Real-time simulation model of the HL-20 lifting body

A proposed manned spacecraft design, designated the HL-20, has been under investigation at Langley Research Center. Included in that investigation are flight control design and flying qualities studies utilizing a man-in-the-loop real-time simulator. This report documents the current real-time simulation model of the HL-20 lifting body vehicle, known as version 2.0, presently in use at NASA Langley Research Center. Included are data on vehicle aerodynamics, inertias, geometries, guidance and control laws, and cockpit displays and controllers. In addition, trim case and dynamic check case data is provided. The intent of this document is to provide the reader with sufficient information to develop and validate an equivalent simulation of the HL-20 for use in real-time or analytical studies

The DaveMLTranslator: An Interface for DAVE-ML Aerodynamic Models

It can take weeks or months to incorporate a new aerodynamic model into a vehicle simulation and validate the performance of the model. The Dynamic Aerospace Vehicle Exchange Markup Language (DAVE-ML) has been proposed as a means to reduce the time required to accomplish this task by defining a standard format for typical components of a flight dynamic model. The purpose of this paper is to describe an object-oriented C++ implementation of a class that interfaces a vehicle subsystem model specified in DAVE-ML and a vehicle simulation. Using the DaveMLTranslator class, aerodynamic or other subsystem models can be automatically imported and verified at run-time, significantly reducing the elapsed time between receipt of a DAVE-ML model and its integration into a simulation environment. The translator performs variable initializations, data table lookups, and mathematical calculations for the aerodynamic build-up, and executes any embedded static check-cases for verification. The implementation is efficient, enabling real-time execution. Simple interface code for the model inputs and outputs is the only requirement to integrate the DaveMLTranslator as a vehicle aerodynamic model. The translator makes use of existing table-lookup utilities from the Langley Standard Real-Time Simulation in C++ (LaSRS++). The design and operation of the translator class is described and comparisons with existing, conventional, C++ aerodynamic models of the same vehicle are given

Correction: African American mitochondrial DNAs often match mtDNAs found in multiple African ethnic groups

After the publication of this work [1], we became aware that AFDIL data set used to construct our database of sub-Saharan mtDNA sequences had been mislabelled, and in fact, did not contain Sierra Leone mtDNA sequences. We have obtained the correct Sierra Leone data set from AFDIL, reconstructed the database using the new file, and reanalyzed all of the data. The size of our database was reduced from 3725 to 3717 since the new Sierra Leone data set contained 109 sequences instead of 117 in themislabelled data set. The swapping of data sets resulted in a cascade of minor corrections to Tables 2, 3, 4, 5, and 6 (see below). We also corrected an error in the entry for BAM013 in Table 7. However, the only major change was that there were a number of matches of African-American sequences to sequences in the mislabelled data set. Thus, the number of African-American matches to single ethnic groups dropped from a total of 16 to 9 (Table 3) representing just 5% of the African American sequences that we compared to the database

Inversion of torsional oscillations for the structure and dynamics of Earth's core

Oscillations in Earth's liquid core with periods of several decades are inferred from variations in the magnetic field. The observed periods are consistent with a type of hydromagnetic wave known as torsional oscillations. These oscillations represent a set of very-low-frequency normal modes in which the internal magnetic field provides the primary restoring force. By adapting the methods of normal-mode seismology, we construct estimates for the internal structure of the magnetic field and several other key parameters, including the viscosity of the inner core. The structure of the recovered field provides useful insights into the nature of convection. We find evidence of columnar convection in the core, and estimate the strength of the field generated by these flows (≈0.3 mT). We also use the normal modes to recover the excitation source for the oscillations. Much of the excitation appears to originate near the surface of a cylinder that is tangent to the equator of the inner core. Distinct events rise above a background level of excitation, and may be related to instabilities in the geodynam

Greening the Grey: A Framework for Integrated Green Grey Infrastructure (IGGI)

