separation
between different sized particles by transiently focusing smaller particles
near saddle-points. We demonstrate this by separating similar-sized particles,
as well as particles that have a large difference in size, using spiral ducts
with square cross-section. The formalism of using bifurcations to manipulate
particle focusing can be applied more broadly to different geometries in
inertial microfluidics which may open new avenues in particle separation
techniques.Comment: 6 pages, 4 figure
Very viscous flows driven by gravity with particular application to slumping of molten glass
This thesis examines the flow of very viscous Newtonian fluids driven by gravity. It is written with concern for specific applications in the optics industry, with emphasis on the slumping of molten glass into a mould, as in the manufacture of optical components, which are in turn used to manufacture ophthalmic lenses. This process is known as thermal replication. However, the work has more general applicability, and disc viscometry, used to determine the viscosity of very viscous fluids, is also considered. In addition, one chapter of the thesis is devoted to the flow of dripping honey, as another example of a very viscous flow to which the model can be applied.
The Stokes creeping-flow equations are used to model the very viscous flows of interest. The main solution method is finite elements, and a purpose-written computer program has been developed to solve the creeping-flow equations by this method. The present program is restricted to solving for either two-dimensional or axisymmetric flows but is extendible to three
dimensions. In addition, semi-analytic series and asymptotic methods are used for some small portions of the work.
The optical applications of this work demand consideration of the topic of computing surface curvature, and therefore second derivatives, from inexact and discrete numerical and experimental data. For this purpose, fitting of B-splines by a least-squares method to coordinate data defining the surface has been used.
Much of the work assumes isothermal conditions, but in the context of the accuracy required in optical component manufacture it is also possible that non-isothermal effects will be important. Consequently, this restriction is eventually relaxed and some consideration given to non-isothermal conditions.
In order to validate the creeping-flow model and finite-element program, comparisons of numerical simulations with experimental results are performed. A preliminary assessment of the importance of non-isothermal conditions to the thermal-replication process is also made by comparing isothermal and non-isothermal simulations with experimental results. The isothermal model is found to best match the experimental data.Thesis (Ph.D.)--School of Applied Mathematics, 1998
Inertial focusing dynamics of spherical particles in curved microfluidic ducts with a trapezoidal cross-section
Inertial focusing in curved microfluidic ducts exploits the interaction of
drag force from the Dean flow with the inertial lift force to separate
particles or cells laterally across the cross-section width according to their
size. Experimental work has identified that using a trapezoidal cross-section,
as opposed to a rectangular one, can enhance the sized based separation of
particles/cells over a wide range of flow rates. Using our model, derived by
carefully examining the way the Dean drag and inertial lift forces interact at
low flow rates, we calculate the leading order approximation of these forces
for a range of trapezoidal ducts, both vertically symmetric and non-symmetric,
with increasing amount of skew towards the outside wall. We then conduct a
systematic study to examine the bifurcations in the particle equilbira that
occur with respect to a shape parameter characterising the trapezoidal
cross-section. We reveal how the dynamics associated with particle migration
are modified by the degree of skew in the cross-section shape, and show the
existence of cusp bifurcations (with the bend radius as a second parameter).
Additionally, our investigation suggests an optimal amount of skew for the
trapezoidal cross-section for the purposes of maximising particle separation
over a wide range of bend radii.Comment: 30 pages, 19 figure
Engagement with a Multi-Component, Preventative Program to Reduce Child Maltreatment: Program Satisfaction and Acceptability
The development and implementation of interventions to prevent child maltreatment (CM) is particularly challenging in view of the numerous stressors experienced by families within the child welfare system (CWS). Difficulties engaging families, particularly those who are most vulnerable, can lead to lower program dose and poorer outcomes. This qualitative study, conducted as part of a larger process evaluation, explored participant perspectives of a newly developed, multi-component, community-based intervention designed to reduce the risk of CM in families with young children. The study involved one-to-one interviews with a sub-sample of mothers (n=12) recruited through statutory and community-based social work services. Several brief program satisfaction questionnaires were also completed by parents. Mothers reported a stronger parent–child bond and greater use of positive parenting strategies (e.g. improved communication and discipline strategies) following the
intervention. Facilitator and group support emerged as strong themes throughout the interviews and were important factors in facilitating engagement and reducing drop-out. High levels of program satisfaction were also reported. The study findings demonstrate how a multi-component program, which combines an evidence-based treatment (EBT) with community-based supports, may offer a promising approach for social work practitioners in reducing CM and in better meeting the more complex needs of families within the CWS. However, a more thorough understanding of the factors which promote program engagement and retention, is crucial to maximizing the benefits of interventions designed to support more vulnerable families
