scholarly journals QUICK ASSESSMENT METHOD FOR CANISTER STRUCTURAL DESIGN OF INA-CBT

2020 ◽  
Vol 15 (2) ◽  
pp. 87-95
Author(s):  
Mulyo Harris Pradono
Keyword(s):  
Sea Water ◽  
Water Pressure ◽  
Assessment Method ◽  
External Pressure ◽  
Sensor System ◽  
Ocean Bottom ◽  
Quick Method ◽  
Steel Material ◽  
External Pressures ◽  
316 L Stainless Steel

Abstract Canister in the Ina-CBT (Indonesian Cable-Based Tsunameter) system is a structure to protect underwater sensor system. Canister and sensor system form the OBU (Ocean Bottom Unit) system. This OBU is connected by land via submarine cable. This canister is used to protect the sensor system from the underwater leakage and water pressure. Because the location of the OBU can usually reach a depth of thousands of meters in the sea, the water pressure on the OBU becomes very large. As an illustration, for a depth of 1000 meters, the pressure on the canister wall is 1 ton per square meter. For this reason, a strong canister structure is needed to withstand water pressure without damage. The strength of this structure can be analyzed using a structural analysis program. However, if a change in pressure and dimension is needed, it needs to be re-modeled to determine its strength which requires time. Therefore a study of a method to determine quickly the strength of the canister is carried out. The results show that this method is very useful to quickly determine the dimensions and initial weight of the canister due to the external pressure load of sea water. For example, with SS 316 L stainless steel material and a canister inner radius of 100 mm, the canister is suitable for further design only for external pressures up to 30 MPa. For pressures above 30 MPa, the thickness and weight of the canisters are becoming impractical for onboard handling.  Keywords: canister, ina-cbt, strength, water pressure, quick method.

scholarly journals Depressurization-Induced Nucleation in the “Polylactide-Carbon Dioxide” System: Self-Similarity of the Bubble Embryos Expansion

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1115
Author(s):  
Dmitry Zimnyakov ◽  
Marina Alonova ◽  
Ekaterina Ushakova
Keyword(s):  
Initial Rate ◽  
Initial Pressure ◽  
External Pressure ◽  
Self Similarity ◽  
Embryo Formation ◽  
Linear Behavior ◽  
Joint Influence ◽  
External Pressures ◽  
Adiabatic Cooling ◽  
Self Similar

Self-similar expansion of bubble embryos in a plasticized polymer under quasi-isothermal depressurization is examined using the experimental data on expansion rates of embryos in the CO2-plasticized d,l-polylactide and modeling the results. The CO2 initial pressure varied from 5 to 14 MPa, and the depressurization rate was 5 × 10−3 MPa/s. The constant temperature in experiments was in a range from 310 to 338 K. The initial rate of embryos expansion varied from ≈0.1 to ≈10 µm/s, with a decrease in the current external pressure. While modeling, a non-linear behavior of CO2 isotherms near the critical point was taken into account. The modeled data agree satisfactorily with the experimental results. The effect of a remarkable increase in the expansion rate at a decreasing external pressure is interpreted in terms of competing effects, including a decrease in the internal pressure, an increase in the polymer viscosity, and an increase in the embryo radius at the time of embryo formation. The vanishing probability of finding the steadily expanding embryos for external pressures around the CO2 critical pressure is interpreted in terms of a joint influence of the quasi-adiabatic cooling and high compressibility of CO2 in the embryos.

scholarly journals Viscoelastic analysis of Calving Glaciers

1980 ◽  
Vol 1 ◽  
pp. 37-41 ◽  
Author(s):  
D. V. Reddy ◽  
W. Bobby ◽  
M. Arockiasamy ◽  
R. T. Dempster
Keyword(s):  
Finite Element ◽  
Sea Water ◽  
Water Pressure ◽  
Computer Code ◽  
Ice Shelf ◽  
Element Analysis ◽  
Ice Shelves ◽  
Shear Moduli ◽  
Relaxation Functions ◽  
Spring Force

