Thesis (M.S.)--Iowa State University, 2005. / Includes bibliographical references (leaves 31-34). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-10Bitstream added on 2014-06-13T20:37:41Z : No. of bitstreams: 1 cunha_mgs_me_guara.pdf: 2546988 bytes, checksum: 7f90dfedf806a463275bbea800769557 (MD5) / O presente trabalho consiste no estudo do comportamento do fluxo sangüíneo na artéria braquial, através de sinais captados por um microfone acoplado no estetoscópio e utilizado para transformar o sinal acústico (sonoro) em elétrico, e enviá-lo para o computador. O estudo foi realizado oferecendo-se diferentes pressões no esfigmomanômetro, o qual foi adaptado com dois manômetros. Um dos manômetros, graduado em mmHg, não foi modificado, possui o selo do INMETRO e atuou como referência, ao outro foi inserido um extensômetro, que transformou o sinal de pressão em sinal elétrico, utilizando uma ponte amplificada, enviando-o para uma placa de aquisição de dados no computador. Foi traçada uma curva de calibração do sinal elétrico (em mV) com relação ao manômetro graduado em mmHg. Foi proposto um protocolo para aquisição destes sinais a serem analisados, baseado em protocolos de aferição de pressão arterial. O comportamento do fluxo sangüíneo foi comparado às diferentes pressões exercidas pelo esfigmomanômetro. Ao analisar estes dados, foram propostos limites de normalidades da intensidade do sinal do fluxo sangüíneo em diferentes freqüências nas cinco fases da escala de Koroktov. O trabalho mostrou também os limites de normalidade da pressão arterial, utilizando-se o sinal adquirido pela extensometria. Finalmente, foi oferecido mais um auxílio no diagnóstico de patologias do sistema cardiovascular. / The present work consists to study the features of blood flow in to the brachial artery through signals detected by a microphone coupled together a stethoscope. This apparatus changes the acoustics in eletric signal and, then, sends to the computer. This study was implemented exhibiting different pressures in the sphygnomanometer, where two manometers, graded in mmHg, were coulpled. One that has the INMETRO certificate of gauging instruments was not modificate and, then, it was used as the standard. In the other, an extensometer was coupled together, which through an amplifier bridge, pressure signals are transformed in electric signals and sent to a data adapter unit connected to the computer. A gauging curve for the eletric signals versus pressure signals was ploted. It was proposed a protocol to adquire these data signals, based on the protocol of brachial pressure measurement. The features of blood flow were compared at different sphygnomanometer pressures. In the analysis process of the data, normality boundaries of intensity were proposed to the blood flow signal at different frequencies in the five phases of the Koroktov scale. The work also showed the normality boundaries of brachial pressure using the data signals adquired by the extensometry process. Finally, it was provided an one more aid in to diagnose pathologies in the cardiovascular system.

Degree Not Listed / Department of Clinical Sciences / Warren L. Beard / Recumbency affects respiratory mechanics and oxygenation in anesthetized horses. Changes in pleural and abdominal pressures that can impair ventilation have not been described in all recumbencies. The objective of this study was to determine the effects of patient positioning on transdiaphragmatic pressures and selected hemodynamic variables. Horses were maintained under total intravenous general anesthesia with nasal oxygen supplementation. Trans-nasal balloon catheters connected to pressure transducers placed within the stomach and thoracic esophagus were used to measure intrathoracic and gastric pressure in standing and anesthetized horses positioned in: right and left lateral recumbency, dorsal recumbency, reverse Trendelenburg position, and Trendelenburg position. Transdiaphragmatic pressures were calculated as the difference between gastric and intrathoracic pressure. Measurements of SpO2, heart rate, systolic, diastolic and mean arterial pressure, and respiratory rate were obtained every 5 minutes. When compared to dorsal recumbency, gastric expiratory pressure is decreased in the standing position. Thoracic expiratory pressure is decreased in standing and reverse Trendelenburg. Transdiaphragmatic expiratory pressure and SpO2 are decreased in Trendelenburg. Heart rate is increased in reverse Trendelenburg. Systolic, diastolic, and mean arterial pressures are decreased in reverse Trendelenburg and increased in left lateral and right lateral. We found there is wide variation in respiratory pressures between horses and positions and they are not predictive of associated changes in hemodynamic variables.

