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The optical response of several magnetic nanoparticle dispersions is studied by angle resolved transmittance at wavelength of 600 nm in zero-field and under an applied magnetic field of 0.1 T, with the purpose of exploring to what extent this could be used as a method of monitoring the colloidal dispersions. In an external magnetic field, magnetic particles will start to order into needle-like structures aligned with the field, which was observed by microscopy. This will change the light scattering caused by the particles. Results showed a clear effect from applying the magnetic field by a dip in the transmitted intensity at angles around 3-5 degrees. The scattering is compared to that of a homogeneous infinite cylinder and theoretical explanations to the effect are discussed. Spectrophotometry at wavelengths between 300-1100 nm is performed and compared with calculations from Kubelka-Munk approximation to give a first characterization of the particle dispersions. Particles used in this project are magnetite, Fe3O4, and maghemite, gamma-Fe2O3, nanoparticles with sizes ranging from 5-250 nm.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第18340号 / 農博第2065号 / 新制||農||1024(附属図書館) / 学位論文||H26||N4847(農学部図書室) / 31198 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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<p> The magnetic properties of MnP2O7, CuP2O7, Co2P2O7 and Ni2P2O7 were studied. They were investigated using magnetic susceptibility and magnetic resonance techniques. They were all found to become magnetically ordered between 10°K and 30°K. In all the predominant exchange interaction was antiferromagnetic. Ni2P2O7 however did show a resultant moment at low temperatures which was attributed to weak ferrornagnetism. The experimental results were analysed in the molecular field approxmation which accounted for their behaviour except in the case of Cu2P2O7 where the High Temperature Series Expansion method was necessary to explain the temperature dependence of its paramagnetic susceptibility. </p> / Thesis / Doctor of Philosophy (PhD)

Iron oxide nanoparticles (IONPs) have been widely studied for a variety of applications, from biomedical applications (e.g., cell separation, drug delivery, contrast agent for magnetic resonance imaging and magnetically mediated energy delivery for cancer treatment) to environmental remediations (e.g., heavy metal removal and organic pollutants degradation). It has been demonstrated that IONPs can induce the production of reactive oxygen species (ROS) via Fenton/Haber-Weiss reactions which has been shown to be one of the key underlying mechanisms of nanoparticles toxicity. This inherent toxicity of nanoparticles has been shown to enhance the efficacy of traditional cancer therapies such as chemotherapy and radiation. In addition, the generation of ROS induced by IONPs has been also studied as advanced oxidation processes (AOP) for wastewater treatment. Recent research has also shown that exposure to an alternating magnetic field can significantly enhance the generation of ROS induced by IONPs. Moreover, the coatings of IONPs play an important role on the surface reactivity of nanoparticles since it can prevent the generation of ROS via Fenton chemistries at the surface of the nanoparticles. In this work, co-precipitated IONPs were functionalized with small molecules including citric acid, sodium phosphate, amino silane and dopamine. The impact of coating on surface reactivity of the as-synthesized particles was studied using methylene blue dye degradation assay under AMF exposure. With the coatings of these small molecules, the IONPs induced ROS generation was significantly decreased because of the dense surface coverage. To study the effect of polymeric coatings, a degradable poly (beta amino ester) (PBAE) polymer coating was synthesized with dopamine as an anchor to bind to nanoparticles. The surface reactivity of the particles was expected to be recovered once the polymer coating was degraded. Furthermore, the impact of non-degradable PEG-based polymer coating on surface reactivity via ROS generation was also investigated using methylene blue decolorization assay with the presence of AMF. The retention of surface reactivity of PEG-based polymer coated IONPs shows promise for cancer treatment. The application of IONPs as heterogeneous catalyst for organic contaminant degradation was investigated. Bisphenol A (BPA) was used as a model compound, and Fenton reactions were induced by IONPs with the presence of hydrogen peroxide and hydroxylamine as well as alternating magnetic field exposure. The kinetics of BPA degradation under water bath and AMF exposure at 37oC was also studied, and the results showed potential applications of IONPs for organic pollutants remediation.