Calving of floating ice shelves is studied by a viscoelastic finite-element analysis. The fan-shaped breaking-up of glaciers due to forces that cause bending on creeping ice is assumed to be axisymmetric. Bending may be due to geometry of the bcdrock, action of tides and waves, and imbalance (at the ice front) between the stress in the ice and the sea-water pressure.The bulk and shear moduli of the ice are represented by relaxation functions of the Prony series, which is a discrete relaxation spectrum composed of a constant and a summation of exponential terms. These properties are also functions of temperature, that varies over the thickness of the ice shelf. The temperature distribution across the thickness of the ice is obtained from calculations based on a linear dependence of thermal conductivity on the temperature. Numerical results are presented for various calving mechanisms. A computer code, VISIC1, is developed by modifying a finite-element viscoelastic code, VISICE, for floating ice islands. The buoyancy of the water is taken into account by a Winkler spring model, with the spring force determined from displaced volume. Locations of crack initiation obtained from the analysis are used to predict the iceberg size immediately after calving.

EVALUATION OF THE SKELETAL AGE METHOD OF ESTIMATING CHILDREN'S DEVELOPMENT

PEDIATRICS ◽  
1954 ◽  
Vol 13 (2) ◽  
pp. 165-173
Author(s):  
DONALD MAINLAND
Keyword(s):  
Standard Deviation ◽  
Assessment Method ◽  
Systematic Difference ◽  
Skeletal Age ◽  
Nutrition Survey ◽  
Quick Method ◽  
Age Assessment ◽  
Variable Error ◽  
Significant Difference ◽  
The Individual

An observer's variable error in skeletal age assessment of hand RGs (i.e., the irregular ion between independent readings of the same film) was studied on 1,124 readings of 326 films from 233 children aged 16 months to 17 years. seventy-nine of the RGs were full-size reproductions in Macyr's Nutrition and Chemical Growth in Childhood; the remainder were actual films of children in Halifax, Canada (healthy Orphanage residents and children examined in a nutrition survey). There was no significant difference in variable error associated with the atlas (Todd, Greulich-Pyle), age of child, sex, differences between skeletal and chronologic age, differences between children, or differences between RGs of the same child, except for a tendency in the Macy Series for the poorest reproductions to have a larger variable error than the best reproductions. ions. In most readings the individual indicators were assessed separately and the results averaged, but a quicker method (over-all appraisal) did not produce a significantly different variable error. The quick method may be useful in large surveys, although it appears too coarse for the study of individual children. The observer's variable error was expressed by standard deviations of approximately three months (Macy Series—both atlases; Nutritirn Series—Greulich-Pyle atlas) and four months (Orphanage Series—both atlases). With a standard deviation of three months an assessor must affix an error of ± 8.3 months to his estimate of a child's progress in skeletal age, in order to obtain confidence limits with 95% probability. If his standard deviation is four months he must allow ± 11.1 months. For evaluation of the assessment method, many observers' estimates of variable error are needed, and an appeal for data is issued. After more than 1200 readings had been made the observer's practice lapsed for about a year. Reassessment of a random sample of RGs then showed, besides variable error, a mean systematic difference of approximately three months from the previous readings of the same films with the same atlas. To avoid this risk, any two films that are to be assessed for skeletal progress should be read within a few weeks of each other, and special precautions are therefore necessary to secure independence of the two readings.

scholarly journals An Investigation of the Basic Physics of Irrigation in Urology and the Role of Automated Pump Irrigation in Cystoscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Dwayne Chang ◽  
Rustom P. Manecksha ◽  
Konstantinos Syrrakos ◽  
Nathan Lawrentschuk
Keyword(s):  
Flow Rate ◽  
External Pressure ◽  
Flow Rates ◽  
Pumping System ◽  
External Pressures ◽  
Basic Physics ◽  
Traditional Irrigation ◽  
Irrigation Solution ◽  
Bladder Fullness

