58 research outputs found
FIGURE 1 in New combinations and names in Heliotropium (Heliotropiaceae) from South America, including a new occurrence for the flora of Ecuador
No full textFIGURE 1. Exsiccate of Heliotropium romeroi incorporated into the National Herbarium of Ecuador (QCNE128782), National Biodiversity Institute (INBio), Quito, Ecuador. Photograph and figure produced by M.G.M. Gonçalves.Published as part of Melo, José Iranildo Miranda De, 2022, New combinations and names in Heliotropium (Heliotropiaceae) from South America, including a new occurrence for the flora of Ecuador, pp. 92-98 in Phytotaxa 568 (1) on page 95, DOI: 10.11646/phytotaxa.568.1.7, http://zenodo.org/record/718431
Kruipspreiding. Deel I: Proefresultaten
No full textDesign & ConstructionCivil Engineering and Geoscience
Op Niveau Wonen en Werken in Werelderfgoed
No full textIn ‘Op Niveau Wonen en Werken in Werelderfgoed’ gaan we op zoek naar het duurzame geheim van het Amsterdamse grachtenpand. Het historisch, architectonisch literatuur- en bronnenonderzoek (waar deze scriptie het eindresultaat van is) omvat een drietal naastgelegen interieurs aan de Keizersgracht in Amsterdam met elementen uit zowel de 17e, 18e, 19e, 20e als 21e eeuw. In de loop van de 20e eeuw verdween de woonfunctie grotendeels uit deze specifieke panden. In de jaren 70 van de 20e eeuw zijn de interieurs van de panden horizontaal aan elkaar gekoppeld: achter de voorgevels ontstond een enorm aaneengeschakeld kantoor. Anno 2013 is het pandencluster fysiek weer los van elkaar gekoppeld. In het bezit van eenzelfde eigenaar werden de panden in 2005 grondig gerestaureerd en deed de woonfunctie zijn herintrede. Aan de hand van onder andere deze transformaties onderzoeken we de verhoudingen en verschijningen van de woon- en werkfunctie door de tijd heen. Is flexibiliteit hierbij het toverwoord en hoe uit deze veronderstelde soepelheid van het interieur zich?Architectural History ThesisHistory of Art, Architecture and Urbanism i.c.w. Interiors, Cities and BuildingsArchitectur
Reconsideration of NS Station Amsterdam Zuid: Proposal for 'a mused´ Parnassusweg
No full textGraduation studio New directions for the Public Interior (2013/2014) is concerned with NS Station Amsterdam Zuid as a major and infrastructural node. While the main entrance of the station is mainly focused on businesspeople and corporate Zuidas, the Parnassusweg entrance gives stage to the other users of Zuidas: to VU students, residents and scolars. This proposal for 'amused' Parnassusweg states that the railway station entrance should be transformed from back door to the city to a(nother) full city gate to Amsterdam Zuid. Nine squares and gardens along Parnassusweg symbolize the nine muses of Parnassus and function as unifying reference points along the road´s currently fragmented area. These urban interventions distinguish potential public space from technocratic infrastructure and provide the opportunity for Parnassusweg to be a street instead of a road. The redesign of the railway station entrance at Parnassusweg provides a functional connection and transit between city and station, between various means of transportation and accommodates travellers coming from different directions. It also symbolizes Mount Parnassus: home of the nine muses, a place where creation and imagination are encouraged and where the various characteristics of all muses come together as an inspirational and ‘significant’ whole.The Architecture of the InteriorArchitectureArchitecture and The Built Environmen
Effect of Automation Transparency on Acceptance of Resolution Advisories in Air Traffic Control
No full textAs air traffic controller workload is a bottleneck on air traffic growth, automation solutions have been proposed. This study investigates the effect of transparency on the acceptance of resolution advisories generated by an adaptive automation tool and the frustration experienced by controllers when using this tool. Two different kinds of transparency were looked at. The first shows the variables the automation uses directly, while the second shows them only indirectly. Both incorporated a preview functionality, which allowed for comparison of the resolution advisory and the controller solution when the automation activated. A human in the loop experiment featuring these different kinds of transparency was performed. The results show that there is no significant difference in acceptance of advisories, workload or frustration ratings obtained from the NASA-TLX between the different levels of transparency. However, the group using the direct form of transparency received more short-term collision alerts and the time that the automation was active was higher than for the group using the indirect transparency. No significant difference in controller trust in the automation was found. In conclusion, there does not appear to be an influence of transparency on controller acceptance of resolution advisories, controller workload, controller frustration or controller trust in the automation. However, the experimenter noticed that most participants in the experiment did not use the information from the preview functionality to compare their solution to the resolution advisory. As they did not use the automation transparency to its full potential, further research on automation transparency is recommended in order to either confirm or dismiss the findings of this study.Aerospace EngineeringControl & Operation
Coal transport Kalimantan, research on different alternatives for coal transport in the province of South Kalimantan, Indonesia.