Power distribution network (PDN) design was a non-existent entity during the early days of microprocessors due to the low frequency of operation. Once the switching frequencies of the microprocessors started moving towards and beyond MHz regions, the parasitic inductance of the PCB tracks and planes started playing an important role in determining the maximum voltage on a PDN. Voltage regulator module (VRM) sup-plies only the DC power for microprocessors. When the MOSFETs inside a processor switches, it consumes currents during transition time. If this current is not provided, the voltage on the supply rails can go below the specifications of the processor. For lower MHz processors few ceramic-capacitors known as ‘decoupling capacitors’ were connected between power and ground to provide this transient current demand. When the processor frequency increased beyond MHz, the number of capacitors also increased from few numbers to hundreds of them. Nowadays, the PDN is said to be comprising all components from VRM till the die location. It includes VRM, bulk capacitors, PCB power planes, capacitor mounting pads and vias, mount for the electronic package, package capacitors, die mount and internal die capacitance. So, the PDN has evolved into a very complex system over the years. A PDN should provide three distinct roles; 1) provide transient current required by the processor 2) act as a stable reference voltage for processor 3) filter out the noise currents injected by the processor. The first two are required for the correct operation of the processor. Third one is a requirement from analog or other sensitive circuits connected to the same PDN. If the noise exits the printed circuit board (PCB), it can result in conducted and radiated EMI, which can in turn result in failure of a product in EMC testing. Every PDN design starts with the calculation of a target impedance which is given as the ratio of maximum allowed ripple voltage to the maximum transient current required by the processor. The transient current is usually taken as half the average input current. The definition of target impedance assumes that the PDN is flat over the entire frequency of operation, which is true only for a resistive network. This is seldom true for a practical PDN, since it contains inductances and capacitances. Because of this, a practical PDN has an uneven impedance versus frequency envelope. Whenever two capacitors with different self resonant frequencies are connected in parallel, their equivalent impedance produces a pole between the self resonant frequencies known as antiresonance peaks. Because of this, a PDN will have phase angles associated with them. Also, these antiresonance peaks are energy reservoirs which will be excited during the normal operation of a processor by the varying currents. The transient current of a microprocessor is modeled as a gamma function, but for practical cases it can be approximated as triangular waveforms during the transition time which is normally 10% of the time period. Depending upon the micro-operations running inside the processor, the peak value of this waveform varies. This is filtered by the on-chip capacitors, package inductance and package capacitors. Due to power gating, clock gating, IO operations, matrix multiplications and magnetic memory readings the waveforms at the board will be like pulse type, and their widths are determined by these operations. In literatures, these two types of waveforms are used for PDN analysis, depending upon at which point the study is conducted. Chapter 1 introduces the need for PDN design and the main roles of a PDN. The issue of antiresonance is introduced from a PDN perspective. Different types of capacitors used on a PDN are discussed with their strengths and limitations. The general nature of the switching noise injected by a microprocessor is also discussed. This chapter discusses the thesis contributions, and the existing work related to the field. Chapter 2 introduces a new method to calculate the target impedance (Zt ) by including the phase angles of a PDN which is based on a maximum voltage calculation. This new Zt equals to conventional Zt for symmetrical triangular switching current waveforms. The value of new Zt is less than the conventional Zt for trapezoidal excitation patterns. By adding the resonance effects into this, a maximum voltage value is obtained in this chapter. The new method includes the maximum voltage produced on a PDN when multiple antiresonance peaks are present. Example simulations are provided for triangular and pulse type excitations. A measured input current wave-form for PIC16F677 microcontroller driving eight IO ports is provided to prove the assumption of pulse type waveforms. For triangular excitation waveform, the maximum voltage predicted based on the expression was ¡0.6153 V, and the simulated maximum voltage was found to be at ¡0.5412 V which is less than the predicted value. But the predicted value based on Zt method was 1.9845 V. This shows that the conventional as well as the new target impedance method leads to over estimating the maximum voltage in certain cases. This is because most of the harmonics are falling on the minimum impedance values on a PDN. If the PDN envelope is changed by temperature and component tolerances, the maximum voltage can vary. So the best option is to design with the target impedance method. When pulse current excitation was studied for a particular PDN, the maximum voltage produced was -139.39 mV. The target impedance method produced a value of -100.24 mV. The maximum voltage predicted by the equation was -237 mV. So this shows that some times the conventional target impedance method leads to under estimating the PDN voltage. From the studies, it is shown that the time domain analysis is as important as frequency domain analysis. Another important observation is that the antiresonance peaks on a PDN should be damped both in number and peak value. Chapter 3 studies the antiresonance peak suppression methods for general cases. As discussed earlier, the antiresonance peaks are produced when two capacitors with different self resonant frequencies are connected in parallel. This chapter studies the effect of magnetic coupling between the mounting