DOCSLIB.ORG

Now Take a Deep Breath Lesson

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Now Take a Deep Breath Lesson 2007 Cayman Island Twilight Zone Expedition Now Take a Deep Breath FOCUS SEATING ARRANGEMENT Physics and physiology of SCUBA diving Classroom style or groups of 2-4 students GRADE LEVEL MAXIMUM NUMBER OF STUDENTS 9-12 (Chemistry/Physics/Biology) 30 FOCUS QUESTION KEY WORDS What physiological problems are associated with Coral Reefs SCUBA diving, and how can these problems be SCUBA overcome? Henry’s Law Boyle’s Law LEARNING OBJECTIVES Dalton’s Law of Partial Pressures Students will be able to define Henry’s Law, Air embolism Boyle’s Law, and Dalton’s Law of Partial Decompression sickness Pressures, and explain their relevance to SCUBA Nitrogen narcosis diving. Oxygen toxicity Nitrox Students will be able to discuss the causes of air Trimix embolism, decompression sickness, nitrogen nar- cosis, and oxygen toxicity in SCUBA divers. BACKGROUND INFORMATION Coral reefs provide habitats for some of the most Students will be able to explain the advantages diverse biological communities on Earth. The of gas mixtures such as Nitrox and Trimix and high species diversity found on both shallow- and closed-circuit rebreather systems. deep-water reefs makes these ecosystems very promising sources of powerful new antibiotic, MATERIALS anti-cancer and anti-inflammatory drugs. In Copies of “Student Worksheet,” one copy for addition, these reefs provide habitat for impor- each student or student group tant food resources, and shallow reefs are an important part of coastal recreation and tourism AUDIO/VISUAL MATERIALS industries and protect shorelines from erosion and None storm damage. Despite the direct importance of coral reefs to many aspects of human well-being, TEACHING TIME shallow- and deep-water reefs are both threat- One or two 45-minute class periods, plus time for ened by human activities. student research 1 2007 Cayman Island Twilight Zone Expedition – Grades 9-12 (Chemistry/Physics/Biology) Focus: Physics and physiology of SCUBA diving oceanexplorer.noaa.gov Around the world, shallow water coral reefs come.html as well as the Exploration Technology have been intensively studied by scientists using section of the Cayman Island Twilight Zone self-contained underwater breathing (SCUBA) Expedition Expedition Education Module at equipment, while deep coral systems are being http://oceanexplorer.noaa.gov/explorations/07twilightzone/back- investigated with submersibles and remotely oper- ground/edu/edu.html ated underwater vehicles (ROVs). Recent explora- tions have found a third type of coral ecosystem If you are not already familiar with coral reefs, between depths of 50 m and 150 m: light-limited you may also want to review the coral reef deep reefs living in what coral ecologists call the tutorials at nos.noaa.gov/education/kits/corals/, and “twilight zone.” These reefs have been studied http://oceanexplorer.noaa.gov/explorations/islands01/back- much less than shallow and deep-water reefs ground/islands/sup10_lophelia.html for more background because they are beyond the safe range of con- on Lophelia reefs. ventional SCUBA equipment, yet are too shallow and close to shore to justify the use of expensive 2. Briefly review background information on the submersibles and ROVs. The few studies of twi- Cayman Island Twilight Zone Expedition, and light zone reefs suggest that these ecosystems not the overall characteristics of coral reefs in shal- only include species unique to this depth range, low water, deep water, and intermediate depths but may also provide important refuges and (the “twilight zone”). Be sure students under- nursery habitats for corals and fishes that inhabit stand that shallow- and deepwater reefs both shallower reefs. This is particularly important in have a high diversity of species and large num- areas