Celda de alta presión y temperatura para el estudio de la hidratación de cementos "in situ" mediante radiación sincrotrón

Programa Oficial de Doutoramento en Enxeñaría Naval e Industrial . 5015V01[Resumen] La difracción de polvo es una técnica científica que consiste en la difracción de rayos X, neutrones o electrones para la caracterización estructural interna de microcristales de un material en forma de polvo. El objetivo del uso de polvo es conseguir una orientación equitativa de los microcristales en todas las direcciones del espacio, lo que provoca que el espacio reciproco tridimensional de la difracción que se tiene con un monocristal se pueda proyectar en una sola dimensión. Si el material a estudiar contiene más de una fase, esta condición se debe cumplir para todas y cada una de las fases lo que permite obtener análisis cuantitativos libres de errores. Para este fin también se puede hace girar la muestra de forma que se mejora el promedio de cristales equitativamente orientados. En concreto la difracción de rayos X que se ofrecen en las fuentes modernas de radiación sincrotrón ofrecen haces de alta intensidad comparados con los tubos de rayos x convencionales, estrechos y altamente colimados y fotones de elevada energía que permite la penetración en entornos de muestras complejos. Los cementos son un caso típico de polvo cristalino, de especial interés científico son los cementos que se usan en la industria petrolera, el cemento Portland se usa para soportar las tuberías metálicas en los pozos y como medio de estanqueidad de los pozos en los que se insertan estas tuberías. Estos pozos pueden ser muy profundos y los cementos están sometidos a altas presiones y temperaturas, esto provoca que el mecanismo de hidratación cambie sustancialmente comparado con el que ocurre a las presiones y temperaturas que se pueden encontrar en superficie. El efecto en el proceso de hidratación de cementos con la temperatura y la presión se ha estudiado usando varios métodos, incluyendo el método de difracción de polvo. Pero debido a la presión a la que estos cementos pueden estar sujetos de en torno a 1 Kilo bar hay relativamente pocos trabajos que examinen como los efectos de los cambios de presión y temperatura afectan al proceso de hidratación. Aunque se ha visto que presiones inferiores a los 200 bares ya pueden afectar significativamente el proceso de hidratación del silicato tricálcico, Ca3SiO5, la fase más importante en el cemento Portland. La falta de información del papel que juega la presión es debida en parte debido a la inexistencia de herramientas para el estudio in situ de la hidratación del cemento. El objetivo de la presente Tesis es diseñar y construir una celda que sea capaz de reproducir estas condiciones de presión y temperatura (al menos 200 bares y 200 °C). Que permita la rápida inyección de la muestra con el objeto de poder medir las primeras etapas de la hidratación. Que permita hacer rotaciones para mejorar la calidad de los datos de difracción de polvo. Con la que se pueda realizar experimentos de difracción de polvo con radiación sincrotrón, lo que implica que la zona donde este la muestra sea casi transparente a los rayos X y de un material suficientemente duro para soportar la alta presión, materiales típicos que cumplen estas condiciones son el “fused-silica” (vidrio silíceo amorfo producido por fusión a elevadas temperaturas del cuarzo) o Zafiro. Y por supuesto servirá no solo para el caso del estudio del cemento sino de cualquiera muestra en forma de polvo cristalino en la que se quiera conocer su estructura mediante el método de difracción de polvo en las susodichas condiciones.[Abstract] Powder diffraction is a scientific technique that consists on the diffraction of X-rays, neutrons or electrons to characterize the internal structure of microcrystals of a material in powder form. The purpose of using powder is to achieve an equitable orientation of the microcrystals in all directions of space; this allows that the three-dimensional reciprocal space of the diffraction given by a single crystal can be projected into a single dimension. If the material to be studied contains more than one phase, this condition must be fulfilled for each and every one of the phases, which allows doing quantitative analysis free of errors. For this purpose, the sample can also be rotated so that the average of equitable oriented crystals is improved. Specifically, the X-ray diffraction offered in modern synchrotron radiation sources offers high intensity beams compared to conventional, narrow and highly collimated x-ray tubes and high-energy photons that allow penetration into complex sample environments. Cements are a typical case of crystalline powder, of special scientific interest are the cements used in the oil industry, Portland cements are used to support the metal pipes in the wells and as a means of sealing the wells in which these pipes are used. These wells can be very deep, and the cements are subjected to high pressures and temperatures, this causes the hydration mechanism to change substantially compared to what happens at the pressures and temperatures that can be found on the surface. The effect on the hydration process of cements with temperature and pressure has been studied using several methods, including the powder diffraction method. But due to the pressure these cements might be subject to, of around 1 Kilobar there are relatively few works that examine how the effects of pressure and temperature changes affect the hydration process. Although it has been seen that pressures lower than 200 bar can already significantly affect the hydration process of the tricalcium silicate, Ca3SiO5, the most important phase in Portland cement. The lack of information on the role played by the pressure is due in part to the lack of tools for the in situ study of cement hydration. The goal of this Thesis is to design and build a cell that can reproduce these pressure and temperature conditions (at least 200 bar and 200 °C). That allows a rapid injection of the sample in order to be able to measure the first stages of hydration. That allows spinning in order to improve the quality of the powder diffraction data. That allows performing powder diffraction experiments with synchrotron radiation, which implies that the area where the sample carrier is almost transparent to X-rays and the material is stiff enough to withstand the high pressure, typical materials that meet these conditions they are fused silica (amorphous siliceous glass produced by melting quartz at high temperatures) or Sapphire. And of course, it could be used not only for the case of study of a cement but of any sample in the form of crystalline powder in which one wants to know its structure by means of the method of powder diffraction in the aforementioned conditions

