LECTURE 3: Fluid Statics
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Estimating Your Air Consumption
10/29/2019 Alert Diver | Estimating Your Air Consumption Estimating Your Air Consumption Advanced Diving Public Safety Diving By Mike Ange Mastering Neutral Buoyancy and Trim Military Diving Technical Diving Scientific Diving and Safety Program Oversight Seeing the Reef in a New Light ADVERTISEMENT Do you have enough breathing gas to complete the next dive? Here's how to find out. It is a warm clear day, and the Atlantic Ocean is like glass. As you drop into the water for a dive on North Carolina's famous U-352 wreck, you can see that the :: captain has hooked the wreck very near the stern. It is your plan to circumnavigate the entire structure and get that perfect photograph near the exposed bow torpedo tube. You descend to slightly below 100 feet, reach the structure and take off toward the bow. Unfortunately, you are only halfway, just approaching the conning tower, when your buddy signals that he is running low on air. Putting safety first, you return with him to the ascent line — cursing the lost opportunity and vowing to find a new buddy. If you've ever experienced the disappointment of ending a dive too soon for lack of breathing gas or, worse, had to make a hurried ascent because you ran out of air, it may surprise you to learn that your predicament was entirely predictable. With a little planning and some basic calculations, you can estimate how much breathing gas you will need to complete a dive and then take steps to ensure an adequate supply. It's a process that technical divers live by and one that can also be applied to basic open-water diving. -
THE SOLUBILITY of GASES in LIQUIDS Introductory Information C
THE SOLUBILITY OF GASES IN LIQUIDS Introductory Information C. L. Young, R. Battino, and H. L. Clever INTRODUCTION The Solubility Data Project aims to make a comprehensive search of the literature for data on the solubility of gases, liquids and solids in liquids. Data of suitable accuracy are compiled into data sheets set out in a uniform format. The data for each system are evaluated and where data of sufficient accuracy are available values are recommended and in some cases a smoothing equation is given to represent the variation of solubility with pressure and/or temperature. A text giving an evaluation and recommended values and the compiled data sheets are published on consecutive pages. The following paper by E. Wilhelm gives a rigorous thermodynamic treatment on the solubility of gases in liquids. DEFINITION OF GAS SOLUBILITY The distinction between vapor-liquid equilibria and the solubility of gases in liquids is arbitrary. It is generally accepted that the equilibrium set up at 300K between a typical gas such as argon and a liquid such as water is gas-liquid solubility whereas the equilibrium set up between hexane and cyclohexane at 350K is an example of vapor-liquid equilibrium. However, the distinction between gas-liquid solubility and vapor-liquid equilibrium is often not so clear. The equilibria set up between methane and propane above the critical temperature of methane and below the criti cal temperature of propane may be classed as vapor-liquid equilibrium or as gas-liquid solubility depending on the particular range of pressure considered and the particular worker concerned. -
Pressure Diffusion Waves in Porous Media
Lawrence Berkeley National Laboratory Lawrence Berkeley National Laboratory Title Pressure diffusion waves in porous media Permalink https://escholarship.org/uc/item/5bh9f6c4 Authors Silin, Dmitry Korneev, Valeri Goloshubin, Gennady Publication Date 2003-04-08 eScholarship.org Powered by the California Digital Library University of California Pressure diffusion waves in porous media Dmitry Silin* and Valeri Korneev, Lawrence Berkeley National Laboratory, Gennady Goloshubin, University of Houston Summary elastic porous medium. Such a model results in a parabolic pressure diffusion equation. Its validity has been Pressure diffusion wave in porous rocks are under confirmed and “canonized”, for instance, in transient consideration. The pressure diffusion mechanism can pressure well test analysis, where it is used as the main tool provide an explanation of the high attenuation of low- since 1930th, see e.g. Earlougher (1977) and Barenblatt et. frequency signals in fluid-saturated rocks. Both