Aaltodoc

Aaltodoc is the institutional repository of Aalto University.

Aaltodoc has a new updated appearance. Instructions for searching and more information is available here.

Otakaari 1 grandhall. Photo: Esa Kapila
 

Communities in DSpace

Select a community to browse its collections.

Now showing 1 - 13 of 13

Recent Submissions

Electrochemical detection of tetracycline in milk using nanocellulose/carbon nanostructure composite electrodes
(2025-04-28) Hämäläinen, Tuomas
 School of Electrical Engineering | Master's thesis
The thesis focuses on electrochemical sensing of tetracycline antibiotic molecule in phosphate buffered saline (PBS) and milk serum. The study was conducted primarily on carbon nanofiber (CNF) electrode using a modification with TEMPO-oxidized cellulose nanofibrils (TOCNF), polyethyleneimine (PEI) and single wall carbon nanotubes (SWCNT). The study includes basic characterization of electrode kinetics using ruthenium, study on the effect of scan rate, study on repeatability and reproducibility as well as analytical studies to determine linear concentration range and the limit of detection. The electrode was shown to have an electrochemically reversible electron transfer process. In low concentrations (1-10 µM) the response was governed mostly by adsorption and in high concentrations (above 25 µM) the deeper adsorption sites start to saturate. In low concentrations the electrode had limit of detection (LOD) of 0.86 µM with sensitivity of 0.82 µA/µM in PBS, and in milk serum LOD was 29.4 µM and 60.48 µM for two oxidation peaks, with sensitivities of 0.143 µA/µM and 0.137 µA/µM.
Scaling of Large Rotor Sails
(2025-04-09) Martin, Jusa
 School of Engineering | Master's thesis
Maritime industry is undergoing a change due to increasing fuel prices and sanctions from emissions. The traditionally conservative maritime industry demands increasingly cost-effective solutions with short payback times from new technologies in order to justify their adoption. Shipowners are seeking alternative methods to reduce fuel consumption and emissions, and one viable option is wind-assisted propulsion systems, such as Flettner rotors. This study focused on the feasibility of scaling Flettner rotors larger, improving power cost-effectively, and scalability. The study utilized a literature review, flow simulations, and simplified cost and strength calculations. Based on these calculations, larger rotor sails can increase power cost-effectively. According to the estimated costs and thrust forces obtained from the simulations, the payback period of the investments may be shorter compared to smaller rotor sail sizes, increasing the commercial attractiveness of the technology. Additionally, the study examined impact of rotor sails on vessel operations, vessel integration, market potential, and maintenance requirements. The results indicated that installing and transporting larger rotor sails is feasible but presents significant challenges. Operational and maintenance generally remain unchanged compared to the smaller sails, but the use of exceptionally tall rotor sails may affect ship routing and port access due to the increased air draft. In conclusion, large-scale rotor sails generate more power cost-effectively, but the increased air draft may have negative effects on market potential. Based on the study, rotor sails represent a promising development direction in wind-assisted shipping, and the topic is worth further research and development.
Assessing the risk of transcranial magnetic stimulation in patients with cranial implants
(2025-04-24) Tillander, Casper
 School of Electrical Engineering | Master's thesis
Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique used in the treatment of various neurological and psychiatric diseases, as well as presurgical mapping of the cortex. Intracranial metallic objects, such as neurosurgical implants, are a contradiction to TMS, leading to certain patients being deprived of its clinical benefit. This thesis evaluated the safety of mechanically fixed cranial implants in the TMS environment, taking into account the forces exerted on and the heating of the implants. This was done theoretically through a finite element methods (FEM) analysis, and experimentally using ex vivo tests derived from standardized tests for the safety assessment of implants in the magnetic resonance imaging (MRI) environment. The ex vivo experiments included twelve common cranial implants. These were evaluated during three TMS protocols commonly employed for the treatment of medication-resistant depression: continuous 1 Hz stimulation, 10 Hz stimulation (comprising 3000 pulses, 4-second bursts with 11–26-second inter-burst intervals), and intermittent theta burst stimulation (iTBS). In addition, TMS protocols employed for presurgical speech