Analytical model to control off - bottom blowouts utilizing the concept of simultaneous dynamic seal and bullheading

The current methods for off - bottom control of blowouts involve pumping kill fluid into the well through an injection string. These are the dynamic kill and the momentum kill. The dynamic kill, which is based on the steady state system analysis approach, and the momentum kill, that is loosely based on the Newton\u27s Second Law of Motion, have been used extensively in off-bottom control of actual blowouts. A comprehensive study of these two concepts was performed. The review included an analytical analysis of the published design techniques for both of these methods. The application of these techniques to several different field and hypothetical cases were compared. The study drew conclusions about the conceptual validity, applications, advantages, substantial shortcomings, and design problems for each method. In this work, an alternative method for controlling an off - bottom blowout was also developed. The method is based on the dynamic kill and bullheading concepts and is called dynamic seal - bullheading . Conceptually, the method involves two important stages in the control process. First, a dynamic seal is established at the injection string depth. Second, this forces a portion of the kill fluid to flow downward displacing, equivalent to bullheading, the remaining formation fluid in the wellbore back into an open formation. The models for each stage of this method were implemented in a computer program to give a design method for estimating the kill parameters such as kill flow rate, kill fluid density, kill fluid volume, pumping time and effect of control depth. The program also calculates the formation fluid influx, surface pressure, bottomhole pressure, and pressure at critical points in the well as a function of time during the control. The proposed method and the conventional dynamic control method were compared for two different off - bottom blowout scenarios using the new computer program. The first scenario is an actual field case and the second is a hypothetical blowout with input data from a real well configuration and reservoir. In both cases, dynamic seal - bullheading would provide a more reliable and conclusive kill in a minimum period of tim

Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers

A document describes the low-cost manufacturing of C103 niobium alloy combustion chambers, and the use of a high-temperature, oxidation-resistant coating that is superior to the standard silicide coating. The manufacturing process involved low-temperature spray deposition of C103 on removable plastic mandrels produced by rapid prototyping. Thin, vapor-deposited platinum-indium coatings were shown to substantially improve oxidation resistance relative to the standard silicide coating. Development of different low-cost plastic thrust chamber mandrel materials and prototyping processes (selective laser sintering and stereolithography) yielded mandrels with good dimensional accuracy (within a couple of mils) for this stage of development. The feasibility of using the kinetic metallization cold-spray process for fabrication of free-standing C1O3 thrusters on removable plastic mandrels was also demonstrated. The ambient and elevated temperature mechanical properties of the material were shown to be reasonably good relative to conventionally processed C103, but the greatest potential benefit is that coldsprayed chambers require minimal post-process machining, resulting in substantially lower machining and material costs. The platinum-iridium coating was shown to provide greatly increased oxidation resistance over the silicide when evaluated through oxyacetylene torch testing to as high as 300 F (= 150 C). The iridium component minimizes reaction with the niobium alloy chamber at high temperatures, and provides the high-temperature oxidation resistance needed at the throat

High energy collimating fine grids

The objective of this project was to demonstrate the fabrication of extremely tight tolerance collimating grids using a high-Z material, specifically tungsten. The approach taken was to fabricate grids by a replication method involving the coating of a silicon grid substrate with tungsten by chemical vapor deposition (CVD). A negative of the desired grid structure was fabricated in silicon using highly wafering techniques developed for the semiconductor industry and capable of producing the required tolerances. Using diamond wafering blades, a network of accurately spaced slots was machined into a single-crystal silicon surface. These slots were then filled with tungsten by CVD, via the hydrogen reduction of tungsten hexafluoride. Following tungsten deposition, the silicon negative was etched away to leave the tungsten collimating grid structure. The project was divided into five tasks: (1) identify materials of construction for the replica and final collimating grid structures; (2) identify and implement a micromachining technique for manufacturing the negative collimator replicas (performed by NASA/JPL); (3) develop a CVD technique and processing parameters suitable for the complete tungsten densification of the collimator replicas; (4) develop a chemical etching technique for the removal of the collimator replicas after the tungsten deposition process; and (5) fabricate and deliver tungsten collimating grid specimens

Relocation and seismotectonic interpretation of the seismic swarm of August – December of 2012 in the Linares area, northeastern Mexico