where shallow reefs are severely stressed, ber of individual organisms, and that deep fore since twilight zone coral ecosystems may provide reef areas (the most seaward portion of a reef) a natural option for recovery. probably do as well, but are virtually unex- plored. Ask students to speculate on why deep Scientific exploration of twilight zone coral reef fore reef areas seem to have been ignored. ecosystems is urgently needed to provide infor- Students should realize that this is primarily mation for their protection, as well as to identify the result of available technology. Give each potentially important sources of drugs and other student or student group a copy of the “Student biological products from organisms that are Worksheet.” Tell students that their assignment endemic to these systems. Helping to meet this is to investigate some of the problems that con- need is the primary focus of the 2007 Ocean front diver scientists, and how these problems Explorer Cayman Island Twilight Zone Expedition. can be managed. The technological keys for this expedition are new diving techniques that allow scientists to 3 Lead a discussion of students’ answers to ques- personally visit deep-water ecosystems without tions on the Worksheet. The following points the need for expensive submersibles. This lesson should be included: introduces students to basic principles of physics and physiology that are the foundation for these • Henry’s Law states that the mass of a gas new techniques. which dissolves in a volume of liquid is pro- portional to the pressure of the gas. LEARNING PROCEDURE 1. To prepare for this lesson: • Boyle’s Law states that the product of the vol- • Review the introductory essays for the 2007 ume and pressure of a gas held at a constant Cayman Island Twilight Zone Expedition at temperature is equal to a constant (PV = k). http://oceanexplorer.noaa.gov/explorations/07twilightzone/wel- So, if the pressure of the gas doubles, the 2 2007 Cayman Island Twilight Zone Expedition – Grades 9-12 (Chemistry/Physics/Biology) oceanexplorer.noaa.gov Focus: Physics and physiology of SCUBA diving volume will be decreased by half; and if the • An air embolism is a bubble of air or other volume of a gas doubles, the pressure must gas that is large enough to wholly or par- decrease by half. tially block a blood vessel. Air embolism in a diver might result from breath-holding as the • Boyle’s Law is important to a diver because diver rises from deep to shallow water, since it means that if a diver takes a lungful of air the air in the diver’s lungs would expand as while he is underwater, that air will expand the external pressure decreased. If the air in his lungs as he rises to the surface. If he expanded enough, it could rupture the lungs holds his breath, the expanding air can rup- and allow bubbles of air to enter the blood- ture his lungs. So the golden rule of diving is: stream. Never hold your breath! • Decompression sickness results from bubbles • Dalton’s Law of Partial Pressures states that forming in a diver’s blood. If the bubbles are the pressure exerted by a mixture of gases is of sufficient size, they may block important equal to the sum of the pressures that would blood vessels, causing pain, paralysis, or be exerted by the gases individually. death. Such bubbles can form when a diver ascends so rapidly that dissolved gases do • Dalton’s Law of Partial Pressures allows a not have time to diffuse out of the blood, diver to predict how much of a specific gas similar to the result of rapidly opening a can will dissolve in her blood at a given depth. of carbonated soda. Decompression sickness This is important, because some gases in divers usually involves bubbles of nitrogen. become toxic or cause mental impairment Oxygen in air does not form such bubbles when their partial pressure in the blood rises because much of the oxygen