6,385 research outputs found
Bitter taste signalling modulates bile acid-induced PYY, but not GLP-1 secretion in healthy humans
No full textPoster session PS 27 Incremental studies on gut hormones - 439.
Published online: 25 August 2020C. Xie, X. Wang, M.J. Bound, R.L. Young, K.L. Jones, M. Horowitz, C.K. Rayner, T. W
Effects of bile acid enemas on GLP-1 and PYY secretion in healthy humans
No full textM.J. Bound, T. Wu, B. Gedulin, M. Horowitz, C.K. Rayne
Effects of the bitter taste receptor agonist, denatonium benzoate, on postprandial glycaemia, gastric emptying and energy intake in type 2 diabetes
No full textOral Presentation #198C. Xie, X. Wang, M.J. Bound, J. Grivell, R.L. Young, K.L. Jones, M. Horowitz, C.K. Rayner, T. W
Vacuum Insulation Panels Applied in Building Constructions
No full textDue to sustainability and due to international treaties, it is desired and required to reduce greenhouse gas emissions drastically. One contributor to these emissions is the burning of fossil fuels for generating power and electricity to be used in and for buildings. Buildings and building-related processes are responsible for about 40% of the primary energy consumption in the European Union. More than half of this energy is applied for heating systems in dwellings and commercial buildings. The European Union therefore has laid down new energy performance requirements for buildings in the European Directive on the Energy Performance of Buildings. Moreover, a reduction of energy losses of buildings during their occupational phase is important for facilitating the implementation of sustainable energy sources in the built environment. Increasing the insulation value of the envelope of buildings may contribute to this reduction of primary energy use. Two strategies can be followed. The first strategy is to increase the thickness of the thermal insulation layer. Until recently, this strategy has primarily been adopted. If, however, German or Swiss Passivhaus standard is applied, the thickness of this insulation layer would increase to beyond 30 cm, resulting in very thick building enclosures. The second, more innovative, strategy for reducing energy losses through the building skin would be the application of more effective thermal insulators. One such more effective thermal insulator is a vacuum insulation panel, abbreviated as VIP. A VIP consists of an open-celled core material which is evacuated and then tightly sealed into a barrier envelope to maintain this vacuum. The vacuum inside the pores of the core material reduces the thermal conductivity of the product significantly, as a result of which the thickness of the insulation layer can be reduced to obtain a certain performance. This reduction of thickness is among the most promising features for large-scale application of VIPs in the building industry. However, integration of VIPs into buildings must be performed very meticulously for several reasons; first, due to its nature a VIP cannot be processed on site and needs careful planning in advance; second, it is very sensitive to mechanical damage thus requiring careful handling; third, thermal bridges along the panel’s edges reduce its performance; fourth, the composite system is highly subjected to aging. This dissertation therefore looks into many of these aspects, presents several calculation tools and shows how VIPs can be applied in façade panels, EPS insulation boards and as under-floor insulation. With the wide-spread proliferation of VIPs in buildings a more sustainable and healthy environment can then be achieved.Building TechnologyArchitectur
Branch and bound method for multiobjective pairing selection
No full textMost of the available methods for selection of input-output pairings for
decentralized control require evaluation of all alternatives to find the optimal
pairings. As the number of alternatives grows rapidly with process dimensions,
pairing selection through an exhaustive search can be computationally forbidding
for large-scale processes. Furthermore, the different criteria can be
conflicting necessitating pairing selection in a multiobjective optimization
framework. In this paper, an efficient branch and bound (BAB) method for
multiobjective pairing selection is proposed. The proposed BAB method is
illustrated through a biobjective pairing problem using selection criteria
involving the relative gain array and the mu-interaction measure. The
computational efficiency of the proposed method is demonstrated by using
randomly generated matrices and the large-scale case study of cross-direction
control. (C) 2010 Elsevier Ltd. All rights reserved
Solar-sail control laws for perturbed Earth-bound trajectories
No full textSolar sailing is a spacecraft propulsion method relying solely on solar radiation pressure to provide thrust and is therefore propellantless by nature. Although it represents a practical and promising propulsion system particularly suited for heliocentric flight regimes, near-term sailcraft missions will remain Earth-bound due to the current technology readiness level. This paper aims to show the suitability of solar sailing for planetocentric applications for future Earth-bound solar-sail missions. In Earth orbit, the sailcraft is subjected to perturbations absent or negligible in heliocentric flight, including the effect of eclipses, non-spherical gravity and aerodynamic drag. The magnitude of these perturbations can be comparable to, or even exceed that of solar radiation pressure and their effect on the solarsail dynamics should be investigated to ensure the sailcraft’s transfer capabilities and controllability. This paper does so by including the gravitational and aerodynamic perturbations in the optimal control problem. From this formulation, steering laws can be derived to optimally change individual orbital elements. These newly derived steering laws form an extension to the laws found by McInnes for unperturbed solar-sail Earth-bound motion. By accounting for the perturbations in the derivation of the steering laws, their effect can be exploited by the sailcraft to achieve orbits otherwise unreachable. The improved maneuverability will be quantified based on the established increase of the targeted orbital element. A range of different starting orbits will be considered to characterize how the perturbations affect the solar-sail maneuvering capabilities in different orbital regimes. As demonstration of the real need for this investigation, NASA’s Advanced Composite Solar Sail System (ACS3) mission will be considered as real-case scenario. This mission is scheduled for launch in mid-2022 and may benefit from the steering laws derived in this paper to proof the maneuverability of solar sails in Earth orbit.Astrodynamics & Space MissionsSpace Engineerin