Rietveld Quantitative Phase Analysis of Oil Well Cement: in Situ Hydration Study at 150 Bars and 150 °C

Oil and gas well cements are multimineral materials that hydrate under high pressure and temperature. Their overall reactivity at early ages is studied by a number of techniques including through the use of the consistometer. However, for a proper understanding of the performance of these cements in the field, the reactivity of every component, in real‐world conditions, must be analysed. To date, in situ high energy synchrotron powder diffraction studies of hydrating oil well cement pastes have been carried out, but the quality of the data was not appropriated for Rietveld quantitative phase analyses. Therefore, the phase reactivities were followed by the inspection of the evolution of non‐overlapped diffraction peaks. Very recently, we have developed a new cell specially designed to rotate under high pressure and temperature. Here, this spinning capillary cell is used for in situ studies of the hydration of a commercial oil well cement paste at 150 bars and 150 °C. The powder diffraction data were analysed by the Rietveld method to quantitatively determine the reactivities of each component phase. The reaction degree of alite was 90% after 7 hours, and that of belite was 42% at 14 hours. These analyses are accurate, as the in situ measured crystalline portlandite content at the end of the experiment, 12.9 wt%, compares relatively well with the value determined ex situ by thermal analysis, i.e., 14.0 wt%. The crystalline calcium silicates forming at 150 bars and 150 °C are also discussed.This research was funded by Spanish MINECO, grant number BIA2017‐82391‐R which is co‐funded by FEDER. We thank Marc Malfois for his help during the experiment performed at NCD‐SWEET beamline at ALBA synchrotron. We also thank Marcus Paul (Dyckerhoff GmbH) for providing the OWC sample with its characterization and helpful discussions

A Multiplex real-time PCR for detection of Mycoplasma gallisepticum and Mycoplasma synoviae in clinical samples from Brazilian commercial poultry flocks

Mycoplasma gallisepticum (MS) and Mycoplasma synoviae (MS) are important avian pathogens and cause economic losses to the poultry industry. Molecular biology techniques are currently used for a rapid detection of these pathogens and the adoption of control measures of the diseases. The aim of this study was to develop and validate a technique for simultaneous detection of MG and MS by multiplex real time polymerase chain reaction (PCR). The complete assay (Multiplex MGMS) was designed with primers and probes specific for each pathogen and developed to be carried out in a single tube reaction. Vaccines, MG and MS isolates and DNA from other Mycoplasma species were used for the development and validation of the method. Further, 78 pooled clinical samples from different poultry flocks in Brazil were obtained and used to determine the sensitivity and specificity of the technique in comparison to 2 real time PCR assays specific for MG (MG PCR) and MS (MS PCR). The results demonstrated an agreement of 100% (23 positive and 44 negative samples) between Multiplex MGMS and MG PCR in the analysis of 67 samples from MG positive and negative poultry flocks, and an agreement of 96.9% between Multiplex MGMS and MS PCR in the analysis of 64 samples from MS positive and negative poultry flocks. Considering the single amplification tests as the gold standard, the Multiplex MGMS showed 100% of specificity and sensitivity in the MG analysis and 94.7% sensitivity and 100% specificity in the MS analysis. This new assay could be used for rapid analysis of MG and MS in the poultry industry laboratories