loops of two capacitors in parallel. The mounting loop area contribute to the parasitic inductance of a capacitor, and it is the major contributing factor to it. Other contributing factors are equivalent series inductance (ESL) and plane spreading inductance. The ESL depends on the size and on how the internal plates of the capacitors are formed. The spreading inductance is the inductance contributed by the parts of the planes connecting the capacitor connector vias to the die connections or to other capacitor vias. If the power and ground planes are closer, the spreading inductance is lower. On one/two layer boards dedicated power/ground planes are absent. So the spreading inductance is replaced by PCB track inductances. The inductance contributed by the mounted area of the capacitor is known as mounting inductance. On one/two layer boards dedicated power/ground planes are absent. So the spreading inductance is replaced by PCB track inductances. The dependencies of various circuit parameters on antiresonance peak are studied using circuit theory. A general condition for damping the antiresonance is formulated. The antiresonance peak reduces with Q factor. The conventional critical condition for antiresonance peak damping needs modification when magnetic coupling is present between the mounting loops of two parallel unequal value capacitors. By varying the connection geometry it is possible to obtain negative and positive coupling coefficients. The connection geometries to obtain these two are shown. An example is shown for positive and negative coupling coefficient cases with simulation and experimental results. For the example discussed, RC Æ 32 - for k Æ Å0.6 and RC Æ 64 - for k Æ ¡0.6, where RC is the critical damping value and k is the magnetic coupling coefficient between the two mounting loops. The reason for this is that, the antiresonance peak impedance value is higher for negative coupling coefficient case than that for positive coupling coefficient case. Above the self resonant frequencies of both the capacitors, the equivalent impedance of the parallel capacitors become inductive. This case is studied with two equal value capacitors in parallel. It is shown that the equivalent inductance is lower for negative coupling coefficient case as compared to positive coupling coefficient case. An example is provided with simulation and experimental results. In the experimental results, parasitic inductance is observed to be 2.6 times lower for negative coupling coefficient case than that for positive coupling coefficient case. When equal value capacitors are connected in parallel, it is advantageous to use a negative coupling geometry due to this. Chapter 4 introduces a new method to damp the antiresonance peak using a magnet-ically coupled resistive loop. Reducing the Q factor is an option to suppress the peak. In this new method, the Q factor reduction is achieved by introducing losses by mag-netically coupling a resistive loop. The proposed circuit is analyzed with circuit-theory, and governing equations are obtained. The optimum value of resistance for achieving maximum damping is obtained through analysis. Simulation and experimental results are shown to validate the theory. From the experimental results approximately 247 times reduction in antiresonance peak is observed with the proposed method. Effectiveness of the new method is limited by the magnetic coupling coefficient between the two mounting loops of capacitors. The method can be further improved if the coupling coefficient can be increased at the antiresonance frequency. Chapter 5 focuses on the third objective of a PDN, that is to reduce the noise injected by the microprocessor. A new method is proposed to reduce the conducted noise from a microprocessor with switched super capacitors. The conventional switched capacitor filters are based on the concept that the flying capacitor switching at high frequency looks like a resistor at low frequency. So for using at audio frequencies the flying capacitors were switching at MHz frequencies. In this chapter the opposite of this scenario is studied; the flying capacitors are the energy storage elements of a switched capacitor converter and they switch at lower frequencies as compared to the noise frequencies. Two basic circuits (1:1 voltage conversion ratio) providing noise isolation were discussed. They have distinct steady state input current waveforms and are explained with PSPICE simulations. The inrush current through switches are capable of destroying them in a practical implementation. A practical solution was proposed using PMOS-PNP pair. The self introduced switching noise of the converter is lower when switching frequency is low and turn ON-OFF time is higher. If power metal oxide semiconductor field effect transistor (MOSFET)s are used, the turn ON and turn OFF are slow. The switching frequency can be lowered based on the voltage drop power loss. The governing equations were formulated and simulated. It is found that the switching frequency can be lowered by increasing the capacitance value without affecting the voltage drop and power loss. From the equations, it is found that the design parameters have a cyclic dependency. Noise can short through the parasitic capacitance of the switches. Two circuits were proposed to improve the noise isolation: 1) T switch 2) ¦ switch. Of these, the ¦ switch has the higher measured transfer impedance. Experimental results showed a noise reduction of (40-20) dB for the conducted frequency range of 150 kHz - 30 MHz with the proposed 1:1 switched capacitor converter. One possible improvement of this method is to combine the noise isolation with an existing switched capacitor converter (SCC) topology. The discussed example had a switching frequency of 700 Hz, and it is shown that this can isolate the switching noise in kHz and MHz regions. In a PDN there are antiresonance peaks in kHz regions. If the proposed circuit is kept close to a microprocessor, it can reduce the excitation currents of these low frequency antiresonance peaks. Chapter 6 concludes the thesis by stating the major contributions and applications of the concepts introduced in the thesis. This chapter also discusses the future scope of these concepts.

