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Designing a semi-automated approach to find potential evidence of corporate greenwashing
No full textGreenwashing can be defined as the mismatch between companies’ positive green communications and their activities that are counterproductive to the fight against climate change. Greenwashing companies can undermine the success of climate policies by hiding their climate footprints and prevent policymakers from realizing the need for further regulations. Thus, the identification of greenwashing should be done timely: this research sets out to find a semi-automated approach that can find evidence of greenwashing. The study of greenwashing is limited to the mismatch between companies’ communications on official websites and their lobbying activities in the European Union. Some steps of the design research approach were used namely the design development, demonstration, and evaluation (via a small-case evaluation) phases. The created approach measures companies’ communication levels of commitment to climate change using a GPT-based sentence classifier and then compares it to their levels of lobbying on climate change using keyword-based filtering on the EU Transparency Register, the official lobbying source for the EU. The proposed method is semi-automated at this stage and can inform a greenwashing appraisal, but it has issues with the accuracy of its analysis. This research partially fills the gaps in the greenwashing literature and advances the research in the use of GPT for classification purposes and in the field of climate lobbying in the EU. This research can teach the implementation of new EU regulations that aim at banning greenwashing: the more detailed the definitions of greenwashing that are used, the easier to find greenwashing automatically, and, therefore, the faster the enforcement of the ban can be.https://github.com/LudovicaBindi/collecting_greenwashing_evidence.git GitHub repository that contains the data collected, used, and produced for this thesis.Engineering and Policy Analysi
Aerodynamics of cylinders in tandem: Experimental investigation by stereoscopic PIV
No full textThis thesis investigates the aerodynamics of two finite wall-mounted cylinders in tandem, focusing on drag reduction as a function of governing parameters.For the experimental wind tunnel campaign, two measurement techniques were employed: balance measurements and stereoscopic particle image velocimetry. While balance measurements exhibited good repeatability, drag values obtained with PIV saw high uncertainty and only limited conclusions could be made from it.Cylinders were mounted to the floor of a closed wind tunnel test section. The trailing cylinder was rigidly attached to the balance underneath, while the leading cylinder could move upstream to the de- sired distance. Stereoscopic PIV images of the wake at various distances upstream and downstream were taken through the transparent sides of the wind tunnel. These images, in combination with the control volume approach, were used to determine the drag of a trailing cylinder.Coefficients of drag, obtained with a balance for isolated cylinders of various aspect ratios, were in line with similar results from the literature, albeit on the higher side. For cylinders in tandem of the same aspect ratio, AR, as the distance between them increased, the CD of a trailing cylinder converged to that of an isolated cylinder. Comparing tandem configurations with different AR and at the same nondi- mensionalized in-between distance, trailing cylinders with larger AR experienced larger drag reduction.Introducing cylinder diameter ratio as an additional degree of freedom showed that smaller diameter trailing cylinders experienced greater drag reduction at close distances. However, at a certain distance further downstream, this trend reversed.The drag reduction values obtained with PIV confirmed the findings from balance measurements. How- ever, due to the limited set of usable data, further work would need to be carried out to gain more confidence in the method.Aerospace Engineering | Aerodynamic
Microsegregation Influence on Austenite Formation from Ferrite and Cementite in Fe–C–Mn–Si and Fe–C–Si Steels
No full textThe production reality of sheet steels from casting to the end product is such that in the cases of ultra- and advanced high-strength steels, we have to deal with the segregation of elements on macro- and microlevels. Both can have a significant impact on the microstructure formation and resulting properties. There are several production stages where it can influence the transformations, i.e., casting, hot rolling process and annealing after cold rolling. In the present work, we focus on the latter, and more specifically, the transformation from ferrite–cementite to austenite, especially the nucleation process, in cold-rolled material. We vary the levels of two substitutional elements, Mn and Si, and then look in detail at the microsegregation and nucleation processes. The classical nucleation theory is used, and both the chemical driving force and strain energy are calculated for various scenarios. In the case of a high Mn and high Si concentration, the nucleation can thus be explained. In the cases of high Mn and low Si concentrations as well as low Mn alloys, more research is needed on the nuclei shapes and strain energy.Team Erik OffermanTeam Joris Di
Flying and Ground Robot Collaboration for Camera-based Search and Rescue
No full textSearch and Rescue (SaR) missions present challenges due to the complexity of the disaster scenarios. Most life losses and injuries occur in developing countries. Robotics has become indispensable for rapidly locating disaster victims. Combining flying and ground robots more effectively serves this purpose due to their complementary features. To this end, a cost-effective framework to perform conventional SaR tasks is presented. The method leverages You Only Look Once and video streams by an Unmanned Ground Vehicle (UGV) and an Unmanned Aerial Vehicle (UAV). In exploiting pose estimation to perform human depth estimation, the susceptibility of the algorithm to variations in poses was unveiled. In tracking object trajectories, the collaboration is advantageous in wide-area cluttered trajectories as opposed to narrow-area unobstructed trajectories. In mapping terrain elevation, errors drop significantly with the assistance of the UAV. Moving forward, devising adaptable strategies tailored to diverse SaR scenarios will be pivotal.Aerospace Engineerin