This report presents innovations from academia and practice designed to green grey infrastructure assets such as bridges, street furniture and coastal engineering structures that need to remain primarily grey for their essential function. We call this integrated green grey infrastructure (IGGI). We collated material on these innovations and assessed them using a critical success factors (CSF) framework that we –co-developed with a team of practitioners in government agencies and companies to help better evaluate the potential benefits and limitations of using IGGI measures compared to traditional grey engineering solutions. The CSF framework is outlined and demonstrated by assessing the engineering performance and ecosystem services benefits of ecological enhancements used in specific operational scale case studies. The case studies presented in this report show that simple, inexpensive ecological enhancement and green engineering solutions can deliver more multifunctional benefits than business as usual solutions for similar or reduced costs. These ecological enhancements and green engineering options have been compiled and assessed for historic conservation areas, urban areas, estuaries and at the coast. This report is intended to support asset managers, engineers, conservation and biodiversity teams, decision-makers, and other end-users to help them better identify IGGI options and evaluate these against business as usual grey engineering approaches

Beam losses from ultra-peripheral nuclear collisions between Pb ions in the Large Hadron Collider and their alleviation

Electromagnetic interactions between colliding heavy ions at the Large Hadron Collider (LHC) at CERN will give rise to localized beam losses that may quench superconducting magnets, apart from contributing significantly to the luminosity decay. To quantify their impact on the operation of the collider, we have used a three-step simulation approach, which consists of optical tracking, a Monte-Carlo shower simulation and a thermal network model of the heat flow inside a magnet. We present simulation results for the case of Pb ion operation in the LHC, with focus on the ALICE interaction region, and show that the expected heat load during nominal Pb operation is 40% above the quench level. This limits the maximum achievable luminosity. Furthermore, we discuss methods of monitoring the losses and possible ways to alleviate their effect.Comment: 17 pages, 20 figure

Toll-Like Receptor Transcriptome in the HPV-Positive Cervical Cancer Microenvironment

The human papillomavirus (HPV) directly infects cervical keratinocytes and interferes with TLR signalling. To shed light on the effect of HPV on upstream receptors, we evaluated TLRs 1–9 gene expression in HPV-negative normal and HPV-positive pre-malignant and malignant ex vivo cervical tissue. Quantitative real-time polymerase chain reaction was performed separately for epithelial and stromal tissue compartments. Differences in gene expression were analyzed by the Jonckheere-Terpstra trend test or the Student's t-test for pairwise comparison. Laser capture microdissection revealed an increase in TLR3 and a decrease in TLR1 mRNA levels in dysplastic and carcinoma epithelium, respectively. In the stroma, a trend of increasing TLR 1, 2, 5, 6, and 9 mRNA levels with disease severity was found. These findings implicate the involvement of TLR3 and TLR1 in early and late cervical carcinogenesis, respectively, suggesting that stromal upregulation of TLRs may play a role in cervical disease progression

Launch-pad abort capabilities of the HL-20 lifting body

The capability of the HL-20 lifting body to perform an abort maneuver from the launch pad to a horizontal landing was studied. The study involved both piloted and batch simulation models of the vehicle. A point-mass model of the vehicle was used for trajectory optimization studies. The piloted simulation was performed in the Langley Visual/Motion Simulator in the fixed-base mode. A candidate maneuver was developed and refined for the worst-case launch-pad-to-landing-site geometry with an iterative procedure of off-line maneuver analysis followed by piloted evaluations and heuristic improvements to the candidate maneuver. The resulting maneuver demonstrates the launch-site abort capability of the HL-20 and dictates requirements for nominal abort-motor performance. The sensitivity of the maneuver to variations in several design parameters was documented

Can lightning be a noise source for a spherical gravitational wave antenna?

The detection of gravitational waves is a very active research field at the moment. In Brazil the gravitational wave detector is called Mario SCHENBERG. Due to its high sensitivity it is necessary to model mathematically all known noise sources so that digital filters can be developed that maximize the signal-to-noise ratio. One of the noise sources that must be considered are the disturbances caused by electromagnetic pulses due to lightning close to the experiment. Such disturbances may influence the vibrations of the antenna's normal modes and mask possible gravitational wave signals. In this work we model the interaction between lightning and SCHENBERG antenna and calculate the intensity of the noise due to a close lightning stroke in the detected signal. We find that the noise generated does not disturb the experiment significantly.Comment: 5 pages, 6 figure