No full textThis master thesis focuses on the transportation of coal from two coalmines in South Kalimantan to the Java sea. Coal has to be transported from the coal mine area, situated hundred kilometre land inward, to a location with sufficient water depth, at the mouth of the river Barito. The biggest challenge for the new transport system is to increase the throughput capacity five times in five years. Three different transport modes have been investigated in this thesis. Those are; transport by barges, conveyor belt transport and hydraulic transport. A comprehensive logistics study is performed with the use of a simulation model. The simulation model is written in Matlab and is a so-called event based model. The transport configuration which is lowest in transport costs, is determined with the results from the simulation model. A transport configuration is a combination of the number of barges, number of berths and the loading capacity of the berths. Hydraulic transportation of coal is an unconventional transport mode. Hydraulic transportation of coal is very similar with the transportation of sand in the dredging industry. The coarse coal is first mixed with water and then transported through a pipeline by means of a number of centrifugal pumps in series. The main differences between a coal-water slurry and a sand-water slurry are the density of the particles and the average particle size. The particle size of coal, when it is exported, is much larger than the average particle size of sand. Larger particle sizes will increase the turbulent behaviour of the slurry. Different formulas for a coal-water slurry are analysed. In the analysis is investigated which influence the particle density and particle size have on the friction head in a particular formula.Ports and WaterwaysHydraulic EngineeringCivil Engineering and Geoscience
Beam or truss mechanism for shear in concrete: Problems converting a beam into a truss
No full textAn unpublished study by Prof. A.W. Beeby shows the differences in strength capacity between a reinforced concrete beam without shear reinforcement and the same beam with a cut-out section at the middle of the span. The cut-out section exists at the bottom part of the beam while the reinforcement still remains. It remarkably turns out that the strength capacity of the beam with the cut-out section is 1.6 times larger compared to the reference beam. The reference beam fails by a flexural shear crack which does not arise in the beam with the cut-out section. On the occasion of Beeby’s experiments and the lack of a simple physical model for a flexural shear crack this thesis has the objective to clarify the difference between a beam and a truss mechanism and the failure due to flexural shear cracks. The study is based on a simple supported beam without shear reinforcement subjected to a oncentrated load with a three point bending test with a slendernessratio of 2.45 and a reinforcement ratio of 0.89%. An analytical study describes the difference between the beam and a simplified truss mechanism. Linear analyses show the differences in stress distributions and deflections. The study shows the same difference in strength capacity as the experiments of Beeby. In addition quite a difference is revealed in the displacements of both mechanism. The truss mechanism shows a larger deformation compared to the beam mechanism. Finite element modelling with DIANA has been used to gain better insight in the difference of the strength capacity. The models use a total strain fixed crack model. The Hordijk-curve describes the tensile properties and an ideal relation describes the compressive properties. The decrease of the poisson ratio and the shear resistance around a crack have been taken into account by a damaged based shear retention model and a damaged based crack model. The finite element models show differences of the strength capacity within the same level of Beeby’s experiments. The force mechanism in both systems is different before the flexural shear crack arises in the beam. After a flexural shear crack occurs both mechanism seems to change into a similar truss mechanism, but detailed analyses show important deviations from this expectation. Variation of the cut-out dimensions shows that a too small gap results in a flexural shear crack and a too large gap in the failing of the cantilever part. Gaps between these limits all change into a truss mechanism which reaches the same level of failure load as the basic truss. The decrease of stiffness of the beam results in more compressive stresses in the truss mechanism preventing the occurrence of the shear crack. If the shear crack does not occur in the beam it results in a higher strength capacity. A dedicated shaped beam which has initially exactly the shape of a shear cracked beam without the concrete part below the crack, has a different strength capacity