Neutron diffraction is an extremely powerful technique in condensed matter research; it can be used to measure crystallographic structures, including some of those undeterminable using X-rays. It is also perhaps the most powerful technique for determining magnetic structures, and for probing the strength of magnetic interactions, revealing information beyond that extractable from a magnetometer. High pressure is used by many condensed matter researchers as an additional thermodynamic variable, or tool to perturb otherwise stable systems, and has been used with neutron diffraction for many years. When coupled with low temperatures, this has led to the discovery of an enormous range of non-ambient phases of matter, with a range of exotic properties, some of which are discussed in this thesis. Pressure has a very strong effect on the magnetic properties of a material, with many of the most unusual magnetic phases existing only at extremely low temperatures, or pressures which can only be reached on very small samples. The main topic for this thesis is the study, development, and implementation of new techniques to combine low temperatures, high pressures, and neutron diffraction measurements from micro sized samples. A new pressure cell has been designed, tested, and commissioned with neutron beam time on the WISH diffractometer at the ISIS neutron facility. The cell is compact, with a total mass of approximately 5 kg, and is capable of generating large loads in excess of 4.5 tonnes force. Depending on the sample size used with the cell, the opposed anvil system is capable of generating a range of different pressures beyond what is widely available for low temperature neutron diffraction measurements. To save wasted experimental time in cooling and warming the device, the cell is capable of varying the applied load continuously down to 5 K, whilst the sample pressure can also be measured in-situ using a compact spectrometer system. Obtaining refineable neutron diffraction data from the small samples (< 1mm3) possible in an opposed anvil pressure cell is challenging due to extremely low ratios of signal-to-background when compared with large volume pressure cells. Finite element analysis (FEA) was performed to minimise the mass of the cell, whilst also minimising the amount of supporting material in the beam. Despite this, the signal from the sample is typically very weak; to overcome this, a novel 3D printed device has been designed and tested to collimate extremely small samples, removing much of the background signal from the surrounding material. It has enabled neutron data to be collected from samples an order of magnitude smaller than previously measurable in the cell. To maximise the pressures achievable in the pressure cell, for a given sample volume, an extended FEA study was performed to understand the evolutions of stresses in the cell, and understand the limitations of using sapphire as an anvil material. To complement this work, a compact piston cylinder cell has also been designed for a combination of different measurements. One of the key challenges in high pressure research is in knowing, or ensuring, that the conditions the sample is under are approximately the same for a variety of different measurements. Since different instruments, and techniques, may not allow for the same apparatus to be used between them, this is not always possible. A compact clamped piston cylinder cell has been designed, suitable for in-situ electrical measurements, with additional potential for simultaneous neutron diffraction measurements. The device is demonstrated through an ultrasonic characterisation of the compound UGe2. In addition to the information obtainable from neutron diffraction, much can be learnt from studying the transport properties of a material. This information can be used alongside neutron data to provide a full understanding of how a material behaves. One technique of interest measures how the electrical properties of a material changes under applied magnetic field. This is difficult to achieve under pressure due to the often anisotropic construction of the pressure cell affecting the magnetic field on the sample in different orientations, and the challenge in getting wires to the sample under pressure. This thesis presents the design, and preliminary testing, of an ultra compact high symmetry piston cylinder cell designed to be taken to sub-Kelvin temperatures and rotationally oriented in applied magnetic field. The spherical construction of the cell means that the field on the sample position is, to a very close approximation, identical in all orientations. Finally, this thesis presents a study of the binary alloy Pd3Fe under pressure. Pd3Fe was recently reported to undergo a large-volume collapse under high pressure at room temperature, resulting in near zero thermal expansion]. There are several competing theories on the mechanism behind this process. To investigate further, a series of single crystal Pd3Fe samples were grown, cut, prepared, and extensively analysed. The results of this study suggest that the cause for the large volume collapse may not be magnetic in nature, as previously expected.

