A spiral guidance approach concept for commercial VTOL operations

The results of an investigation of the guidance and navigation requirements for VTOL spiral descents in the presence of winds are reported. Models were developed to describe the spiral maneuver and candidate guidance laws were formulated and analyzed. An important element of the guidance scheme is a unique wind estimator which uses the perturbations in bank angle and heading to improve the knowledge of the winds. Finally, recommendations for additional research, including a flight program, were outlined to evaluate the spiral guidance concept

Navigation and guidance requirements for commercial VTOL operations

The NASA Langley Research Center (LaRC) has undertaken a research program to develop the navigation, guidance, control, and flight management technology base needed by Government and industry in establishing systems design concepts and operating procedures for VTOL short-haul transportation systems in the 1980s time period. The VALT (VTOL Automatic Landing Technology) Program encompasses the investigation of operating systems and piloting techniques associated with VTOL operations under all-weather conditions from downtown vertiports; the definition of terminal air traffic and airspace requirements; and the development of avionics including navigation, guidance, controls, and displays for automated takeoff, cruise, and landing operations. The program includes requirements analyses, design studies, systems development, ground simulation, and flight validation efforts

Display/control requirements for VTOL aircraft

Quantative metrics were determined for system control performance, workload for control, monitoring performance, and workload for monitoring. Pilot tasks were allocated for navigation and guidance of automated commercial V/STOL aircraft in all weather conditions using an optimal control model of the human operator to determine display elements and design

Optimum mixing of inertial navigator and position fix data

Optimum mixing of inertial navigator and position fix dat

Preliminary investigation of cooling-air ejector performance at pressure ratios from 1 to 10

Preliminary investigation was made of conical cooling air ejector at primary pressure ratios from 1 to 10. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The gross thrust of the ejector and nozzle were compared. Several ratios of the spacing between the nozzle and shroud exit to the nozzle exit diameter were investigated for several shroud to nozzle exit diameter ratios. Maximum gross thrust loss occurred under conditions of zero cooling-air flow and was as much as 35 percent below nozzle jet thrust. For minimum thrust loss, ejector should be designed with as low diameter and spacing ratio as possible

Preliminary Assessment of Nonpoint Source Related Ambient Toxicity in and around Lower Galveston Bay

In 1991 aquaculture researchers at the old SeaArama facility in Galveston believed that mortality they were observing in their larval shrimp cultures was a result of toxicity of ambient water in the Gulf of Mexico. The researchers utilized near-shore Gulf of Mexico water for rearing larval shrimp. They hypothesized that 2-butoxyethanol was the toxic agent, originating from Galveston Bay waters flowing into the Gulf following heavy rainfall. However, data were not available to support this hypothesis. The US Environmental Protection Agency (EPA) and the Texas Natural Resource Conservation Commission (TNRCC) in a combined effort decided to conduct a water quality study to investigate these concerns. The purposes of the study were to assess the potential for ambient toxicity in lower Galveston Bay and the Gulf of Mexico following rainfall events, and to determine the need for additional studies for a more complete assessment. A total of five stations were sampled during three sampling events: (I) November 1992, (II) June 1993 and (III) February 1994. Sampling stations included Galveston Bay near Redfish Reef, Galveston Channel, and near-shore Gulf of Mexico off Galveston Island. Two additional industrialized areas were also sampled, Texas City Ship Channel and Chocolate Bay. An attempt was made to sample following significant rainfall in the Galveston Bay watershed to assess the potential impact of nonpoint source pollution on bay water quality. Ambient surface water samples were collected for chemical analysis of conventional parameters, EPA priority pollutants (heavy metals, VOCs, semi-volatiles, pesticides and PCBS), and chronic toxicity testing with mysids and inland silversides. Overall, chemical water quality was good for all sites. The chemical analysis yielded no violations of state water quality standards. Bis(2-ethylhexyl)phthalate at the Gulf of Mexico station exceeded the EPA criterion for protection of human health in February 1994, although the significance is doubtful as this is a common lab contaminant. In November 1992 dissolved nickel approached the state's chronic water quality standard at Chocolate Bay. Chronic toxicity data for mysids and inland silversides, although limited, did not indicate significant chronic effects to either species. Because this was a screening study data should be considered preliminary. Chemical and toxicity data indicate that aquatic life uses in the open bay areas sampled are not impacted by toxic substances originating from non-point sources. The need for future open bay type nonpoint source surface water studies is considered low. Studies to assess localized and/or episodic effects of urban storm water discharges and industrial and agricultural runoff (e.g., western near-shore areas of Galveston Bay; Chocolate Bayou upstream of the area sampled in this study) would be of greater value

Modulating signaling networks by CRISPR/Cas9-mediated transposable element insertion

In a recent past, transposable elements (TEs) were referred to as selfish genetic components only capable of copying themselves with the aim of increasing the odds of being inherited. Nonetheless, TEs have been initially proposed as positive control elements acting in synergy with the host. Nowadays, it is well known that TE movement into host genome comprises an important evolutionary mechanism capable of increasing the adaptive fitness. As insights into TE functioning are increasing day to day, the manipulation of transposition has raised an interesting possibility of setting the host functions, although the lack of appropriate genome engineering tools has unpaved it. Fortunately, the emergence of genome editing technologies based on programmable nucleases, and especially the arrival of a multipurpose RNA-guided Cas9 endonuclease system, has made it possible to reconsider this challenge. For such purpose, a particular type of transposons referred to as miniature inverted-repeat transposable elements (MITEs) has shown a series of interesting characteristics for designing functional drivers. Here, recent insights into MITE elements and versatile RNA-guided CRISPR/Cas9 genome engineering system are given to understand how to deploy the potential of TEs for control of the host transcriptional activity.Fil: Vaschetto, Luis Maria Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I; Argentin

Scaffold Translation: Barriers Between Concept and Clinic

Translation of scaffold-based bone tissue engineering (BTE) therapies to clinical use remains, bluntly, a failure. This dearth of translated tissue engineering therapies (including scaffolds) remains despite 25 years of research, research funding totaling hundreds of millions of dollars, over 12,000 papers on BTE and over 2000 papers on BTE scaffolds alone in the past 10 years (PubMed search). Enabling scaffold translation requires first an understanding of the challenges, and second, addressing the complete range of these challenges. There are the obvious technical challenges of designing, manufacturing, and functionalizing scaffolds to fill the Form, Fixation, Function, and Formation needs of bone defect repair. However, these technical solutions should be targeted to specific clinical indications (e.g., mandibular defects, spine fusion, long bone defects, etc.). Further, technical solutions should also address business challenges, including the need to obtain regulatory approval, meet specific market needs, and obtain private investment to develop products, again for specific clinical indications. Finally, these business and technical challenges present a much different model than the typical research paradigm, presenting the field with philosophical challenges in terms of publishing and funding priorities that should be addressed as well. In this article, we review in detail the technical, business, and philosophical barriers of translating scaffolds from Concept to Clinic. We argue that envisioning and engineering scaffolds as modular systems with a sliding scale of complexity offers the best path to addressing these translational challenges.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90495/1/ten-2Eteb-2E2011-2E0251.pd