single and al., (1990). The basic assumptions of this model make it dual porosity models are considered. In either case, the applicable specifically in the low-frequency range of attenuation coefficient is a function of the frequency. pressure fluctuations. Introduction Theories describing wave propagation in fluid-bearing porous media are usually derived from Biot’s theory of poroelasticity (Biot 1956ab, 1962). However, the observed high attenuation of low-frequency waves (Goloshubin and Korneev, 2000) is not well predicted by this theory. One of possible reasons for difficulties in detecting Biot waves in real rocks is in the limitations imposed by the assumptions underlying Biot’s equations. Biot (1956ab, 1962) derived his main equations characterizing the mechanical motion of elastic porous fluid-saturated rock from the Hamiltonian Principle of Least Action. -
8. Decompression Procedures Diver
TDI Standards and Procedures Part 2: TDI Diver Standards 8. Decompression Procedures Diver 8.1 Introduction This course examines the theory, methods and procedures of planned stage decompression diving. This program is designed as a stand-alone course or it may be taught in conjunction with TDI Advanced Nitrox, Advanced Wreck, or Full Cave Course. The objective of this course is to train divers how to plan and conduct a standard staged decompression dive not exceeding a maximum depth of 45 metres / 150 feet. The most common equipment requirements, equipment set-up and decompression techniques are presented. Students are permitted to utilize enriched air nitrox (EAN) mixes or oxygen for decompression provided the gas mix is within their current certification level. 8.2 Qualifications of Graduates Upon successful completion of this course, graduates may engage in decompression diving activities without direct supervision provided: 1. The diving activities approximate those of training 2. The areas of activities approximate those of training 3. Environmental conditions approximate those of training Upon successful completion of this course, graduates are qualified to enroll in: 1. TDI Advanced Nitrox Course 2. TDI Extended Range Course 3. TDI Advanced Wreck Course 4. TDI Trimix Course 8.3 Who May Teach Any active TDI Decompression Procedures Instructor may teach this course Version 0221 67 TDI Standards and Procedures Part 2: TDI Diver Standards 8.4 Student to Instructor Ratio Academic 1. Unlimited, so long as adequate facility, supplies and time are provided to ensure comprehensive and complete training of subject matter Confined Water (swimming pool-like conditions) 1. -
Bioinspired Inner Microstructured Tube Controlled Capillary Rise
Bioinspired inner microstructured tube controlled capillary rise Chuxin Lia, Haoyu Daia, Can Gaoa, Ting Wanga, Zhichao Donga,1, and Lei Jianga aChinese Academy of Sciences Key Laboratory of Bio-inspired Materials and Interfacial Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 100190 Beijing, China Edited by David A. Weitz, Harvard University, Cambridge, MA, and approved May 21, 2019 (received for review December 17, 2018) Effective, long-range, and self-propelled water elevation and trans- viscosity resistance for subsequent bulk water elevation but also, port are important in industrial, medical, and agricultural applica- shrinks the inner diameter of the tube. On turning the peristome- tions. Although research has grown rapidly, existing methods for mimetic tube upside down, we can achieve capillary rise gating water film elevation are still limited. Scaling up for practical behavior, where no water rises in the tube. In addition to the cap- applications in an energy-efficient way remains a challenge. Inspired illary rise diode behavior, significantly, on bending the peristome- by the continuous water cross-boundary transport on the peristome mimetic tube replica into a “candy cane”-shaped pipe (closed sys- surface of Nepenthes alata,herewedemonstratetheuseof tem), a self-siphon is achieved with a high flux of ∼5.0 mL/min in a peristome-mimetic structures for controlled water elevation by pipe with a diameter of only 1.0 mm. bending biomimetic plates into tubes. The fabricated structures have unique advantages beyond those of natural pitcher plants: bulk wa- Results ter diode transport behavior is achieved with a high-speed passing General Description of the Natural Peristome Surface. -
What Is High Blood Pressure?
