814 research outputs found
Evaluating deterrents of illegal behaviour in conservation: Carnivore killing in rural Taiwan
No full textRules restricting resource use are ubiquitous to conservation. Recent increases in poaching of iconic species such as African elephant and rhino have triggered high-profile interest in enforcement. Previous studies have used economic models to explore how the probability and severity of sanctions influence poacher-behaviour. Yet despite evidence that compliance can be substantial when the threat of state-imposed sanctions is low and profits high, few have explored other factors deterring rule-breaking. We use the randomised response technique (RRT) and direct questions to estimate the proportion of rural residents in north-western Taiwan illegally killing wildlife. We then model how potential sources of deterrence: perceived probabilities of detection and punishment, social norms and self-imposed guilt, relate to non-compliant behaviour (reported via RRT). The perceived likelihood of being punished and two types of social norms (injunctive and descriptive) predict behaviour and deter rule-breaking. Harnessing social norms that encourage compliance offers potential for reducing the persecution of threatened species
Extracting Boer-Mulders functions from p+D Drell-Yan processes
No full textWe extract the Boer- Mulders functions of valence and sea quarks in the proton from unpolarized p + D Drell- Yan data measured by the FNAL E866 Collaboration. Using these Boer- Mulders functions, we calculate the cos2 phi asymmetries in unpolarized pp Drell- Yan processes, both for the FNAL E866/ NuSea and the BNL Relativistic Heavy Ion Collider experiments. We also estimate the cos2 phi asymmetries in the unpolarized p (P) over bar Drell- Yan processes at GSI.Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)37ARTICLE5null7
Breakwaters under construction exposed to oblique waves
No full textDuring the construction of breakwaters contractors often encounter undesired reshaping of exposed core material. This reshaping is comparable to the deformation process of berm breakwaters in which the outer profile reshapes into a more stable s-curve. In the case of oblique waves this deformation is enhanced by a longshore transport of stones leading to even more loss of material and damage. Throughout the years few formulas were derived for both processes which describe the behaviour of berm breakwaters as well as gravel beaches reasonably well. These formulas however turned out to be inadequate when it comes to describing the behaviour of core material. In particular the influence of the wide grading of quarry run, commonly used as core material, is to a large extent unknown and generally not described in the available relations. To investigate this influence of the stone grading on both the two-dimensional deformation and longshore transport new physical model tests were carried out in the wave basin at Delft University of Technology. In total 12 tests were executed in which two different gradings, three different angles of wave attack and two different wave spectra were tested. Data collected from the tests included wave and profile measurements together with the displacements of stones, originating from two colour beams which were applied in the middle of the trunk. These data along with visual observations eventually led to a conceptual model describing stone movements in both transverse and longshore direction. Using Matlab three-dimensional profile and erosion models were generated from which the different profile parameters were determined. With respect to the distance from origin, for each test an exponential relation was derived to describe the stone displacements. After determination of the area of uniform transport these exponential relations were used to calculate the total longshore transport by means of extrapolation and multiple integrations. Subsequently all parameters found were compared to the formulas currently available for both processes. Regarding the deformation parameters the test results produced the best fit with the formulas derived in [MERLI 2009]. Still on several occasions a deviant relation was found concerning the influence of wave obliquity. In addition, the formulas became less accurate for the narrow grading used in the tests, which fell outside the range tested by Merli. However, for the crest height of the deformed profile test results deviated completely from the available formula as no influence was found whatsoever for all tested parameters. Here the deviation was contributed to a higher instability of the part above the initial deformation, partly due to the steepness of the slope. On the subject of the longshore transport clear trends were found describing the influence of the varying parameters. Both a higher wave