Optimal Static Characteristics of Amphibious PAR Vehicles

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Konstantin I. Matveev
Keyword(s):  
Water Surface ◽  
High Performance ◽  
Static Friction ◽  
Solid Surfaces ◽  
Vertical Position ◽  
Optimal Position ◽  
Optimal Values ◽  
Jet Theory ◽  
New Generation ◽  
The Ideal

Power augmented ram platform vehicle is a high-performance air-assisted amphibious transport of the new generation. The objective of this study is to determine the optimal position of the platform flap for low-speed operations on water and solid ground. The static friction of vehicle hulls on solid surfaces and the static deformation of the water surface are combined with results of the ideal jet theory to predict forces and the platform position. The optimal values for the flap gap are obtained that maximize the recovered static thrust on solid surfaces and the vehicle vertical position on the water surface.

scholarly journals Review of Functional Treatments for Modified Wood

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 327
Author(s):  
Morwenna J. Spear ◽  
Simon F. Curling ◽  
Athanasios Dimitriou ◽  
Graham A. Ormondroyd
Keyword(s):  
High Performance ◽  
Responsive Materials ◽  
Wood Modification ◽  
Wide Range ◽  
Natural Wood ◽  
Impregnation Modification ◽  
New Applications ◽  
New Generation ◽  
Dimensional Instability ◽  
Modified Wood

Wood modification is now widely recognized as offering enhanced properties of wood and overcoming issues such as dimensional instability and biodegradability which affect natural wood. Typical wood modification systems use chemical modification, impregnation modification or thermal modification, and these vary in the properties achieved. As control and understanding of the wood modification systems has progressed, further opportunities have arisen to add extra functionalities to the modified wood. These include UV stabilisation, fire retardancy, or enhanced suitability for paints and coatings. Thus, wood may become a multi-functional material through a series of modifications, treatments or reactions, to create a high-performance material with previously impossible properties. In this paper we review systems that combine the well-established wood modification procedures with secondary techniques or modifications to deliver emerging technologies with multi-functionality. The new applications targeted using this additional functionality are diverse and range from increased electrical conductivity, creation of sensors or responsive materials, improvement of wellbeing in the built environment, and enhanced fire and flame protection. We identified two parallel and connected themes: (1) the functionalisation of modified timber and (2) the modification of timber to provide (multi)-functionality. A wide range of nanotechnology concepts have been harnessed by this new generation of wood modifications and wood treatments. As this field is rapidly expanding, we also include within the review trends from current research in order to gauge the state of the art, and likely direction of travel of the industry.

scholarly journals A study on the numerical modelling of UHPFRC-strengthened members

2018 ◽  
Vol 199 ◽  
pp. 09001
Author(s):  
Renaud Franssen ◽  
Serhan Guner ◽  
Luc Courard ◽  
Boyan Mihaylov
Keyword(s):  
Numerical Modelling ◽  
High Performance ◽  
Concrete Structures ◽  
Concrete Members ◽  
High Durability ◽  
Tension Tests ◽  
The World ◽  
Aging Infrastructure ◽  
New Generation ◽  
Modelling Approach

The maintenance of large aging infrastructure across the world creates serious technical, environmental, and economic challenges. Ultra-high performance fibre-reinforced concretes (UHPFRC) are a new generation of materials with outstanding mechanical properties as well as very high durability due to their extremely low permeability. These properties open new horizons for the sustainable rehabilitation of aging concrete structures. Since UHPFRC is a young and evolving material, codes are still either lacking or incomplete, with recent design provisions proposed in France, Switzerland, Japan, and Australia. However, engineers and public agencies around the world need resources to study, model, and rehabilitate structures using UHPFRC. As an effort to contribute to the efficient use of this promising material, this paper presents a new numerical modelling approach for UHPFRC-strengthened concrete members. The approach is based on the Diverse Embedment Model within the global framework of the Disturbed Stress Field Model, a smeared rotating-crack formulation for 2D modelling of reinforced concrete structures. This study presents an adapted version of the DEM in order to capture the behaviour of UHPFRC by using a small number of input parameters. The model is validated with tension tests from the literature and is then used to model UHPFRC-strengthened elements. The paper will discuss the formulation of the model and will provide validation studies with various tests of beams, columns and walls from the literature. These studies will demonstrate the effectiveness of the proposed modelling approach.

scholarly journals Optimization of Dynamic Task Location within a Manipulator’s Workspace for the Utilization of the Minimum Required Joint Torques