ANSWERS Lifestyle + Risk Reduction by heart High Blood Pressure BLOOD PRESSURE SYSTOLIC mm Hg DIASTOLIC mm Hg What is CATEGORY (upper number) (lower number) High Blood NORMAL LESS THAN 120 and LESS THAN 80 ELEVATED 120-129 and LESS THAN 80 Pressure? HIGH BLOOD PRESSURE 130-139 or 80-89 (HYPERTENSION) Blood pressure is the force of blood STAGE 1 pushing against blood vessel walls. It’s measured in millimeters of HIGH BLOOD PRESSURE 140 OR HIGHER or 90 OR HIGHER mercury (mm Hg). (HYPERTENSION) STAGE 2 High blood pressure (HBP) means HYPERTENSIVE the pressure in your arteries is higher CRISIS HIGHER THAN 180 and/ HIGHER THAN 120 than it should be. Another name for (consult your doctor or immediately) high blood pressure is hypertension. Blood pressure is written as two numbers, such as 112/78 mm Hg. The top, or larger, number (called Am I at higher risk of developing HBP? systolic pressure) is the pressure when the heart There are risk factors that increase your chances of developing HBP. Some you can control, and some you can’t. beats. The bottom, or smaller, number (called diastolic pressure) is the pressure when the heart Those that can be controlled are: rests between beats. • Cigarette smoking and exposure to secondhand smoke • Diabetes Normal blood pressure is below 120/80 mm Hg. • Being obese or overweight If you’re an adult and your systolic pressure is 120 to • High cholesterol 129, and your diastolic pressure is less than 80, you have elevated blood pressure. High blood pressure • Unhealthy diet (high in sodium, low in potassium, and drinking too much alcohol) is a systolic pressure of 130 or higher,or a diastolic pressure of 80 or higher, that stays high over time. -
THE SOLUBILITY of GASES in LIQUIDS INTRODUCTION the Solubility Data Project Aims to Make a Comprehensive Search of the Lit- Erat
THE SOLUBILITY OF GASES IN LIQUIDS R. Battino, H. L. Clever and C. L. Young INTRODUCTION The Solubility Data Project aims to make a comprehensive search of the lit erature for data on the solubility of gases, liquids and solids in liquids. Data of suitable accuracy are compiled into data sheets set out in a uni form format. The data for each system are evaluated and where data of suf ficient accuracy are available values recommended and in some cases a smoothing equation suggested to represent the variation of solubility with pressure and/or temperature. A text giving an evaluation and recommended values and the compiled data sheets are pUblished on consecutive pages. DEFINITION OF GAS SOLUBILITY The distinction between vapor-liquid equilibria and the solUbility of gases in liquids is arbitrary. It is generally accepted that the equilibrium set up at 300K between a typical gas such as argon and a liquid such as water is gas liquid solubility whereas the equilibrium set up between hexane and cyclohexane at 350K is an example of vapor-liquid equilibrium. However, the distinction between gas-liquid solUbility and vapor-liquid equilibrium is often not so clear. The equilibria set up between methane and propane above the critical temperature of methane and below the critical temperature of propane may be classed as vapor-liquid equilibrium or as gas-liquid solu bility depending on the particular range of pressure considered and the par ticular worker concerned. The difficulty partly stems from our inability to rigorously distinguish between a gas, a vapor, and a liquid, which has been discussed in numerous textbooks. -
Statistical Mechanics I: Exam Review 1 Solution