Objective. To investigate the effects of height, external pressure, and bladder fullness on the flow rate in continuous, non-continuous cystoscopy and the automated irrigation fluid pumping system (AIFPS).Materials. Each experiment had two 2-litre 0.9% saline bags connected to a continuous, non-continuous cystoscope or AIFPS via irrigation tubing. Other equipment included height-adjustable drip poles, uroflowmetry devices, and model bladders.Methods. In Experiment 1, saline bags were elevated to measure the increment in flow rate. In Experiment 2, saline bags were placed under external pressures to evaluate the effect on flow rate. In Experiment 3, flow rate changes in response to variable bladder fullness were measured.Results. Elevating saline bags caused an increase in flow rates, however the increment slowed down beyond a height of 80 cm. Increase in external pressure on saline bags elevated flow rates, but inconsistently. A fuller bladder led to a decrease in flow rates. In all experiments, the AIFPS posted consistent flow rates.Conclusions. Traditional irrigation systems were susceptible to changes in height of irrigation solution, external pressure application, and bladder fullness thus creating inconsistent flow rates. The AIFPS produced consistent flow rates and was not affected by any of the factors investigated in the study.

Managing External Pressures through Corporate Diplomacy

2007 ◽  
Vol 33 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Wolfgang Amann ◽  
Shiban Khan ◽  
Oliver Salzmann ◽  
Ulrich Steger ◽  
Aileen Lonescu-Somers
Keyword(s):  
Case Studies ◽  
Genetically Modified ◽  
Food Products ◽  
External Pressure ◽  
Environmental Responsibility ◽  
Genetically Modified Food ◽  
Pressure Groups ◽  
Tax Revenues ◽  
External Pressures ◽  
Public Pressure

Today's corporations face many demands from a plethora of different stakeholders, which are often incongruous. While shareholders demand a decent return on their investment, employees demand safe and well-paid jobs, communities stress upon their tax revenues and public pressure groups call for more social and environmental responsibility. Corporations thus require a great deal of corporate diplomacy to prioritise and – where necessary and possible – reconcile these different demands. This paper describes a framework for managerial/corporate attitudes and external pressure levels. Four case studies illustrate varying attitudes towards corporate diplomacy determine the outcome of controversies over genetically modified food products.

Structural, phase transition, mechanical and thermodynamic properties of TMNs under external pressures: A first-principles study

2018 ◽  
Vol 32 (15) ◽  
pp. 1850181 ◽  
Author(s):  
Xin Tan ◽  
Yinan Dong ◽  
Yuan Ren ◽  
Xuan Li ◽  
Hui Qi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Elastic Constants ◽  
Density Functional ◽  
Mechanical Stability ◽  
Structural Phase ◽  
Potential Method ◽  
External Pressure ◽  
Nanocomposite Films ◽  
External Pressures ◽  
Energy Relations

The plane-wave pseudo-potential method, which is based on density functional theory, is used to determine the structure, elastic constants and phase transition properties of transition metal nitride (TMN; TM = Ti, Zr, Hf, V, Nb and Ta) nanocomposite films under external pressures. Enthalpy–pressure and volume–energy relations of TMNs with different structures are calculated, and their relative stability is discussed. Mechanical stability of external pressure is calculated, and changes in elastic constants with external pressure are analyzed. The present study obtains influence of external pressure on the mechanical properties of material. By analyzing total energy–volume relation, enthalpy–pressure relation and mechanical stability, phase transition law of TMNs under external pressure is obtained.

scholarly journals EXPERIMENTAL, NUMERICAL AND ANALYTICAL INVESTIGATIONS OF WIND-INDUCED NET PRESSURES FOR INDUSTRIAL BUILDINGS WITH ENVELOPE POROSITIES

2016 ◽  
Vol 7 ◽  
pp. 58
Author(s):  
Vanessa Saubke ◽  
Rüdiger Höffer
Keyword(s):  
Spatial Distribution ◽  
Numerical Model ◽  
Wind Tunnel ◽  
External Pressure ◽  
Navier Stokes ◽  
Industrial Building ◽  
Wind Tunnel Experiments ◽  
Industrial Buildings ◽  
External Pressures

The magnitude and the spatial distribution of wind-induced net pressures (external and internal) on buildings are frequently discussed among research communities and construction industries. This paper deals with this topic based on a case study about an industrial building in Denmark, which was damaged due to the wind impact during a storm when a large part of the roof covering was blown off. In order to detect the reason for the damage the wind-induced loads were studied by i) wind tunnel experiments on the external pressures due to different wind directions, ii) analytical investigations of internal pressure due to envelope porosities and planned openings and iii) numerical analyses for the internal and the external pressure. The Reynolds averaged Navier-Stokes (RANS) method is employed to build a numerical model. The experimental, analytical and numerical results are compared with the indicated characteristic loads from the Eurocode.