load and wider grading lead to an increase of the longshore transport. For the wider grading, however, this increase gave a rather distorted image, as not all fractions in the mixture were transported evenly. Due to segregation the coarsest fractions were mostly transported in the transverse direction while the finer fractions were transported further away in the longitudinal direction. Alternatively, computation of the longshore volume transport proved to be more representative. Regarding the effect of wave obliquity an increase in angle of wave attack of 30 to 45 degrees was accompanied by a decrease in longshore transport; though this decrease was less than already available formulas indicated. However despite the fact that it describes a completely different trend concerning this particular influence, the best fit was found after multiplying the relation derived by [ALIKHANI 1996] with a factor 100.Hydraulic EngineeringCivil Engineering and Geoscience
Asfalt in de waterbouw
No full textDit document bevat de vijfde brochure van de Vereniging voor Bitumineuze Werken (VBW) getiteld "Asfalt in de waterbouw". De brochure bevat een achttal artikelen m.b.t. dit onderwerp: - Totstandkoming van de leidraad voor toepassing van asfalt in de waterbouw; voorgeschiedenis, opzet en toekomstig gebruik; door ir. E.H. Ebbens - Overzicht asfalttoepassingen in de waterbouw; door Prof. ir. J.F. Agema - Materiaaltechnologie; door H.J.A.J. Gruis - Ontwerpen van waterbouwkundige asfaltbekledingen; door ir. J.A. van Herpen - Resultaten uit recent onderzoek; door ir. H. Roos - Uitvoering van bitumineuze dijkbekledingen; door ir. G.L.M. Mulders - Bouwen en beheren; door ir. W. Bandsma - Beheer en onderhoud van waterkeringen; door ing. L.A. Philips
Flavor separation of the Boer-Mulders function from unpolarized pi(-)p and pi D- Drell-Yan processes
No full textWe show that measuring the cos2 phi angular dependence in unpolarized Drell-Yan processes with pi(-) beams colliding on proton and deuteron targets can determine the ratio of the Boer-Mulders functions for d and u quarks inside the proton h(1)(perpendicular to,d)/h(1)(perpendicular to,u), which is still lack of theoretical constraint. The comparison of the cos2 phi asymmetries measured in unpolarized pi(-)p and pi D- Drell-Yan processes, which are accessible at CERN by the COMPASS Collaboration, can help to discriminate whether h(1)(perpendicular to) effects or QCD vacuum effects are preferred by data. (c) 2006 Published by Elsevier B.V.Physics, MultidisciplinarySCI(E)18ARTICLE5494-49863
Performative architecture as a guide line for transformation of the defence line of Amsterdam
No full textThe main topic that is researched in this study is: what performative architecture is and its role in the design process and product. In the scope of performative architecture the aim is to focus what a building does rather than what it is and the fact that architecture should have the capability of being adaptable to changing time, conditions and environment. A design problem is taken under consideration and designed from the scope of performative architecture. The design problem is the transformation of the Defence Line around Amsterdam, designing new buildings with the recent technologies as additions to the forts remaining from 1900’s. A “performative model”, which supports design from the conceptual stage until production of scale prototypes is structured by the author for this specific design problem. This performative model is used as a case study for the research of the role of the computational design tools in the design process and product of performative architecture. In addition to the design process, the role of using computer-aided manufacturing to increase performativity is envisioned and the proceeds of it to the relationship of design and manufacturing are also researched.Computational Design and Fabrication Technologies in ArchitectureArchitectureArchitectur
Wind turbine control: Advances for load mitigations and hydraulic drivetrains
No full textIn the last decades, tremendous efforts have been put in advancements of wind turbine technology by scientific research and industrial developments. One of the focal areas has been the upscaling of turbines to increase power capacity. However, by enlarging turbine sizes, the square-cube law dictates rising costs per unit of power capacity. To break this trend of increased expenses, more advanced control techniques are key in facilitating load reductions and system level advances. The synthesis of novel controller designs, and advancements of existing strategies, are in this thesis effectuated by leveraging well-established control theory. This method resulted in analysis tools, that gave rise to practical applicable implementations, of which some are evaluated on real-world setups. The employed approach has thereby shown to stimulate further advancements of wind turbine technology...Due to the Corona epidemic, this promotion has been moved from March 31, 2020 to September 11, 2020. The PDF still contains the original promotion date.Team Jan-Willem van Wingerde
