Fixed-wing approach techniques for complex environments

2015 ◽  
Vol 119 (1218) ◽  
pp. 999-1016
Author(s):  
P. R. Thomas ◽  
S. Bullock ◽  
U. Bhandari ◽  
T. S. Richardson
Keyword(s):  
Complex Environments ◽  
Flight Tests ◽  
Qualitative And Quantitative ◽  
Alternative Approach ◽  
Potential Benefits ◽  
Quantitative Understanding ◽  
Control Authority ◽  
The Stability ◽  
Glide Slope ◽  
Space Requirements

AbstractThe landing approach for fixed-wing small unmanned air vehicles (SUAVs) in complex environments such as urban canyons, wooded areas, or any other obscured terrain is challenging due to the limited distance available for conventional glide slope descents. Alternative approach methods, such as deep stall and spin techniques, are beneficial for such environments but are less conventional and would benefit from further qualitative and quantitative understanding to improve their implementation. Flight tests of such techniques, with a representative remotely piloted vehicle, have been carried out for this purpose and the results are presented in this paper. Trajectories and flight data for a range of approach techniques are presented and conclusions are drawn as to the potential benefits and issues of using such techniques for SUAV landings. In particular, the stability of the vehicle on entry to a deep stall was noticeably improved through the use of symmetric inboard flaps (crow brakes). Spiral descent profiles investigated, including spin descents, produced faster descent rates and further reduced landing space requirements. However, sufficient control authority was maintainable in a spiral stall descent, whereas it was compromised in a full spin.

scholarly journals Medicines Counterfeiting in Africa: A View from Zimbabwe

2017 ◽  
Vol 1 ◽  
pp. maapoc.0000017 ◽  
Author(s):  
Shingai D. Gwatidzo ◽  
Petronella K. Murambinda ◽  
Zivanai Makoni
Keyword(s):  
Public Health ◽  
Public Education ◽  
Medical Devices ◽  
Quantitative Data ◽  
Regulatory Authority ◽  
Medicinal Products ◽  
Street Vendors ◽  
Qualitative And Quantitative ◽  
Leading Role ◽  
Control Authority

With the sprouting of unregulated outlets on the streets of Zimbabwe, common questions that are raised include: (i) what is the Medicines Control Authority of Zimbabwe (MCAZ) doing about these street vendors? and (ii) is the law against unregulated markets and proliferation of substandard and falsified (SF) medicines being actively enforced? There is no doubt that this is a new challenge for MCAZ because of the risks involved with SF medicines. Notwithstanding the rather strong regulatory framework for the regulated market that the MCAZ has major control over, and its demonstrable regulatory prowess over the last 20 years as a National Medicines Regulatory Authority (NMRA), MCAZ is increasingly challenged to take a leading role in addressing this rising phenomenon. MCAZ has attempted to address the problem through collaboration with the Zimbabwe Republic Police (ZRP), public education and inspections by port officials at ports of entry. However, the problem still persists. A general lack of concrete qualitative and quantitative data on the commonly encountered SF medicinal products on the Zimbabwe market is another major issue. This is evidently a multi-layered problem and as the Shona adage goes “chara chimwe hachitswanye inda” (loosely translated “one thumb cannot crush all lice”), there is need for engaging local and regional partners in a bid to fulfil the MCAZ's mandate of protecting public health by ensuring medicines and medical devices intended for sale and distribution in Zimbabwe, are safe, effective and of good quality.

scholarly journals Environmental impact of intensive farming in sloping areas

2018 ◽  
Vol 174 ◽  
pp. 01001
Author(s):  
Giovanni Bosco ◽  
Lucia Simeoni
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Sprinkler Irrigation ◽  
High Yield ◽  
Qualitative And Quantitative ◽  
Intensive Farming ◽  
Yield Production ◽  
Large Water ◽  
The Stability ◽  
Irrigation Runoff

The increased demand for food causes intensive farming with high yield production and large water consumption to extend significantly. Depending on soil properties, seasonal rainfall, surface drainage and water resources, hence the consumption-infiltration balance, the ground water table might be raised or depleted; soils could be saturated or remain partly saturated with negative pore pressures. As a result sloping grounds may become prone to shallow slides, as mudflows, or deep seated movements, involving large volumes of soil, especially after rupture of major watering lines or after long uncontrolled irrigations. Within this framework the paper investigates the possible effects of replacing grassland with intensive apple farming on the stability conditions of slopes. Apples require frequent watering, especially during spring and summer to meet qualitative and quantitative productive standards. Also, sprinkler irrigation is often used to protect against hail. From the precipitation, irrigation, runoff, evaporation and plant transpiration balance, the evolution of the pore water pressure distribution within an average year is calculated. Then the modified shear strength of the unsaturated-saturated soils is determined and the factor of safety against sliding is calculated.