This work presents a methodology to extract and evaluate signals in functional magnetic resonance imaging (fMRI) in the temporal dimension. It is assumed that it is possible to separate the signals from brain activations of a given protocol of other signals such as breathing, heartbeat, involuntary eye movements, and others. This paper proposes a methodological way, get through simulated and controlled measure the efficiency of the Model of Independent Component Analysis (ACI) for fMRI images to separate these signals experiments. To validate the experiments it was necessary to generate simulated data. The data generated were formed for three (3) signs that did not have a Gaussian distribution, in an array of temporal dimension 80 x 80 x 64. Within this set of signs have been added three (3) signal blocks of size 5 x 5 x 64 that simulated activations of FRH protocols. After this process, an array of mixture was added so that the signals could not be identified. Only after the data gave mixed-if the process of completing the pre-processing with the bleaching and centering of the variables to the model following ACI was performed to separate the signals that were mixed, thereby finding the estimated component signals. Different amounts of Gaussian signals were added until no more would be possible to extract the component which would correspond to a signal FRH testing the theory that ACI has efficiency in extracting components of non-Gaussian data. The model was run in real signals, where a volunteer performing a hearing protocol, the results data of each slice extracted resonance are evident throughout this work, in some slices was possible to extract the expected component with a degree of correlation between the acceptable component and signal protocol FRH, as in other slices could not perform the extraction of these signals. As a final result a statistical correlation map for each slice resulting from the estimated component and the raw data was generated, the signals were evaluated on the assumption of acceptance only to greater than 0.72 correlation with statistical significance at 95% confidence. / Este trabalho apresenta uma metodologia para extrair e avaliar sinais em imagens de ressonância magnética funcional (fMRI) na dimensão temporal. Assume-se que é possível separar os sinais de ativações cerebrais de um determinado protocolo dos demais sinais como respiração, batimentos cardíacos, movimentos involuntários dos olhos e outros. Este trabalho propõe de forma metodológica, buscar através de experimentos simulados e controlados medir a eficiência do Modelo de Análise de Componentes Independentes (ACI) em imagens de fMRI para separar esses sinais. Para validar os experimentos foi necessário gerar dados simulados. Os dados gerados foram formados por 3 (três) sinais que não possuíam distribuição gaussiana, em uma matriz temporal de dimensão 80 x 80 x 64. Dentro desse conjunto de sinais foram adicionados 3 (três) blocos de sinais de dimensão 5 x 5 x 64 que simulavam ativações de protocolos da FRH. Após esse processo uma matriz de mistura foi adicionada para que os sinais não pudessem ser identificados. Somente após os dados misturados deu-se o processo da realização do pré-processamento, com a centralização e o branqueamento das variáveis, para que na sequência o modelo de ACI fosse executado para separar os sinais que estavam misturados, encontrando assim as componentes estimadas dos sinais. Foram adicionadas diferentes quantidades de sinais gaussianos, até que não mais fosse possível extrair a componente que teria um sinal que correspondesse a FRH, testando a teoria de que ACI tem eficiência em extrair componentes de dados não gaussianas. O modelo foi executado em sinais reais, onde um voluntário executava um protocolo auditivo, os dados dos resultados de cada fatia extraída da ressonância estão evidenciados ao longo deste trabalho, em algumas fatias foi possível extrair a componente esperada com um grau de correlação aceitável entre a componente e o sinal do protocolo da FRH, já em outras fatias não foi possível realizar a extração desses sinais. Como resultado final foi gerado um mapa estatístico de correlação para cada fatia, resultante entre a componente estimada e os dados brutos, os sinais foram avaliados sobre a hipótese de aceitação apenas para correlação maior que 0,72 com significância estatística de 95% de confiança.