Airship Fabrics

1921 ◽  
Vol 25 (127) ◽  
pp. 332-356
Keyword(s):  
Mechanical Strength ◽  
Internal Pressure ◽  
Specific Weight ◽  
Proper Treatment ◽  
Factors Affecting ◽  
Chief Factors

A proper treatment of the construction and properties of airship fabrics would require a book rather than an essay. In what follows, it is possible therefore to deal briefly only with the principal types of fabrics, classified according to the main functions of each, describing their structure and behaviour and the chief factors affecting their permanence when in service. There are, then three main classes :—I. Fabrics for the envelopes of non-rigid airships.II. Fabrics for the gasbags of rigid airships.III. Fabrics for the outer covers of rigid airships.In all cases low specific weight (expressed here in grammes per square metre) is clearly of the greatest importance.I. Fabrics of this class must possess gas-holding properties, mechanical strength and pliability. The internal pressure (equal to about 30111ms. of water) which maintains the shape of the envelope sets up in its fabric considerable tension, and this is increased by the distributed weight of the whole ship.

Domesday Woodland in Southwest England

Antiquity ◽  
1936 ◽  
Vol 10 (39) ◽  
pp. 306-324 ◽  
Author(s):  
F. W. Morgan
Keyword(s):  
Eleventh Century ◽  
Historical Geography ◽  
Fundamental Importance ◽  
Factors Affecting ◽  
Present Essay ◽  
Gradual Disappearance ◽  
Valuable Element ◽  
Domesday Book ◽  
Chief Factors ◽  
Surface Geology

The distribution of woodland and the stages of its gradual disappearance were of fundamental importance in the early historical geography of England. Wood was a valuable element in medieval economy and one of the chief factors affecting the nature of settlement, The evidence concerning the extent of the woodland in early England is of two kinds : (1) the surface geology, which provides a basis for the reconstruction of the original extent ; (2) the statistics of the Domesday Book: these refer to the eleventh century, but they may have some retrospective value. The present essay is an attempt to examine the Domesday evidence for the south and south-western counties of Berkshire, Hampshire, Wiltshire, Dorset, Somerset, Devon and Cornwall.

Simulation Analysis of the Pressure Carrying Capacity of X80 Pipe with Plain Dents

2019 ◽  
Vol 944 ◽  
pp. 835-840
Author(s):  
Peng Song ◽  
Zheng Long Li ◽  
Yu Ran Fan ◽  
Lei Guo ◽  
Xi Xi Zhang ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Carrying Capacity ◽  
Formation Process ◽  
Simulation Analysis ◽  
Hydraulic Test ◽  
Factors Affecting ◽  
Element Simulation ◽  
Simulation Based

In order to study the pressure carrying capacity of X80 pipe with plain dents, the formation process and the hydraulic test were analyzed by finite element simulation. Based on this, the sensitivity analysis of the factors affecting the pressure carrying capacity of the pipeline, such as the internal pressure, the confinement state and the material performance, is carried out. Research results show that springback amount of the pipeline decreases due to the initial internal pressure, and constraint state has little effect on the pressure carrying capacity while increases with the increasing of the material tensile properties. When the depth of the dent is less than 6% pipe diameter or the strain of the dent is less than 6%, the dent has little impact to the pressure carrying capacity of the pipe.

Mechanical Strength Analysis and Structure Improvement of Diaphragm Chamber Based on Finite Element Method

2013 ◽  
Vol 690-693 ◽  
pp. 1945-1949
Author(s):  
Xue Qin Ling ◽  
Peng Fu ◽  
Wei Zhang ◽  
Yang Chen
Keyword(s):  
Finite Element ◽  
Mechanical Strength ◽  
Production Costs ◽  
Strength Analysis ◽  
Manufacturing Cost ◽  
Long Distance ◽  
Element Analysis ◽  
Factors Affecting ◽  
Structure Improvement ◽  
Major Factors

Diaphragm chamber is the key component in fluid end of high pressure diaphragm pump for long distance pipeline transportation. Structural dimensions are the major factors affecting mechanical strength and manufacturing cost of diaphragm chamber. In this paper, diaphragm chamber was simulated by finite element analysis software ANSYS. Mechanical strength of diaphragm chamber was checked in the light of ASMEVIII-2. The structure of diaphragm chamber was modified for the purpose of extending service life and reducing production costs. The analysis results provide some theoretical guidance for research and development of diaphragm chambers and relevant products.