A Taxonomy of Terror

2019 ◽  
pp. 151-186
Author(s):  
Julia Round
Keyword(s):  
Quantitative Research ◽  
Qualitative And Quantitative ◽  
Previous Discussion ◽  
Alternative Approach ◽  
Moral Rules

This chapter develops the previous discussion by examining Misty’suse of Gothic themes in its stories. It discusses the typical themes of the Misty tales, using qualitative and quantitative research into the entire corpus of 443 stories. This chapter reflects on various claims about Misty’s content, and applies Pat Mills’ girls’ comics formulae (slave, Cinderella, friend, mystery) to its stories. It then suggests an alternative approach developed from the author’s analysis of plot summaries to produce an inductive list of common plot tropes (such as external magical, internal power, backfiring actions, and more). It relates these tropes to established Gothic themes (ambivalence, redemption) and concludes that, although the fare of Misty was not as consistently negative as readers might remember, it was perhaps more shocking due to inconsistency with moral ‘rules’.

On Investigating Energy Stability for Cellular Automata Based PageRank Validation Model in Green Cloud

2019 ◽  
Vol 9 (4) ◽  
pp. 66-85 ◽  
Author(s):  
Arnab Mitra
Keyword(s):  
Cellular Automata ◽  
Environmental Sustainability ◽  
Vital Role ◽  
Energy Stability ◽  
Web Resources ◽  
Computing Model ◽  
Alternative Approach ◽  
Low Energy Consumption ◽  
The Stability

PageRank plays a vital role towards the preparation of the index for web resources. The index is processed by crawling down the relevant websites. Hence, the validation of computed PageRank is crucially significant towards the reliability enhancement of processed indexed list. On the other hand, energy efficiency and the stability of a system are crucially towards the environmental sustainability. In this regard, an energy stability-based PageRank validation model in Cellular Automata is presented in this research which facilitates a very low energy consumption by its physical components. Detailed investigations in view of energy stability explore the role of energy stability towards the validation of PageRank. Hence, an alternative approach towards the validation of PageRank using energy stability is presented in this research. Analytical results obtained with proposed approach for several Clouds further explore its potential capability as a green computing model in the Cloud.

Tailored Structural Design and Aeromechanical Control of Axial Compressor Stall—Part I: Development of Models and Metrics

2004 ◽  
Vol 126 (1) ◽  
pp. 52-62 ◽  
Author(s):  
O. G. McGee ◽  
M. B. Graf ◽  
L. G. Fre´chette
Keyword(s):  
Structural Design ◽  
Axial Compressor ◽  
Feedback Stabilization ◽  
Feedback Controllers ◽  
Pressure Sensing ◽  
Stall Inception ◽  
Control Authority ◽  
The Stability ◽  
The Impact ◽  
Control Part

This two-part paper presents general methodologies for the evaluation of passive compressor stabilization strategies using tailored structural design and aeromechanical feedback control (Part I), and quantitatively compares the performance of several aeromechanical stabilization approaches which could potentially be implemented in gas turbine compression systems (Part II). Together, these papers offer a systematic study of the influence of ten aeromechanical feedback controllers to increase the range of stable compressor operation, using static pressure sensing and local structural actuation to postpone modal stall inception. In this part, the stability of aeromechanically compensated compressors was determined from the linearized structural-hydrodynamic equations of stall inception. New metrics were derived, which measure the level of aeromechanical damping, or control authority of aeromechanical feedback stabilization. They indicate that the phase between the pressure disturbances and the actuation is central to assess the impact of aeromechanical interactions on compressors stability.

Friction-Induced Dynamics of Axially-Moving Media in Contact With an Actively-Positioned Surface

2008 ◽  
Author(s):  
V. Kartik ◽  
Evangelos Eleftheriou
Keyword(s):  
Data Storage ◽  
Surface Friction ◽  
Design Parameters ◽  
Moving Medium ◽  
Critical Design ◽  
Flexible Material ◽  
Potential Benefits ◽  
Axially Moving ◽  
The Stability ◽  
Moving Media

The dynamics of an axially-moving flexible medium are examined in the context of an application where the medium is partially supported by a frictional surface, that actively-orients itself relative to the direction of transport. The stability and motion of the medium are of interest in a magnetic tape data storage application where the orientation of a sensing surface is continuously altered in order to ‘follow’ the medium’s motion. Moving media that are in contact with such guiding surfaces experience friction excitations induced by the relative motion in addition to what is observed with a stationary guiding surface. Friction-induced bending moments, as well as tension fluctuation beyond the permissible limits for the flexible material can erode the potential benefits of such active positioning. This paper describes some of these dynamic phenomena using the simplified example of a planar guiding surface whose orientation is dynamically altered relative to the moving medium. A physical model for the friction-induced excitation of the moving medium is developed, and the dynamics are analyzed for their effect on critical design parameters such as the achievable bandwidth of the active control algorithm, as well as with respect to constraints on the geometry and positioning of the guiding surface.