mapping and post-neurosurgery recovery were evaluated based on the data collected from the aforementioned protocols. The results demonstrate that none of the tested implants experienced forces sufficient to compromise the integrity of the cranial screws securing them to the cortical bone. A thermal analysis showed that eleven out of the twelve implants remained below the established safety threshold of 43 °C during all TMS protocols. However, one implant, the 3D Cranial Mesh Plate (100 × 100 × 0.6 mm), exceeded this thermal threshold across all stimulation protocols, constituting a likely safety concern. These findings suggest that while most cranial implants are likely safe in the TMS environment, specific implant designs, such as large surface-area mesh plates, may require additional caution or contraindication.
Seismic analysis and design methods of reinforced concrete structures for nuclear power plants in compliance with Regulatory Guides on nuclear safety
(2025-04-25) Lättilä, Toni
 School of Engineering | Master's thesis
Regulatory Guides on nuclear safety are a set of guides known as YVL guides, which are published by Radiation and Nuclear Safety Authority of Finland. YVL guides specify detailed safety requirements concerning the implementation of safety level in accordance with the Nuclear Energy Act (990/1987). This thesis studies the impact of YVL guide compliant seismic analysis methods on design of reinforced concrete structures and the quantities of required reinforcement. The considered methods are equivalent static, response spectrum and time history analyses. This thesis comprises of literature review and case study. Literature review provides the necessary theoretical foundation for seismic analysis and reinforcement calculations based on results of the analysis methods. Case study consists of seismic analyses and reinforcement calculations for two buildings to evaluate the impact of the methods on the reinforcement quantities and computational efficiency. Computational models were developed with Patran software, seismic analyses were performed with MSC Nastran and the reinforcement calculations with IVODIM software. The reinforcement quantities obtained with each method were compared, and the efficiency of the methods was evaluated based on computational time costs. The findings showed that equivalent static analysis was computationally efficient, but significantly overestimated reinforcement. Response spectrum analysis produced more reasonable reinforcement with low computational cost but resulted in an excessive amount of overall reinforcement. Time history analysis had a moderate time cost and provided optimized reinforcement. While time history analysis had the highest computational cost, the study confirms that redundant time steps can be omitted without compromising accuracy, significantly reducing computational time. The findings support the use of time history analysis in seismic design of nuclear power plants. This method offers economic benefits by optimizing reinforcement, which can lower construction costs. Modern computers can handle the computational demands efficiently and the use of time history analysis should not be limited by time or budget constraints in nuclear projects.
Compliance assessment of Google Cloud Kubernetes clusters using Kubernetes Compliance Evaluation Matrix
(2025-04-27) Bin Khalid, Talha
 School of Electrical Engineering | Master's thesis
The goal of the thesis was to assess different Cloud Security Posture Management (CSPM) tools that help with the compliance of Google Kubernetes Engine (GKE) clusters over CIS GKE benchmarks. CIS benchmarks are industry standard security benchmarks that help with keeping the underlying assets secure in an ever evolving security landscape. The research was commissioned by Nordcloud - an IBM company to help assess which tools should be used internally for its various clients. The scope of this research was to study only three tools - Google Kubernetes Engine (GKE) Enterprise edition, Microsoft Defender for Cloud and Kube Bench. The initial chapters of this thesis briefly explain the concepts of Cloud, Containers, Kubernetes and CSPM tools in general. The thesis then goes into the details of GKE Enterprise, MS Defender for Cloud and Kube Bench. By following the details provided in this thesis, the reader can successfully replicate the implementation and use of these tools. A Kubernetes Compliance Evaluation Matrix (KCEM) was developed and used to compare the aforementioned tools amongst each other. This KCEM consists of 7 different criteria, and it can be used as a standard decision matrix to assess any CSPM tool over CIS compliance benchmarks for any type of Kubernetes installation. The goal of the thesis was fulfilled, and the results can be found in the conclusion section.