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Hall effect magnetic sensors have gradually gained dominance in the market of magnetic sensors during the past decades. The compatibility of Hall sensors with conventional CMOS technologies makes monolithic Hall sensor microsystem possible and economic. An attractive application is the contactless current sensor by using Hall sensors to measure the magnetic field generated by the electrical current. However, Hall sensors exhibit several non-idealities, i.e., offset, noise and sensitivity drift, which limit their precision. Therefore, effective techniques to reduce these imperfections are desired. This thesis presents the design of a new readout scheme for Hall magnetic sensor with low offset, low noise and low sensitivity drift. The Hall sensor is realized in N-well as Hall plate and modeled in Verilog-A for the purpose of co-simulation with interface circuits. The self-calibrated system is composed of two identical Hall plates, preamplifiers and a first-order ΣΔ modulator, which can be fully integrated monolithically. Four-phase spinning current technique and chopper stabilization technique have been employed to reduce the offset and 1/fnoise of Hall platesand OTA, respectively. Integrated coils are used to generate the reference magnetic field for calibration. The preamplifiers amplify the signal and separate the Hall voltage and reference voltage. The ΣΔ modulator reduces the thermal drift by using Hall voltage as the modulator input and reference voltage as the DAC output. This new calibration technique also compensates the thermal drifts of the biasing current and readout circuits. The overall system is implemented in NXP140nm CMOS process with 1.8V supply. The Virtuoso/Spectre simulation results show residual drifts lower than 10ppm/ ̊C, which are 3-5 times lower than the state of the art. The input magnetic field and temperature range are ±100mT and -40 ̊C to 120 ̊C, respectively.

Syftet med arbetet var att undersöka hur ett nyproducerat batterihybridfartyg av PSV-typ (plattform supply vessel) bör operera för att uppnå en så energieffektiv drift som möjligt utan att äventyra säkerhet eller redundanskrav. Att framföra ett fartyg så energieffektivt som möjligt är något som är av hög prioritet till sjöss, dels ur ett ekonomiskt perspektiv men även ur miljösynpunkt, då sjöfartsbranschen ständigt arbetar för en minskad miljöpåverkan. Även nyproducerade fartyg, byggda med modern teknik som ger goda förutsättningar för en energieffektiv drift ställer stora krav på att det tydligt framgår hur fartyget ska framföras för att nyttja fartygets fulla potential och uppnå optimal drift. För att ta fram procedurer över hur fartygen bör operera har loggade och teoretiska data från fartyget Coey Viking sammanställts, och presenteras i samråd med Viking Supply Ships. Resultatet innefattar generatorkombinationers specifika bränsleförbrukning, lågtrycks-dual-fuel-motorers generella miljöpåverkan med avseende på metanslip och fartygets loggade effektförbrukning till kaj. Resultatet visade att hög generatorlast resulterade i optimal specifik bränsleförbrukningen, att låga generatorlaster genererade stort metanslip samt att en förändrad elkraftstyrning tillsammans med fartygets energilagring möjliggör en förbättrad drift till kaj med en minskad miljöpåverkan. Arbetet öppnar upp för vidare forskning inom optimal peak-shaving-effekt, hur energilagringens storlek påverkar driftsmöjligheter och hur peak-shaving till kaj på ett stabilt sätt reglertekniskt bör styras. / The purpose of this undertaking was to investigate a new built battery-hybrid-vessel of PSV-type (platform supply vessel) and its operational ability to achieve the most energy efficient operation without jeopardizing safety or redundancy. The energy efficient operation of a vessel is of great priority in the maritime industry, not only because of economical profit but also based on environmental perspective, since the maritime industry is constantly aiming towards a decreased environmental impact. Newly built vessels containing modern technology opens up great opportunity in achieving energy efficient operation, though it sets high standard regarding correct operation of the vessel to use its full potential and achieve optimal running. To be able to present procedures regarding the vessel’s operation, logged and theoretical data from the vessel Coey Viking has been compiled and is presented in consultation with Viking Supply Ships. The results refered to different generator combination’s specific fuel consumption, the general environmental impact of low pressure dual fuel engines with respect to methane slip and the vessel’s logged power consumption in port.  The result indicated that a high generator load resulted in optimal specific fuel consumption, while low generator loads resulted in poor specific fuel consumption together with an increase in methane slip. The result also showed that the vessel’s energy storage together with a change in the PMS-system (Power Management System) would enable an improved power supply in port with shore connection. The paper raises questions to be answered in further research regarding optimal peak-shaving effect, what impact the size of the energy storage would have on operational capability and how peak shaving in port with shore connection appropriately should be regulated.

