1,177 research outputs found
State-space model identification and feedback control of unsteady aerodynamic forces
Unsteady aerodynamic models are necessary to accurately simulate forces and
develop feedback controllers for wings in agile motion; however, these models
are often high dimensional or incompatible with modern control techniques.
Recently, reduced-order unsteady aerodynamic models have been developed for a
pitching and plunging airfoil by linearizing the discretized Navier-Stokes
equation with lift-force output. In this work, we extend these reduced-order
models to include multiple inputs (pitch, plunge, and surge) and explicit
parameterization by the pitch-axis location, inspired by Theodorsen's model.
Next, we investigate the na\"{\i}ve application of system identification
techniques to input--output data and the resulting pitfalls, such as unstable
or inaccurate models. Finally, robust feedback controllers are constructed
based on these low-dimensional state-space models for simulations of a rigid
flat plate at Reynolds number 100. Various controllers are implemented for
models linearized at base angles of attack , and . The resulting control laws are
able to track an aggressive reference lift trajectory while attenuating sensor
noise and compensating for strong nonlinearities.Comment: 20 pages, 13 figure
Acrylamide formation in potato products
End of Project ReportAcrylamide, a substance classified as a potential carcinogen, occurs in heated
starchy foods at concentrations many times in excess of levels permitted in
drinking water. Early surveys indicated that levels of acrylamide in potato
products such as French fries and potato crisps were the highest of the
foodstuffs investigated. The present project addressed this issue by
determining levels of acrylamide precursors (asparagine and reducing sugars)
in raw potatoes and levels of acrylamide in (i) potato products from different
storage regimes, (ii) spot-sampled potatoes purchased from a local
supermarket, (iii) samples that received pre-treatments and were fried at
different temperatures and (iv) French fries reheated in different ovens.A risk
assessment of the estimated acrylamide intake from potato products for
various cohorts of the Irish population was also conducted
Status Report on Acrylamide in Potato Products
End of Project ReportThis status report was conducted as part of Task 1 of a research project (RMIS No. 5265) on the development and quantification of acrylamide in potatoes and potato products funded under the Food Institutional Research Measure (FIRM) of the Department of Agriculture and Food as part of the National Development Plan. Teagasc acknowledges the support of theDepartment of Agriculture and FoodAcrylamide is a toxin that can potentially occur in high concentrations in heated starchy foods especially potato products such as crisps and french fries. In model systems isotopic substitution studies have demonstrated that acrylamide is formed via the Maillard type reaction between the amino acid aspargine and a carbonyl source such as the reducing sugars glucose and fructose. Levels of acrylamide in cooked potato products are primarily influenced by the levels of reducing sugars in the product and this in turn is influenced by storage time, temperature and variety of potato used. During cooking acrylamide formation begins to occur at temperatures above 100°C and increases up to temperatures of 220°C but decreases thereafter due to thermal degradation of the compound. Risk assessment studies on acrylamide intakes have been conducted in a number of countries and mg/kg body weight daily intakes have been estimated to be between 0.2-0.8. Adequate analytical techniques exist for quantification of acrylamide in potato and are mainly based around liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) techniquesDepartment of Agriculture, Food and the Marin
Modern sedative agents and techniques used in dentistry for patients with special needs: A review
According to the World Health Organisation, approximately 1.3 billion people worldwide experience substantial disability due to physical, mental or sensory impairment. People with special needs require special consideration and more time or altered delivery methods when receiving dental treatments. Various factors, such as patients' lack of cooperation, cognitive impairment and complex medical status, may lead dental practitioners to recommend conscious sedation. Several pharmacological agents and administrative routes are available, which achieve varying levels of sedation ranging from minimal to deep. Pre-operative assessment and careful case selection are necessary to determine the appropriate sedative agent, route of administration and level of sedation for each patient. Thus, a thorough understanding of the pharmacokinetics, risks and benefits, and implications of various sedatives available for PSN is essential to achieve the desired clinical outcomes. This review critically presents the considerations associated with the use of various sedative agents for PSN in dentistry. Considerations include patients' pre-anaesthesia medical comorbidities, cardiorespiratory adverse effects and cooperativeness, and the viable alternative treatment modalities
Fitting a 3D Morphable Model to Edges: A Comparison Between Hard and Soft Correspondences
We propose a fully automatic method for fitting a 3D morphable model to
single face images in arbitrary pose and lighting. Our approach relies on
geometric features (edges and landmarks) and, inspired by the iterated closest
point algorithm, is based on computing hard correspondences between model
vertices and edge pixels. We demonstrate that this is superior to previous work
that uses soft correspondences to form an edge-derived cost surface that is
minimised by nonlinear optimisation.Comment: To appear in ACCV 2016 Workshop on Facial Informatic
Utilizing stimulated Raman scattering microscopy to study intracellular distribution of label-free ponatinib in live cells
Stimulated Raman scattering (SRS) microscopy represents a powerful method for imaging label-free drug dis-tribution with high resolution. SRS was applied to image label-free ponatinib with high sensitivity and speci-ficity in live human chronic myeloid leukemia (CML) cell lines. This was achieved at biologically relevant, na-nomolar concentrations; allowing determination of ponatinib uptake and sequestration into lysosomes during the development of acquired drug resistance and an improved understanding of target engagement
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