Locally optimal control laws for Earth-bound solar sailing with atmospheric drag
No full textSolar sailing is a spacecraft propulsion method relying solely on solar radiation pressure to provide thrust and is therefore propellantless by nature. Although it represents a practical and promising propulsion system particularly suited for heliocentric flight regimes, the majority of sailcraft missions flown to date have remained Earth-bound and more Earth-bound missions are scheduled for the near future. However, the fundamental dynamics and trajectory optimization of a solar sail around the Earth have only been investigated to a limited extent, often neglecting the effect of non-negligible perturbations in the dynamics and the optimal control problem. Among these perturbations are the effect of eclipses, non-spherical gravity, and aerodynamic drag. Their magnitude can be comparable to, or even exceed that of solar radiation pressure and their effect on the solar-sail dynamics should be investigated to ensure the sailcraft's transfer capabilities and controllability. This article does so by including these perturbations in the dynamics and by considering aerodynamic drag in the optimal control problem. Using this formulation, it is shown that the optimal control problem is independent of the solar-sail loading parameter and that, by solving it, locally optimal steering laws can be derived to effectively change individual orbital elements. These newly derived steering laws form an extension to the laws found by McInnes for unperturbed solar-sail Earth-bound motion. By accounting for the perturbations in the derivation of the steering laws, it is possible to characterize how the perturbations affect the solar-sail maneuvering capabilities. This is quantified based on the established increase of the targeted orbital element. Furthermore, a range of different starting orbits will be considered to analyze the effects of perturbations in different orbital regimes. As demonstration of the real need for this investigation, NASA's Advanced Composite Solar Sail System (ACS3) mission will be considered as real-case scenario. This mission is scheduled for launch in mid-2022 and may benefit from the steering laws derived in this article to prove the maneuverability of solar sails in Earth orbit.Astrodynamics & Space MissionsSpace Engineerin
Book Review: Reginald M.J. Oduor’s Introduction to Ethics
No full textTITLE OF BOOK: Introduction to Ethics
AUTHOR: Reginald M.J. Oduor
Nairobi: Sophia Publications Ltd., 2009, 116 pages
COVER: Paperback
ISBN: 9966-7457-0-X
This book is a product of more than a decade of Oduor’s experience in teaching ethics (moral philosophy) at the University of Nairobi. In the course of this introduction, the reader gets to see the techniques of philosophic reflection in action, as they are employed to scrutinise various pertinent moral questions
X-ray structure of a putative reaction intermediate of 5-aminolaevulinic acid dehydratase
No full textThe X-ray structure of yeast 5-aminolaevulinic acid dehydratase, in which the catalytic site of the enzyme is complexed with a putative cyclic intermediate composed of both substrate moieties, has been solved at 0.16 nm (1.6 Å) resolution. The cyclic intermediate is bound covalently to Lys(263) with the amino group of the aminomethyl side chain ligated to the active-site zinc ion in a position normally occupied by a catalytic hydroxide ion. The cyclic intermediate is catalytically competent, as shown by its turnover in the presence of added substrate to form porphobilinogen. The findings, combined with those of previous studies, are consistent with a catalytic mechanism in which the C–C bond linking both substrates in the intermediate is formed before the C–N bond
3D printed mycelium-bound bio-based sound absorbing panels
No full textThe built environment contributes in a large extend to the global greenhouse gas emissions. With a growing demand for new buildings another view on building products is required. This thesis focusses on creating a biobased sound absorbing panel made from a mycelium bound biomaterial derived from urban waste. The production method for this panel is 3D printing, since with this production method changing demands can be met. In this thesis six experiments are executed regarding the development of a printable material from urban waste, the sound absorbing properties of the designed panel and 3D printing. To create a printable paste from urban waste, a couple of urban waste materials have been reviewed. Brewery’s grain came out as the most promising growth medium for mycelium. This material is mixed with flour and water to create a printable paste. The impedance tube B&K 4206 is used to discover the acoustic properties. For the 3D printing a UR5 robot in combination with a LDM WASP extruder 3.0 XL is used. To control the robot movement, Rhino with Grasshopper in combination with the plug-in Robots is used. For understanding the acoustic behavior of the panels, multiple variables regarding printing and design parameters have been tested.The final product of this research is a 3D printed panel which can be made with a mixture of brewery’s grain, all-purposes flour, water, and mycelium from the Pleurotus.Architecture, Urbanism and Building Sciences | Building Technolog
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