1,101 research outputs found
Use of experimental design to investigate processing conditions and K value effects in poly(vinyl chloride) window profile extrusion
Statistical experimental design has been used on a laboratory scale, twin screw extruder to investigate how processing conditions and polymer K value affect both the extrusion process and important extrudate properties: viz. Charpy impact strength, colour, gloss, and degree of gelation. It is demonstrated how this approach can be used to define the optimum processing window. Although in production situations it may be impractical or too expensive to vary large numbers of variables over a wide processing range, it is possible to use the experimental design approach without initiating unwieldy experimental programmes by using Evolutionary Operation. This is illustrated with reference to extrusion line trials
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Evaluation of boundary-layer type in a weather forecast model utilising long-term Doppler lidar observations
Many studies evaluating model boundary-layer schemes focus either on near-surface parameters or on short-term observational campaigns. This reflects the observational datasets that are widely available for use in model evaluation. In this paper we show how surface and long-term Doppler lidar observations, combined in a way to match model representation of the boundary layer as closely as possible, can be used to evaluate the skill of boundary-layer forecasts. We use a 2-year observational dataset from a rural site in the UK to evaluate a climatology of boundary layer type forecast by the UK Met Office Unified Model. In addition, we demonstrate the use of a binary skill score (Symmetric Extremal Dependence Index) to investigate the dependence of forecast skill on season, horizontal resolution and forecast leadtime. A clear diurnal and seasonal cycle can be seen in the climatology of both the model and observations, with the main discrepancies being the model overpredicting cumulus capped and decoupled stratocumulus capped boundary-layers and underpredicting well mixed boundary-layers. Using the SEDI skill score the model is most skillful at predicting the surface stability. The skill of the model in predicting cumulus capped and stratocumulus capped stable boundary layer forecasts is low but greater than a 24 hr persistence forecast. In contrast, the prediction of decoupled boundary-layers and boundary-layers with multiple cloud layers is lower than persistence. This process based evaluation approach has the potential to be applied to other boundary-layer parameterisation schemes with similar decision structures
Puffed Noncommutative Nonabelian Vortices
We present new solutions of noncommutative gauge theories in which coincident
unstable vortices expand into unstable circular shells. As the theories are
noncommutative, the naive definition of the locations of the vortices and
shells is gauge-dependent, and so we define and calculate the profiles of these
solutions using the gauge-invariant noncommutative Wilson lines introduced by
Gross and Nekrasov. We find that charge 2 vortex solutions are characterized by
two positions and a single nonnegative real number, which we demonstrate is the
radius of the shell. We find that the radius is identically zero in all
2-dimensional solutions. If one considers solutions that depend on an
additional commutative direction, then there are time-dependent solutions in
which the radius oscillates, resembling a braneworld description of a cyclic
universe. There are also smooth BIon-like space-dependent solutions in which
the shell expands to infinity, describing a vortex ending on a domain wall.Comment: 21 pages, 3 eps figures. v2: published version, analytic solution
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Genetic Assimilation and Canalisation in the Baldwin Effect
The Baldwin Effect indicates that individually learned behaviours acquired during an organism’s lifetime can influence the evolutionary path taken by a population, without any direct Lamarckian transfer of traits from phenotype to genotype. Several computational studies modelling this effect have included complications that restrict its applicability. Here we present a simplified model that is used to reveal the essential mechanisms and highlight several conceptual issues that have not been clearly defined in prior literature. In particular, we suggest that canalisation and genetic assimilation, often conflated in previous studies, are separate concepts and the former is actually not required for non-heritable phenotypic variation to guide genetic variation. Additionally, learning, often considered to be essential for the Baldwin Effect, can be replaced with a more general phenotypic plasticity model. These simplifications potentially permit the Baldwin Effect to operate in much more general circumstances
Wearable device to assist independent living.
Older people increasingly want to remain living independently in their own homes. The aim of the ENABLE project is to develop a wearable device that can be used both within and outside of the home to support older people in their daily lives and which can monitor their health status, detect potential problems, provide activity reminders and offer communication and alarm services. In order to determine the specifications and functionality required for development of the device user surveys and focus groups were undertaken and use case analysis and scenario modeling carried out. The project has resulted in the development of a wrist worn device and mobile phone combination that can support and assist older and vulnerable wearers with a range of activities and services both inside and outside of their homes. The device is currently undergoing pilot trials in five European countries. The aim of this paper is to describe the ENABLE device, its features and services, and the infrastructure within which it operates
Нерешенные вопросы диагностики и лечения синдрома острого повреждения желудка
Освещены основные вопросы развития, диагностики и лечебных мероприятий синдрома острого повреждения желудка. Определены основные направления в изучении данного состояния.Main questions of development, diagnosis and treatment of syndrome of acute lesion of the stomach are featured. Main directions in the investigation of this state were determined
The Clinical and Serological Effect of a Gluten-Free Diet in Border Terriers with Epileptoid Cramping Syndrome
Background: Canine epileptoid cramping syndrome (CECS) is a paroxysmal movement disorder of Border Terriers (BTs). These dogs might respond to a gluten-free diet.
Objectives: The objective of this study was to examine the clinical and serological effect of a gluten-free diet in BTs with CECS.
Animals: Six client-owned BTs with clinically confirmed CECS.
Methods: Dogs were prospectively recruited that had at least a 6-month history of CECS based on the observed phenomenology (using video) and had exhibited at least 2 separate episodes on different days. Dogs were tested for anti-transglutaminase 2 (TG2 IgA) and anti-gliadin (AGA IgG) antibodies in the serum at presentation, and 3, 6, and 9 months after the introduction of a gluten-free diet. Duodenal biopsies were performed in 1 dog.
Results: Serum TG2 IgA titers were increased in 6/6 BTs (P = .006) and AGA IgG titers were increased in 5/6 BTs at presentation compared to those of controls (P = .018). After 9 months, there was clinical and serological improvement in all BTs with CECS strictly adhering to a gluten-free diet (5/5). One dog had persistently increased antibody titers. This dog scavenged horse manure. On the strict introduction of a gluten-free diet this dog also had an improved clinical and serological response. The diet-associated improvement was reversible in 2 dogs on completion of the study, both of which suffered a relapse of CECS on the re-introduction of gluten.
Conclusions: Canine epileptoid cramping syndrome in BTs is a gluten-sensitive movement disorder triggered and perpetuated by gluten and thus responsive to a gluten-free diet
Deltaron Dibaryon Structure in Chiral SU(3) Quark Model
We discuss the structure of Deltaron dibaryon in the chiral SU(3) quark
model. The energy of Deltaron is obtained by considering the coupling of the
and (hidden color) channels. The effects of various
parameters on the Deltaron mass are also studied. It is shown that the mass of
Deltaron is lower than the mass of but higher than the mass of
.Comment: 15 pages, Late
Scalar Solitons on the Fuzzy Sphere
We study scalar solitons on the fuzzy sphere at arbitrary radius and
noncommutativity. We prove that no solitons exist if the radius is below a
certain value. Solitons do exist for radii above a critical value which depends
on the noncommutativity parameter. We construct a family of soliton solutions
which are stable and which converge to solitons on the Moyal plane in an
appropriate limit. These solutions are rotationally symmetric about an axis and
have no allowed deformations. Solitons that describe multiple lumps on the
fuzzy sphere can also be constructed but they are not stable.Comment: 24 pages, 2 figures, typo corrected and stylistic changes. v3:
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