Deadbands Tell No Tails: X-56A Dynamic Actuation Requirements

2020 ◽  
Author(s):  
Alexander M. Pankonien ◽  
Peter M. Suh ◽  
Jacob R. Schaefer ◽  
Robert M. Mitchell
Keyword(s):  
State Of The Art ◽  
Ride Quality ◽  
Flight Testing ◽  
Nonlinear Simulation ◽  
The Past ◽  
Actuation System ◽  
Testing Data ◽  
Aircraft Performance ◽  
Number Of Cycles ◽  
Significant Effort

Abstract Following significant effort over the past several years by AFRL and NASA, the X-56A flight vehicle has proven to be a useful platform for exploring controllers and distributed actuation on a flexible, swept flying-wing. The program sought to advance the state of the art in airworthiness for vehicles encountering flutter, leading to relaxed design constraints that could drastically decrease structural weight and improve aircraft performance. Specifically, the vehicle was designed to encounter different forms of flutter: body-freedom flutter, and wing-bending torsion flutter, making it an ideal candidate for identifying dynamic actuation challenges. Flight testing led to fundamental observations by controller designers about the actuation needs for such a vehicle. Namely, the small inherent actuator deadband led to significant constant-amplitude limit cycle oscillations of the system during post-flutter controlled flight. This work captures these observations by exploring theoretical changes in the actuators via a nonlinear simulation tuned with flight testing data and shows that a 60% reduction in actuator deadband can improve ride quality by nearly 50%. The results are combined into a set of actuation challenges for the adaptive structures community at large, including precise actuation for a large number of cycles over multiple timescales, with a relevant baseline described by original actuation system.

Modern Methods of Investigating Flutter and Vibration

1964 ◽  
Vol 68 (642) ◽  
pp. 357-373 ◽  
Author(s):  
H. P. Y. Hitch
Keyword(s):  
Vibration Analysis ◽  
Testing Methods ◽  
Flight Testing ◽  
Critical Response ◽  
The Past ◽  
Prediction And Prevention ◽  
Modern Methods ◽  
Aircraft Performance

SummaryThe past several years have seen a steady advance in the techniques employed in flutter and vibration analysis. At the same time aircraft performance has been improved on every front and margins have had to be reduced: it is only by making full use of these modern methods that the accepted margins of safety have been preserved.The paper reviews the processes which are currently used in the prediction and prevention of aircraft flutter in contrast to those of a few years back. The more recent types of flutter which have had to be considered are discussed briefly in relation to the methods which have been developed to deal with them. Ground and Flight testing methods are reviewed together with the use to which the results are put.Finally there is a discussion of the increasing need to predict sub-critical response. The methods employed are discussed in relation to the more important problems.

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

1990 ◽  
Vol 48 (1) ◽  
pp. 438-439
Author(s):  
Carl E. Henderson
Keyword(s):  
Electron Microprobe ◽  
Processing Speed ◽  
Word Processing ◽  
State Of The Art ◽  
Computer Control ◽  
Third Party ◽  
Disk Storage ◽  
The Past ◽  
User Facility ◽  
Instrument Control

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

scholarly journals Inflammation, epigenetics, and metabolism converge to cell senescence and ageing: the regulation and intervention

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xudong Zhu ◽  
Zhiyang Chen ◽  
Weiyan Shen ◽  
Gang Huang ◽  
John M. Sedivy ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cellular Response ◽  
State Of The Art ◽  
Cell Senescence ◽  
Therapeutic Interventions ◽  
Cell Fate Decision ◽  
The Past ◽  
Fate Decision ◽  
The Individual ◽  
Remarkable Progress

AbstractRemarkable progress in ageing research has been achieved over the past decades. General perceptions and experimental evidence pinpoint that the decline of physical function often initiates by cell senescence and organ ageing. Epigenetic dynamics and immunometabolic reprogramming link to the alterations of cellular response to intrinsic and extrinsic stimuli, representing current hotspots as they not only (re-)shape the individual cell identity, but also involve in cell fate decision. This review focuses on the present findings and emerging concepts in epigenetic, inflammatory, and metabolic regulations and the consequences of the ageing process. Potential therapeutic interventions targeting cell senescence and regulatory mechanisms, using state-of-the-art techniques are also discussed.

scholarly journals Security assurance cases—state of the art of an emerging approach

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Mazen Mohamad ◽  
Jan-Philipp Steghöfer ◽  
Riccardo Scandariato
Keyword(s):  
State Of The Art ◽  
Tool Support ◽  
Security Assurance ◽  
The Past ◽  
Depth Analysis ◽  
Structured Argumentation ◽  
Security Properties ◽  
Standards And Regulations ◽  
Assurance Cases ◽  
Security Standards

AbstractSecurity Assurance Cases (SAC) are a form of structured argumentation used to reason about the security properties of a system. After the successful adoption of assurance cases for safety, SAC are getting significant traction in recent years, especially in safety-critical industries (e.g., automotive), where there is an increasing pressure to be compliant with several security standards and regulations. Accordingly, research in the field of SAC has flourished in the past decade, with different approaches being investigated. In an effort to systematize this active field of research, we conducted a systematic literature review (SLR) of the existing academic studies on SAC. Our review resulted in an in-depth analysis and comparison of 51 papers. Our results indicate that, while there are numerous papers discussing the importance of SAC and their usage scenarios, the literature is still immature with respect to concrete support for practitioners on how to build and maintain a SAC. More importantly, even though some methodologies are available, their validation and tool support is still lacking.

