scholarly journals Evaluation of Effectiveness of Waterjet Propulsor for a Small Underwater Vehicle

2021 ◽  
Vol 28 (4) ◽  
pp. 30-41
Author(s):  
Lech Rowinski ◽  
Maciej Kaczmarczyk
Keyword(s):  
Small Diameter ◽  
Mechanical Damage ◽  
Underwater Vehicle ◽  
Propulsion System ◽  
The Body ◽  
Head Losses ◽  
Current Design ◽  
And Performance ◽  
Semi Empirical ◽  
Surface Vessel

Abstract The goal of the project described is to replace the existing propulsion system of a small underwater vehicle with a solution less prone to mechanical damage and ensuring a lower risk of the entanglement of fibrous objects suspended in the body of water. Four typical marine screws are utilised in the current design of the vehicle. One possible solution of the problem is the application of waterjet propulsors located inside the body of the vehicle instead. The general condition of the application of the new solution was to secure at least the same motion control capabilities of the vehicle while the basic capability is its propulsion effectiveness at the required speed. Specific features of the considered waterjet propulsor, when compared with their application in surface vessel propulsion, are the lack of the head losses and the low significance of cavitation issues. One of the difficulties in the considered case is the small diameter of the propulsor in comparison to commercially available waterjet units, which have diameters between 0.1 [m] and 1.0 [m]. There is very little data regarding the design and performance of devices in the 0.02 to 0.05 [m] range. Methods utilised to forecast the performance of the new propulsion system are presented and results compared. These were semi-empirical calculations, numerical calculations and tests of real devices. The algorithm that is based on semi-empirical calculations is of particular interest while it offers possibility quick assessment of performance of a propulsor composed of several well defined components. The results indicate the feasibility of modification of the propulsion system for the considered vehicle if all the existing circumstances are taken into account.

Reliability-Based Limit States Design for Onshore Pipelines

2002 ◽  
Author(s):  
Maher Nessim ◽  
Tom Zimmerman ◽  
Alan Glover ◽  
Martin McLamb ◽  
Brian Rothwell ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Traditional Approach ◽  
Large Diameter ◽  
Small Diameter ◽  
Mechanical Damage ◽  
Design Approach ◽  
Design Parameters ◽  
Pipe Failure ◽  
Limit States ◽  
Current Design

The traditional approach to pipelines design is to select a wall thickness that maintains the hoop stress below the yield strength multiplied by a safety factor. The main design condition implied by this approach is yielding (and by extension burst) of the defect-free pipe. Failure statistics show that this failure mode is virtually impossible as the majority of failures occur due to equipment impact and various types of defects such as corrosion and cracks. Recent investigations show that these failure causes are much more sensitive to wall thickness than to steel grade. As a consequence, current design methods produce variable levels of safety for different pipelines — small-diameter, low-pressure pipelines for example have been shown to have higher failure risks due to mechanical damage than large-diameter, high-pressure pipelines. In addition, the current design approach has been shown to have limited ability to deal with new design parameters, such high steel grades, and unique loading conditions such as frost heave and thaw settlement. The paper shows how these limitations can be addressed by adopting a reliability-based limit states design approach. In this approach, a pipeline is designed to maintain a specified reliability level with respect to its actual expected failure mechanisms (known as limit states). Implementation involves identifying all relevant limit states, selecting target reliability levels that take into account the severity of the failure consequences, and developing a set of design conditions that meet the target reliability levels. The advantages of this approach include lower overall cost for the same safety level, more consistent safety across the range of design parameters, and a built-in ability to address new design situations. Obstacles to its application for onshore pipelines include lack of familiarity with reliability-based approaches and their benefits and lack of consensus on how to define reliability targets. The paper gives an overview of the reliability-based design approach and demonstrates its application using an example involving design for mechanical damage.

scholarly journals Structure and Properties of ZnSnP2 With the Application in Photovoltaic Devices by Using CdS and ZnTe Buffer Layers