8.333: Statistical Mechanics I Fall 2007 Test 1 Review Problems The first in-class test will take place on Wednesday 9/26/07 from 2:30 to 4:00 pm. There will be a recitation with test review on Friday 9/21/07. The test is ‘closed book,’ but if you wish you may bring a one-sided sheet of formulas. The test will be composed entirely from a subset of the following problems. Thus if you are familiar and comfortable with these problems, there will be no surprises! ******** You may find the following information helpful: Physical Constants 31 27 Electron mass me 9.1 10− kg Proton mass mp 1.7 10− kg ≈ × 19 ≈ × 34 1 Electron Charge e 1.6 10− C Planck’s const./2π ¯h 1.1 10− Js− ≈ × 8 1 ≈ × 8 2 4 Speed of light c 3.0 10 ms− Stefan’s const. σ 5.7 10− W m− K− ≈ × 23 1 ≈ × 23 1 Boltzmann’s const. k 1.4 10− JK− Avogadro’s number N 6.0 10 mol− B ≈ × 0 ≈ × Conversion Factors 5 2 10 4 1atm 1.0 10 Nm− 1A˚ 10− m 1eV 1.1 10 K ≡ × ≡ ≡ × Thermodynamics dE = T dS+dW¯ For a gas: dW¯ = P dV For a wire: dW¯ = Jdx − Mathematical Formulas √π ∞ n αx n! 1 0 dx x e− = αn+1 2 ! = 2 R 2 2 2 ∞ x √ 2 σ k dx exp ikx 2σ2 = 2πσ exp 2 limN ln N! = N ln N N −∞ − − − →∞ − h i h i R n n ikx ( ik) n ikx ( ik) n e− = ∞ − x ln e− = ∞ − x n=0 n! � � n=1 n! � �c P 2 4 P 3 5 cosh(x) = 1 + x + x + sinh(x) = x + x + x + 2! 4! · · · 3! 5! · · · 2πd/2 Surface area of a unit sphere in d dimensions Sd = (d/2 1)! − 1 1. -
Lecture 3 Buoyancy (Archimedes' Principle)
LECTURE 3 BUOYANCY (ARCHIMEDES’ PRINCIPLE) Lecture Instructor: Kazumi Tolich Lecture 3 2 ¨ Reading chapter 11-7 ¤ Archimedes’ principle and buoyancy Buoyancy and Archimedes’ principle 3 ¨ The force exerted by a fluid on a body wholly or partially submerged in it is called the buoyant force. ¨ Archimedes’ principle: A body wholly or partially submerged in a fluid is buoyed up by a force equal to the weight of the displaced fluid. Fb = wfluid = ρfluidgV V is the volume of the object in the fluid. Demo: 1 4 ¨ Archimedes’ principle ¤ The buoyant force is equal to the weight of the water displaced. Lifting a rock under water 5 ¨ Why is it easier to lift a rock under water? ¨ The buoyant force is acting upward. ¨ Since the density of water is much greater than that of air, the buoyant force is much greater under the water compared to in the air. Fb air = ρair gV Fb water = ρwater gV The crown and the nugget 6 Archimedes (287-212 BC) had been given the task of determining whether a crown made for King Hieron II was pure gold. In the above diagram, crown and nugget balance in air, but not in water because the crown has a lower density. Clicker question: 1 & 2 7 Demo: 2 8 ¨ Helium balloon in helium ¨ Helium balloon in liquid nitrogen ¤ Demonstration of buoyancy and Archimedes’ principle Floatation 9 ¨ When an object floats, the buoyant force equals its weight. ¨ An object floats when it displaces an amount of fluid whose weight is equal to the weight of the object. -
Buoyancy Compensator Owner's Manual
BUOYANCY COMPENSATOR OWNER’S MANUAL 2020 CE CERTIFICATION INFORMATION ECLIPSE / INFINITY / EVOLVE / EXPLORER BC SYSTEMS CE TYPE APPROVAL CONDUCTED BY: TÜV Rheinland LGA Products GmbH Tillystrasse 2 D-90431 Nürnberg Notified Body 0197 EN 1809:2014+A1:2016 CE CONTACT INFORMATION Halcyon Dive Systems 24587 NW 178th Place High Springs, FL 32643 USA AUTHORIZED REPRESENTATIVE IN EUROPEAN MARKET: Dive Distribution SAS 10 Av. du Fenouil 66600 Rivesaltes France, VAT FR40833868722 REEL Diving Kråketorpsgatan 10 431 53 Mölndal 2 HALCYON.NET HALCYON BUOYANCY COMPENSATOR OWNER’S MANUAL TRADEMARK NOTICE Halcyon® and BC Keel® are registered trademarks of Halcyon Manufacturing, Inc. Halcyon’s BC Keel and Trim Weight system are protected by U.S. Patents #5855454 and 6530725b1. The Halcyon Cinch is a patent-pending design protected by U.S. and European law. Halcyon trademarks and pending patents include Multifunction Compensator™, Cinch™, Pioneer™, Eclipse™, Explorer™, and Evolve™ wings, BC Storage Pak™, Active Control Ballast™, Diver’s Life Raft™, Surf