Mechanical Design Concept for 1000-MVA Superconducting Turboalternator

1971 ◽  
Vol 93 (4) ◽  
pp. 1166-1168 ◽  
Author(s):  
Philip Thullen ◽  
Joseph L. Smith
Keyword(s):  
Mechanical Strength ◽  
Critical Speed ◽  
Mechanical Design ◽  
Specific Weight ◽  
Design Concept ◽  
Thermal Isolation ◽  
Physical Size ◽  
Structural Rigidity ◽  
Terminal Voltage ◽  
Isolation Requirements

A design concept for the construction of a 1000-mva superconducting alternator is determined by consideration of (a) electrical requirements, (b) thermal isolation requirements, (c) mechanical strength, and (d) structural rigidity. The alternator consists of a rotating superconducting field winding and stationary water cooled stator. This study indicates that a superconducting machine will have lower specific weight and smaller physical size, higher critical speed, increased efficiency, lower synchronous reactance, increased I22t, and higher terminal voltage than conventional machines.

Influence of Plaque Stiffness on Change of Blood Vessel Geometry Leading Hemodynamical Changes in PVA-H Stenosis Models

2012 ◽  
Author(s):  
Yasutomo Shimizu ◽  
Shuya Shida ◽  
Kenichi Funamoto ◽  
Toshiyuki Hayase ◽  
Makoto Ohta
Keyword(s):  
Mechanical Properties ◽  
Blood Flow ◽  
Internal Pressure ◽  
Flow Pattern ◽  
Flow Patterns ◽  
Parent Artery ◽  
Steady Flows ◽  
Factors Affecting ◽  
Stenosis Severity ◽  
Stenotic Arteries

One of the main factors affecting blood flow conditions in stenotic arteries is plaque geometry. Plaques can be deformed by the internal pressure, and hence plaque behavior varies depending on its stiffness. Blood flow pattern around a plaque is complicated by plaque behavior, and these complications may lead to growth of the plaque itself. Thus, we can say that geometry and mechanical properties of a plaque, and blood flow will affect each other. To understand the relationship between plaque stiffness and flow pattern, flow measurement using elastic models, which mimic the mechanical properties of blood vessels, is required. Flow patterns with steady flows and a range of hydrostatic pressures were observed by particle image velocimetry. The results show that the model is deformed by hydrostatic pressures. Furthermore, flow patterns are also changed as the results of model deformation, especially at reattachment points. Simultaneously, we performed a numerical simulation for finding a critical parameter of the flow patterns. These results show that the reattachment length increases in the model with high stenosis severity and in a vertically oriented parent artery. In conclusion, a parent artery and plaque can deform because of internal pressure, and these deformation will affect blood flow patterns.

THE IMPACTS OF CUSTOMERS’ DELAY-RISK SENSITIVITIES ON A QUEUE WITH BALKING

2009 ◽  
Vol 23 (3) ◽  
pp. 409-432 ◽  
Author(s):  
Pengfei Guo ◽  
Paul Zipkin
Keyword(s):  
Cost Function ◽  
Utility Function ◽  
Value Of Information ◽  
Queueing System ◽  
Specific Weight ◽  
Stochastic Orders ◽  
Factors Affecting ◽  
Equilibrium Behavior ◽  
Weight Distributions ◽  
The Relationship

Congestion and its uncertainty are big factors affecting customers’ decision to join a queue or balk. In a queueing system, congestion itself is resulted from the aggregate joining behavior of other customers. Therefore, the property of the whole group of arriving customers affects the equilibrium behavior of the queue. In this paper, we assume each individual customer has a utility function which includes a basic cost function, common to all customers, and a customer-specific weight measuring sensitivity to delay. We investigate the impacts on the average customer utility and the throughput of the queueing system of different cost functions and weight distributions. Specifically, we compare systems where these parameters are related by various stochastic orders, under different information scenarios. We also explore the relationship between customer characteristics and the value of information.