2021 ◽  
Keyword(s):  
Solar Cell ◽  
Density Functional ◽  
Empirical Relation ◽  
Harmonic Approximation ◽  
The Body ◽  
Buffer Layers ◽  
Maximum Efficiency ◽  
The Density Functional Theory ◽  
And Performance ◽  
Semi Empirical

Ab initio calculations have been performed by the linearized augmented plane wave (LAPW) method as implemented in the WIEN2K code within the density functional theory to obtain the structural, electronic and optical properties of ZnSnP2 in the body centered tetragonal (BCT) phase. The six elastic constants (C11, C12, C13, C33, C44 and C66) and mechanical parameters have been presented and compared with the available experimental data. The thermodynamic calculations within the quasi-harmonic approximation is used to give an accurate description of the pressure-temperature dependence of the thermal-expansion coefficient, bulk modulus, specific heat, Debye temperature, entropy Grüneisen parameters. Based on the semi-empirical relation, we have determined the hardness of the material; which attributed to different covalent bonding strengths. Further, ZnSnP2 solar cell devices have been modeled; device physics and performance parameters have analyzed for ZnTe and CdS buffer layers. Simulation results for ZnSnP2 thin layer solar cell show the maximum efficiency (22.9%) with ZnTe as the buffer layer. Most of the investigated parameters are reported for the first time.

Alternative Fastening Mechanism for Shear Connectors with Cold-Formed Steel Shapes Involved in Composite Sections

2020 ◽  
Vol 1003 ◽  
pp. 79-86
Author(s):  
Xavier Fernando Hurtado Amézquita ◽  
Maritzabel Molina Herrera
Keyword(s):  
Mechanical Damage ◽  
Stress Transfer ◽  
Experimental Program ◽  
Shear Connectors ◽  
Current Design ◽  
Full Capacity ◽  
Steel Sections ◽  
Cold Formed Steel ◽  
And Performance ◽  
Steel Shapes

Over the past few decades, the use of steel-concrete composite sections has increased globally, in order to take advantage of compression strength in concrete and tensile strength in steel, ensuring its fastening through stress transfer elements denominated shear connectors. The main connection systems endorsed by the current design codes are used by applying welding as fastening mechanism to fix connectors. However, this thermal procedure produces concentration of residual stresses during cooling process, and risk of perforation in Cold-Formed Steel sections (CFS), affecting the behavior efficiency of the composite sections. In this research, self-drilling screws are proposed as an alternative mechanical system for connectors fastening. An experimental program was carried out to validate capacity and performance of the system, through Full-Scale Beam Tests. According to results, self-drilling screws are a viable alternative to be used as fastening mechanism in shear connectors for CFS and concrete composite sections. Composite system achieved to develop full capacity, even in inelastic range, without disconnection between materials. Self-drilling screws remained fixed on steel shapes without mechanical damage, allowing greater deformations, than structural service conditions.

scholarly journals Fundamental Materialistic Properties of ZnSnP2 for Solar Energy Conversion and Environmental Friendly Photovoltaic Devices

2020 ◽  
Vol 19 ◽  
Keyword(s):  
Solar Cell ◽  
Density Functional ◽  
Empirical Relation ◽  
Harmonic Approximation ◽  
The Body ◽  
Buffer Layers ◽  
Maximum Efficiency ◽  
Full Potential ◽  
And Performance ◽  
Semi Empirical

Ab initio calculations have been performed by the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2K code within the density functional theory to obtain the fundamental physical properties of ZnSnP2 in the body centered tetragonal (BCT) phase. The six elastic constants (C11, C12, C13, C33, C44 and C66) and mechanical parameters have been presented and compared with the available experimental data. The thermal properties within the quasi-harmonic approximation is used to give an accurate description of the pressure-temperature dependence of the thermal-expansion coefficient, bulk modulus, specific heat, Debye temperature, entropy Grüneisen parameters. Based on the semi-empirical relation, we have determined the hardness of the material; which attributed to different covalent bonding strengths. Further, ZnSnP2 solar cell devices have been modeled; device physics and performance parameters have analyzed for ZnTe and CdS buffer layers. Simulation results for ZnSnP2 thin layer solar cell show the maximum efficiency (22.9%) with ZnTe as the buffer layer. Most of the investigated parameters are reported for the first time.