Finding Companions in the YSES IFS Data
No full textPlanet formation is a topic that still has many unanswered questions, particularly regarding the formation of wide orbit giant planets. Detecting more of these types of planets can aid understanding of how they form by giving examples of what kind of planets exist. Direct imaging is uniquely well suited to detecting these kinds of planets, which is why several direct imaging surveys have been launched with this goal. Including the Young Suns Exoplanet Survey, which is looking specifically for wide orbit giant planets around young solar analogues.The survey makes use of the IRDIS instrument on the VLT, which images in parallel with the IFS. By analyzing the IRDIS data, the researchers have already detected three planets in two systems. However, the IFS data has not yet been analyzed. That was the goal for this thesis: to contribute to YSES and the broader scientific community by analyzing the IFS data to search for potential companions.In total, 41 observations of 37 different star systems were analyzed. The data was pre- and post-processed (with SDI), and candidate companions were identified and examined. Eight candidate companions were found in five systems. Of those candidates, all were determined to be background stars and not related to the host. Two were bright single stars. One system had two M-dwarf candidate companions that were in a binary system together. The last two systems each had two candidate companions, and in both cases it was revealed that these candidates form a triple system of their own, with one of the candidates being an unresolved binary. One of these triple systems was previously thought to be an equal mass binary with the host star, however this thesis has proved that this is not the case.All of the systems analyzed also had detection limits computed. This gives a good idea for what size of objects could have been seen if they had been in the images. For most systems, the limit after SDI is around 5-10 Jupiter masses at 0.3"-0.5". This leaves room for planetary mass companions in these systems which could be found in follow-up observations. The two background triple systems should also have follow-up observations performed, as this configuration is somewhat unusual and warrants further study.Aerospace Engineerin
Project-Specific Cost Escalation Modeling: Crafting a Stochastic Tool for Predicting escalation: Modeling escalation
No full textGaining insights into anticipated future expenses is essential for both the planning and construction phases of a project. A significant factor in future costs, particularly over extended periods, is the variability of material and labor prices. the change in costs over time, known as ’cost escalation,’ has been the focus of numerous research efforts. These studies primarily aim to forecast the Construction Cost Index (CCI), a composite index representing a standardized array of materials and labor typical in construction projects. This research presents a novel approach to forecast cost escalations, tailored to individual construction projects, addressing the shortcomings of predictions of a generic Construction Cost Index (CCI). Traditional CCI predictions, while providing some foresight, are limited by their generic nature and often overlook the specific material and labor variations within different projects. Additionally, current research generally fails to account for the uncertainty in the forecasts of the change in the material price and the estimate of the construction cost. In response to these challenges, this research pivots around the following research question: How can cost escalation for various types of construction projects be predicted, accounting for uncertainties in final construction costs and the forecast? Addressing this question involves selecting distinct indices for various project resources, such as steel, concrete, and labor, and combining these predicted indices in line with each resource’s cost. To achieve this, the study evaluates several time-series forecasting models, namely the vector error correction model (VECM), the vector autoregression (VAR) model, and the Holt-Winters model. For each model an automatic forecasting process is created, which automatically checks the suitability of the model, select the appropriate variables (in case of a multivariate model) and selects parameters. These models are evaluated for their accuracy across different time-frames and forecasting horizons. The Holt-Winters model, in particular, showed promise in providing reliable confidence intervals and point forecasts. The study’s testing phase revealed varying degrees of success, as volatile indices like copper and steel proved to be challenging, whereas forecasts for less volatile indices achieved higher accuracy. This outcome suggests room for improvement in refining these forecasting methods. The project-specific forecasts, including cost uncertainties, are developed by inputting cost estimates associated to the material price at current day value. The cost estimates input includes material and labor costs and their uncertainties. The uncertainties are represented through a three v point estimate (optimistic, pessimistic, and most likely values). This input is then transformed into a PERT distribution which is a transformation of the Beta distribution. The final stage involves combining the PDFs of each project activities cost (considering the cost of each specific resource) with the monthly forecast PDFs in a Monte Carlo simulation, providing a detailed cost distribution histogram of total cost and the individual resources cost. The tool’s functionality was demonstrated through a case study on a highway construction project. In this demonstration, specific project data, including material and labor cost estimates, were inputted into a hybrid web and Excel interface. This setup facilitates visualization and manipulation of project information. The tool processes these inputs via the AFP and Monte Carlo simulation, yielding comprehensive outputs such as histograms and statistical properties of the output. This is visible for total project costs and resource-specific escalations. This demonstration effectively showcased the tool’s capability to offer detailed insights into cost escalation, addressing the variability and uncertainty in construction projects. It underscored the tool’s alignment with the study’s objective of providing nuanced, project-specific cost escalation forecasts, moving beyond traditional CCI predictions. In conclusion, this study introduces a tool that caters to specific project resources, timelines, and uncertainties in cost escalations. While current limitations prevent its immediate practical application, this proof-of-concept lays the groundwork for future improvements. Focus of future research should be on refining accuracy and comparing the tool’s forecasts with escalation of historic projects to establish more robust insight into the actual escalation of projects.Civil Engineering | Construction Management and Engineerin