A detailed study has been made of the atmospheric pressure chemical vapour deposition (CVD) of tungsten carbide coatings onto powder metallurgy (PM) BT42 grade high speed steel (HSS) indexable cutting tool inserts. The pyrolysis of tungsten hexacarbonyl (W(CO)6) deposition route was utilised in conjunction with a laboratory-scale hot-wall CVD reactor. After numerous coating runs, deposition conditions were established under which rudimentary tungsten carbide coatings could be deposited at 350°C. The characteristics of these coatings were determined using an established characterisation procedure. This involved the following techniques: X-ray diffraction, ball cratering, Auger electron spectroscopy (AES), optical microscopy, fractography/scanning electron microscopy (SEM), profilometry, scratch adhesion testing and micro-indentation hardness testing.

Ulcers of the human skin are difficult to cure and a massive burden to patients. Their treatment costs in the UK are in excess of £ 100 million annually (1989). Both suffering and costs can be reduced significantly by establishing if an ulcer is responding to treatment. Any measurement device must not make any contact with the patient in order to avoid pain, damage or infection of the wound. This work describes a novel non invasive measurement method for superficial skin ulcers. Measurement is carried out using a new version of colour coded structured light method to obtain three dimensional surface data. A set of parallel stripes of light is projected onto the ulcerated skin and observed by a camera. The stripes are displaced by an amount which is related to the shape of the skin. It is shown how stripe parameters such as colour, distance, width and coding may be optimised with respect to the object of interest to maximise the performance of the method. Two newly developed stripe extraction algorithms ensure that the centre positions of the projected stripes are found with a precision better than 0.1 mm. From the position of the stripes on the skin a computer then calculates a representation of its shape by triangulation. This is stored in a three dimensional surface map. The volume of a skin ulcer is the difference between the measured base of the lesion and the original healthy skin. The work demonstrates that the original shape may be simulated by a specialised spline interpolation method which is based on the surroundings of the ulcer. The technique is implemented in a portable instrument which is capable of measuring the area and volume of a wide range of different ulcers and pressure sores with a standard deviation of less than 5% of the total figure. With the current equipment the measurement is made in half a second and its result is available after less than 5 minutes. The technique works well in subdued ambient lighting and on most ulcers. In cases where the ulcer is wet, specular reflection may cause problems but the system is usually able to correct for them. The instrument is suitable for a large variety of ulcers but is not able to measure wounds which undermine the skin, extend outside the normal field of view or are highly flexible.

Due to a globally aging population, there is a growing demand for smart home technology which can serve to monitor the health and safety of adults. Therefore, sleep monitoring has emerged as a crucial tool to improve the health and autonomy of adults. While polysomnography (PSG) is an effective and accurate tool for sleep monitoring, it is obtrusive as the user must wear the instruments during the experiment. Therefore, there has been a growing interest in deploying unobtrusive sleep monitoring devices, specifically for long-term patient monitoring. This thesis proposes multiple algorithms applicable to unobtrusive pressure sensitive sensor arrays in order to assess sleep quality. These algorithms can be listed as adaptive movement detection, sensor data fusion and bed occupancy detection. This thesis also investigates long-term sleep pattern changes from previously recorded data. The methods developed in the thesis can be of interest for future clinical remote patient monitoring systems.

