Respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), are pathological conditions affecting the airways of the respiratory system. Currently more than 90 million people are suffering from respiratory diseases, and COPD is predicted to become the third leading cause of death in the world by 2030. Inhalation devices are commonly used in the treatment of respiratory diseases, where an aerosolised medication is delivered to the lungs of the patient via inhalation. The inspiratory flow rate is one of the main factors affecting the drug deposition in the lung, but is currently not controlled in most inhalation systems. The purpose of this master thesis is to design, manufacture and characterize a passive flow regulator device for portable inhalation systems. The designed prototype utilises the principle of a Venturi nozzle and membrane deflection to create a variable flow constriction, which acts as a negative feedback loop for the flow rate regulation. The flow regulator is based on a previously working device used for controlling exhalation flow rate in the range of 3 L/min. Experimental results are evaluated and compared to an analytical solution of the classical Venturi design. Additionally, membrane deflection is measured to analyse the physical behaviour of the membrane within the device. The flow regulating device is scaled up for inhalation flow rate ranges (>30 L/min) and a flow rate sensor is constructed for the measurements. The passive control of flow rates using a deflecting membrane is deemed promising. However, further improvements of the scaled up model used for inhalation are necessary.

The growing popularity of photovoltaic (PV) generation systems leads to an increase in the number of residential and commercial grid-tied PV systems that interconnect to the distribution circuit. This affects the characteristics of the distribution circuit; for example, the assumption that the voltage profile of a radial line decreases down-stream becomes invalid because of the addition of the PV system on the line. This poses new challenges when setting the parameters of voltage regulating devices. Add to that the fact that PV systems are intermittent, especially on cloudy days, which make the line even more difficult to regulate, and the number of switching occurrences of the regulating devices increases, thus accelerating wear-and-tear to the utility’s equipment. The objective of this thesis is to develop an index which qualitatively indicates the impact of PV system(s) on operation, efficiency, reliability, and lifetime of voltage regulation equipment. Tests on the proposed index will be performed on several cases including circuits containing state-of-the art methods that integrate PV systems with minimum impact to utility equipment. Investigation of methods to further mitigate equipment wear by selecting the best interconnect point on the circuit will also be conducted to test the proposed index. The development and validation of the proposed index will entail power system modeling and simulation of distributed generation using PSCAD. The proposed index resulted from this study will provide a useful tool to allow utility companies pick the optimum locations for distributed generation to minimize their negative impact on the distribution lines as well as to determine the need for extra mitigation equipment.

DC-DC converters can be separated into two main groups: switching converters and linear regulators. Linear regulators such as Low Dropout Regulators (LDOs) are straightforward to implement and have a very stable output with low voltage ripple. However, the efficiency of an LDO can fluctuate greatly, as the power dissipation is a function of the device’s input and output. On the other hand, a switching regulator uses a switch to regulate energy levels. These types of regulators are more versatile when a larger change of voltage is needed, as efficiency is relatively stable across larger steps of voltages. However, switching regulators tend to have a larger output voltage ripple, which can be an issue for sensitive systems. An approach to utilize both in cascaded configuration while providing a negative output voltage will be presented in this paper. The proposed two-stage conversion system consists of a switching pre-regulator that can track the negative output voltage of the second stage (LDO) such that the difference between input and output voltages is always kept small under varying output voltage while maintaining the high overall conversion efficiency. Computer simulation and hardware results demonstrate that the proposed system can track the negative output voltage well. Additionally, the results show that the proposed system can provide and maintain good overall efficiency, load regulation, and output voltage ripple across a wide range of outputs.

Recent developments in high power rated Voltage Source Converters (VSCs) have resulted in their successful application in Multi-Terminal HVDC (MTDC) transmission systems and also have potential in the Medium Voltage DC (MVDC) distribution systems. This work presents the findings of stability studies carried out on a zonal MVDC architecture for the shipboard power distribution system. The stability study is confined to rotor angle stability of the power system, i.e. the transient and small signal stability analysis. The MTDC ring structure similar to MVDC shipboard power system was implemented in MATLAB/Simulink to look at the transient behavior of the MVDC system. Small signal stability analysis has been carried out with the help of Power System Toolbox (PST) for both MVAC as well as MVDC architectures. Later, Participation Analysis has been carried out to address the small signal instability in the case of MVAC architecture and methods for enhancement were also presented.

No description available.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23797号 / 医博第4843号 / 新制||医||1058(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川口 義弥, 教授 藤田 恭之, 教授 小濱 和貴 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Denna 5 poängs rapport behandlar realisering och inställning av mjukvarubaseradePID-regulatorer. Den tänkte läsaren är en ingenjör som är intresserad av hur en PIDregulatorimplementeras och trimmas med AMIGO (Approximate M-constrainedintegral gain optimization) metoden. Alla matematiska resonemang förklaras stegvisoch utförligt. Huvudsyftet med rapporten är att inhämta kunskap från referenserna,och formulera denna kunskap så att den blir lättillgänglig för ingenjörer som praktisktarbetar med PID-regulatorer.Målet med denna rapport är att svara på frågorna:• Hur fungerar en PID-regulator?• Hur kan en PID-regulator implementeras?• Hur trimmas en PID-regulator med AMIGO-metoden? / This 5 point report discusses realisation and tuning of software based PID-controllers.The intended reader is an engineer that is interested in how a PID-controller isimplemented and tuned with the AMIGO (Approximate M-constrained integral gainoptimization) method. All mathematical reasoning is explained in detail step by step.The main purpose with this report is to gather knowledge from the reference sources,and clearly present this knowledge, so that it is accessible for engineers that workwith PID-controllers.• How does a PID-controller function?• How can a PID-controller be implemented?• How is a PID-controller tuned?

