Time-to-Contact-Based Control Laws for Flare Trajectory Generation and Landing Point Tracking in Autorotation

For many rotorcraft platforms, incorrect timing of the autorotation flare and deceleration maneuvers may result in significant aircraft damage and injury to the crew, or worse. There is a clear need for new pilot cueing and control augmentation technologies that lead to a higher probability of a successful autorotation landing. This paper describes a recent effort to develop two different Tau (time-to-contact)-based autorotation controllers from two different approaches that can be used to drive visual aids to help guide a pilot to apply the required control inputs to complete a safe autorotative landing

Improved Imputation of Common and Uncommon Single Nucleotide Polymorphisms (SNPs) with a New Reference Set

Statistical imputation of genotype data is an important technique for analysis of genome-wide association studies (GWAS). We have built a reference dataset to improve imputation accuracy for studies of individuals of primarily European descent using genotype data from the Hap1, Omni1, and Omni2.5 human SNP arrays (Illumina). Our dataset contains 2.5-3.1 million variants for 930 European, 157 Asian, and 162 African/African-American individuals. Imputation accuracy of European data from Hap660 or OmniExpress array content, measured by the proportion of variants imputed with R^2^>0.8, improved by 34%, 23% and 12% for variants with MAF of 3%, 5% and 10%, respectively, compared to imputation using publicly available data from 1,000 Genomes and International HapMap projects. The improved accuracy with the use of the new dataset could increase the power for GWAS by as much as 8% relative to genotyping all variants. This reference dataset is available to the scientific community through the NCBI dbGaP portal. Future versions will include additional genotype data as well as non-European populations

Methods for specifying the target difference in a randomised controlled trial : the Difference ELicitation in TriAls (DELTA) systematic review

Peer reviewedPublisher PD

Characterization and plant expression of glyphosate-tolerant enolpyruvylshikimate phosphate synthase

Abstract BACKGROUND: Glyphosate tolerance is a dominant trait in modern biotech crops. RESULTS: A gene encoding a glyphosate-tolerant EPSP synthase (aroA 1398 ) from bacterial strain ATX1398 was cloned and characterized. The protein is initiated at a GTG translational start codon to produce a protein that provides robust glyphosate resistance in Escherichia coli (Mig) Cast & Chalm. The aroA 1398 protein was expressed and purified from E. coli, and key kinetic values were determined (K i = 161 µM; K m (PEP) = 11.3 µM; k cat = 28.3 s −1 ). The full-length enzyme is 800-fold more resistant to glyphosate than the maize EPSP synthase while retaining high affinity for the substrate phosphoenol pyruvate. To evaluate further the potential of aroA 1398 , transgenic maize events expressing the aroA 1398 protein were generated. T 0 plants were screened for tolerance to glyphosate sprays at 1.3× commercial spray rates, and T 1 plants were selected that completely resisted glyphosate sprays at 1×, 2× and 4× recommended spray rates in field trials. CONCLUSION: These data suggest that aroA 1398 is a suitable candidate for conferring glyphosate tolerance in transgenic crop plants

Developments of electric cars and fuel cell hydrogen electric cars

The world continues to strive in the search for clean power sources to run the millions of different vehicles on the road on daily basis as they are the main contributors to toxic emissions releases from internal combustion engines to the atmosphere. These toxic emissions contribute to climate change and air pollution and impact negatively on people's health. Fuel cell devices are gradually replacing the internal combustion engines in the transport industry. Some notable challenges of the PEMFC technology are discussed in this paper. High costs, low durability and hydrogen storage problems are some of the major obstacles being examined in this investigation. The paper explores the latest advances in electric cars technology and their design specifications. The study also compares the characteristics and the technologies of the three types of electric cars now available in the market.interna

Model-Based Control and Pilot Cueing Techniques for Autorotation Maneuvers

Autorotation maneuvers are performed by pilots to safely land after an engine failure in a helicopter. These maneuvers are difficult due to the small window for successful timing, the wide range of possible entry conditions, and the potentially catastrophic consequences of a mistake. This work focuses on automation of the autorotation maneuver and the development of cues to aid in piloted autorotations. Specifically, this work is broken into three main categories: landing point tracking and reachability determination near landing, model predictive control through touchdown, and a landing site reachability determination algorithm and pilot cue. The landing point tracking scheme utilizes a biomimetic strategy called tau theory to generate sub-optimal trajectories nearly instantaneously. A point-mass physical model of the helicopter is then applied to predict states and control along an input trajectory. These predicted states can be used to determine the feasibility of the given trajectory. A set of candidate trajectories can be generated and evaluated using these methods to find a sub-optimal set of reachable landing points. This set of landing points can be used to cue a pilot to aid with landing point selection. The Nonlinear Model Predictive Control (NMPC) method proposed here offers several potential benefits over existing control methods including the capability to intelligently balance state constraints on three outputs using only two control inputs. This multi-input multi-output NMPC method solves for the optimal control inputs in closed form using the same point-mass helicopter model employed above. This ensures deterministic runtime and enables real-time execution, a necessities for aerial vehicles. An algorithm to determine the reachable landing points in descent phase is presented along with implementation of two Head Up Displays driven by the algorithm. Limited piloted studies are presented to evaluate the usefulness of such a cue.Ph.D

Falling with Style: Automation and Pilot Cueing During Autorotation Maneurvers

Presented on November 14, 2019 at 6:00 p.m. in the Global Learning Conference Center, Room 236.Brian Eberle is a PhD candidate in the George W. Woodruff School of Mechanical Engineering at Georgia Tech.Runtime: 03:18 minute