‘Man Is Ill Because He Is Badly Constructed’: Artaud, Klossowski and Deleuze in Search for the Earth Inside

2011 ◽  
Vol 5 (1) ◽  
pp. 18-34 ◽  
Author(s):  
Rick Dolphijn
Keyword(s):  
Performance Art ◽  
Holy Spirit ◽  
The Body ◽  
Deleuze And Guattari ◽  
The Earth ◽  
The Holy Spirit ◽  
Life Itself ◽  
Body Without Organs ◽  
Ways Of Thinking ◽  
And Performance

Starting with Antonin Artaud's radio play To Have Done With The Judgement Of God, this article analyses the ways in which Artaud's idea of the body without organs links up with various of his writings on the body and bodily theatre and with Deleuze and Guattari's later development of his ideas. Using Klossowski (or Klossowski's Nietzsche) to explain how the dominance of dialogue equals the dominance of God, I go on to examine how the Son (the facialised body), the Father (Language) and the Holy Spirit (Subjectification), need to be warded off in order to revitalize the body, reuniting it with ‘the earth’ it has been separated from. Artaud's writings on Balinese dancing and the Tarahumaran people pave the way for the new body to appear. Reconstructing the body through bodily practices, through religion and above all through art, as Deleuze and Guattari suggest, we are introduced not only to new ways of thinking theatre and performance art, but to life itself.

The Fiery Pacific: Volcanic Eruptions and Settler-State Theatricality in Oceania, 1780–1900

2014 ◽  
Vol 55 (3) ◽  
pp. 362-392
Author(s):  
Diana Looser
Keyword(s):  
Seventeenth Century ◽  
Performance Studies ◽  
Art History ◽  
Volcanic Eruptions ◽  
The Body ◽  
Red Color ◽  
Form Part ◽  
And Performance ◽  
Grand Opera ◽  
The City

In the closing scene of René-Charles Guilbert de Pixérécourt's melodramaLa Tête de mort; ou, Les Ruines de Pompeïa(1827), audiences at Paris's Théâtre de la Gaîté were presented with the spectacular cataclysm of an erupting Mount Vesuvius that invaded the city and engulfed the hapless characters in its fiery embrace. “The theatre,” Pixérécourt writes, “is completely inundated by this sea of bitumen and lava. A shower of blazing and transparent stones and red ash falls on all sides…. The red color with which everything is struck, the terrible noise of the volcano, the screaming, the agitation and despair of the characters … all combine to form this terrible convulsion of nature, a horrible picture, and altogether worthy of being compared to Hell.” A few years later, in 1830, Daniel Auber's grand operaLa Muette de Portici(1828), which yoked a seventeenth-century eruption of Vesuvius with a popular revolt against Spanish rule in Naples, opened at the Théâtre de Monnaie in Brussels. The Belgian spectators, inspired by the opera's revolutionary sentiments, poured out into the streets and seized their country's independence from the Dutch. These two famous examples, which form part of a long genealogy of representing volcanic eruptions through various artistic means, highlight not only the compelling, immersive spectacle of nature in extremis but also the ability of stage scenery to intervene materially in the narrative action and assimilate affective and political meanings. As these two examples also indicate, however, the body of scholarship in literary studies, art history, and theatre and performance studies that attends to the mechanical strategies and symbolic purchase of volcanic representations has tended to focus mainly on Europe; more research remains to be undertaken into how volcanic spectacles have engaged with non-European topographies and sociopolitical dynamics and how this wider view might illuminate our understanding of theatre's social roles.

scholarly journals A Ten-Year Review of Primary School Flexible Learning Environments: Interior Design and IEQ Performance

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 183
Author(s):  
Diksha Vijapur ◽  
Christhina Candido ◽  
Özgür Göçer ◽  
Shirley Wyver
Keyword(s):  
Primary School ◽  
Learning Environments ◽  
Interior Design ◽  
High Energy ◽  
The Body ◽  
Learning Activities ◽  
Indoor Environmental Quality ◽  
Flexible Learning ◽  
Physical Infrastructure ◽  
And Performance