Stability of Vertically Bent Pipelines Buried in Sand

2004 ◽  
Vol 126 (3) ◽  
pp. 382-390 ◽  
Author(s):  
Sahel N. Abduljauwad ◽  
Hamdan N. Al-Ghamedy ◽  
Junaid A. Siddiqui ◽  
Ibrahim M. Asi ◽  
Naser A. Al-Shayea
Keyword(s):  
Internal Pressure ◽  
Three Dimensional ◽  
Computer Software ◽  
Specific Weight ◽  
Bend Angle ◽  
Element Analysis ◽  
Minimum Cover ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

This paper discusses the stability of underground pipelines with preformed vertical bends buried in sandy soil. More specifically, the minimum cover height required to prevent the pipe from bowing under the action of forces due to temperature change and internal pressure is estimated. The variables considered include the pipe and soil materials, diameter, thickness, overburden height, bend radius, bend angle, internal pressure, fluid specific weight, and temperature variation. A comprehensive three-dimensional finite element analysis is carried out. The results are extracted from the output obtained. These results are put in a database which is used to develop general regression models to determine the relationships among the different variables. Different buckling modes are also considered. All of these results and models are entered into a computer software program for ready access.

A NOTE ON THE DETECTION OF UNDERSEA CRAFT BY MEANS OF LOW FREQUENCY RADIATION FROM AIRCRAFT

1945 ◽  
Vol 23a (6) ◽  
pp. 77-85
Author(s):  
D. W. R. McKinley
Keyword(s):  
Field Strength ◽  
General Expression ◽  
Low Frequency ◽  
Factors Affecting ◽  
Shore Station ◽  
Chief Factors ◽  
Frequency Radiation

A semiquantitative examination is made of the chief factors affecting both the transmission of low frequency radiation from an aircraft to a submarine and the return of this energy to the aircraft by scattering. A general expression is derived for the returning field strength and graphs are shown for a representative set of conditions. It is indicated that, even under the most favourable conditions, the amount of energy returned is below the level of detectability, if the submarine is submerged more than 10 ft. However, it is also pointed out that communication between a shore station and an undersea craft should be feasible under certain conditions.

Computational Simulation of the Joint Shape after as-Reflowed Soldering

2010 ◽  
Vol 177 ◽  
pp. 651-656
Author(s):  
Ning Zhang ◽  
Li Tian ◽  
Yao Wu Shi ◽  
Jian Lin ◽  
Yong Ping Lei ◽  
...  
Keyword(s):  
Surface Tension ◽  
Specific Gravity ◽  
Computational Simulation ◽  
Wetting Angle ◽  
Interactive Software ◽  
Factors Affecting ◽  
Soldering Process ◽  
Chief Factors ◽  
The One ◽  
Joint Shape

Using the interactive software, this study was mainly focused on developing a 3-D joint shape after the as-reflowed soldering which is the one of chief factors affecting the reliability. From the results, the soldering process can be simulated and observed directly. By changing the various conditions and constraints, such as surface tension, wetting angle and specific gravity, it makes a comparison between the simulated result and the experimental one. The simulated parameters are based on those of the traditional eutectic Sn-Pb solder. After slicing and comparing the different profiles of the simulated shape, the 3-D simulated geometry fits well with the experimental one.

scholarly journals Treatment strategy of allergic rhinitis in the face of modern world threats

2018 ◽  
Vol 72 (2) ◽  
pp. 1-12 ◽  
Author(s):  
Piotr Rapiejko ◽  
Dariusz Jurkiewicz ◽  
Wioletta Pietruszewska ◽  
Beata Zielnik-Jurkiewicz ◽  
Jarosław Woroń ◽  
...  
Keyword(s):  
Allergic Rhinitis ◽  
Allergen Immunotherapy ◽  
Modern World ◽  
Proper Treatment ◽  
Treatment Persistence ◽  
Factors Affecting ◽  
The Face ◽  
Selection Of ◽  
Specific Allergen

Allergic rhinitis (AR) is the most common form of allergy, which - as epidemiological research has shown - applies to nearly 25% of the population. AR significantly affects the quality of life of the patient, and the more severe the disease, the greater the risk of developing bronchial asthma. One of the factors affecting the severity of symptoms and the degree of their control is air pollution. In some patients, despite proper treatment, persistence or only partial remission of symptoms (uncontrolled allergic rhinitis) is observed. This can lead to an increase in comorbidities - inflammation of the paranasal sinuses, otitis media and asthma - both in children and in adults. The treatment of allergic rhinitis, in accordance with the standards, consists in: education of the patient, elimination of the allergen from the environment and factors intensifying the course of the disease, selection of proper pharmacotherapy and specific allergen immunotherapy. Many factors influence the selection of the antihistamine used, e.g., the opportunity of safe increase of the dosage.

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