Ethical issues in palliative care research

2015 ◽  
Author(s):  
David Casarett
Keyword(s):  
Palliative Care ◽  
Ethical Issues ◽  
Research Participation ◽  
Ethical Aspects ◽  
Interventional Study ◽  
Care Research ◽  
Qualitative And Quantitative ◽  
Decision Making Capacity ◽  
Potential Benefits ◽  
Study Designs

Recent growth in palliative care research has created a heterogeneous field that encompasses both qualitative and quantitative techniques, and descriptive as well as interventional study designs. Despite the valuable knowledge that has been produced by this research, and the promise of future important advances, its progress has been impeded by a persistent uncertainty about the ethics of these studies. For instance, there have been concerns raised about whether patients near the end of life should ever be asked to participate in research, although others have objected to this extreme position. Nevertheless, the combination of ethical and practical issues can create substantial barriers to palliative care research. This chapter discusses five ethical aspects of palliative care research that investigators and clinicians should consider in designing and conducting palliative care research. These include (1) the study’s potential benefits to future patients, (2) the study’s potential benefits to subjects, (3) the study’s risks to subjects, (4) subjects’ decision-making capacity, and (5) the voluntariness of subjects’ choices about research participation.

Combination of experiments and CFD analysis for in-flight wings deflections estimation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamid Reza Ovesy ◽  
Ali Gharibi ◽  
Reza Khaki
Keyword(s):  
Correlation Method ◽  
Linear Regression Method ◽  
Cfd Analysis ◽  
Concentrated Load ◽  
Flight Tests ◽  
Content Type ◽  
Aerodynamic Loads ◽  
Rear Wing ◽  
Alternative Approach ◽  
Ground Test

Purpose This study aims to develop a new correlation method for prediction of in-flight wings deflections by integration of the experimental ground tests with computational fluid dynamics (CFD) analysis. Design/methodology/approach The ground test results are implemented in the curve fitting process to determine deflections at 66 specific points (SPs) on the front and rear wing torque box. By using the obtained deflections and the corresponding applied loads, an experimental deflection equation (EDE) for each point is established through the Castigliano’s theorem. The CFD aerodynamic loads of typical aircraft, which have been obtained earlier by the authors, are once again used in the current research. The total applied loads to each part are achieved via summation of inertia and aerodynamic loads. The obtained loads are transformed to the equivalent concentrated loads at the SPs. By substituting the concentrated load values in the EDEs, the SPs deflections are achieved for mentioned flight conditions. The resulted deflections and the corresponding input flight parameters, i.e. M and α, are incorporated into a linear regression method for development of the appropriate in-flight deflection equations (IFDEs). The validity of IFDEs is approved by comparing IFDEs’ deflections with the corresponding ones calculated through EDEs for different flight conditions. Findings As an alternative approach to the fairly expensive flight tests, the IFDEs can be used to predict the in-flight wing deflections with comparable degree of accuracy. Originality/value Prediction of actual wing deflections distributions without flight tests execution at any given flight condition.

scholarly journals A Simple Analytical Model for Estimating the Dissolution-Driven Instability in a Porous Medium

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 60
Author(s):  
Layachi Hadji
Keyword(s):  
Stability Problem ◽  
Three Dimensional ◽  
Step Function ◽  
New Approach ◽  
Engineering Mathematics ◽  
Alternative Approach ◽  
Function Base ◽  
The Stability ◽  
Rayleigh Benard ◽  
Profile Approach

This article deals with the stability problem that arises in the modeling of the geological sequestration of carbon dioxide. It provides a more detailed description of the alternative approach to tackling the stability problem put forth by Vo and Hadji (Physics of Fluids, 2017, 29, 127101) and Wanstall and Hadji (Journal of Engineering Mathematics, 2018, 108, 53–71), and it extends two-dimensional analysis to the three-dimensional case. This new approach, which is based on a step-function base profile, is contrasted with the usual time-evolving base state. While both provide only estimates for the instability threshold values, the step-function base profile approach has one great advantage in the sense that the problem at hand can be viewed as a stationary Rayleigh–Bénard problem, the model of which is physically sound and the stability of which is not only well-defined but can be analyzed by a variety of existing analytical methods using only paper and pencil.

scholarly journals A Vision-Based Method for Determining Aircraft State during Spin Recovery

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2401
Author(s):  
Tomasz Kapuscinski ◽  
Piotr Szczerba ◽  
Tomasz Rogalski ◽  
Pawel Rzucidlo ◽  
Zygmunt Szczerba
Keyword(s):  
Rotation Axis ◽  
Recovery Process ◽  
Jaccard Index ◽  
Multimedia Data ◽  
Correct Identification ◽  
Flight Tests ◽  
Data Annotation ◽  
Qualitative And Quantitative ◽  
Displacement Direction ◽  
The Right

This article proposes a vision-based method of determining in which of the three states, defined in the spin recovery process, is an aircraft. The correct identification of this state is necessary to make the right decisions during the spin recovery maneuver. The proposed solution employs a keypoints displacements analysis in consecutive frames taken from the on-board camera. The idea of voting on the temporary location of the rotation axis and dominant displacement direction was used. The decision about the state is made based on a proposed set of rules employing the histogram spread measure. To validate the method, experiments on flight simulator videos, recorded at varying altitudes and in different lighting, background, and visibility conditions, were carried out. For the selected conditions, the first flight tests were also performed. Qualitative and quantitative assessments were conducted using a multimedia data annotation tool and the Jaccard index, respectively. The proposed approach could be the basis for creating a solution supporting the pilot in the process of aircraft spin recovery and, in the future, the development of an autonomous method.

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