KTH is funding a project whose goal is to send a satellite into space. This project is called MIST (Miniature Student Satellite) which is assembled by a team of students at KTH. On the satellite there are experiments that are invented by other teams, in two of those experiments a power supply is required. This thesis is a technical investigation on how to design the power supply to both of those experiments, which are called SiC and Piezo LEGS. Piezo LEGS will investigate how their nanosized motors will behave and function in a space environment. SiC will investigate how their silicone carbide transistors will be affected by the space environment. A team made of four other students was selected to produce SiC experiments and a PCB in which this work is included. A literature study was done to get a better understanding of how power supplies work and to know how to select a good power supply. When the power supplies were selected they were simulated to meet the requirements. The next step was to do a Printed Circuit Board(PCB) for the SiC experiment and Piezo LEGS to be able to test the power supplies functionality in the physical world. Both of the converters reached the required output and characteristics working on their respective PCB. More time is needed for long time testing and optimization on the PCB layouts. / MIST (Miniature Student Satellite) är ett av KTH subventionerat projekt vilket har som mål att skicka upp en satellit i rymden. Projektet kommer omfatta flera olika experiment. Piezo LEGS ska undersöka en motors funktionalitet i rymdmiljö. SiC ska undersöka hur Silicon carbide halvledare och transistorer påverkas av rymdmiljön. Båda experimenten kräver varsin strömförsörjning för att fungera. Detta projekt ska undersöka kraven på strömförsörjning samt testa prototypen av ett kretskort för densamma. Först genomfördes en förstudie av de två typer av regulatorer som vanligtvis används som strömförsörjning, den linjära regulatorn och switch-mode regulatorn för att förklara olika strömförsörjningsteknologier, samt ta reda på de olika miljökraven. Baserat på förstudiens resultat erhölls kunskap för hur tester ska tas fram för funktionalitet av regulatorerna så att de når kraven för MIST för att sedan kunna producera de båda regulatorerna. Målet är att resultatet av simuleringarna på strömförsörjningen ska stämma överens med utfallet av kretskorten som produceras. Mätningar genomfördes på prototyp kretskort som visade att simuleringarna var korrekta och gav strömförsörjningen rätt resultat på kretskorten. Några av funktionerna på regulatorerna hann ej testas på grund av tidsbrist och mycket framtida arbete kvarstår.

<p> Repair of double-strand breaks is critical for the preservation of genomic integrity and cellular viability. A predominant pathway implicated in the repair of such lesions is the evolutionarily conserved non-homologous end-joining (NHEJ) pathway. Among the major constituents of this pathway in Saccharomyces cerevisiae is Nej1, for which a clear biochemical function has not been determined. The results presented in this work demonstrate that Nej1 exhibits a DNA binding activity comparable to Lif1, with an apparent dissociation constant of 1.8 μM. Characterization of the DNA binding activity revealed that although short ~20 bp substrates can suffice, binding is enhanced with longer substrates (>300). This DNA binding activity supports the hypothesis that Nej1 plays a direct role in the repair of DNA double-strand breaks. Structure-function studies indicated that the C-terminus of Nej1 is not only required, but is sufficient, for mediating DNA interactions. Structural characterization revealed that Nej1 exists as a dimer, and that residues 1-244 are sufficient for dimer formation. Examining the ability of this truncated Nej1 (aa 1-244) to perform NHEJ, revealed a defect in end-joining as measured by an in vivo plasmid repair assay. Preliminary functional and structural studies on the Nej1-Lif1 complex suggest that the proteins stably co-purify and the complex binds DNA with a higher affinity than each independent component. The significance of these results is discussed with reference to current literature on Nej1 and other end-joining factors (mammalian and yeast), specifically the recently identified putative mammalian homologue of Nej1, XLF. Collectively, these results demonstrate that although there are several functional similarities, there also appear to be important differences in the structure-function relationships of Nej1 and XLF, and Nej1/XLF and Lif1/Xrcc4.</p> / Thesis / Master of Science (MSc)

Kaiso is a novel member of the BTB/POZ (Broad complex, Tramtrak, Bric a brac,/Pox virus and zinc finger) zinc finger family of transcriptional regulators that have many roles in development and tumorigenesis. Kaiso was first identified as a binding partner for p 120ctn, an Armadillo catenin with roles in cell adhesion and stabilization of cadherins at the cell membrane. Kaiso is both an activator and repressor of gene transcription and interacts with two distinct types of DNA sequence; a consensus Kaiso binding site (KBS) TCCTGCNA and methylated CpG dinucleotide pairs (i.e. CpGCpG). Thus far p120's nuclear role is to inhibit Kaiso-mediated regulation of its target genes. Some of the Kaiso target genes identified to date include, matrilysin, rapsyn, and MTA2. The Kaiso homologue in Xenopus laevis (frog) has also been shown to regulate the cell cycle regulator CCND 1. Sequence analysis of the human CCND1 promoter revealed several potential Kaiso binding elements including both KBS and methylatable CpGs. My research demonstrated that Kaiso binds to the CCND1 promoter in vitro and in vivo to both KBS-specific and CpG-specific regions. Furthermore, I determined that Kaiso may act as either a repressor or activator of the human CCND 1 gene depending on the cellular environment. Altogether these data support my hypothesis that Kaiso is a regulator of the CCND1 gene. Future studies looking at the significance of KBS versus CpG-binding on Kaiso's mechanism of regulation are required to determine the significance of this regulation. Furthermore, studies examining the cell cycle-dependent changes in Kaiso levels may reveal how alterations in Kaiso expression affect Kaiso target genes including CCND1. / Thesis / Master of Science (MSc)