We relocated 52 events of 2.5 ≤ Mc ≤ 3.6 from a seismic sequence of over 250 events that occurred during July-December 2012 southwest of the Linares area, northeastern Mexico. To examine this swarm four seismic stations were installed in the region and operated during different time periods from September to December. Relocation of the swarm showed that the earthquake hypocentral depths were at 8 (±5) km, and the time residuals had values ≤ 0.38 s. The fault plane solutions were generated for individual earthquakes and through the use of the composite mechanism technique. The focal mechanism solutions show pure reverse faulting; the SW dipping NNW – SSE trending nodal plane is the inferred fault plane (strike ~150°, dip ~50° and rake ~67°), which reveals that maximum horizontal stress (SHmax > Shmin > Sv) predominates in the area. RESUMEN En este trabajo relocalizamos 52 sismos en el rango de 2.5 ≤ Mc ≤ 3.6 de una secuencia sísmica de más de 250 eventos que ocurrió al suroeste de la ciudad de Linares, N.L., durante los meses de julio – diciembre de 2012, en el noreste de México. Para estudiar este enjambre se instalaron cuatro estaciones sismológicas en la región de interés, las cuales operaron durante diferentes periodos entre septiembre y diciembre. La relocalización de la secuencia demostró que las profundidades hipocentrales fueron de 8 (±5) km, y los residuales de los tiempos de arribo tuvieron valores ≤ 0.38 s. Se generaron soluciones del plano de falla para sismos individuales, así como a través de la técnica de mecanismos compuestos. La solución de los mecanismos focales encontrada corresponde con fallamiento inverso con rumbo NNW-SSE y buzamiento hacia el SW para el plano nodal inferido (rumbo ~150°, buzamiento ~50° y ángulo de deslizamiento ~67°), el cual revela que el esfuerzo horizontal máximo predomina en el área de estudio (SHmax > Shmin > Sv)

Electrochemical Polishing of Chemical Vapor Deposited Niobium Thin Films

Combining chemical vapor deposition (CVD) with electrochemical polish (EP) operations is a promising route to producing performance-capable superconducting films for use in the fabrication of cost-effective components for superconducting radiofrequency (SRF) particle accelerators and superconducting quantum computers. The post-deposition EP process enables a critically necessary reduction in surface roughness of niobium thin films to promote optimal superconducting surface conditions. In this work, surface morphology, roughness, and crystal orientation of the CVD-grown and EP-polished niobium films were investigated. The grain growth and polishing mechanisms were analyzed. The CVD films were found to comprise steps, kinks, and pyramidal features, resulting in undesirable large peak-to-valley distances. The electrochemical polish was demonstrated to significantly diminish the height of pyramids and effectively minimize the overall surface roughness. In contrast to buffered chemical polishing (BCP), EP results showed a probable dependence on crystal orientation, suggesting this process was influenced by locally enhanced current density and thickness variations of oxide dielectrics. These understandings identify the EP principles tied to CVD-grown Nb films that allow further refinement of surface profiles for film-based SRF application

EVALUACIÓN PRELIMINAR DE LA CALIDAD DEL AGUA PARA CONSUMO HUMANO DE LA POBLACIÓN DEL DISTRITO DE SAMA Y ALTERNATIVAS DE TRATAMIENTO

El presente trabajo fue desarrollado con el fin de estudiar los problemas ambientales en el distrito de Sama, en especial la calidad de agua que consume la población de Las Yaras, los anexos de Buena Vista y Miraflores. El trabajo muestra los problemas de salud que causa el arsénico en la población, la dosificación promedio teórica que ingiere una persona, la utilización de aluminio reciclado para obtener sulfato de aluminio como coagulante y precipitador del arsénico y la remoción obtenida por este componente. También se propone un plan de acción para la zona con el fin de mejorar la calidad ambiental

Abordaje selectivo anterolateral para manejo de fracturas de la región toracolumbar (T12, L1, L2) descripción de una técnica quirúrgica por incisión mínima

La unión toracolumbar es el área más frecuentemente afectada por el trauma cerrado de columna vertebral. Anatómicamente es una zona transicional entre la columna torácica rígida y la lumbar móvil. Se presentan con mayor frecuencia en fracturas por acuñamiento o por estallido, con o sin déficit neurológico. El tratamiento se realiza por abordaje anterolateral en pacientes con acuñamientos inveterados, cifosis postraumática y estallidos con déficit parcial que ameriten descompresión. Se describe una técnica efectuada por ortopedistas-cirujanos de columna, realizada con incisión mínima mediante abordaje apleural,subdiafragmático, retroperitoneal, evitando la toracostomia, practicada en disección cadavérica y reporte preliminar de su aplicación en pacientes con trauma toracolumbar.Se practicó disección cadavérica de la técnica cuya incisión es de 10cm, inicia en el borde externo de los paravertebrales siguiendo la dirección de las costillas falsas. Para fracturas de T12 se expone T11 a L1, se resecan las costillas onceava y doceava, continuando con disección extrapleural subdiafragmática retroperitoneal. Para fracturas de L1 que requiere exposición vertebral T12 a L2, se resecan la costilla doceava y se continúa la disección descrita anteriormente. Para fracturas de L2 que requiere exposición vertebral de L1 a L3, no se realiza resección costal y se efectúa una disección retroperitoneal.Por el mismo abordaje se efectúa descompresión medular, reconstrucción con injertos óseos costales o de cresta ilíaca, interposición de cestas de titanio y fijación interna según el caso. Se realiza además un estudio descriptivo tipo serie de casos con pacientes intervenidos con este abordaje. Se expone la experiencia en disección cadavérica y reparos, posibles complicaciones La experiencia clínica comprende 21 pacientes intervenidos con fracturas por acuñamiento, cifosis postraumática, estallido con déficit neurológico parcial. La fijación interna la efectuamos mediante un sistema de barras y tornillosvertebrales realizando reducción de la fractura y deformidad asociada