Transformation of the Kruispuntkerk: Design through standarization
No full textThis paper aims to explore the applicability of the standardization of heritage and sustainability values in the context of church transformations in the Netherlands. Through comparative research on available assessment tools, specifically focusing on church transformations, the study investigates whether these tools extend beyond their original purpose of standardization, and therefore, if this standardization of values can be used in the design process. The central question is articulated as follows: How can standardization of sustainability and heritage values be used in the design process of church transformations in the Netherlands?The comparative literature research identifies two pertinent tools, DuMo and BPSC, both addressing standardization of sustainability and heritage values with distinct methodologies. The analysis of these tools' applicability in practice leads to the second phase of the research, aiming to determine if the core indicators of these tools can facilitate in the decision-making process of church transformation design.While assessment tools primarily seek to standardize values, this paper explores their potential applications standardization of values can have in the design approach. Although not initially created for the purpose of design, the standardization achieved through these tools can enhance comprehension of various considerations in different stages of the design process. In conclusion, this research contributes to the existing framework on the standardization of heritage and sustainability values, specifically within the context of church transformations in the Netherlands.The KruispuntkerkZero waste churchArchitecture, Urbanism and Building Sciences | Heritage & Architectur
Microwave spectroscopy of interacting Andreev spins
No full textAndreev bound states are fermionic states localized in weak links between superconductors which can be occupied with spinful quasiparticles. Microwave experiments using superconducting circuits with InAs/Al nanowire Josephson junctions have recently enabled probing and coherent manipulation of Andreev states but have remained limited to zero or small magnetic fields. Here, we use a flux-tunable superconducting circuit compatible in magnetic fields up to 1T to perform spectroscopy of spin-polarized Andreev states up to ∼250mT, beyond which the spectrum becomes gapless. We identify singlet and triplet states of two quasiparticles occupying different Andreev states through their dispersion in magnetic field. These states are split by exchange interaction and couple via spin-orbit coupling, analogously to two-electron states in quantum dots. We also show that the magnetic field allows to drive a direct spin-flip transition of a single quasiparticle trapped in the junction. Finally, we measure a gate- and field-dependent anomalous phase shift of the Andreev spectrum, of magnitude up to ∼0.7π. Our observations demonstrate alternative ways to manipulate Andreev states in a magnetic field and reveal spin-polarized triplet states that carry supercurrent.QRD/Kouwenhoven LabQRD/Goswami LabQN/Kouwenhoven LabAndersen La
Influences of Nanostructures of Sn and Ir for the Oxygen Evolution Reaction in Polymer Electrolyte Membrane Water Electrolysis
No full textThe influence of nanostructures and interaction of Sn and Ir in oxygen evolution catalysts in a polymer electrolyte membrane electrolyzer were investigated. For this aim, two synthesis methods, namely, the one-step solution combustion method and the precipitation-deposition method with sodium borohydride reduction, were evaluated to prepare distinct nanostructures. Sn addition to Ir-based oxygen evolution reaction catalysts has been reported to yield materials with higher activity; however, in our case, this was observed only for Sn/Ir catalysts prepared by the precipitation-deposition method. The nanolayer of Sn/SnO2 deposited over metallic Ir particles was identified to enhance the interfacial contacts, resulting in synergistic interactions. By deconvolution of the polarization curves into constituting contributions, the performance improvement was attributed to the higher exchange current density of the Sn/Ir powder as a consequence of a higher number of surface reaction sites created by the Sn-Ir interactions.ChemE/Catalysis Engineerin
Approximate dynamic programming for constrained linear systems: A piecewise quadratic approximation approach
No full textApproximate dynamic programming (ADP) faces challenges in dealing with constraints in control problems. Model predictive control (MPC) is, in comparison, well-known for its accommodation of constraints and stability guarantees, although its computation is sometimes prohibitive. This paper introduces an approach combining the two methodologies to overcome their individual limitations. The predictive control law for constrained linear quadratic regulation (CLQR) problems has been proven to be piecewise affine (PWA) while the value function is piecewise quadratic. We exploit these formal results from MPC to design an ADP method for CLQR problems with a known model. A novel convex and piecewise quadratic neural network with a local–global architecture is proposed to provide an accurate approximation of the value function, which is used as the cost-to-go function in the online dynamic programming problem. An efficient decomposition algorithm is developed to generate the control policy and speed up the online computation. Rigorous stability analysis of the closed-loop system is conducted for the proposed control scheme under the condition that a good approximation of the value function is achieved. Comparative simulations are carried out to demonstrate the potential of the proposed method in terms of online computation and optimality.Team Bart De SchutterTeam Ton van den BoomDelft Center for Systems and Contro
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