<div>Many two-phase flow systems might undergo flow instabilities even if the system is adiabatic but operates near the saturation conditions, especially in vertical flow conditions. Such instabilities are caused by <i>flashing</i> of the fluid in flow. Flashing is a sudden phase change in the fluid caused when local saturation enthalpy falls below the fluid enthalpy and the excess energy is used as latent heat for gas generation.</div><div> In the current analysis, a mathematical model is presented for analysis of such instability analytically. The conservation equations have been obtained by statistical averaging in time and space. Then, the concerned system is divided into various regions based on flow conditions, and these averaged equations are used to describe the flow. For flashing-based instability, two parameters are derived from constitutive relationships for the fluid. These two parameters are <i>Flashing Boundary</i> and <i>Gas Generation due to Flashing</i>. These parameters provide for the closure of the mathematical model. Some simple models for flashing have been developed and discussed.</div><div> The mathematical model is then solved analytically for <i>Uniform Heat</i> and <i>Flat Model</i> for the heater and flashing region respectively. The solution is in terms of the characteristic equation which is used to predict the onset of instability caused by flashing. The results are then plotted on the Subcooling-Phase Change number plane. It is observed that inlet and outlet restrictions in the flow does <b>not</b> affect the onset of flashing induced instability as the flow rate is coupled with the pressure drop of the system. This is important as these restrictions play a major role in other two-phase flow instabilities such as <i>Density Wave Oscillations</i></div><div> Finally, the stability boundary in the stability plane is compared to experimental data present for flashing. The comparison was made with data of S. Shi, A. Dixit, and F. Inada. The stability boundary satisfactorily agrees with the experimental data thus corroborating the present mathematical model and analysis.</div>