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 288
Author(s):  
Adam Wolniakowski ◽  
Charalampos Valsamos ◽  
Kanstantsin Miatliuk ◽  
Vassilis Moulianitis ◽  
Nikos Aspragathos
Keyword(s):  
High Performance ◽  
Human Robot Interaction ◽  
Optimal Position ◽  
End Effector ◽  
Joint Torques ◽  
Dynamic Task ◽  
Arbitrary Position ◽  
Simulation Results ◽  
Set Up ◽  
Task Placement

The determination of the optimal position of a robotic task within a manipulator’s workspace is crucial for the manipulator to achieve high performance regarding selected aspects of its operation. In this paper, a method for determining the optimal task placement for a serial manipulator is presented, so that the required joint torques are minimized. The task considered comprises the exercise of a given force in a given direction along a 3D path followed by the end effector. Given that many such tasks are usually conducted by human workers and as such the utilized trajectories are quite complex to model, a Human Robot Interaction (HRI) approach was chosen to define the task, where the robot is taught the task trajectory by a human operator. Furthermore, the presented method considers the singular free paths of the manipulator’s end-effector motion in the configuration space. Simulation results are utilized to set up a physical execution of the task in the optimal derived position within a UR-3 manipulator’s workspace. For reference the task is also placed at an arbitrary “bad” location in order to validate the simulation results. Experimental results verify that the positioning of the task at the optimal location derived by the presented method allows for the task execution with minimum joint torques as opposed to the arbitrary position.

scholarly journals Design aspects of (super)hydrophobic mesh based oil-collecting device with improved efficiency

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Weikang Xu ◽  
Zhentao Zhang ◽  
Xiaomei Cai ◽  
Yazhen Hong ◽  
Tianliang Lin ◽  
...  
Keyword(s):  
3D Printing ◽  
Water Surface ◽  
High Performance ◽  
Oil Spills ◽  
Real Life ◽  
Oily Wastewater ◽  
Coating Materials ◽  
The Past ◽  
Oil Storage ◽  
Future Success

AbstractEffective treatment of frequent oil spills and endless discharged oily wastewater is crucial for the ecosystem and human health. In the past two decades, the collection of oil from water surface has been widely studied through the simple fabrication of superhydrophobic meshes with various coating materials, but little attention is paid to the design aspects of the meshes based oil-collecting device and practical oil collection. Here, 3D-printing devices with different configurations of (super)hydrophobic meshes, circular truncated cone (CTC), cylinder and inverted CTC, and the same inverted cone-shaped structure (below the meshes for temporary oil storage) are investigated. Results demonstrate that the CTC meshes based device especially for an oblate one not only shows higher stability and discharge of the collected oils than previous reports, but also allows floating oils to enter the (super)hydrophobic mesh faster. We anticipate that future success in developing high-performance (super)hydrophobic meshes and the further optimization of the CTC mesh-based device parameters will make our proposed device more practical for the treatment of real-life oil spills.

Recent Advances in the Study of Film Cooling on the Gas Turbine Blade

2014 ◽  
Vol 971-973 ◽  
pp. 143-147 ◽  
Author(s):  
Ping Dai ◽  
Shuang Xiu Li
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Film Cooling ◽  
Gas Turbines ◽  
High Performance ◽  
Leading Edge ◽  
Development Trend ◽  
Research Progress ◽  
Gas Turbine Blade ◽  
New Generation

The development of a new generation of high performance gas turbine engines requires gas turbines to be operated at very high inlet temperatures, which are much higher than the allowable metal temperatures. Consequently, this necessitates the need for advanced cooling techniques. Among the numerous cooling technologies, the film cooling technology has superior advantages and relatively favorable application prospect. The recent research progress of film cooling techniques for gas turbine blade is reviewed and basic principle of film cooling is also illustrated. Progress on rotor blade and stationary blade of film cooling are introduced. Film cooling development of leading-edge was also generalized. Effect of various factor on cooling effectiveness and effect of the shape of the injection holes on plate film cooling are discussed. In addition, with respect to progress of discharge coefficient is presented. In the last, the future development trend and future investigation direction of film cooling are prospected.

Electrophoresis-Microwave Synthesis of S, N-Doped Graphene Foam for High-Performance Supercapacitors

2021 ◽  
Author(s):  
Wenqiang Wang ◽  
Wenyi Zhang ◽  
Gengchao Wang ◽  
Chunzhong Li
Keyword(s):  
Electrode Material ◽  
Microwave Synthesis ◽  
High Performance ◽  
Three Dimensional ◽  
Graphene Foam ◽  
Composition And Structure ◽  
Doped Graphene ◽  
The Ideal

The three-dimensional self-standing architecture of heteroatom-doped graphene is the ideal electrode material for supercapacitors. However, the facile control of its composition and structure is still a challenge. Herein we have...