DIVERSIDADE GENÉTICA DE MYCOPLASMA SYNOVIAE NO BRASIL

Mycoplasma synoviae (MS) é um agente infeccioso que acomete galinhas e perus, podendo causar doença respiratória crônicae sinovite infecciosa com graus variados de manifestações clínicas. Esta espécie possui diferentes cepas que podem ser caracterizadaspor técnicas de análise genética. O objetivo deste estudo foi analisar a diversidade de um gene específico (vlhA) em amostras de MSde granjas de produção de aves de diferentes locais do Brasil. Amostras de traquéias foram obtidas de aves de 35 lotes de granjaspositivas para MS de diferentes estados do país. DNA total destas amostras foi extraído pela metodologia de sílica e após foi realizadadupla amplificação de uma região variável (284 a 341 pares de bases - pb) da extremidade 5´ do gene vlhA pela técnica dareação em cadeia da polimerase (nested-PCR). As amostras positivas foram sequenciadas e analisadas comparativamente para aconstrução da árvore filogenética e avaliação do tamanho de uma região interna específica (PRR). Os resultados demonstraram aocorrência de 16 diferentes sequências de aminoácidos nas 35 amostras avaliadas e a análise filogenética mostrou a ocorrência de 8diferentes clados. A sequência de aminoácidos da respectiva cadeia polipeptídica também apresentou diversidade entre as amostras.A região variável PRR foi a que apresentou maior polimorfismo e as amostras foram classificadas em 5 tipos previamente caracterizados(A, C, D, E e F) e um novo tipo (G) encontrado em amostras de granjas do estado do Rio Grande do Sul. Estes resultadosdemonstraram que as amostras de MS de granjas de produção avícola do Brasil apresentam diversidade no gene vlhA

High pressure and temperature spinning capillary cell for in-situ synchrotron X-ray powder diffraction

In situ research of materials under moderate pressures (hundreds of bar) is essential in many scientific fields. These range from gas sorption to chemical and biological processes. One industrially important discipline is the hydration of oil well cements. Existing capillary cells in this pressure range are static as they are easy to design and operate. This is convenient for the study of single-phase materials; however, powder diffraction quantitative analyses for multiphase systems cannot be performed accurately as a good powder average cannot be attained. Here, the design, construction and commissioning of a cost-effective spinning capillary cell for in situ powder X-ray diffraction is reported, for pressures currently up to 200 bar. The design addresses the importance of reducing the stress on the capillary by mechanically synchronizing the applied rotation power and alignment on both sides of the capillary while allowing the displacement of the supports needed to accommodate different capillaries sizes and to insert the sample within the tube. This cell can be utilized for multiple purposes allowing the introduction of gas or liquid from both ends of the capillary. The commissioning is reported for the hydration of a commercial oil well cement at 150 bar and 150°C. The quality of the resulting powder diffraction data has allowed in situ Rietveld quantitative phase analyses for a hydrating cement containing seven crystalline phases.The design, production and commissioning of this cell was carried out at the ALBA synchrotron as part of Edmundo Fraga’s PhD project. This work was financially supported by the Spanish Ministry of Economy and Competitiveness through Grants BIA2014-57658-C2-1-R and BIA2017-82391-R which are co-funded by FEDER. We are grateful to Prof. Angus Wilkinson, Georgia Institute of Technology Atlanta, for sharing his knowledge and details on the high pressure cell developed by his team. We also thank Dr. Marcus Paul, Dyckerhoff-Lengerich, Germany, for fruitful discussion on Oil Well Cements. The cell was commissioned at BL11-NCD-SWEET beamline

A compact and versatile dynamic flow cryostat for photon science

We have developed a helium gas flow cryostat for use on synchrotron tender to hard X-ray beamlines. Very efficient sample cooling is achieved because the sample is placed directly in the cooling helium flow on a removable sample holder. The cryostat is compact and easy to operate; samples can be changed in less than 5 min at any temperature. The cryostat has a temperature range of 2.5-325 K with temperature stability better than 0.1 K. The very wide optical angle and the ability to operate in any orientation mean that the cryostat can easily be adapted for different X-ray techniques. It is already in use on different beamlines at the European Synchrotron Radiation Facility (ESRF), ALBA Synchrotron Light Facility (ALBA), and Diamond Light Source (DLS) for inelastic X-ray scattering, powder diffraction, and X-ray absorption spectroscopy. Results obtained at these beamlines are presented here

Rietveld quantitative phase analysis of oil well cement : in situ hydration study at 150 bars and 150 °C

Oil and gas well cements are multimineral materials that hydrate under high pressure and temperature. Their overall reactivity at early ages is studied by a number of techniques including through the use of the consistometer. However, for a proper understanding of the performance of these cements in the field, the reactivity of every component, in real-world conditions, must be analysed. To date, in situ high energy synchrotron powder diffraction studies of hydrating oil well cement pastes have been carried out, but the quality of the data was not appropriated for Rietveld quantitative phase analyses. Therefore, the phase reactivities were followed by the inspection of the evolution of non-overlapped diffraction peaks. Very recently, we have developed a new cell specially designed to rotate under high pressure and temperature. Here, this spinning capillary cell is used for in situ studies of the hydration of a commercial oil well a cement paste at 150 bars and 150 °C. The powder diffraction data were analysed by the Rietveld method to quantitatively determine the reactivities of each component phase. The reaction degree of alite was 90% after 7 hours, and that of belite was 42% at 14 hours. These analyses are accurate, as the in situ measured crystalline portlandite content at the end of the experiment, 12.9 wt%, compares relatively well with the value determined ex situ by thermal analysis, i.e., 14.0 wt%. The crystalline calcium silicates forming at 150 bars and 150 °C are also discussed