4,895 research outputs found
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
Felama® Almond
No full textThe almond breeding program at the Agrifood Research and Technology Center of Aragon (CITA) began in 1974, focusing on self-compatibility and late flowering while ensuring fruit quality and productivity in new planting systems. Self-compatible cultivars are crucial in modern plantations. ‘Aylés’, ‘Moncayo’, and ‘Guara’ were the program’s initial releases (Felipe and R Socias i Company 1987), with ‘Guara’ being the first cultivar introduced to the industry in Spain in 1988 combining self-compatibility and late flowering. Other self-compatible cultivars released in the early stages of the breeding program were ‘Blanquerna’, ‘Cambra’, and ‘Felisia’ (R Socias i Company and Felipe 1999). New self-pollinating cultivars with high fruit quality have been selected. In 2005, ‘Soleta’ and ‘Isabelona’ were introduced, both self-pollinating, late-flowering, and of high fruit quality (Bielsa et al. 2021; R Socias i Company and Felipe 2007). These varieties have been widely used in high-density planting systems. Two extralate flowering cultivars were released, Diamar (Mardía®) and Vialfas (R Socias i Company et al. 2008, 2015). The introduction of late and very late flowering cultivars has significantly reduced frost damage and allowing the expansion of almond cultivation inland Spain. ‘Felama’ has recently been released due to its high productivity, medium vigor, uniform and balanced branching, late flowering, and early fruit maturation, indicating high marketability in areas without the risk of spring frost
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
Trunk growth rate frequencies as water stress indicator in almond trees
No full textThe continuous monitoring of water stress will increase the accuracy of the deficit irrigation scheduling. Almonds
are very sensitive to water stress conditions and an important water consumer. Recently, a novel approach to the
use of trunk growth rate (TGR) data has been proposed for olive trees. These works suggested the use of TGR
frequencies to evaluate water status of the trees. The aim of the current work was to compare the seasonal pattern
of three different indicators derived from the daily curves of trunk diameter fluctuations with midday stem water
potential. During three consecutive seasons (2017–2019), an irrigation experiment was carried out in a mature
almond orchard (cv Vairo) at Dos Hermanas (Seville, Spain). Four irrigation treatments replicated in four blocks
were evaluated using the daily curves of midday stem water potential and trunk diameter fluctuations. The
different irrigation treatments were: Control, full irrigated conditions; RDI-1 (irrigation scheduling based on
midday stem water potential with a deficit irrigation during kernel filling [values around − 1.2 MPa]); RDI-2
(similar to RDI-1 but with a more severe water stress [− 2 MPa]) and incomplete recovery after harvest due to
limitation of the seasonal amount of water (around 100 mm); SDI, sustained deficit irrigation with a seasonal
applied water equal to RDI-2. Trunk diameter fluctuations were measured with a wireless band dendrometer. The
daily curves were processed to obtain three different indicators. Maximum daily shrinkage (MDS) was the difference between the daily maximum and minimum. Trunk growth rate (TGR) was the difference between two
consecutive daily maximums. The frequencies of several ranges of TGR were compared with the midday stem
water potential. Weekly frequencies of values greater than 0.3 mm day− 1 decreased with the reduction of midday
stem water potential, but the pattern changed greatly in different seasons. The weekly frequency of values between − 0.1 and 0 and between 0 and 0.1 mm day− 1 were steadier in different seasons. Differences between
seasons were related to growth pattern and yield
Pattern of trunk diameter fluctuations of almond trees in deficit irrigation scheduling during the first seasons
No full textIrrigation needs in mature almond orchards are very high. Although almond trees grow in rainfed conditions, the
yield response is very sensitive to irrigation. Continuous monitoring of the water status could be an adequate tool
to optimize deficit irrigation. In this sense, trunk diameter fluctuations appeared as a very promising indicator at
the beginning of the century, but few data have been published. The aim of this work is to check threshold values
of maximum daily shrikage (MDS) and identify possible limitations to their use in commercial orchards. The
experiment was performed in a commercial farm in Dos Hermanas (Seville, Spain) during the 2017 season on a
7-years-old orchard (cv Vairo). The irrigation treatments were Control (100% ETc), sustained deficit irrigation
(SDI) with a maximum seasonal irrigation of 100 mm and two regulated deficit treatments (RDI). Both RDI
treatments (RDI-1 and RDI-2) were scheduled using the signal of maximum daily shrinkage (signal) and the