compared to a regular shear cracked beam. The dedicated shaped beam proves that the crack shape itself has no influence on the ability of converting into a truss. It turns out that in the regular beam it is impossible to develop a perfect truss mechanism after a flexural shear crack due to the concrete that is still present beneath the crack. The concrete beneath the crack causes a different stress distribution in the top of the beam compared to the dedicated shaped beam without this concrete. A hypothesis is given for the failure of the shear crack. The acquired knowledge of the influence of the concrete beneath the crack and the stiffness of the beam allows other design possibilities. It is possible to design a concrete truss, if among other, the yielding of steel, crushing of the concrete and the deformation capacity of the truss are taken into account. Further research is for instance possible for unbonded reinforcement and beams with a descending height.Structural and Building EngineeringStructural EngineeringCivil Engineering and Geoscience
Development Of Granular Structure In Cu90co10 Ribbons Through Furnace And Current Annealing
No full textOn-line measurements of resistance and temperature in melt-spun Cu90 Co10 ribbons are made using two different annealing techniques: conventional furnace annealing, and linearly varying current Joule heating. The aim of this paper is to consider the electrical current, flowing through the sample during the annealing, as a possible parameter to control thermal treatment parameters and thus the microstructure of these systems. Although an exact way to obtain the temperature from the annealing current remains a difficult task, the on-line changes in resistance with current allows one to identify structural changes in the sample during annealing. Also, because the temperature is found to increase continuously with electrical current, it is possible to calibrate the Joule heating system to precisely determine the annealing temperature.365 I30413043Allia, P., Baricco, M., Tiberto, P., Vinai, F., (1993) Rev. Sci. Instr., 64, p. 1053Da Silva, F.C.S., Ferrari, E.F., Knobel, M., (1998) J. Appl. Phys., 84, p. 5366Allia, P., Knobel, M., Tiberto, P., Vinai, F., (1994) J. Magn. Magn. Mater., 133, p. 243Knobel, M., Allia, P., Gomez-Polo, C., Chiriac, H., Vzquez, M., (1995) J. Phys. D: Appl. Phys., 28, p. 2398. , and references thereinYu, R.H., Zhang, X.X., Tejada, J., Zhu, J., Knobel, M., Tiberto, P., Allia, P., Vinai, F., (1995) J. Appl. Phys., 78, p. 5062Allia, P., Baricco, M., Tiberto, P., Vinai, F., (1993) Phys. Rev. B, 47, p. 3118Allia, P., Baricco, M., Knobel, M., Tiberto, P., Vinai, F., (1994) Mater. Sci. Eng. A, 179-180, p. 361Da Silva, F.C.S., Ferrari, E.F., Knobel, M., (1999) J. Appl. Phys., 86, p. 7170Ferrari, E.F., Da Silva, F.C.S., Knobel, M., (1997) Phys. Rev. B, 56, p. 6086Miranda, M.G.M., Rodriguez, G.J.B., Antunes, A.B., Baibich, M.N., Ferrari, E.F., Da Silva, F.C.S., Knobel, M., (1998) J. Magn. Magn. Mater., 185, p. 33
Scanning Probe Microscopy Facility for Operando Study of Redox Processes on Lithium ion Battery Electrodes
No full textAn Atomic Force Microscope (AFM) is combined with a special designed glovebox system and coupled to a Galvanostat/Potentiostat to allow measurements on electrochemical properties for battery research. An open cell design with electrical contacts makes it possible to reach the electrode surface with the cantilever so as to perform measurements during battery operation. A combined AFM-Scanning Electro-Chemical Microscopy (AFM-SECM) approach makes it possible to simultaneously obtain topological information and electrochemical activity. Several methods have been explored to provide the probe tip with an amount of lithium so that it can be used as an active element in a measurement. The “wet methods” that use liquid electrolyte appear to have significant drawbacks compared to dry methods, in which no electrolyte is used. Two dry methods were found to be best applicable, with one method applying metallic lithium to the tip and the second method forming an alloy with the silicon of the tip. The amount of lithium applied to the tip was measured by determining the shift of the resonance frequency which makes it possible to follow the lithiation process. A FEM-based probe model has been used to simulate this shift due to mass change. The AFM-Galvanostat/Potentiostat set-up is used to perform electrochemical measurements. Initial measurements with lithiated probes show that we are able to follow ion currents between tip and sample and perform an electrochemical impedance analysis in absence of an interfering Redox-probe. The active probe method developed in this way can be extended to techniques in which AFM measurements can be combined with mapping electrochemical processes with a spatial resolution.</p
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