Optimal Position of Ion Source for High Performance of IEC

2005 ◽  
Vol 47 (4) ◽  
pp. 1265-1269 ◽  
Author(s):  
Hodaka Osawa ◽  
Takayuki Ishibashi ◽  
Masami Ohnishi ◽  
Kiyoshi Yoshikawa
Keyword(s):  
High Performance ◽  
Ion Source ◽  
Optimal Position

scholarly journals A method of laser ultrasound tomography for solid surfaces mapping

2018 ◽  
Vol 145 ◽  
pp. 05009 ◽  
Author(s):  
Vasily Zarubin ◽  
Anton Bychkov ◽  
Alexander Karabutov ◽  
Varvara Simonova ◽  
Elena Cherepetskaya
Keyword(s):  
High Performance ◽  
Surface Profile ◽  
Solid Surfaces ◽  
Laser Ultrasound ◽  
Ray Method ◽  
Ultrasound Tomography ◽  
Bodies Of Revolution ◽  
Suggested Approach ◽  
Preliminary Preparation ◽  
Production Inspection

Surface control is an important problem for production inspection in industry. Traditionally it is solved using mechanical and optical profilometry, providing high spatial resolution. However, such methods are inappropriate for bodies immersed in opaque liquids and require preliminary preparation of samples. Current work focuses on an application of a method of laser ultrasound tomography to mapping of solid surfaces. The suggested approach combines high acoustical resolution, high performance and allows profilometry of contaminated and immersed samples. An automated prototype for real-time surface profile measurements is constructed and tested on several bodies of revolution. Linear approximation of a cylinder profile obtained by the prototype shows maximum approximation inconsistency of 15 μm. The results are verified by those obtained by the conventional x-ray method.

scholarly journals Percepción de los entrenadores de alto rendimiento de atletismo: caracterización de su perfil polifacético (Perception of high performance track and field coaches: characterization of their multifaceted profile)

Retos ◽  
2015 ◽  
pp. 42-47
Author(s):  
Angeles Filgueira Perez
Keyword(s):  
High Performance ◽  
Target Population ◽  
Track And Field ◽  
Personal Qualities ◽  
High Level ◽  
Almost All ◽  
Methodological Aspects ◽  
The Ideal

En el presente estudio se ha tratado de obtener una aproximación al perfil ideal del entrenador de alto rendimiento en atletismo. En el mundo del deporte de alta competición, el entrenador debe desarrollar funciones de maestro, técnico y líder, lo cual hace difícil delimitar sus competencias (conocimientos, habilidades y cualidades personales). Por tanto, la principal motivación de este trabajo es establecer el papel que debe desempeñar el entrenador para la preparación física, técnica, táctica, psicológica y moral del deportista de alto nivel. Para ello, se ha considerado como población objeto de estudio al conjunto de entrenadores de alto rendimiento que en el momento de la investigación estuviesen activo, ya que interesaba realizar este estudio desde su propia perspectiva. Los datos recogidos forman parte de una investigación más amplia, llevada a cabo mediante encuesta, para la que se diseñó un cuestionario de 78 preguntas en el que se abarcaban tres temas: el perfil del entrenador y del deportista, así como la figura del formador de entrenadores en el Practicum. En este trabajo nos centramos en el primer tema y el análisis de la información obtenida nos permite concluir que la que práctica totalidad de los entrenadores de atletismo consideran necesario dominar con precisión los aspectos técnico-metodológicos. Además, consideran que su ética profesional debe estar regida por los principios de autonomía y beneficencia, de modo que valores como la honestidad y la justicia deben primar en el desarrollo de sus funciones.Abstract: In the current study, we have tried to get an approximation of the ideal profile of high performance coaches in athletics. In the high-level sports world, the coach must develop the role of teacher, technician and leader,  which makes it difficult to delimit  his/her competencies (knowledge, skills and personal qualities). Therefore, the main motivation of this work is to define the role that the coach plays in relation  to the physical, technical, tactical, psychological and moral preparation of elite athletes. Keeping this aim as an objective, we have considered as the target population the high performance coaches who are active at the time of the investigation, since we were interested  in knowing their own perspective. The data that was collected is a part of a wider investigation, conducted by a survey, for which we designed a questionnaire of 78 questions divided on three topics: the profile of the coach and the athlete, as well as the figure of the coach educator in the Practicum. In this work, we focus on the first topic and the analysis of the information that we obtained allows us to conclude that almost all the track and field coaches find it necessary to dominate the technical and methodological aspects. They also consider that professional ethics must be governed by the principles of autonomy and care that values   like honesty and justice must prevail in the performance of their work.

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