Nanomechanical resonators (NR) are cantilevers or doubly clamped nanowires (NW) which vibrate at their resonance frequency. These nanowires with picogram-level mass and frequencies of the order of MHz can resolve added mass in the attogram (10-18 g) range, enabling detection of a few molecules of cancer biomarkers based on the shift in resonance frequency. Such biomarker detection can help in the early stage detection of cancer and also aid in monitoring the treatment procedure in a more advanced stage. Optical transduction is one of the methods to measure the resonance frequency of the cantilever. However, there is a dependence of measured resonance frequency on the polarization of light and the laser power coupled as thermal energy into the cantilever during the measurement. This thesis presents a numerical model of the nanocantilever and shows the variation in resonance frequency and amplitude due to varied amounts of energy absorption by the NW from the laser during resonance measurements. This thesis answers questions on the effects of laser heating by calculating the temperature distribution in the NW, which changes the Young’s modulus and stiffness, causing a resonance downshift. It also shows the variation of resonance amplitude, affecting signal strength in measurements, by considering the effects of structural damping. In this work, a numerical model of the nanowire was analyzed to determine the temperature rise of the NW due to laser heating. The maximum temperature was calculated to be about 500 K with 1 mW of laser power absorbed in Silicon NWs and it is shown that the nanowire tip would reach its melting point for about 2.6 mW of laser power absorbed by it. The resonance shift due to attained temperature of the NW was calculated. The frequency is predicted to decrease by 24 kHz for a 11.6 MHz resonator, when 2mW of laser power is absorbed. However, the frequency shift is mode-dependent and is larger for higher modes. The variation in vibration amplitude around the resonance peaks is calculated based on the effects of structural damping. This can be used to decide on the suspension height of the NW above the substrate, before fabrication. This calculation also provides a method to study the variation in material damping due to temperature. Finally, a semi-analytical method for calculating the frequency of a cantilever beam with varying Young’s modulus is derived to examine the validity of the results calculated above. An effective Young’s modulus value for the laser heated NW is given, which serves as a correction factor for the resonance shift. The derivation is then extended to calculate the resonance shift with an addition of a mass to the beam of varying Young’s modulus. / Graduate / 2019-12-13

