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)

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Degradación físico-química de suelos agrícolas en San Pedro Lagunillas, Nayarit

The objective of this study was to evaluate soil degradation to propose strategies for remediation and recovery of the agricultural soils of San Pedro Lagunillas, Nayarit, Mexico. Soils maintained with natural but slightly grazed vegetation were compared against seasonal agricultural soils used for more than 20 years for the production of various crops. Eight sites (four cultivated and four non-cultivated) were studied, in each one of them agricultural soils (cultivated) were located at a distance of 30 to 80m with respect to their counterpart or soils with natural vegetation (non-cultivated). Samples of the following strata were obtained: 0 to 10, 10 to 20 and 20 to 30 cm of depth; Was quantified: weight of particles smaller than 2 mm, pH, organic matter, extractable phosphorus; Potassium, calcium and magnesium exchangeable, and texture. The rate of infiltration of water was also measured. We performed an analysis of variance and Tukey's mean test (α = 0.05). It is concluded that traditional cultivation practices caused adverse changes in chemical parameters (MO, P extractable, and K) in the first 20 cm of soil. The physical properties were also deteriorated as the infiltrated sheet and rate of infiltration were reduced by about 50% in the soils cultured. The results of this work make evident the need to take appropriate measures to avoid the physical and chemical degradation of cultivated soils, in order to preserve this resource and maintain its productivityEl objetivo de este estudio fue evaluar la degradación de suelos para proponer estrategias de remediación y recuperación de los suelos agrícolas de San Pedro Lagunillas, Nayarit, México. Se compararon suelos mantenidos con vegetación natural pero ligeramente pastoreados contra suelos agrícolas de temporal utilizados por más de 20 años para la producción de diversos cultivos. Se estudiaron ocho sitios (cuatro cultivados y cuatro no cultivados), en cada uno de ellos los suelos agrícolas (cultivados) se ubicaron a una distancia entre 30 a 80m con respecto a su contra parte o suelos con vegetación natural (no cultivados). Se obtuvieron muestras de los siguientes estratos:0 a 10, 10 a 20 y 20 a 30 cm de profundidad; se cuantificó: peso de partículas menores a 2 mm, pH, materia orgánica, fósforo extractable; potasio, calcio y magnesio intercambiables, y textura. También se midió la velocidad de infiltración de agua. Se realizó un análisis de varianza y la prueba de medias de Tukey (α=0.05). Se concluye que las prácticas de cultivo tradicionales provocaron cambios adversos en los parámetros químicos (MO, P extractable, y K) en los primeros 20 cm de suelo. Las propiedades físicas también se vieron deterioradas ya que la lámina infiltrada y velocidad de infiltración se redujeron cerca del 50% en los suelos cultivados. Los resultados de este trabajo hacen evidente la necesidad de tomar medidas convenientes para evitar la degradación física y química de los suelos cultivados, con el propósito de preservar este recurso y mantener su productivida

Deep carbon export from a southern ocean iron-fertilized diatom bloom

Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here we report the results of a five-week experiment carried out in the closed core of a vertically coherent, mesoscale eddy of the Antarctic Circumpolar Current, during which we tracked sinking particles from the surface to the deep-sea floor. A large diatom bloom peaked in the fourth week after fertilization. This was followed by mass mortality of several diatom species that formed rapidly sinking, mucilaginous aggregates of entangled cells and chains. Taken together, multiple lines of evidence-although each with important uncertainties-lead us to conclude that at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor. Thus, iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments

Translocon-associated Protein Subunit SSR3 Determines and Predicts Susceptibility to Paclitaxel in Breast Cancer and Glioblastoma.

PurposePaclitaxel (PTX) is one of the most potent and commonly used chemotherapies for breast and pancreatic cancer. Several ongoing clinical trials are investigating means of enhancing delivery of PTX across the blood-brain barrier for glioblastomas. Despite the widespread use of PTX for breast cancer, and the initiative to repurpose this drug for gliomas, there are no predictive biomarkers to inform which patients will likely benefit from this therapy.Experimental designTo identify predictive biomarkers for susceptibility to PTX, we performed a genome-wide CRISPR knockout (KO) screen using human glioma cells. The genes whose KO was most enriched in the CRISPR screen underwent further selection based on their correlation with survival in the breast cancer patient cohorts treated with PTX and not in patients treated with other chemotherapies, a finding that was validated on a second independent patient cohort using progression-free survival.ResultsCombination of CRISPR screen results with outcomes from patients with taxane-treated breast cancer led to the discovery of endoplasmic reticulum (ER) protein SSR3 as a putative predictive biomarker for PTX. SSR3 protein levels showed positive correlation with susceptibility to PTX in breast cancer cells, glioma cells, and in multiple intracranial glioma xenografts models. KO of SSR3 turned the cells resistant to PTX while its overexpression sensitized the cells to PTX. Mechanistically, SSR3 confers susceptibility to PTX through regulation of phosphorylation of ER stress sensor IRE1α.ConclusionsOur hypothesis generating study showed SSR3 as a putative biomarker for susceptibility to PTX, warranting its prospective clinical validation

Deep carbon export from a Southern Ocean iron-fertilized diatom bloom.

Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here we report the results of a five-week experiment carried out in the closed core of a vertically coherent, mesoscale eddy of the Antarctic Circumpolar Current, during which we tracked sinking particles from the surface to the deep-sea floor. A large diatom bloom peaked in the fourth week after fertilization. This was followed by mass mortality of several diatom species that formed rapidly sinking, mucilaginous aggregates of entangled cells and chains. Taken together, multiple lines of evidence—although each with important uncertainties—lead us to conclude that at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor. Thus, iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments

Deficiency of the splicing factor RBM10 limits EGFR inhibitor response in EGFR-mutant lung cancer.

Molecularly targeted cancer therapy has improved outcomes for patients with cancer with targetable oncoproteins, such as mutant EGFR in lung cancer. Yet, the long-term survival of these patients remains limited, because treatment responses are typically incomplete. One potential explanation for the lack of complete and durable responses is that oncogene-driven cancers with activating mutations of EGFR often harbor additional co-occurring genetic alterations. This hypothesis remains untested for most genetic alterations that co-occur with mutant EGFR. Here, we report the functional impact of inactivating genetic alterations of the mRNA splicing factor RNA-binding motif 10 (RBM10) that co-occur with mutant EGFR. RBM10 deficiency decreased EGFR inhibitor efficacy in patient-derived EGFR-mutant tumor models. RBM10 modulated mRNA alternative splicing of the mitochondrial apoptotic regulator Bcl-x to regulate tumor cell apoptosis during treatment. Genetic inactivation of RBM10 diminished EGFR inhibitor-mediated apoptosis by decreasing the ratio of (proapoptotic) Bcl-xS to (antiapoptotic) Bcl-xL isoforms of Bcl-x. RBM10 deficiency was a biomarker of poor response to EGFR inhibitor treatment in clinical samples. Coinhibition of Bcl-xL and mutant EGFR overcame the resistance induced by RBM10 deficiency. This study sheds light on the role of co-occurring genetic alterations and on the effect of splicing factor deficiency on the modulation of sensitivity to targeted kinase inhibitor cancer therapy