Shuttle™, No-Lock Connector™, Helios™, Proteus™, and Apollo™ lighting systems, Scout Light™, Pathfinder™ reels, Defender™ spools, and the RB80™ rebreather. WARNINGS, CAUTIONS, AND NOTES Pay special attention to information provided in warnings, cautions, and notes accompanied by these icons: A WARNING indicates a procedure or situation that, if not avoided, could result in serious injury or death to the user. A CAUTION indicates any situation or technique that could cause damage to the product, and could subsequently result in injury to the user. WARNING This manual provides essential instructions for the proper fitting, adjustment, inspection, and care of your new Buoyancy Compensator. Because Halcyon’s BCs utilize patented technology, it is very important to take the time to read these instructions in order to understand and fully enjoy the features that are unique to your specific model. -
Future Towed Arrays - Operational Drivers and Technology Solutions
UDT 2019 Sensors & processing, Sonar arrays for improved operational capability Future towed arrays - operational drivers and technology solutions Prowse D. Atlas Elektronik UK. [email protected] Abstract — Towed array sonars provide a key capability in the suite of ASW sensors employed by undersea assets. The array lengths achievable and stand-off distance from platforms provide an advantage over other types of sonar in terms of the signal to noise ratio for detecting and classifying contacts of interest. This paper identifies the drivers for future towed arrays and explores technology solutions that could enable towed array sonar to provide the capability edge in the 21st Century. 1 Introduction 2.2 Maritime Autonomous Systems and sensors for ASW Towed arrays are a primary sensor for ASW acoustic detection and classification. They are used extensively by Recent advancement in autonomous systems and submarine and ASW surface combatants as part of their technology is opening up a plethora of new ASW armoury of tools against the submarine threat. As the capability opportunities and threats, including concepts nature of ASW evolves, the design and technology that involve the use of a towed array sensor on an incorporated into future ASW towed arrays will also need unmanned underwater or surface vessel in order to support to adapt. This paper examines the drivers behind the shift mission objectives. in ASW and explores the technology space that may provide leading edge for future capability. The use of towed arrays on autonomous systems has been studied to show how effective this type of capability can The scope of towed arrays that this paper considers be. -
The Life of a Surface Bubble
molecules Review The Life of a Surface Bubble Jonas Miguet 1,†, Florence Rouyer 2,† and Emmanuelle Rio 3,*,† 1 TIPS C.P.165/67, Université Libre de Bruxelles, Av. F. Roosevelt 50, 1050 Brussels, Belgium; [email protected] 2 Laboratoire Navier, Université Gustave Eiffel, Ecole des Ponts, CNRS, 77454 Marne-la-Vallée, France; fl[email protected] 3 Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, 91405 Orsay, France * Correspondence: [email protected]; Tel.: +33-1691-569-60 † These authors contributed equally to this work. Abstract: Surface bubbles are present in many industrial processes and in nature, as well as in carbon- ated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play. Keywords: bubble; film; drainage; evaporation; lifetime 1. Introduction Bubbles have attracted much attention in the past for several reasons. First, their ephemeral Citation: Miguet, J.; Rouyer, F.; nature commonly awakes children’s interest and amusement. Their visual appeal has raised Rio, E. The Life of a Surface Bubble. interest in painting [1], in graphism [2] or in living art.