Submitted by Caio Augusto Garcia Ribeiro (cabecapequena@gmail.com) on 2018-08-02T00:52:57Z No. of bitstreams: 1 RibeiroCaio-FEB-2018.pdf: 5387665 bytes, checksum: 45fcc05a73039b3f0dc0abc7ea10d407 (MD5) / Rejected by Minervina Teixeira Lopes null (vina_lopes@bauru.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: - corrigir data de defesa; - inserir Ata de Defesa em substituição a Ata de Qualificação. Agradecemos a compreensão. on 2018-08-02T16:56:48Z (GMT) / Submitted by Caio Augusto Garcia Ribeiro (cabecapequena@gmail.com) on 2018-08-02T18:17:42Z No. of bitstreams: 1 RibeiroCaio-FEB-2018.pdf: 5361717 bytes, checksum: 4fc2f5302908b269a3ebe3ecc8d0821f (MD5) / Approved for entry into archive by Minervina Teixeira Lopes null (vina_lopes@bauru.unesp.br) on 2018-08-02T18:43:53Z (GMT) No. of bitstreams: 1 ribeiro_cag_me_bauru.pdf: 5338756 bytes, checksum: 867db632d4c47abc4ed6f4626038d817 (MD5) / Made available in DSpace on 2018-08-02T18:43:53Z (GMT). No. of bitstreams: 1 ribeiro_cag_me_bauru.pdf: 5338756 bytes, checksum: 867db632d4c47abc4ed6f4626038d817 (MD5) Previous issue date: 2018-06-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O ar-condicionado tem-se tornado um dos grandes responsáveis pelo aumento da demanda de energia elétrica no Brasil e no mundo, pois com o desenvolvimento econômico combinado a redução de preço dos equipamentos de ar-condicionados, mais residências e comércios os utilizam em busca de conforto térmico. Mas o uso pode acarretar em um aumento considerável na conta de energia, já que o ar-condicionado é o aparelho doméstico com alto consumo de energia. A solução imediata apontada por Sivak (2009) e Shan et al. (2013) para que o crescimento do uso de arcondicionado não provoque uma crise energética no mundo seria desenvolver aparelhos com a mesma qualidade de refrigeração dos atuais, mas que consumiriam bem menos energia. O aparelho mais utilizado em residências, pequenos comércios e escritórios, é o split system, com o evaporador do tipo Hi-wall, equipamento que tem algumas limitações em relação a sua distribuição de ar, que provoca bolsões de ar quente e frio no mesmo ambiente, além de provocar desconfortos localizados. O controle desse evaporador é baseado na temperatura de retorno, ou seja, se a temperatura no retorno não atingir a temperatura estabelecida o mesmo opera em sua potência máxima por um tempo maior que o necessário, desperdiçando assim energia elétrica, ou a temperatura pode ser alcançada antes no retorno do que no ambiente, provocando assim desconforto térmico por mais tempo. Assim, será proposta neste trabalho uma solução numérica, utilizando um código CFD, a partir das equações diferencias de energia combinada com as equações de Navier–Stokes, em um modelo turbulento semi empírico k-epsilon de duas equações, considerando as três dimensões. Partindo de um caso padrão foram outros 11 casos alterando a altura do evaporador e o ângulo de insuflamento. Com os resultados pôde-se avaliar qual dos 11 casos foi mais eficiente do ponto de vista energético o qual produz melhor conforto térmico, para assim avaliar melhorias que podem ser aplicadas no evaporador hi-wall. / Air conditioning has become one of the main factors responsible for the increase in the electric demand in Brazil and in the world, since with economic development combined with the price reduction of air conditioning equipment, more residences and businesses use them to reach thermal comfort. But the use can lead to a considerable increase in the energy bill, since air conditioning is the household appliance with a high energy consumption. The immediate solution pointed out by Sivak (2009) and Shah et al. (2013), so that the growth of the use of air conditioning does not cause an energy crisis in the world, would be to develop devices with the same quality of refrigeration of the present, but that would consume much less energy. The most commonly devices used in residence, small shops and offices, are Split System, whit a high wall as internal unit, this evaporator has some limitations in the air distribution, which causes hot and cold zones in the same environment, as well as causing localized discomfort. The evaporator control is based on the return temperature, so if the return temperature does not reach the set temperature, the Air Conditioner will operate at its maximum power for a time longer than necessary, thus wasting electrical energy or the set temperature can be reached before in the evaporator than in the environment, thus causing thermal discomfort for longer. Thus, a numerical solution, using a CFD code, will be proposed using the energy-difference equations combined with the Navier-Stokes equations, considering a turbulent flow based in a semi-empirical k-epsilon turbulent model of two equations, considering the three dimensions. And using a model as standard, another 11 models were simulated by changing the height of the evaporator and the angle of inflation. With the results, it can be evaluated which of the 12 cases is more energy efficient and which causes better thermal comfort. And than identify improvements that can be applied in hi-wall units.

An experimental study on post dryout heat transfer regime in annuli with flow obstacles was conducted in the High-pressure Water Test (HWAT) loop at the Royal Institute of Technology in Stockholm, Sweden. An annulus consisting of two concentric heated pipes (12.7x24.3) mm, with total heated length equal to 3650 mm was employed as a test section. Three kinds of flow obstacles were used: pin-spacers, cylindrical obstacles and grid obstacles. The experiments performed in the test section with pin-spacers only were considered as the reference case. In two consecutive sets of runs, additional obstacles were placed inside the flow channel while keeping the pin spacers in the same positions. In that way the net effect of obstacles on heat transfer was measured. The experimental investigations were performed in a wide range of the operational conditions: mass flux (500-1750) kg/(m2s), inlet subcooling (10-40) K and system pressure (5-7) MPa. The wall superheat was measured at 88 different axial positions (40 on the inner tube and 48 on the outer tube) for the conditions mentioned above. A local heat transfer coefficient was calculated based on the measured annulus wall temperatures and the saturated fluid (water) properties. The results show an enhancement of the heat transfer coefficient downstream of flow obstacles. The most significant influence has been observed in case of pin spacers. This result is consistent with blockage area of various obstacles, which was the highest in case of pin spacers. The data obtained in more than 200 runs were compared with two pre-dryout and post-dryout correlations. The correlations show a slight over-prediction of the heat transfer coefficient in both pre-dryout and post-dryout regions. The thesis contains a detailed description of experimental procedures as well as an analysis of the results of measurements. / QC 20111024 / SKC: Post Dryout Regime

