Pitch Stability of an Unpowered Ground Effect Vehicle

2010 ◽  
Author(s):  
Meagan Hubbell ◽  
Steven Hard ◽  
Matthew Boots ◽  
Mary Ann Clarke ◽  
James E. Smith
Keyword(s):  
Center Of Pressure ◽  
Ground Effect ◽  
Longitudinal Direction ◽  
Russian Government ◽  
Induced Drag ◽  
Unique Approach ◽  
The Subject ◽  
Design Requirements ◽  
And Function ◽  
Positive Results

The ground effect regime was first utilized in the early 1900’s with the advent of transatlantic flight. Aircraft such as the Dornier DO-X would fly close to the surface of the water in order to increase its payload and range. Since that time, research has been periodic with the largest resurgence of ground effect interest in the 1960’s. The Russian government became involved in developing aircraft designed solely for ground effect flight. The design of these aircraft was difficult due to the inherent problems that exist within ground effect. There are natural instabilities that occur, especially in the longitudinal direction that are antagonized by shifting payload weights. Past researchers have handled the unique design requirements of ground effect through the usage of high-tail devices which operate outside of ground effect and power augmented ground effect which artificially generates the lift force through the use of thrust vectoring. The Center for Industrial Research Applications (CIRA) has developed a single passenger, unpowered, subsonic aircraft that relies on gravitational forces for momentum. AirRay combines the benefits of ground effect i.e. the increased lift and decreased induced drag, with a unique approach to maintaining stability. The design of AirRay faced many challenges as a result of flying in the ground effect regime, similar to those found in the prior efforts. These include natural instabilities, primarily in the longitudinal direction, that cause the glider to want to pitch up. In addition the size requirements for a single rider to maximize maneuverability, as well as the potential for updrafts on a downhill slope are added constraints to the design of the ground effect vehicle. These issues, and others, are the subject of current study. This paper has focused on the most important aspect of the design, longitudinal stability. This research has shown positive results with respect to the effectiveness of slots, on passively controlling the movement of the center-of-pressure at varying angles of attack. The 40 degree slot located at 20% of the chord line was most advantageous in stabilizing movement. These results indicate a craft can be designed that can be stable and function in the majority of the flight conditions that have been specified.

Aero-Hydrodynamic Aspects of Power-augmented Ram Wings

2013 ◽  
Vol 57 (02) ◽  
pp. 86-97
Author(s):  
Konstantin I. Matveev
Keyword(s):  
Water Surface ◽  
Center Of Pressure ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Horizontal Plate ◽  
Water Flows ◽  
Dimensional Interaction ◽  
Effect Theory ◽  
The Subject ◽  
Linearized Model

The subject of this article is the two-dimensional interaction of air and water flows under a power-augmented ram wing. The extreme ground effect theory is applied for the air flow, whereas the water flow is treated with a linearized model based on a method of hydrodynamic singularities. Calculated aerodynamic characteristics of power-augmented ram platforms and water surface deformations at moderate and high Froude numbers are presented for a horizontal plate with a flap, a trimmed plate without a flap, and an S-shaped profile. Additionally, plates in contact with water are modeled. The transition from airborne to waterborne states is accompanied by drastic variations of the lift and center of pressure. It is found that solutions can be nonunique when the plate trailing edge is very close to the water surface.

Physicianship and the Rebirth of Medical Education

2018 ◽  
Author(s):  
J. Donald Boudreau ◽  
Eric Cassell ◽  
Abraham Fuks
Keyword(s):  
Medical Education ◽  
Educational Process ◽  
Medical Attention ◽  
Patient Centeredness ◽  
Goals Of Medicine ◽  
The Subject ◽  
Definition Of ◽  
And Function ◽  
William Osler ◽  
The Relationship

This book reimagines medical education and reconstructs its design. It originates from a reappraisal of the goals of medicine and the nature of the relationship between doctor and patient. The educational blueprint outlined is called the “Physicianship Curriculum” and rests on two linchpins. First is a new definition of sickness: Patients know themselves to be ill when they cannot pursue their purposes and goals in life because of impairments in functioning. This perspective represents a bulwark against medical attention shifting from patients to diseases. The curriculum teaches about patients as functional persons, from their anatomy to their social selves, starting in the first days of the educational program and continuing throughout. Their teaching also rests on the rock-solid grounding of medicine in the sciences and scientific understandings of disease and function. The illness definition and knowledge base together create a foundation for authentic patient-centeredness. Second, the training of physicians depends on and culminates in development of a unique professional identity. This is grounded in the historical evolution of the profession, reaching back to Hippocrates. It leads to reformulation of the educational process as clinical apprenticeships and moral mentorships. “Rebirth” in the title suggests that critical ingredients of medical education have previously been articulated. The book argues that the apprenticeship model, as experienced, enriched, taught, and exemplified by William Osler, constitutes a time-honored foundation. Osler’s “natural method of teaching the subject of medicine” is a precursor to the Physicianship Curriculum.

scholarly journals GMO Genetic Elements Thesaurus (GMO-GET): a controlled vocabulary for the consensus designation of introduced or modified genetic elements in genetically modified organisms