ESTUDIO NUMÉRICO DEL ESCALADO DE UN SISTEMA DE COMBUSTIÓN SIN LLAMA Y EL EFECTO DEL NÚMERO DE BOQUILLAS DE DESCARGA DE AIRE

En este trabajo se evalúa mediante simulaciones numéricas la obtención y estabilidad del régimen de combustión sin llama para un sistema de calentamiento cuya geometría fue escalada a partir de un prototipo de laboratorio que opera a 40 kW. Adicionalmente se evaluó el efecto de descargar el aire de combustión por dos o cuatro boquillas. Las simulaciones se llevaron a cabo para un cuarto del dominio del sistema para el que se contó con un mallado hexaédrico que cumple con los criterios de malla establecidos para simulaciones de sistemas reactivos, donde se utilizaron modelos apropiados para modelar la turbulencia, la radiación y la combustión. Se encontró que el sistema escalado puede operar bajo el régimen de combustión sin llama de manera estable a potencias entre 200 y 400 kW. La obtención del régimen se de combustión sin llama se mejora significativamente cuando el aire de combustión se descarga por dos boquillas comparado con la descarga por cuatro boquillas, al tener como criterios de estabilidad la uniformidad de la temperatura y de las especies CO y CO2 en la zona de reacción del horno

Sodium-Glucose Co-Transporter Type 2 Inhibitors and Heart Failure: A Review of the State of the Art

Heart Failure (HF) is a cardiovascular condition with high morbidity and mortality that conditions one of the most critical problems in public health. Despite advances in recent decades, patients continue to have major cardiovascular events and marked reduction in their quality of life. Sodium-Glucose Cotransporter Type 2 Inhibitors (SGLT2 Inhibitors) initially entered the market to treat hyperglycemia in patients with type 2 diabetes mellitus (T2DM), however the discovery of the cardiovascular benefits in patients with HF, regardless of the presence or absence of T2DM positioned it as a new pillar in clinical management. In this state-of-the-art review resulting from a comprehensive literature search (Medline, Cochrane and EMBASE), we describe the impact of SGLT2 Inhibitors on mortality and rehospitalizations in patients with HF and we propose a therapeutic plan for patients with HF to maximizes the benefits

Concurrent chemo-radiotherapy following neoadjuvant chemotherapy in locally advanced breast cancer

<p>Abstract</p> <p>Background</p> <p>Despite broad advances in multimodal treatment of locally advanced breast cancer (LABC), 30 to 40% of patients develop loco-regional relapse. The aim of this study was to analyze in a retrospective manner the effectiveness of concurrent chemo-radiotherapy (CCRTh) after neoadjuvant chemotherapy (NCT) in patients with LABC.</p> <p>Methods</p> <p>One hundred twelve patients with LABC (stage IIB-IIIB) were treated with NCT (5-fluorouracil 500 mg/m², doxorubicin 50 mg/m², and cyclophosphamide 500 mg/m²(FAC), or doxorubicin 50 mg/m²and cyclophosphamide 500 mg/m²(AC) IV in four 21-day courses) followed by CCRTh (60 Gy breast irradiation and weekly mitomycin 5 mg/m², 5-fluorouracil 500 mg/m², and dexamethasone 16 mg, or cisplatin 30 mg/m², gemcitabine 100 mg/m²and dexamethasone 16 mg), and 6–8 weeks later, surgery and two additional courses of FAC, AC, or paclitaxel 90 mg/m²weekly for 12 weeks, and in case of estrogen-receptor positive patients, hormonal therapy.</p> <p>Results</p> <p>Stages IIB, IIIA and -B were 21.4, 42.9, and 35.7%, respectively. Pathological complete response (pCR) in the breast was 42% (95% CI, 33.2–50.5%) and, 29.5% (95% CI, 21.4–37.5%) if including both the breast and the axillary nodes. Multivariate analysis showed that the main determinant of pCR was negative estrogen-receptor status (HR = 3.8; 95% CI, 1.5–9; <it>p </it>= 0.016). The 5-year disease-free survival (DFS) was 76.9% (95% CI, 68.2–84.7%). No relationship between pCR and DFS was found. Multivariate analysis demonstrated that the main DFS determinant was clinical stage (IIB and IIIA <it>vs. </it>IIIB, HR = 3.1; 95% CI, 1.02–9.74; <it>p </it>= 0.04). Only one patient had local recurrence. Five-year overall survival was 84.2% (95% CI, 75–93.2%). The toxicity profile was acceptable.</p> <p>Conclusion</p> <p>This non-conventional multimodal treatment has good loco-regional control for LABC. Randomized clinical trials of preoperative CCRTh following chemotherapy, in patients with LABC are warranted.</p