In this dissertation a study of enhanced hyperthermia for cancer treatment through the use of magnetic nanoparticles is presented. Hyperthermia has been in use for many years, as a potential alternative method in cancer treatment, and high frequency microwave radiation has been used successfully to raise the tumor temperature to around 42°C in superficial tumors without causing damage to surrounding healthy tissues. Magnetic fluid hyperthermia involves the use of magnetic nanoparticles injected into the tumor before exposure to microwave radiation. The magnetic energy in the nanoparticles is converted into heat allowing for a more rapid rise of temperature in the tumor to the desired level. In addition, the nanoparticles allow the electromagnetic absorption to be focused in the tumor and can be used to treat deep tumors in organs, such as the liver. Iron oxide magnetic nanoparticles were considered for this study as they are non-toxic and bio-compatible. For the case of breast cancer, the values for the temperature and specific absorption rate (SAR) in the tumor and in the healthy tissue were obtained through simulations and validated by measurement done on phantom models. Various characteristics of the nanoparticles such as radius, magnetic susceptibility and concentration were considered. In order to take the effect of the blood flow, which causes cooling and helps maintain the body temperature, various blood perfusion rates for a tumor in the liver were studied. A human male model in SEMCAD X, in which blood flow can be adjusted, was used for simulations. The tumor was injected with the nanoparticles and the change in temperature upon exposure to electromagnetic radiation was observed. The simulated results were compared with measured results on a liver phantom model in which saline solution was used to model blood flow. There was good agreement between the measured and simulated results.

To reduce emissions, new technological solutions can be of use. One technology which is currently being developed is the Green Revolution Energy Converter, GREC. GREC is an engine with the aim to produce electricity from temperature gradients.  This project is part of a greater project that is divided in two with different focus areas. These two projects aim to deliver a specification of the next step of the prototype, called: Lab Model v3, which is expected to be built in spring 2023. The aim of this report is to contribute with new knowledge about the heat transfer on the hot section of the GREC model. The goal is to design the heat block and conductive fin, HB and CF, to deliver high amount of heat to a volume of air which is called the work generating volume, WGV. This includes evaluating two different heat transfer techniques which in this report are called None Pipe Heat Transfer, NPHT, and Pipe Heat Transfer, PHT. The temperature distribution within the CF and the HB, as well as the heat transfer to the WGV are analyzed.  This analysis is performed for different radii and thicknesses of the CF and HB, different flow rates of the heat carrier in the PHT case, and for different heat source temperatures to see if the two models are applicable in real life applications. The real life application for the NPHT model is a fuel cell vehicle and for the PHT model a district heating system.  To obtain the result, ANSYS Workbench is used to create the model of GREC and MATLAB is used to calculate heat transfer coefficient and pressure losses. Furthermore, an iterative method using COMSOL Multiphysics and ANSYS Workbench was necessary to obtain temperatures of the CF, HB and WGV. The chosen method for this study comes with several uncertainties. However the trends seen in the results can still be considered credible, but exact numbers and other detailed conclusions should be avoided.  For the NPHT model, a large model in terms of radius and thickness, results in the highest total heat rate. This is due to the combination of a large CF and heat source area. The NPHT model with smallest radius and largest thickness results in the most even temperature distribution for the NPHT cases.  The PHT model presents a more even temperature distribution on the surface of the CF than the NPHT model. The largest heat rate from the different configurations derived from the PHT model is approximately three times larger than the heat rate derived from the NPHT model with the same dimensions. Moreover, a higher flow rate on the water in the pipes of the PHT model, does not affect the heat rate or temperature distribution on the CF. Therefore, a lower flow rate could be applied to save pump power. Another conclusion to this project is that the PHT model could be applicable in a district heating system with 80 ◦C, since the heat transfer coefficient values do not differ much between 80 ◦C and 100 ◦C. The NPHT model might also be applicable in a real life application. In that case, the size of CF plays a larger role than the temperature of the heat source in terms of the possible heat rate output. A final conclusion is that size, type of heat source and design of the GREC plays a vital role in terms of temperature distribution on CF and heat rate to WGV. The GREC has the potential to be applicable in real life applications in regards of heat transfer solutions.