<p>Advancements in 3D printing technology have provided (1) easy access to low-cost, open- source robotics, and (2) a fast fabrication technique for analytical devices among others. Using the robotics of a 3D printer, a mass spectrometry-based reaction screening device was built as a low- cost, modest throughput alternative to expensive, very fast systems. Using the 3D printer for fabrication, ion mobility devices were fabricated. Fundamental studies of the motion of ions in these devices were performed in addition to applications of ion mobility-mass spectrometry using a 3D printed drift tube ion mobility spectrometer.</p><p><br></p><p>With only simple modification, 3D printer kits provide nearly all the necessary parts for a functional reaction screening device. Replacing the hotend assembly with custom parts to hold a syringe, precise volumes of reaction mixtures can be dispensed, and high voltage applied to the needle for direct analysis of solutions by mass spectrometry. Direct analysis of reaction mixtures in a 96-well microtiter plates was completed in approximately 105 minutes (~65 seconds per reaction mixture, including washing of syringe). Following analysis, product distributions derived from the electrospray mass spectra were represented as heatmaps and optimum reaction conditions were determined. Using low-cost, open-source hardware, a modest throughput for reaction screening could be achieved using electrospray ionization mass spectrometry.</p><p><br></p><p>The manipulation of ions at reduced pressures is very well understood, whereas the efficient manipulation of ions at atmospheric pressure is far less understood. Using 3D printing, multiple iterations of atmospheric pressure drift tube ion mobility spectrometers were fabricated with one and two turns in the drift path. Optimum electrode geometries for ion transmission and resolution were determined by both simulation and experiment. Racetrack effects, where ions on the inside of turns have a shorter path than ions on the outside, were determined to be highly detrimental to resolving power. Drift tubes with two turns in opposite directions (a chicane) corrected for racetrack effects and had only marginally poorer resolving power than a straight drift tube. Additionally, ion intensities were nearly identical between optimized straight and turned ion paths, showing that these manipulations can be done with high efficiency. The focusing of ions at reduced pressure using RF ion funnels at reduced pressure can have nearly 100 percent transmission. At atmospheric pressure, RF fields are not nearly as efficient at focusing ions. By using non-uniform DC fields at atmospheric pressure, ions can be focused, but not nearly to the extent as at reduced pressure.</p><p><br></p><div><div><div><p>The coupling of atmospheric pressure drift tube ion mobility with ion trap mass spectrometry is inefficient due to the mismatch in duty cycle between the two instruments. For this reason, increasing the amount of data collected from a single experiment is of high importance. Fourier transform ion mobility increases the duty cycle from less than 1% to 25%. When ions are fragmented in the mass spectrometer, they maintain the frequency characteristic of the precursor. Therefore, ions can be fragmented without isolation in the ion trap (reducing duty cycle further) and related precursors and product ions identified through their drift time. Two-dimensional tandem mass spectrometry is a method to collect all tandem mass spectrometry information in a single scan. When coupled with ion mobility, this data can be used to generate functional group- specific ion mobility spectra where ion intensity is measured along a precursor or neutral loss scan line. This was demonstrated for a lipid sample in which head-group specific ion mobility spectra were obtained using head-group specific precursor and neutral loss scan lines.</p></div></div></div>

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Since the last decade there is an important increase of high-rise buildings in Peru, especially in urban areas. Therefore, it is necessary to assess if the Peruvian Seismic Code is applicable for this type of buildings which have long natural periods as their main characteristic. The main objective of this article is to compare the results of the base shear and story drift ratios of Peruvian seismic design code E.030 with those of the ASCE 7-16 standard to the case of high-rise buildings, this due to the fact that there is limited information for tall buildings in Peru or comparison between national or international code for this type of structures. These high rise buildings have square and rectangular plan floors. Half of them have moment frames and reinforce concrete slab around the rigid core and the others have post-tensioned slab as their vertical load resisting system and central core walls with peripheral columns as the lateral force resisting system. Hence, the response spectrum analysis (RSA) is carried out for every case of the four tall buildings with different configurations using both seismic codes. Then results are compared with the linear response history analysis (LRHA) considering five Peruvian ground motions records, which were scaled to 0.45g PGA. It was verified that generally both the base shear and the interstory drifts calculated using ASCE7-16 are less than that obtained with the seismic code E.030.

The success of Internet of Things solutions allowed the establishment of new applications such as smart hydroponic agriculture. One typical problem in such an application is the rapid degradation of the deployed sensors. Traditionally, this problem is resolved by frequent manual maintenance, which is considered to be ineffective and may harm the crops in the long run. The main purpose of this thesis was to propose a machine learning approach for automating the detection of sensor fault drifts. In addition, the solution’s operability was investigated in a cloud computing environment in terms of the response time. This thesis proposes a detection algorithm that utilizes RNN in predicting sensor drifts from time-series data streams. The detection algorithm was later named; Predictive Sliding Detection Window (PSDW) and consisted of both forecasting and classification models. Three different RNN algorithms, i.e., LSTM, CNN-LSTM, and GRU, were designed to predict sensor drifts using forecasting and classification techniques. The algorithms were compared against each other in terms of relevant accuracy metrics for forecasting and classification. The operability of the solution was investigated by developing a web server that hosted the PSDW algorithm on an AWS computing instance. The resulting forecasting and classification algorithms were able to make reasonably accurate predictions for this particular scenario. More specifically, the forecasting algorithms acquired relatively low RMSE values as ~0.6, while the classification algorithms obtained an average F1-score and accuracy of ~80% but with a high standard deviation. However, the response time was ~5700% slower during the simulation of the HTTP requests. The obtained results suggest the need for future investigations to improve the accuracy of the models and experiment with other computing paradigms for more reliable deployments.

