Recent Efforts Enabling Martian Rotorcraft Missions

The Mars Helicopter (MH), launching as a part of the Mars 2020 mission, will begin a new era of planetary exploration. Mars research has historically been conducted through landers, rovers, and satellites. As both government and private industries prepare for human exploration of the Martian surface within two decades, more in depth knowledge of what awaits on the surface is critical. Planetary aerial vehicles increase the range of terrain that can be examined, compared to traditional landers and rovers and have more near surface capability than orbiters. The Jet Propulsion Laboratory (JPL) and NASA Ames are currently exploring possibilities for a Mars Science Helicopter (MSH), a second-generation Mars rotorcraft with the capability of conducting science investigations independently of a lander or rover (although this type of vehicle could also be used assist rovers or landers in future missions). Preliminary designs of coaxial-helicopter and hexacopter configurations have targeted the minimum capability of lifting a payload in the range of two to three kilograms with an overall vehicle mass of approximately twenty kilograms. These MSH designs sizes are constrained by the aeroshell dimensions(currently focused on employing legacy Pathfinder or MSL aeroshells), rather than vehicle structural or aeroperformance limitations. Feasibility of the MSH configurations has been investigated considering packaging/deployment, rotor aerodynamics, and structural analysis studies. Initial findings suggest not only the overall feasibility of MSH configurations but also indicate that improvements up to 11.1 times increase in range or 1.3 times increase in hover time might be achievable, even with an additional science payload, compared to the current design of the MH

Parametric studies of advanced turboprops

The effects of geometric variables (sweep and twist) on the structural performance of advanced turboprops are investigated. The investigation is limited to aerodynamically efficient turboprops using an acceptable design configuration as a baseline. The baseline configuration is modified using a seven by seven array of independently varying sweep and twist parameters while maintaining acceptable aerodynamic efficiency. The turboprop structural performance is evaluated in terms of critical speeds, tip displacements, and vibration frequencies where geometric nonlinearities are included. The results obtained are presented in such a manner as to highlight the effects of sweep and twist on the structural performance of aerodynamically efficient turboprop configurations

A versatile source of polarization-entangled photons

We propose a method for the generation of a large variety of entangled states, encoded in the polarization degrees of freedom of N photons, within the same experimental setup. Starting with uncorrelated photons, emitted from N arbitrary single photon sources, and using linear optical tools only, we demonstrate the creation of all symmetric states, e.g., GHZ- and W-states, as well as all symmetric and non-symmetric total angular momentum eigenstates of the N qubit compound.Comment: 4 pages, 3 figure

Takagi-Taupin Description of X-ray Dynamical Diffraction from Diffractive Optics with Large Numerical Aperture

We present a formalism of x-ray dynamical diffraction from volume diffractive optics with large numerical aperture and high aspect ratio, in an analogy to the Takagi-Taupin equations for strained single crystals. We derive a set of basic equations for dynamical diffraction from volume diffractive optics, which enable us to study the focusing property of these optics with various grating profiles. We study volume diffractive optics that satisfy the Bragg condition to various degrees, namely flat, tilted and wedged geometries, and derive the curved geometries required for ultimate focusing. We show that the curved geometries satisfy the Bragg condition everywhere and phase requirement for point focusing, and effectively focus hard x-rays to a scale close to the wavelength.Comment: 18 pages, 12 figure

Mid-Infrared Optical Frequency Combs based on Difference Frequency Generation for Molecular Spectroscopy

Mid-infrared femtosecond optical frequency combs were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain in the 1.5 \mu m signal, which yields powers above 500 mW (3 \mu W/mode) in the idler with spectra covering 2.8 \mu m to 3.5 \mu m. Potential for broadband, high-resolution molecular spectroscopy is demonstrated by absorption spectra and interferograms obtained by heterodyning two combs.Comment: 11 pages, 8 figure

SeO₂-Mediated Oxidative Transposition of Pauson–Khand Products

Oxidative transpositions of bicyclic cyclopentenones mediated by selenium dioxide (SeO₂) are disclosed. Treatment of Pauson–Khand reaction (PKR) products with SeO₂ in the presence or absence of water furnishes di- and trioxidized cyclopentenones, respectively. Mechanistic investigations reveal multiple competing oxidation pathways that depend on substrate identity and water concentration. Functionalization of the oxidized products via cross-coupling methods demonstrates their synthetic utility. These transformations allow rapid access to oxidatively transposed cyclopentenones from simple PKR products

2nd International Summer School on "Carbon and related nanomaterials: synthesis, characterization, properties and applications in energy"