dissolved in a above a particular level. diver’s blood is quickly bound by hemoglo- bin, and normal metabolism further reduces • Henry’s Law tells divers that breathing gas blood oxygen concentration. at higher-than-normal pressures will cause their bodies to absorb more gases than are • Nitrogen narcosis is an effect similar to absorbed at lower pressures. Absorbed gases alcohol intoxication that may occur when can cause decompression sickness as well as the partial pressure of nitrogen in a diver’s toxic effects, and divers must follow certain blood rises above about 3 atmospheres (cor- procedures to avoid these problems. responding to a depth of about 30 m). The severity of the impairment depends upon indi- • To a scuba diver Henry’s Law tells us that vidual susceptibility as well as environmental at higher pressure our bodies will absorb conditions (temperature, time of day, etc.). more gases. At great depths, the amount of nitrogen (and other gases) absorbed into our • Oxygen may become toxic at partial pres- blood and tissue is greater than the amount sures above 1.4 atmospheres, causing con- absorbed at shallow depths. That is why a vulsions. Individual thresholds vary widely diver going to 100’ has a greater risk of and depend upon degree of exertion as well decompression illness than a diver who dives as environmental conditions. only 30 feet. Since the shallow diver has absorbed less gas, it is less likely to come out • At the surface, pure oxygen has a partial of solution in the body. pressure of 1.0 atmosphere. Since pressure increases by 1.0 atm for every 10 m of 3 2007 Cayman Island Twilight Zone Expedition – Grades 9-12 (Chemistry/Physics/Biology) Focus: Physics and physiology of SCUBA diving oceanexplorer.noaa.gov depth, the 1.4 atm threshold for oxygen toxic- THE BRIDGE CONNECTION ity would be reached at a depth of 4 m, or www.vims.edu/bridge/ – In the “Site Navigation” menu about 13 ft. Note that pure oxygen is some- on the left, click on “Ocean Science Topics,” then times used at depths of 6 m or less to shorten “Human Activities,” then “Recreation” for links to decompression times.
Load more

Recommended publications
  • The Use of Heliox in Treating Decompression Illness
    The Diving Medical Advisory Committee DMAC, Eighth Floor, 52 Grosvenor Gardens, London SW1W 0AU, UK www.dmac-diving.org Tel: +44 (0) 20 7824 5520 [email protected] The Use of Heliox in Treating Decompression Illness DMAC 23 Rev. 1 – June 2014 Supersedes DMAC 23, which is now withdrawn There are many ways of treating decompression illness (DCI) at increased pressure. In the past 20 years, much has been published on the use of oxygen and helium/oxygen mixtures at different depths. There is, however, a paucity of carefully designed scientific studies. Most information is available from mathematical models, animal experiments and case reports. During a therapeutic compression, the use of a different inert gas from that breathed during the dive may facilitate bubble resolution. Gas diffusivity and solubility in blood and tissue is expected to play a complex role in bubble growth and shrinkage. Mathematical models, supported by some animal studies, suggest that breathing a heliox gas mixture during recompression could be beneficial for nitrogen elimination after air dives. In humans, diving to 50 msw, with air or nitrox, almost all cases of DCI can be adequately treated at 2.8 bar (18 msw), where 100% oxygen is both safe and effective. Serious neurological and vestibular DCI with only partial improvements during initial compression at 18 msw on oxygen may benefit from further recompression to 30 msw with heliox 50:50 (Comex therapeutic table 30 – CX30). There have been cases successfully treated on 50:50 heliox (CX30), on the US Navy recompression tables with 80:20 and 60:40 heliox (USN treatment table 6A) instead of air and in heliox saturation.