No / Nickel coated multi-walled carbon nanotubes (Ni-MWCNTs) having exceptional mechanical properties, thermal conductivity and dispersibility can effectively overlap in cementitious matrix, thus forming an enhanced and thermal conductive network. They are therefore a promising nanofiller for modifying cement and concrete materials. This paper studies the compressive properties of reactive powder concrete (RPC) filled with different aspect ratios of Ni-MWCNTs, including strength, toughness, Young's modulus and Poisson's ratio. It is concluded that the incorporation of 0.06 vol.% Ni-MWCNTs with an aspect ratio of 1500 maximally increases the compressive strength and toughness of RPC by 20.24%/20.39 MPa and 43.89%/56.35 (N·m), respectively. However, Young's modulus and Poisson's ratio of Ni-MWCNTs modified composites do not significantly be improved. Besides, a constitutive model of Ni-MWCNTs reinforced RPC under uniaxial compression is established based on the continuum damage mechanics theory, reasonably predicting the relationship between compressive strength and deformation of composites. The modification mechanism of Ni-MWCNTs is also investigated through the temperature distribution monitoring inside composites, Scanning Electron Microscope (SEM) observation and energy dispersive x-ray spectrometry (EDS) analysis of Ni-MWCNTs reinforced RPC. The thermal conductive network formed by Ni-MWCNTs in matrix reduces the temperature difference and improves the temperature uniformity inside composites, thereby decreasing thermal stresses, primary cracks and defects of composites. Furthermore, the incorporation of Ni-MWCNTs makes the RPC microstructures dense, decreases the average CaO to SiO2 ratio, and inhibits the development of cracks inside RPC, thus achieving effective enhancement to RPC. / National Science Foundation of China (52178188, 51978127 and 51908103), and the Fundamental Research Funds for the Central Universities (DUT21RC(3)039).

Yes / In the drying process of a can making industry, the drying efficiency of a thermal drying oven can be improved by adjusting the volumetric air flow rate of the blower. To maximize drying efficiency, an optimal flow rate is needed. Consequently, a three-dimensional computational fluid dynamics (CFD) is used to provide simulation according to the response of air velocity, air temperature and evaporated solvent concentration with respect to changes in volumetric air flow rate in the drying oven. An experimental study has been carried out to determine the evaporation rate of the solvent. To validate the models, the process data obtained from the CFD is compared with that obtained from actual data. In the accurate models, the simulation results demonstrate that the decrease in volumetric air flow rate provides no major discrepancy of the air velocity patterns in all dimensions and decreases the maximum temperature in the oven. Consequently, this decrease in volumetric air flow rate rapidly increases the evaporated solvent concentration in the beginning and then gradually decreases over the length of the oven. In addition, further reduction of the flow rate gives lower heat loss of the oven up to 83.67%. / The authors would like to thank The Thailand Research Fund (TRF) under The Royal Golden Jubilee Ph.D. Program (PHD/0158/2550), The Institutional Research Grant (The Thailand Research Fund) (IRG 5780014) and Chulalongkorn University (Contract No. RES_57_411_21_076) for financial support to this work.