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-06-01T14:42:01Z No. of bitstreams: 1 Isamara.pdf: 1900151 bytes, checksum: bf2306ee5b36c025c99dadb0b3ed1c84 (MD5) / Made available in DSpace on 2017-06-01T14:42:01Z (GMT). No. of bitstreams: 1 Isamara.pdf: 1900151 bytes, checksum: bf2306ee5b36c025c99dadb0b3ed1c84 (MD5) Previous issue date: 2017-03-17 / The objective of this study was to study the influence of magnetized water intake on body weight gain, body morphometry and reproductive system, semen characteristics and body and scrotal area temperatures with digital infrared thermography in young Nellore bulls in extensive management and In confinement. Twenty bulls with initial age of 14 months were used, divided into two groups: Treated - water ingestion treated by magnetic field; And Control - drinking water intake. Four collections were made, 2 in extensive management (14 and 18 months of age) and 2 in confinement (20 and 21 months of age), in which they were measured: climatic factors, rectal temperature, body weight, wither height, Length, width and height of the testicles, semen collection and infrared digital thermography of the eyeball, mufla, flank, ischium and scrotum. It was concluded that the intake of water treated by magnetic field was not efficient in relation to weight gain in pasture and in confinement, as well as for body morphometry and reproductive system. In confinement, there was also no influence of water treated by magnetic field on the quantitative and qualitative characteristics of the semen. Digital infrared thermography proved to be effective for measuring body and scrotal areas, where the grazing group treated with magnetic field water showed higher temperatures for the ocular globe, mufla, flank and ischium. For the scrotal pouch, the pasture, the temperature of the spermatic cord and testis were higher in the treated group; And in confinement, the temperature of the testes and tail of the epididymis were higher in the group with drinking water intake. / Objetivou-se estudar a influência da ingestão da água magnetizada no ganho de peso corpóreo, morfometria corpórea e do aparelho reprodutor, características do sêmen e temperaturas de áreas do corpo e escroto com termografia digital de infravermelho em touros jovens da raça Nelore em manejo extensivo e em confinamento. Foram utilizados 20 touros com idade inicial de 14 meses, divididos em dois grupos: Tratado - ingestão de água tratada por campo magnético; e Controle - ingestão de água potável. Foram realizadas 4 coletas sendo 2 em manejo extensivo (14 e 18 meses de idade) e 2 em confinamento (20 e 21 meses de idade), nas quais foram aferidos: fatores climáticos, temperatura retal, peso corpóreo, altura de cernelha, mensuração do comprimento, largura e altura dos testículos, colheita de sêmen e termografia digital por infravermelho do globo ocular, mufla, flanco, ísquio e escroto. Conclui-se que a ingestão da água tratada por campo magnético não se apresentou eficiente em relação ao ganho de peso a pasto e em confinamento, assim como para morfometria corpórea e do aparelho reprodutor. Em confinamento, também não houve influência da água tratada por campo magnético sobre as características quantitativas e qualitativas do sêmen. A termografia digital por infravermelho se mostrou eficaz para mensuração das áreas do corpo e da bolsa escrotal, onde a pasto o grupo com ingestão de água tratada por campo magnético apresentou temperaturas superiores para globo ocular, mufla, flanco e ísquios. Para bolsa escrotal, a pasto, a temperatura do cordão espermático e testículo foram superiores no grupo tratado; e em confinamento, a temperatura do testículo e cauda dos epidídimos foram superiores no grupo com ingestão de água potável.

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