A METHOD OF DETERMINING THE TIME BREAK ON DEEP SEA SEISMIC RECORDS FROM THE WATER SOUND ARRIVALS

Geophysics ◽  
1944 ◽  
Vol 9 (2) ◽  
pp. 163-174
Author(s):  
W. B. Agocs
Keyword(s):  
Deep Sea ◽  
Water Wave ◽  
Sea Water ◽  
Ocean Bottom ◽  
Linear Variation ◽  
Abrupt Changes ◽  
Lateral Distance ◽  
Seismic Records ◽  
First Arrival ◽  
Depth Curve

A method is presented whereby, through the use of the direct water wave first arrival from a shot fired on the ocean bottom, and the first and second reflections of sound from the surface of the sea, the following data may be obtained: (1) the ratio of the depth of the shot below the surface of the sea to the lateral distance between the shot and detector; (2) the lateral distance between the shot and the detector at the bottom of the sea; and finally, (3) the time of detonation or the time break in terms of the time scale of the detecting recorder. The velocity of sound in sea water shows a linear variation of the velocity with depth in definite zones with rather abrupt changes in slope of the velocity‐depth curve from zone to zone. Curvature due to refraction is found to be negligible in the calculations made for true oceanic depths. Sample computations are given.

Field trial of fibre‐optic multi‐component sensor system for application in ocean bottom seismic

2006 ◽  
Author(s):  
Mark Thompson ◽  
Lasse Amundsen ◽  
Per Ivar Karstad ◽  
Jan Langhammer ◽  
Hilde Nakstad ◽  
...  
Keyword(s):  
Field Trial ◽  
Sensor System ◽  
Ocean Bottom ◽  
Fibre Optic

Structural Reinforcement of Viewports in Spherical Pressure Hull for Manned Submersibles

2014 ◽  
Vol 48 (3) ◽  
pp. 17-24 ◽  
Author(s):  
Bhaskaran Pranesh ◽  
Dharmaraj Sathianarayanan ◽  
Sethuraman Ramesh ◽  
Gidugu Ananda Ramadass
Keyword(s):  
Atmospheric Pressure ◽  
Hoop Stress ◽  
Sea Water ◽  
External Pressure ◽  
Element Analysis ◽  
Structural Reinforcement ◽  
Replacement Method ◽  
Axis Of Symmetry ◽  
Spherical Pressure ◽  
Design Pressure

AbstractManned submersibles are underwater vehicles. These vehicles are equipped with an atmospheric pressure casing called a spherical pressure hull, which can accommodate up to three people. The spherical pressure hull facilitates safe passage to high-pressure environments. It has circular openings that serve as viewports to enable underwater viewing and intervention. The regions near the openings are the weakest in the pressure hull and must be reinforced. Reinforcement of the viewports is performed using the area replacement method. The amount of material removed from the viewport opening must be replaced along the axis of symmetry of the opening. This is the minimum amount of material that must be placed along the circumference of the viewports. Reinforced viewports in the pressure hull are analyzed using finite element analysis, and the stresses are classified into primary and secondary stresses. The reinforcements of the viewports are carried out in such a way that the calculated primary and secondary stresses are below the permissible limits.Abbreviations:P ‐ External pressure (design pressure)Dm ‐ Mean diameter of the pressure hullRm ‐ Mean radius of the pressure hullt ‐ Thickness of the pressure hullσ ‐ Hoop stressPy ‐ Pressure at yield strength of the materialPb ‐ Buckling pressureE ‐ Young’s modulus of the materialγ ‐ Poisson’s ratioMSW ‐ Meters of sea water

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