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Paulien Adamse ◽  
Emilie Dagand ◽  
Karen Bohmert-Tatarev ◽  
Daniela Wahler ◽  
Manoela Miranda ◽  
...  
Keyword(s):  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Controlled Vocabulary ◽  
Data Systems ◽  
Genetic Elements ◽  
Related Information ◽  
Detection And Identification ◽  
Unique Approach ◽  
The Subject ◽  
And Control

Abstract Background Various databases on genetically modified organisms (GMOs) exist, all with their specific focus to facilitate access to information needed for, e. g., the assistance in risk assessment, the development of detection and identification strategies or inspection and control activities. Each database has its unique approach towards the subject. Often these databases use different terminology to describe the GMOs. For adequate GMO addressing and identification and exchange of GMO-related information it is necessary to use commonly agreed upon concepts and terminology. Result A hierarchically structured controlled vocabulary describing the genetic elements inserted into conventional GMOs, and GMOs developed by the use of gen(om)e-editing is presented: the GMO genetic element thesaurus (GMO-GET). GMO-GET can be used for GMO-related documentation, including GMO-related databases. It has initially been developed on the basis of two GMO databases, i.e. the Biosafety Clearing-House and the EUginius database. Conclusion The use of GMO-GET will enable consistent and compatible information (harmonisation), also allowing an accurate exchange of information between the different data systems and thereby facilitating their interoperability. GMO-GET can also be used to describe genetic elements that are altered in organisms obtained through current targeted genome-editing techniques.

scholarly journals EPIDEMIC ENCEPHALITIS AND SIMPLE HERPES

1927 ◽  
Vol 8 (6) ◽  
pp. 713-726 ◽  
Author(s):  
Simon Flexner
Keyword(s):  
Guinea Pig ◽  
Past Experience ◽  
The State ◽  
Encephalitis Virus ◽  
Point Of View ◽  
Epidemic Encephalitis ◽  
Direct Corollary ◽  
The Subject ◽  
Positive Results ◽  
Epidemic Diseases

The purpose of this paper is to explain the state of our knowledge of the etiology of epidemic encephalitis, and especially to draw a line of demarcation between the established virus of simple herpes and the hypothetical virus of epidemic encephalitis. It had already been shown that the experimental observations on rabbits do no suffice to prove the identity of the herpes with the encephalitis virus. The discussion of the subject in this paper shows that identity cannot be postulated on the basis of the performed guinea pig experiments. Attention has been drawn to the significant fact that there is lack of harmony in the positive results of those investigators who believe that the incitants of epidemic encephalitis have been discovered. An attempt has been made to attribute some of the discrepancies reported by these investigators either to accidental and contaminating microbic agents, or to the uncovering of virulent agents preexisting in a latent state in the animals employed for inoculation, the existence of which was not previously known or suspected. Since past experience leads us to believe in a single incitant for widespread epidemic diseases, it is probable that, when certainly discovered, the microbe of epidemic encephalitis will prove to be simple and not multiple. The direct corollary to this point of view is that up to the present, the etiology of epidemic encephalitis has not been determined.

Communist International Front Organizations: Their Nature and Function

1956 ◽  
Vol 9 (1) ◽  
pp. 76-87 ◽  
Author(s):  
Bernard S. Morris
Keyword(s):  
Psychological Warfare ◽  
Satisfactory Method ◽  
And Function ◽  
Positive Results

IT was once suggested that the basic trait of psychological warfare—and, incidentally, the greatest asset to those that practice it—is its lack of known positive results.1 No satisfactory method has yet been developed to measure the effects of a propaganda campaign on its chosen audience. This characteristic is at once the greatest weakness of propaganda and psychological warfare (how does the operator know whether his effort was well spent or not?) and their greatest strength (if there is no reliable evaluation of the effort, it had better be continued, or even intensified, lest ground be lost).

Aerodynamic ground effects on DLRF6 vehicle

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mojtaba Tahani ◽  
Mehran Masdari ◽  
Ali Bargestan
Keyword(s):  
Stokes Equations ◽  
Ground Effect ◽  
Longitudinal Direction ◽  
Propulsion System ◽  
Navier Stokes ◽  
Noticeable Effect ◽  
Navier Stokes Equations ◽  
Vehicle Performance ◽  
Content Type ◽  
Logical Connection

Purpose The overall performance of an aerial vehicle strongly depends on the specifics of the propulsion system and its position relative to the other components. The purpose of paper is this factor can be characterized by changing several contributing parameters, such as distance from the ground, fuselage and wing as well as the nacelle outlet velocity and analyzing the aerodynamic performance. Design/methodology/approach Navier–Stokes equations are discretized in space using finite volume method. A KW-SST model is implemented to model the turbulence. The flow is assumed steady, single-phase, viscous, Newtonian and compressible. Accordingly, after validation and verification against experimental and numerical results of DLRF6 configuration, the location of the propulsion system relative to configuration body is examined. Findings At the nacelle outlet velocity of V/Vinf = 4, the optimal location identified in this study delivers 16% larger lift to drag ratio compared to the baseline configuration. Practical implications Altering the position of the propulsion system along the longitudinal direction does not have a noticeable effect on the vehicle performance. Originality/value Aerial vehicles including wing-in-ground effect vehicles require thrust to fly. Generating this necessary thrust for motion and acceleration is thoroughly affected by the vehicle aerodynamics. There is a lack of rigorous understanding of such topics owing to the immaturity of science in this area. Complexity and diversity of performance variables for a numerical solution and finding a logical connection between these parameters are among the related challenges.