scholarly journals The state of the art in soybean transcriptomics resources and gene coexpression networks

2021 ◽  
Author(s):  
Fabricio Almeida-Silva ◽  
Kanhu C Moharana ◽  
Thiago M Venancio
Keyword(s):  
State Of The Art ◽  
The State ◽  
Gene Coexpression Network ◽  
Rna Seq ◽  
Transcriptomic Data ◽  
The Past ◽  
Gene Coexpression ◽  
Genomics Research ◽  
Public Repositories ◽  
Coexpression Networks

Abstract In the past decade, over 3000 samples of soybean transcriptomic data have accumulated in public repositories. Here, we review the state of the art in soybean transcriptomics, highlighting the major microarray and RNA-seq studies that investigated soybean transcriptional programs in different tissues and conditions. Further, we propose approaches for integrating such big data using gene coexpression network and outline important web resources that may facilitate soybean data acquisition and analysis, contributing to the acceleration of soybean breeding and functional genomics research.

scholarly journals Virus Eradication and Synthetic Biology: Changes with SARS-CoV-2?

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 569
Author(s):  
Jean-Nicolas Tournier ◽  
Joseph Kononchik
Keyword(s):  
Clinical Trials ◽  
Synthetic Biology ◽  
Viral Disease ◽  
Virus Eradication ◽  
Disease Eradication ◽  
The Public ◽  
The Past ◽  
The World ◽  
Significant Effort

The eradication of infectious diseases has been achieved only once in history, in 1980, with smallpox. Since 1988, significant effort has been made to eliminate poliomyelitis viruses, but eradication is still just out of reach. As the goal of viral disease eradication approaches, the ability to recreate historically eradicated viruses using synthetic biology has the potential to jeopardize the long-term sustainability of eradication. However, the emergence of the severe acute respiratory syndrome-coronavirus (SARS-CoV)-2 pandemic has highlighted our ability to swiftly and resolutely respond to a potential outbreak. This virus has been synthetized faster than any other in the past and is resulting in vaccines before most attenuated candidates reach clinical trials. Here, synthetic biology has the opportunity to demonstrate its truest potential to the public and solidify a footing in the world of vaccines.

scholarly journals Beyond Mindfulness

Open Theology ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas G. Plante
Keyword(s):  
Research Evidence ◽  
State Of The Art ◽  
Empirical Studies ◽  
Religion And Spirituality ◽  
Spiritual Values ◽  
Quality Research ◽  
The Past ◽  
Enormous Amount ◽  
Consulting Psychology ◽  
Areas Of Interest

AbstractSince the publication of Bergin’s classic 1980 paper “Psychotherapy and Religious Values” in the Journal of Clinical and Consulting Psychology, an enormous amount of quality research has been conducted on the integration of religious and spiritual values and perspectives into the psychotherapy endeavor. Numerous empirical studies, chapters, books, blogs, and specialty organizations have emerged in the past 35 years that have helped researchers and clinicians alike come to appreciate the value of religion and spirituality in the psychotherapeutic process. While so much has been accomplished in this area of integration, so much more needs to occur in order for the psychotherapeutic world to benefit from the wisdom of the great religious and spiritual traditions and values. While state-of-the-art quality research has and continues to demonstrate how religious and spiritual practices and values can be used effectively to enhance the benefits of behavioral and psychological interventions, too often the field either gets overly focused on particular and perhaps trendy areas of interest (e.g., mindfulness) or fails to appreciate and incorporate the research evidence supporting (or not supporting) the use of certain religiously or spiritually informed assessments and interventions. The purpose of this article is to reflect on where the field integrating religion, spirituality and psychotherapy has evolved through the present and where it still needs to go in the future. In doing so I hope to reflect on the call for integration that Bergin highlights in his classic 1980 paper.

Climate and environmental context of the Mongol invasion of Syria and defeat at ‘Ayn Jālūt (1258–1260 CE)

Erdkunde ◽  
2021 ◽  
Vol 75 (2) ◽  
pp. 87-104
Author(s):  
Nicola Di Cosmo ◽  
Sebastian Wagner ◽  
Ulf Büntgen
Keyword(s):  
Strategic Alliances ◽  
Turning Point ◽  
Environmental Changes ◽  
Environmental Variability ◽  
State Of The Art ◽  
Eastern Mediterranean ◽  
The Caucasus ◽  
Mountainous Regions ◽  
The Past ◽  
Climate Reconstructions

After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.

scholarly journals Multifaceted origins of sex differences in the brain

2016 ◽  
Vol 371 (1688) ◽  
pp. 20150106 ◽  
Author(s):  
Margaret M. McCarthy
Keyword(s):  
Sex Differences ◽  
State Of The Art ◽  
Human Subjects ◽  
Special Issue ◽  
Molecular Analyses ◽  
The Past ◽  
Current State ◽  
Biological Variable ◽  
Males And Females ◽  
The Brain

Studies of sex differences in the brain range from reductionistic cell and molecular analyses in animal models to functional imaging in awake human subjects, with many other levels in between. Interpretations and conclusions about the importance of particular differences often vary with differing levels of analyses and can lead to discord and dissent. In the past two decades, the range of neurobiological, psychological and psychiatric endpoints found to differ between males and females has expanded beyond reproduction into every aspect of the healthy and diseased brain, and thereby demands our attention. A greater understanding of all aspects of neural functioning will only be achieved by incorporating sex as a biological variable. The goal of this review is to highlight the current state of the art of the discipline of sex differences research with an emphasis on the brain and to contextualize the articles appearing in the accompanying special issue.

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