Flexible Learning Environments (FLEs) arose as enablers for implementation of student-centric pedagogical approaches. Interior design is the key to the success of FLEs, providing the physical infrastructure needed for students to engage on several learning activities, from individual to group work, which take place in a variety of zones ranging from low to high energy. Therefore, a harmonious synergy between the interior design and subsequent Indoor Environmental Quality (IEQ) performance of FLEs’ physical configuration and learning activities is needed. The objective of this paper is to systematically review (in accordance with the PRISMA method) existing literature related to FLEs within primary school settings, typically catering to children aged 5–12 years old, to understand the body of work investigating the design and performance of FLEs over the last decade (2010–2020). Key findings suggest that the proximity and acoustic and visual permeability of zones found in FLEs may give rise to inadequate IEQ conditions delivered to students. In addition, it could be inferred from the results of the literature review that interior design and IEQ have not been sufficiently investigated in an integrated manner.

Analog Study and Performance of the New 440-Ft Ferries for the State of Washington

1975 ◽  
Vol 12 (02) ◽  
pp. 146-162
Author(s):  
J. A. Beverley ◽  
R. L. Koch ◽  
E. C. Stewart ◽  
J. Weiks
Keyword(s):  
System Performance ◽  
The State ◽  
Design Tool ◽  
Propulsion System ◽  
Similar Data ◽  
Electrical System ◽  
And Performance ◽  
Analog Study ◽  
Walla Walla

This paper describes the ac-rectified dc propulsion system designed for the two ferry vessels, MV Spokane and MV Walla Walla, and reports the results of an analog study conducted as a design tool. Similar data are presented showing the results obtained by recording electrical system performance during builder's trials.

Dance Imagery for Technique and Performance

2014 ◽  
Author(s):  
Eric Franklin
Keyword(s):  
Deep Understanding ◽  
The Body ◽  
Artistic Expression ◽  
Contemporary Dance ◽  
Improve Technique ◽  
Dance Class ◽  
Dance Improvisation ◽  
Dance Imagery ◽  
And Performance ◽  
Dance Educators

Renowned master teacher Eric Franklin has thoroughly updated his classic text, Dance Imagery for Technique and Performance, providing dancers and dance educators with a deep understanding of how they can use imagery to improve their dancing and artistic expression in class and in performance. These features are new to this edition: • Two chapters include background, history, theory, and uses of imagery. • 294 exercises offer dancers and dance educators greater opportunities to experience how imagery can enhance technique and performance. • 133 illustrations facilitate the use of imagery to improve technique, artistic expression, and performance. Franklin provides hundreds of imagery exercises to refine improvisation, technique, and choreography. The 295 illustrations cover the major topics in the book, showing exercises to use in technique, artistic expression, and performance. In addition, Franklin supplies imagery exercises that can restore and regenerate the body through massage, touch, and stretching. And he offers guidance in using imagery to convey information about a dancer’s steps and to clarify the intent and content of movement. This new edition of Dance Imagery for Technique and Performance can be used with Franklin’s Dynamic Alignment Through Imagery, Second Edition, or on its own. Either way, readers will learn how to combine technical expertise with imagery skills to enrich their performance, and they will discover methods they can use to explore how imagery connects with dance improvisation and technique. Dance Imagery for Technique and Performance uses improvisation exercises to help readers investigate new inner landscapes to create and communicate various movement qualities, provides guidelines for applying imagery in the dance class, and helps dancers expand their repertoire of expressiveness in technique and performance across ballet, modern, and contemporary dance. This expanded edition of Dance Imagery for Technique and Performance supplies imagery tools for enhancing or preparing for performance, and it introduces the importance of imagery in dancing and teaching dance. Franklin’s method of using imagery in dance is displayed throughout this lavishly illustrated book, and the research from scientific and dance literature that supports Franklin’s method is detailed. The text, exercises, and illustrations make this book a practical resource for dancers and dance educators alike.

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