"Itzt kommen die Soldaten"

2019 ◽  
Author(s):  
Tilman Venzl
Keyword(s):  
Literary History ◽  
18Th Century ◽  
Military History ◽  
Form And Function ◽  
Social Structural ◽  
History Of ◽  
The Subject ◽  
And Function ◽  
The Military ◽  
First Time

In the 18th century, as many as 300 German-language plays were produced with the military and its contact and friction with civil society serving as focus of the dramatic events. The immense public interest these plays attracted feeds not least on the fundamental social structural change that was brought about by the establishment of standing armies. In his historico-cultural literary study, Tilman Venzl shows how these military dramas literarily depict complex social processes and discuss the new problems in an affirmative or critical manner. For the first time, the findings of the New Military History are comprehensively included in the literary history of the 18th century. Thus, the example of selected military dramas – including Lessing's Minna von Barnhelm and Lenz's Die Soldaten – reveals the entire range of variety characterizing the history of both form and function of the subject.

Synagogue as Infrastructure in Everyday Life of Batumi Jewish Community

2021 ◽  
Vol 14 (3-4) ◽  
pp. 323-338
Author(s):  
Nino Abakelia
Keyword(s):  
Everyday Life ◽  
Jewish Community ◽  
Black Sea ◽  
The Black Sea ◽  
Culturally Specific ◽  
Sacred Place ◽  
Black Sea Region ◽  
The Subject ◽  
Ethnographic Data ◽  
And Function

Abstract The subject under scrutiny is Sephardic and Ashkenazi synagogues in Batumi (the Black Sea Region of Georgia) that reveal both universal and culturally specific forms. The paper is based on ethnographic data gathered during fieldwork in Batumi, in 2019, and on the theoretical postulates of anthropology of infrastructure. The article argues that the Batumi synagogues could be viewed and understood as ‘infrastructure’ in their own right, as they serve as objects through which other objects, people, and ideas operate and function as a system. The paper attempts to demonstrate how the sacred edifices change their trajectory according to modern conditions and how the sacred place is inserted and coexists inside a network of touristic infrastructure.

scholarly journals Everything You Always Wanted to Know about β3-AR * (* But Were Afraid to Ask)

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 357 ◽  
Author(s):  
Giorgia Schena ◽  
Michael J. Caplan
Keyword(s):  
Adrenergic Receptor ◽  
Species Differences ◽  
Current Clinical Practice ◽  
Substantial Body ◽  
Cellular Models ◽  
Wide Range ◽  
The Subject ◽  
And Function ◽  
Novel Therapeutic ◽  
Do So

The beta-3 adrenergic receptor (β3-AR) is by far the least studied isotype of the beta-adrenergic sub-family. Despite its study being long hampered by the lack of suitable animal and cellular models and inter-species differences, a substantial body of literature on the subject has built up in the last three decades and the physiology of β3-AR is unraveling quickly. As will become evident in this work, β3-AR is emerging as an appealing target for novel pharmacological approaches in several clinical areas involving metabolic, cardiovascular, urinary, and ocular disease. In this review, we will discuss the most recent advances regarding β3-AR signaling and function and summarize how these findings translate, or may do so, into current clinical practice highlighting β3-AR’s great potential as a novel therapeutic target in a wide range of human conditions.

scholarly journals XXXI.—On the Limits of our Knowledge respecting the Theory of Parallels

1864 ◽  
Vol 23 (3) ◽  
pp. 433-450
Author(s):  
Kelland
Keyword(s):  
Human Mind ◽  
Practical Application ◽  
Very Old ◽  
Metaphysical Problem ◽  
Pure Logic ◽  
History Of ◽  
The Subject ◽  
The Right ◽  
Negative Conclusion ◽  
Positive Results

The subject of this paper is a very old one, and may to many appear to be sufficiently worn; but I venture to hope, that there are some to whom a glimpse of the successive approaches of the human mind towards the right understanding of a question of pure logic, may have an interest,—even although the problem solved be an abstract one, and the conclusion a negative conclusion, having little practical application. Like the kindred problem of the quadrature of the circle, or the metaphysical problem of “Knowing and Being,” the theory of parallels has been attacked in various directions, and although it is true that no one ever reached the goal he aimed at, yet it is not the less certain that great and positive results have followed in the history of human attainment. If no other lesson has been learnt, this at least may have been: that in reasoning it is necessary to look warily around and abroad at every step, seeing that admissions, the most obviously inadmissible, or evasions the most palpable, have foiled generations of thinkers, whilst those who have detected their errors have fallen into others of an equally destructive character.

Sign in / Sign up

Export Citation Format

Share Document