Modelling of stress development and fault slip in and around a producing gas reservoir
No full textMany gas fields are currently being produced in the northern Netherlands. Induced seismicity related to gas production has become a growing problem in the Netherlands in the past two decades. To date, a few hundred induced seismic events occurred. Induced seismicity is generally assumed to be the result of induced reactivation of discontinuities in the subsurface. Field data of the Groningen and Annerveen gas fields as well as other Rotliegend gas fields in the Netherlands are analysed. A large amount of seismic cross sections through seismic events is studied. It is very likely that the seismic events are the result of reactivation of existing discontinuities (like faults) in or near the reservoirs. The objective of the research presented in this dissertation is to obtain a better understanding of the mechanisms of gas production induced reactivation of faults by means of 3D geomechanical modelling of gas reservoirs. It is a step towards future assessment of expected seismic energy release when (further) developing gas fields in the Netherlands. Furthermore, attention is given to the development of several quantification methods, used for the analysis of the calculation results. Quantification methods include relative shear displacements, seismic moment, stress paths, mobilised shear capacity and total stress changes per unit depletion. The geomechanical models represent the geometries found in the seismic cross sections. The models contain a disk-shaped gas reservoir in an extensional stress regime. A steeply dipping normal fault plane intersects the reservoir and divides it into two compartments: a footwall and a hanging wall reservoir compartment. Stress development and fault slip during gas depletion are analysed. Gas depletion can lead to both normal and reverse fault slip on the same fault plane. In the given setting of a steeply dipping normal fault in an extensional stress regime, normal fault slip due to differential reservoir compaction is the dominant mechanism, rather than reverse fault slip. The effect of differential reservoir compaction is most pronounced for a configuration, where the top of the hanging wall reservoir compartment is positioned exactly opposite to the bottom of the footwall reservoir compartment, resulting in a relatively large amount of fault slip over a narrow area. Normal fault slip is supported by equal depletion of both reservoir compartments. Reverse fault slip is supported by differential pore pressure development due to reservoir compartmentalisation. Especially the combination of a relatively stiff surrounding rock and differential pore pressure development due to reservoir compartmentalisation can result in relatively large amounts of reverse fault slip. Both normal and reverse fault slip are promoted by a Young's modulus or Poisson's ratio of the surrounding rock larger than those of the reservoir rock (Esur > Eres or νsur > νres). The initial state of stress is relatively closer to the failure line than in case of a smaller stiffness contrast. Esur < Eres and νsur < νres oppose the reactivation of the fault. Values of νsur lower than 0.2 seem to have no significant influence on the calculated maximum normal fault slip. Calculations indicated that the Young's modulus of the surrounding rock is a more important parameter influencing gas depletion induced fault slip than the Poisson's ratio of the surrounding rock. Calculations with a 3D anisotropic tectonic stress field show a strong dependency of the amount of calculated fault slip on the direction of the maximum horizontal stress with respect to the fault strike direction. Most normal fault slip occurs when the maximum horizontal stress is directed parallel to the fault strike. Minimum normal fault slip is calculated for a maximum horizontal stress direction perpendicular to the strike direction of the fault. A larger horizontal stress component parallel to the azimuth of the fault has a limiting effect on the fault slip. Total fault slip can consist of a dip slip and a strike slip component. In case of a horizontal reservoir, no significant strike slip is observed when the fault strike direction is a principal stress direction. A certain amount of strike slip is observed for calculations with an angle between the maximum horizontal stress direction and the fault strike direction of 31°, 45° and 59°. Strike slip contributes to both normal and reverse fault slip.Civil Engineering and Geoscience
- …