<p>    Drift tubes (DT) are prominent tools used in Ion Mobility Spectrometry (IMS) to separate ions in the gas phase due to their difference in mobility. While prominently used for small ions (< 10nm), their use for larger particles (up to 100nm) is limited and can only be attempted at atmospheric pressure due to diffusion. A system that specializes in high sensitivity larger particles (up to 1000nm) is the Differential Mobility Analyzer (DMA), but lacks in resolution (< 10 for particles 30-1000nm). The idea behind this work is to be able to design a new IMS system based on similar<br> principles to the DT but that allows high resolution and sensitivity for a large range of sizes if possible. The primary idea revolves around the principle of non-constant linear fields to try and control the width of the ion packet as it travels through the system. The first attempt was an Inverted Drift Tube (IDT) which lacked sufficient<br> sensitivity. This was followed by the development of the Varying Field Drift Tube (VFDT) which was the first of such systems to perform better than a regular DT, but only marginally. Finally, the last version of the system included a secondary pulse and labeled High Voltage Pulse - Varying Field Drift Tube (HVP-VFDT), which solved<br> some of the issues of the VFDT and was able to achieve resolving powers of 250, 3-5 times higher than regular DT.</p> <p><br>    In the IDT system, a gas flow is used to drive the packet of ions through the drift region while a linearly increasing electric field which is in the opposite direction of the flow is used to slow down the ions and separate them. In this regime it is the largest ions that arrive at the detector first, hence the name Inverted Drift Tube.This technique would allow larger ions and particles to be detected. At the same time, the linear field can be shown to have diffusion constriction (auto-correction) properties, where the broad distributions may be narrowed in the axial direction. However, the gas flow is difficult to control well and the parabolic velocity profile of the gas flow in the tube is a unfavorable factor for the system. </p> <p><br></p> <p>    To avoid the issue of the parabolic velocity but still take into account the VFDT takes the advantage of the diffusion auto-correction, the gas flow is suppressed and a linearly decreasing field is used to drive the ions. By solving the Nernst-Planck equation, we show that the VFDT has a spatial resolving power that is much higher than that of the regular DT. A DT was built and tested using a mixture of tetraalkylammonium salts. The transformation from the raw variable arrival time distribution to collision cross section or mobility diameter is derived and the linear relationship<br> makes it simple for calibration and transformation. A resolving power of over 90 is achieved experimentally although higher resolving powers were expected theory. <br>  <br>  It turns out that the difference between theory and experiments had to do with the fact that in the VFDT, the spatial and time resolving powers are different.This<br> is due to the low drift velocity at the end of the drift tube. To increase this velocity, a high voltage pulse is applied at a certain time depending on the ion/s of interest with a new system, HVP-VFDT. The system was tested numerically and experimentally where several parameters where tested resulting in a higher resolving powers when compared with DT and VFDT systems.The simulation results showed that the transmission efficiency and resolving power can be controlled by raising or lowering the field. Overall, the experimental setup tested reached resolving powers of 250 with moderate gate pulses. The HVP-VFDT system also shows that the distribution may be narrowed over the initial one, something impossible with a real drift tube and<br> opens a myriad of possibilities, including resolving powers of several thousands under low pressure and RF fields. <br>    <br>  The next step will be to couple the system to a Mass Spectrometer which is expected to be completed in the near future. To understand how a DT works with   RF fields and low pressure, a collaboration was done with David Clemmer’s lab and his 4 meter drift tube that can achieve resolutions of 150 in Helium at 4torr. Here, we tested a set of polymers and compared the results to those acquired in Nitrogen with a DMA. The shape and structure of the polymers in the gas phase was studied showing<br> self-similar assemblies that corresponds to a globule with an appendix sticking out. <br>  <br>    </p>

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