This thesis presents a combination of numerical and experimental studies performed to assess the influence of the warm prestress effect on the cleavage fracture toughness of two ferritic pressure vessel steels. The aims of the research are to gain a detailed knowledge of the materials low temperature response under uniaxial and fracture conditions; to examine, using the finite element method, crack tip stress fields during warm prestress LUCF load cycles; and provide a clear and consistent method of classifying the warm prestress effect. An experimental programme investigated the room temperature and low temperature response of two candidate steels, A533B and BS1501. These steels were tested uniaxially under monotonic and cyclic conditions, and in the cracked condition in the as-received and warm prestressed conditions. Application of a three parameter statistical model to the experimental data showed that the distribution of data in the as received and warm prestressed conditions can be described accurately. The shift in the cleavage toughness distribution following warm prestressing was predicted by combining the statistical model with a validated analytical model of the warm prestress effect. Repeated proof loading was shown to increase cleavage toughness in A533B steel, providing the loading was load controlled. There were negligible effects of repeated proof loading on BS1501 steel. Some further enhancement of cleavage fracture toughness was observed when sub critical crack extension was introduced following warm prestressing, although the results were highly scattered. The finite element method was employed to simulate experimental fracture events. It was found from these simulations that fracture occurs following warm prestressing, when the reloaded crack tip stress distribution matches the as-received fracture crack tip stress distribution. The stress matching was observed to occur well into the elastic stress field ahead of the crack tip. This fracture criterion was employed to provide predictions of cleavage toughness following varying applied preload levels. The results were compared to experimental data sets and various analytical models. The Chell model of the warm prestress effect was observed to provide the best agreement with the finite element predictions. Crack tip blunting during the preload steps was found to have no influence on the predictions of cleavage fracture toughness. Differences in hardening response of the material was also shown to have little influence of the predictions of cleavage toughness. Simulations incorporating sub critical crack extension prior to reloading to fracture demonstrated that cleavage 'toughness can be enhanced further by limited crack extension. Large increments of crack growth were shown to reduce the warm prestress effect. The finite element predictions were validated against the appropriate analytical solution proposed by Chell and experimental results.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Com o aumento da expectativa de vida populacional, tem-se a Ãlcera por pressÃo (UP) como um dos agravos com elevada incidÃncia. Assim, esforÃos para o desenvolvimento de pesquisas que resultem em contribuiÃÃes reais para a prÃtica clÃnica dos enfermeiros assistenciais sÃo necessÃrios. Por isso, optou-se em realizar esta revisÃo integrativa, um dos mÃtodos da PrÃtica Baseada em EvidÃncias que tem por objetivo incorporar as evidÃncias encontradas na literatura à prÃtica assistencial e/ou gerencial. Para isso, a presente investigaÃÃo objetivou analisar as evidÃncias disponÃveis na literatura sobre as intervenÃÃes de enfermagem aplicadas para o tratamento das UP em pacientes acamados. Para seleÃÃo dos artigos, foram utilizadas cinco bases de dados (CINAHAL, SCOPUS, COCHRANE, LILACS e PUBMED) alÃm da revista ESTIMA. A amostra dessa revisÃo foi composta por 27 artigos, referentes a intervenÃÃes, de Ãmbito geral, utilizadas para tratar UP. ApÃs anÃlise dos artigos incluÃdos, os resultados apontaram que a eletromagnÃtico-terapia possui evidÃncias do seu beneficio para cicatrizaÃÃo das UP, porÃm nÃo existem diretrizes sobre sua aplicabilidade. Isto tambÃm foi descrito para o Ultrassom terapÃutico e a V. A. C. terapia. Quanto ao processo de limpeza de ferida, foram descritas utilizaÃÃo de vÃrias substÃncias, dentre essas, nÃo foi encontrada evidÃncia de que uma se sobressaia em relaÃÃo à outra. Na questÃo alimentar, ficou evidente que os pacientes que recebem suplementaÃÃo de proteÃnas, zinco e vitamina C em suas dietas, tendem a cicatrizar a UP em um menor perÃodo. Ao abordar a etiliologia das UP, enfocou-se o reposiciosamento e as superfÃcies de suporte (SS). Ficou patente que os pacientes devem ser reposicionados a cada duas horas, quando deitados, e a cada 15 minutos, quando sentados, como forma de minimizar as forÃas de pressÃo e cisalhamento. No entanto, a evidÃncia referente a esse cuidado possui limitaÃÃes que impedem concluir quanto ao real alÃvio de pressÃo que causa. Com relaÃÃo à forma de mensurar a UP, um Ãnico estudo fez parte da amostra desta dissertaÃÃo, de modo que este apenas descreveu a aplicaÃÃo da