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Multiple-pilot injection strategies with both moderate and short time separations (dwells) are investigated in a light-duty diesel engine. Both conventional and optical engine experiments are performed. By implementing triple-pilot injection strategies with short dwells between the individual injections, combustion noise can be significantly reduced. The sound pressure level was reduced by nearly
The objective of this paper is to present the main results of an engineering-research project dealing with model-based evaluation of waste streams treatment from a biotech company. This has been extensively done in domestic treatment systems, but is equally important, and with different challenges in industrial wastewater treatment. A new set of biological (activated sludge, anaerobic digestion),
Deep and rapid decarbonization of the building sector requires energy demand reductions and the incorporation of renewable-energy sources. Energy retrofitting of existing buildings is a central strategy in climate mitigation and has often been highlighted as a cost-effective strategy. However, decisions on these strategies are often hampered by modeling assessments that are limited by contextual,
Considerable research has been conducted in Scotland to reconstruct Younger Dryas glaciers and palaeoclimatic conditions, but our understanding remains incomplete. In this contribution, we examine the Gaick, a dissected plateau that extends over ∼520 km 2 in the Central Grampians, Scotland. The extent and style of Younger Dryas glaciation in the Gaick has been repeatedly contested, although a mo
Solitary insects that feed on floral nectar must use innate knowledge to find their first flower. While innate preferences for flower colours are often described as fixed, species-specific traits, the nature and persistence of these preferences have been debated, particularly in relation to ontogenetic processes such as learning. Here we present evidence for a strong context-dependence of innate c
Cracks in concrete structures can have a negative impact on durability and aesthetic appearance. It is therefore important to estimate crack widths before construction, and to use suitable reinforcement amounts to limit crack widths. Crack widths are however hard to predict in restrained structures, as cracking reduces the stiffness, which in turn reduces the restraint and thereby the amount of cr
The communication of requirements within software development is vital for project success. Requirements engineering and testing are two processes that when aligned can enable the discovery of issues and misunderstandings earlier, rather than later, and avoid costly and time-consuming rework and delays. There are a number of practices that support requirements-test alignment. However, each organis
ObjectivesCultural behaviors are theoretically linked to future life chances but empirical literature is scant. We use heavy metal as an example of cultural identities due to its high salience. We first assess the social morphology of metal preferences in terms of socio-economic and socio-structural positions, and then asses the short term outcomes of being a heavy metal fan on education and healt
Kazakhstan, Kenya, Kyrgyzstan and Tanzania share a past and present as authoritarian states. Dominant parties are in power in Tanzania and Kazakhstan, while elections are competitive but not democratic in Kenya and Kyrgyzstan. Returns for political support (clientelism), and persecution of political adversaries and the electorate (repression), are key components in all four states. This dissertati
The mechanical, optical, and electrical properties of III-V semiconductor heterostructures are investigated in thisthesis. The semiconductor materials are grown by metal-organic vapor phase epitaxy, yielding wire shaped crystals(nanowires) having a length of ~ 1 μm and diameter of ~ 100 nm. Nanowires are relevant for many applications,such as optical detectors, photovoltaics, light emitting diodes
Ice throw is a significant risk factor in the vicinity of wind turbines located in cold climate areas. We present a method to estimate the ice chunk trajectories. First, similar to the common practice, only translation is accounted for and the object trajectory is determined by gravity and the aerodynamic drag force. The sensitivity of the trajectories to the launch positions, wind speed, turbine
The dynamic response of cantilevers to a hydrodynamic load has been studied numerically. The Reynolds number of the flow was fixed at 5000 and the variation in re-duced velocity was achieved by varying the Young’s modulus of the cantilever. Cantilevers with aspectratios of 5 and 10 were considered for reduced velocities in the range 2 to 30. The simulations were performed using a strongly coupled
Jet impingement cooling is commonly used in gas turbines. Usually the spent air from the upstream jets forms a cross-flow past the downstream jets, which degrades their heat transfer performance. In the present study, a new method was proposed to promote the jet penetration and enhance the impingement heat transfer. By placing a delta-winglet vortex generator pair (VGP) in the cross-flow upstream