Functional and Genetic Analysis of Coronavirus Replicase-Transcriptase Proteins
The coronavirus replicase-transcriptase complex is an assembly of viral and cellular proteins that mediate the synthesis of genome and subgenome-sized mRNAs in the virus-infected cell. Here, we report a genetic and functional analysis of 19 temperature-sensitive (ts) mutants of Murine hepatitis virus MHV-A59 that are unable to synthesize viral RNA when the infection is initiated and maintained at the non-permissive temperature. Both classical and biochemical complementation analysis leads us to predict that the majority of MHV-A59 ORF1a replicase gene products (non-structural proteins nsp1–nsp11) form a single complementation group (cistron1) while the replicase gene products encoded in ORF1b (non-structural proteins nsp12–nsp16) are able to function in trans and comprise at least three, and possibly five, further complementation groups (cistrons II–VI). Also, we have identified mutations in the non-structural proteins nsp 4, nsp5, nsp10, nsp12, nsp14, and nsp16 that are responsible for the ts phenotype of eight MHV-A59 mutants, which allows us to conclude that these proteins are essential for the assembly of a functional replicase-transcriptase complex. Finally, our analysis of viral RNA synthesis in ts mutant virus-infected cells allows us to discriminate three phenotypes with regard to the inability of specific mutants to synthesize viral RNA at the non-permissive temperature. Mutant LA ts6 appeared to be defective in continuing negative-strand synthesis, mutant Alb ts16 appeared to form negative strands but these were not utilized for positive-strand RNA synthesis, and mutant Alb ts22 was defective in the elongation of both positive- and negative-strand RNA. On the basis of these results, we propose a model that describes a pathway for viral RNA synthesis in MHV-A59-infected cells. Further biochemical analysis of these mutants should allow us to identify intermediates in this pathway and elucidate the precise function(s) of the viral replicase proteins involved
Implementation of a Data Management Quality Management Framework at the Marine Institute, Ireland
Peer reviewed
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.The International Oceanographic Data and Information Exchange of UNESCO’s Intergovernmental Oceanographic
Commission (IOC-IODE) released a quality management framework for its National Oceanographic Data Centre (NODC)
network in 2013. This document is intended, amongst other goals, to provide a means of assistance for NODCs to establish
organisational data management quality management systems. The IOC-IODE’s framework also promotes the accreditation
of NODCs which have implemented a Data Management Quality Management Framework adhering to the guidelines laid
out in the IOC-IODE’s framework. In its submission for IOCE-IODE accreditation, Ireland’s National Marine Data Centre
(hosted by the Marine Institute) included a Data Management Quality Management model; a manual detailing this model and
how it is implemented across the scientific and environmental data producing areas of the Marine Institute; and, at a more
practical level, an implementation pack consisting of a number of templates to assist in the compilation of the documentation
required by the model and the manual.This work is part supported by the Irish Government and the European Maritime & Fisheries Fund as part of the EMFF Operational Programme for 2014-2020
Pore level simulation of miscible injection with gravity domination
Gravity assisted miscible CO2 injection into oil reservoirs is an efficient method of enhancing oil recovery. CO2 injection into aquifers for sequestration purposes is another application of miscible displacement under gravity control. This paper reports pore scale simulation studies to determine the role of different parameters on the frontal stability of the miscible displacement process under gravity. The simulation studies were performed using the Finite Element Analysis technique. The simulation model was initially validated by matching results with flow visualization experimental studies using glass micromodels. The Navier-Stokes, continuity and convection-diffusion equations were used in the simulation instead of ideal Darcy law. Wide ranges of parameters applicable for Enhanced Oil Recovery and CO2 sequestration have been used in the sensitivity study. Dip angles (Θ) between 0o and 180o (for updip and down-dip situations), different domain velocities, density differences of 50 to 900 kg/m3 between the injecting and displaced fluids and viscosity ratios from 1 to 50 (to include light and heavy oils) have been investigated. Snapshots were captured in each simulation case for visual comparison of the frontal advancement. In addition, breakthrough saturation was plotted against cos (Θ) to quantify the competition between viscous and gravity forces in gravity dominated miscible displacement process. The pore scale study suggests that stability of a miscible process can be influenced by several factors. When gravity acts in favor of displacement and there is a moderate to large density difference, angular tilt is the most important parameter influencing displacement. When the density difference is small then the mobility ratio and flow velocity also play a role. When gravity opposes displacement and buoyancy forces are dominating, results show little sensitivity to the actual tilt angle. Better displacement is seen for lower density difference and for higher flow velocity, while, again, the mobility ratio only impacts on displacement when the density difference is quite small.Zeeshan Mohiuddin, Yvonne Stokes and Manouchehr Haghigh
- …