midday stem water potential (SWP). In RDI-1, full irrigation conditions were provided before kernel filling and
during postharvest, using the threshold values suggested in the bibliography. During kernel filling, the water
stress level was designed to be -1.5 MPa (SWP) and 1.75 (signal). RDI-2 trees were irrigated using the same
scheduling as RDI-1, but target water stress values were higher in kernel filling (-2 MPa and 2.75) and with a
maximum seasonal amount of water of 100 mm. SWP in Control trees was near the McCutchan and Shackel
baseline for most of the season. None of the deficit treatments reached the signal values suggested. Moreover, the
signal values were almost equal between treatments, with no water stress effect. The trunk growth rate (TGR)
presented clear differences depending on the water status
Comments on “Precipitation kinetics of Al–1.12Mg2Si–0.35Si and Al–1.07Mg2Si–0.33Cu alloys”
No full textIt is shown that in analysing DSC data of precipitation reactions in Al–1.12Mg2Si–0.35Si, Al–1.07Mg2Si–0.33Cu and Al–1.0Mg2Si–0.5Ag alloys in work by Gaber et al., accurate values for the activation energies are obtained by applying the method derived by the present author (the Type B-1.92 method). Values obtained from other analysis methods reported by Gaber et al. are less accurate. Averaging activation energies obtained by different methods introduces inaccuracies and obscures these inaccuracies, especially if the set of methods applied includes highly inaccurate ones, such as the Ozawa and Takhor methods
Optical Flow Based State Estimation for an Indoor Micro Aerial Vehicle
No full textThis work addresses the problem of indoor state estimation for autonomous flying vehicles with an optic flow approach. The paper discusses a sensor configuration using six optic flow sensors of the computer mouse type augmented by a three-axis accelerometer to estimate velocity, rotation, attitude and viewing distances. It is shown that the problem is locally observable for a moving vehicle. A Kalman filter is used to extract these states from the sensor data. The resulting approach is tested in a simulation environment evaluating the performance of three Kalman filter algorithms under various noise conditions. Finally, a prototype of the sensor hardware has been built and tested in a laboratory setup. Paper published: Verveld, M.J., Chu, Q.P., De Wagter, C. and Mulder, J.A. “Optic Flow Based State Estimation for an Indoor Micro Air Vehicle” AIAA Guidance, Navigation, and Control Conference, August 2010, Toronto, Canada AIAA 2010-8209, DOI: 10.2514/6.2010-8209Aerospace EngineeringControl & Simulatio
Transient time-averaged spectra of rapidly-modulated semiconductor lasers
No full textUsing the computed solution of multimode rate equations, and including wavelength-chirping effects via the dependence of the refractive index on carrier concentration, it is possible to calculate time-averaged spectra of rapidly-modulated lasers. The averaging time may be used to simulate the effects of measuring equipment with a specific time response. The results show a characteristic line structure within the dominant longitudinal mode spectrum, and are in qualitative agreement with experimental measurements reported by other author
Gift inscription in Minions of the Moon: a little book of song and story
No full textThis edition includes a gift inscription possibly penned by the author, Madison Julius Cawein, "Frank on Valentines Day, 1914. M.J." Madison Julius Cawein (1865-1914).Cawein, Madison Julius, 1865-1914
Cooling and heating rate dependence of precipitation in an Al-Cu alloy
No full textDifferential scanning calorimetry and X-ray diffraction were used to study the cooling and heating rate dependence of precipitation in an Al-1.66 at.% Cu alloy. After homogenizing, cooling at a rate of 22 K min?1 (SC22) is sufficient to retain all copper in solid solution. GP-zone formation during subsequent heat treatment is hindered; this is ascribed to an insufficient number of (excess) vacancies. After a water quench (WQ) a large number of GP zones are formed during subsequent storage at room temperature for 1 h. The heat content of the GP-zone dissolution effect can quantitatively be described in terms of the heat of precipitation of GP I zones and the solid solubilities as derived from the GP I zone solvus. The heat content of the combined ??-/?-phase precipitation effect appeared to be proportional to the number of copper atoms precipitated, yielding an average value for the heat of copper precipitation of 36 kJ mol?1 copper. The activation energy for ??-phase formation is 0.75 eV for SC22 specimens and 1.10 ± 0.10 eV for WQ specimens. The differences in reported activation energies for ??-phase formation are discussed in terms of mobility of dissolve atoms (related to the vacancy concentration), interfacial energy and direction of growth (normal or perpendicular to the ??-phase plate)
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