Del 13 al 17 de Julio de 2020 tuvo lugar en Jaca (Huesca) en el marco de los Cursos Extraordinarios de la Universidad de Zaragoza la “Segunda escuela de verano sobre “Nanomateriales de carbono y sistemas relacionados: Síntesis, caracterización, propiedades y aplicaciones en Energía”, dirigido por el Dr. Raúl Arenal (INA-LMA-Universidad de Zaragoza) y por el Dr. Wolfgang Maser (Instituto de Carboquímica, ICB-CSIC, Zaragoza). Se trata de un curso multidisciplinario ofreciendo una introducción al campo de los nanomateriales de carbono y sistemas relacionadas (sistemas 2D, TMDs, perovskitas entre otros). Es una temática de actualidad, de gran interés científico y de especial relevancia tecnológica en lo que se refiere a las aplicaciones en el campo de las energías renovables. El curso estaba dirigido sobre todo a estudiantes universitarios de máster o doctorandos en ciencias (física, química e ingeniería) con interés en la nanociencia y la nanotecnología. Los docentes proporcionaron una amplia y comprehensiva base científica para entender los materiales y sus fascinantes propiedades. Eso incluye igualmente una descripción de las metodologías experimentales y teóricas como técnicas de procesado y de integración de los nanomateriales en dispositivos funcionales, con enfoque especial en el campo de las energías renovables. Las clases se construyeron de una manera sistemática describiendo los diferentes tipos de nanomateriales y sus principales métodos de síntesis, su química y procesado en forma de dispersiones, las técnicas más importantes para su caracterización, las técnicas de ensamblado macroscópico y por último sus varias aplicaciones en el campo de energía renovable (celdas solares, baterías e hidrógeno verde) y tecnologías relacionadas en sensores y actuadores. La finalidad del curso era mostrar la importancia de los nanomateriales de carbono y sistemas relacionados para el avance científico y tecnológico. Asimismo, demostrar que para hacer realidad este progreso y aprovechar el alto potencial de los nanomateriales de carbono se requiere un esfuerzo inter- y multidisciplinar, interactuando científicos y tecnólogos especializados en diferentes disciplinas. Y que, por lo tanto, estos nanomateriales son objetos idóneos para adquirir una amplia base de conocimiento científico-tecnológico. A lo largo del curso, 10 docentes de diferentes instituciones (Instituto de Carboquímica (ICB-CSIC), Instituto de Nanociencia y Materiales de Aragón (INMA)-Universidad de Zaragoza, así como el Instituto Catalán de Nanociencia y Nanotecnología (ICN2-CSIC) y las Universidades de Murcia, Cartagena, Montpellier (Francia) y Sussex (Reino Unido)), especializados en las diversas temáticas mencionadas anteriormente impartieron un total de 20 horas lectivas. Con ello, se consiguió cubrir de una manera muy amplia los diferentes aspectos relacionados con las nanoestructuras de carbono. El curso terminó con un examen final que permitió a los participantes obtener un total de 0, 5 créditos ECTS reconocidos por la Universidad de Zaragoza. Gracias al gran esfuerzo por parte del equipo de la Escuela de Verano el Jaca el curso se pudo realizar cumpliendo un estricto protocolo de medidas COVID- 19. De esta manera se consiguió la participación de 17 alumnos procedentes de España, Bélgica y Francia con una diversa especialización científica en física, química, ingeniería y materiales..

Perceptions of care & patient-provider communication by varying identity groups in a collegiate health clinic

LGBTQ patients experience discrimination and poor access to quality health care, but there is little inquiry on the experiences of LGBTQ patients in student health clinic. The purpose of this study was to examine the quality of patient-provider communication (PPC) among sexual and gender minority patients, especially those who have intersecting minority identities, in a student healthcare setting. An online survey measured PPC using the Communication Assessment Tool (CAT) and contextual questions regarding identity and perceptions of judgment. Analysis tested intersectional variance in both. A convenience and snowball sample of 102 respondents, 18+, that utilized health services at a public university in the southeastern United States were surveyed in the summer of 2019. Patients of Color (M = 8.16, SD = 5.69) perceived stronger PPC than Whites (M = 5.41, SD = 5.27), which deviates from much of the current literature available. Heterosexuals (M = 7.82, SD = 5.65) perceived stronger PPC than LGBQ (M = 4.56, SD = 4.98) patients, which aligns with most current literature. Additional research is recommended for generalizability among student health populations in other university campuses and preliminary findings indicate a need to improve PPC between clinicians and sexual minority patients in student health settings. Experience Framework This article is associated with the Policy & Measurement lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this lens

3D Computer Vision Models Predict DFT-Level HOMO-LUMO Gap Energies from Force-Field-Optimized Geometries

We investigate 3D deep learning methods for predicting quantum mechanical energies at high-theory-level accuracy from inexpensive, rapidly computed molecular geometries. Using space-filled volumetric representations (voxels), we explore the effects of radial decay from atom centers and rotational data augmentation on learnability. We test several published computer vision models for 3D shape learning, and construct our own architecture based on 3D inception networks with physically meaningful kernels. We provide a framework for further studies and propose a modeling challenge for the computer vision and molecular machine learning communities