Escala de PUSH como forma de documentar a UP. Outro ponto crucial foi a abordagem quanto ao conhecimento dos enfermeiros e as tÃcnicas de cuidados empregadas por eles ao tratar UP. Percebeu-se que prevalece a desinformaÃÃo destes em decorrÃnca do desconhecimento que inicia na graduaÃÃo. Diante desse quadro, pensa-se em como as UP estÃo sendo tratadas e para isso analisaram-se as evidÃncias empregadas diante da dor, do odor e do exsudato. Quanto à dor, ficou clara a recomendaÃÃo do gel de benzidamina e a pomada EMLA, principalmente antes da realizaÃÃo procedimentos, como desbridamento. Quanto ao odor, nÃo foram encontrados estudos que descrevessem a melhor forma de minimizÃ-lo. Para a quantidade de exsudato, este està intimamente relacionado ao perÃodo de cicatrizaÃÃo que a UP encontra-se. Em se tratando das coberturas propriamente ditas, os estudos selecionados abordaram o hidrocoloide, a aloe vera, terapia normotermica e o colÃgeno. Estas coberturas foram abordadas em UP com diferentes estÃgios de cicatrizaÃÃo e ambos os estudos apresentaram taxa de cura adequada com ao descrever o uso de cada uma delas. Entretanto, nÃo foram identificadas evidÃncias que comprovem a superioridade de uma destas terapias. Logo, reforÃa-se a necessidade da busca de conhecimento contÃnuo por parte dos enfermeiros, bem como a importÃncia da avaliaÃÃo global dos pacientes que sÃo submetidos a seus cuidados, haja vista que as contribuiÃÃes reais para prÃtica de tratamento de UP ainda sÃo limitadas. Com isso, urgem que sejam desenvolvidos ensaios clÃnicos para elucidar muitas das respostas que ainda nÃo estÃo explÃcitas. / With the increase in life expectancy, pressure ulcer (PU) has become one of the high incidence injuries. Thus, it is necessary to develop research efforts that result in actual contributions to the clinical practice of nurse assistants. So, we chose to perform this integrative review, one of the methods of Evidence-Based Practice that aims to incorporate the evidence found in the literature to assistance and/or management practice. Therefore, this research aimed to analyze the evidence available in the literature on the nursing interventions applied to the PU treatment in bedridden patients. For articles selection we used five databases (CINAHAL, Scopus, Cochrane, LILACS and PubMed) and Estima Journal. The sample of this review was composed of 27 articles related to interventions of general purpose used in PU treatment. After analyzing the articles included, the results showed that electromagnetic therapy has evidence of its benefit for healing of PU; however there are no guidelines for its applicability. This has also been described for Therapeutic ultrasound and VAC therapy. Regarding the wound cleaning process, they described the use of many substances, such as aloe vera, tap water and saline solution. They also approached the use of hydro massage. We did not find any evidence that among these substances one stood out more than others. Regarding the food issue, we verified that patients who receive supplemental protein, zinc and vitamin C in their diets tend to heal the PU in a shorter period. By dealing with the etiology of PU, we focused on repositioning and support surfaces (SS). It became evident that the patients should be repositioned every two hours when lying down and every 15 minutes when sitting, as a way of minimizing the pressure and shear forces. However, the evidence for this care has limitations that don not allow us to conclude on the real pressure relief it causes. Regarding the method of PU measurement, a single study composed the sample of this dissertation, so it only described the application of the Pressure Ulcer Scale for Healing (PUSH) as a way of documenting PU. Another crucial point was the approach to knowledge of nurses and care techniques employed by them when treating PU. We noticed the prevalence of lack of information among them that starts at graduation. Given this situation, we reflect on how PU is being treated, and thus we analyzed the evidence used against pain, odor and exudate. As for the pain, we verified the recommendation of benzydamine gel and EMLA cream, especially before performing procedures such as debridement. As for the odor, we did not find any study describing the best way to minimize it. As for the amount of exudate, it is closely related to the healing period of PU. Regarding the coverage itself, the studies selected approached the hydrocolloid, aloe vera, normothermic wound therapy and collagen. The coverage were approached in PU with different healing stages, and both studies presented appropriate cure rate when describing the use of each one of them. However, there were no evidences to prove the superiority of any of these therapies. Thus, we reinforce the need for the continuous pursuit of knowledge made by nurses, as well as the importance of the overall assessment of patients who are submitted to their care, given that the actual contributions to the PU treatment practice are still limited. Therefore, there is urgent need to develop clinical trials to elucidate many of the answers that are not yet explicit.