Det konstrueras i stor utsträckning bristfälliga detaljlösningar på byggnader i dagsläget. Den bärande stommen i konstruktionen prioriteras ofta medan det inte ägnas lika mycket fokus åt att tillgodose de byggnadsfysiska aspekterna. Anledningen till de bristfälliga detaljerna är även att den som utför arbetet saknar rätt kunskap och tid. För att skapa en förbättring behövs ett hjälpmedel! Kunskap och erfarenhet om hur bra detaljer skapas finns redan i företag, svårigheten är dock att sprida kunskapen till de som är i behov av den. Målet med denna rapport är att skapa en metodik som blir startskottet för ett omfattande arbete kring framtagandet av ett detaljbibliotek, vars syfte är att sprida byggnadsfysiska kunskaper inom företaget och inspirera konstruktörer till att konstruera bra detaljlösningar. Biblioteket ska innehålla byggnadsfysiskt utredda detaljlösningar som analyserats enligt den utarbetade metodiken. Metodiken kommer göra det möjligt att på ett enkelt sätt utvärdera detaljlösningar, för att sedan presentera dessa med uträknade värden och rekommendationer i detaljbiblioteket. Via intervjuer med konstruktörer och en omfattande genomgång av byggnadsprojekt, har 7st detaljlösningar valts ut för att utredas och sedan exemplifiera hur dokumenten i detaljbiblioteket kommer att gestalta sig. Exemplen går att se i rapporten, och de kommer även att utgöra embryot till det slutgiltiga detaljbiblioteket. Detaljbiblioteket kommer sedan ligga ute på Sweco Structures interna nätverk, så att detaljerna blir lättåtkomliga för de som är i behov av dem. / It is constructed inadequate detail solutions of buildings in the current situation. The carrying frame of the structure is often given priority while it is not given as much focus to solve the building physical aspects. The reason for the inadequate detail is also that the person doing the don´t has the right knowledge or time. In order to create an improvement, a tool is needed!  Knowledge and experience of how well the details are created already exists at the company, the difficulty is to spread the knowledge to those who are in need of it. The objective of this report is to create a methodology that will mark the start of an extensive work on the development of a detail library whose purpose is to spread building physical skills within the company and inspire constructors to construct good detail solutions. The library will include good building physical detail solutions which were analyzed according to the produced methodology. The method will allow to easily evaluate detail solutions, and to present them with calculated values and recommendations in detail library. Through interviews with designers and a comprehensive review of construction projects, has 7 detail solutions been selected to be examined, and then illustrate how the documents in detail the library will be presented. The examples will be seen in the report, and they will also serve as the embryo of the definitive and large detail library. Detailed library will then be placed at Sweco Structures internal network, so that the details are easily accessible for those who are in need of them.

This thesis describes the development of a sensing technique for temperature nonuniformity along the line of sight through combustion exhaust, geared for gas turbine applications. Tunable diode laser absorption spectroscopy is used to measure three absorption lines and compute a variable to characterize the level of temperature nonuniformity along the laser path. Nonuniformity information is obtained from one line of sight sensor because the absorption has a nonlinear dependence on temperature. This dependence is analyzed to determine the behaviour, shape, and response of absorption lines measured through mediums with nonuniform temperature profiles. Based on this analysis a new line selection process for nonuniformity sensing is developed. A sensor for temperature nonuniformity is proposed and demonstrated through computer simulations and experiments in the exhaust of a laboratory-scale combustor. The nonuniformity variable, U, is shown to monotonically track the level of temperature nonuniformity along the laser path. The capabilities of this sensing technique are determined based on a comprehensive analysis of errors and their effect on sensor performance. Methods to mitigate these errors are described, and the overall sensor capability is determined based on the characteristics of state of the art diode laser and absorption sensor technology. Such a sensor is capable of measuring minimum temperature deviations of 17% or more, which is well within the needed capabilities for industrial applications. Furthermore, the results and knowledge presented in this thesis apply to other absorption based sensing techniques.

Drilling operation expanded through deep water environments starting from mid-1980. As water depth increased, hydrate bearing formation in the shallow ocean floor is observed and that started to cause problems during drilling and production operations. Problems due to hydrate dissociation and forming during operations are also reported by the companies working in those environments many times. Although there are several factors affect the dissociation of shallow hydrate bearing sediments, heat flux from deeper sections of the well through shallower section during the operation is the major one. In order to mitigate that risk in this study, Black Sea is taken as a reference drilling environment. Hydrate phase boundary of the region is calculated via using actual temperature and pressure data gathered during drilling operations. Generic wellbore is defined and common drilling operation sequence is simulated in this defined wellbore. Heat transfer from section target depths to the shallow wellbore section is observed during simulations. Reducing effect of low inlet temperatures and a low circulation rate on wellbore temperatures are determined. In addition positive effect of riser boosting on depressing wellbore temperature in the well head is determined. Black Sea deep water hydrate stability zone is determined between 2210-2275m. Target depth limitation for generic well designed in drilling operations is determined as 4600m.