The main goal of the project was to develop new experimental techniques to further investigate the phase diagram of the ferromagnetic superconductor UGe2 at high pressures. Of particular interest is the metamagnetic transition (FM1-FM2) which is thought to play the key role in the unconventional superconductivity in UGe2. The project attempted to detect experimentally the critical ferromagnetic fluctuations associated with the FM1-FM2 transition. The development of the experimental equipment constitutes a substantial part of the project and includes: (1) a 2-axis Rotation Stage for High Pressures, (2) an Ultrasonic Sapphire Anvil Cell and (3) a High Pressure Pulse Echo Setup. (1) allows transport measurement on single crystal samples with simultaneous two-axis rotation at temperatures down to 2 K, magnetic fields up to 9T and pressures up to 5GPa to be made. (2) employs Resonant Ultrasound Spectroscopy on a sample in the anvil type cell with an optical access at cryogenic temperatures. (3) uses the Pulse Echo Technique inside a cylinder type cell allowing for ultrasonic measurements on samples with a well-defined orientation. The design, technical challenges and tests results are presented and discussed. The existing techniques, used in the project, included Inelastic Neutron Scattering. A single crystal of UGe2 was studied at 12 kbar with a large volume two-layered piston-cylinder cell. No critical fluctuations were detected at Tx associated with the FM1-FM2 transition. Instead, a small inelastic signal below this transition temperature was observed at the threshold of the instrument sensitivity. The fluctuations at TC associated with the paramagnetic-to-ferromagnetic transition (PM-FM) were detected and the energy scale of these fluctuations was found to have decreased, as compared to the ambient pressure case, in proportion to the resistivity - a result supporting recent theory. The elastic constant c11 of a single crystal of UGe2 was measured as a function of temperature using (3) at ambient pressure as well as pressures up to 11 kbar. The elastic constant exhibits clear features associated with the two transitions, PM-FM and FM1-FM2. The temperature dependence of the elastic constant at ambient pressure was modelled with two main contributions (Schottky-like and Wiess-like) to the magnetic heat capacity coming from the two energy scales, Tx and TC, as well as two corresponding Gruneisen parameters, Ωx and ΩC. The values of Gruneisen parameters obtained from the data fitting were in good agreement with the values determined from the slope of the phase transition lines on the phase diagram. The temperature dependence of the elastic constant at high pressures was modelled according to the two-component system with coupled moments. The behaviour of the fitting parameters (including the Ωx and ΩT ) was consistent with the phase diagram of UGe2 and captured important features of c11 temperature evolution. The way forward would be to continue the measurements of c11 at higher pressures but also to repeat the measurements at different ultrasonic frequencies in order to obtain the temperature dependence of the ultrasonic attenuation which will provide more insight on the FM1-FM2 transition.