    [Show full text]
  • Development of the Crew Dragon ECLSS
    ICES-2020-333 Development of the Crew Dragon ECLSS Jason Silverman1, Andrew Irby2, and Theodore Agerton3 Space Exploration Technologies, Hawthorne, California, 90250 SpaceX designed the Crew Dragon spacecraft to be the safest ever flown and to restore the ability of the United States to launch astronauts. One of the key systems required for human flight is the Environmental Control and Life Support System (ECLSS), which was designed to work in concert with the spacesuit and spacecraft. The tight coupling of many subsystems combined with an emphasis on simplicity and fault tolerance created unique challenges and opportunities for the design team. During the development of the crew ECLSS, the Dragon 1 cargo spacecraft flew with a simple ECLSS for animals, providing an opportunity for technology development and the early characterization of system-level behavior. As the ECLSS design matured a series of tests were conducted, including with humans in a prototype capsule in November 2016, the Demo-1 test flight to the ISS in March 2019, and human-in-the-loop ground testing in the Demo-2 capsule in January 2020 before the same vehicle performs a crewed test flight. This paper describes the design and operations of the ECLSS, the development process, and the lessons learned. Nomenclature AC = air conditioning AQM = air quality monitor AVV = active vent valve CCiCap = Commercial Crew Integrated Capability CCtCap = Commercial Crew Transportation Capability CFD = computational fluid dynamics conops = concept of operations COPV = composite overwrapped
    [Show full text]
  • Dysbarism - Barotrauma
    DYSBARISM - BAROTRAUMA Introduction Dysbarism is the term given to medical complications of exposure to gases at higher than normal atmospheric pressure. It includes barotrauma, decompression illness and nitrogen narcosis. Barotrauma occurs as a consequence of excessive expansion or contraction of gas within enclosed body cavities. Barotrauma principally affects the: 1. Lungs (most importantly): Lung barotrauma may result in: ● Gas embolism ● Pneumomediastinum ● Pneumothorax. 2. Eyes 3. Middle / Inner ear 4. Sinuses 5. Teeth / mandible 6. GIT (rarely) Any illness that develops during or post div.ing must be considered to be diving- related until proven otherwise. Any patient with neurological symptoms in particular needs urgent referral to a specialist in hyperbaric medicine. See also separate document on Dysbarism - Decompression Illness (in Environmental folder). Terminology The term dysbarism encompasses: ● Decompression illness And ● Barotrauma And ● Nitrogen narcosis Decompression illness (DCI) includes: 1. Decompression sickness (DCS) (or in lay terms, the “bends”): ● Type I DCS: ♥ Involves the joints or skin only ● Type II DCS: ♥ Involves all other pain, neurological injury, vestibular and pulmonary symptoms. 2. Arterial gas embolism (AGE): ● Due to pulmonary barotrauma releasing air into the circulation. Epidemiology Diving is generally a safe undertaking. Serious decompression incidents occur approximately only in 1 in 10,000 dives. However, because of high participation rates, there are about 200 - 300 cases of significant decompression illness requiring treatment in Australia each year. It is estimated that 10 times this number of divers experience less severe illness after diving. Physics Boyle’s Law: The air pressure at sea level is 1 atmosphere absolute (ATA). Alternative units used for 1 ATA include: ● 101.3 kPa (SI units) ● 1.013 Bar ● 10 meters of sea water (MSW) ● 760 mm of mercury (mm Hg) ● 14.7 pounds per square inch (PSI) For every 10 meters a diver descends in seawater, the pressure increases by 1 ATA.
    [Show full text]
  • Optimal Breathing Gas Mixture in Professional Diving with Multiple Supply
    Proceedings of the World Congress on Engineering 2021 WCE 2021, July 7-9, 2021, London, U.K. Optimal Breathing Gas Mixture in Professional Diving with Multiple Supply Orhan I. Basaran, Mert Unal compressors and cylinders, it was limited to surface air Abstract— Professional diving existed since antiquities when supply lines. In 1978, Fleuss introduced the first closed divers collected resources from the bottom of the seas and circuit oxygen breathing apparatus which removed carbon lakes. With technological advancements in the recent century, dioxide from the exhaled gas and did not form bubbles professional diving activities also increased significantly. underwater. In 1943, Cousteau and Gangan designed the Diving has many adverse effects on human physiology which first proper demand-regulated air supply from compressed are widely investigated in order to make dives safer. In this air cylinders worn on the back. The scuba equipment with study, we focus on optimizing the breathing gas mixture minimizing the dive costs while ensuring the safety of the the high-pressure regulator on the cylinder and a single hose divers. The methods proposed in this paper are purely to a demand valve was invented in Australia and marketed theoretical and divers should always have appropriate training by Ted Eldred in the early 1950s [1]. and certificates. Also, divers should never perform dives With the use of Siebe dress, the first cases of decompression without consulting professionals and medical doctors with expertise in related fields. sickness began to be documented. Haldane conducted several experiments on animal and human subjects in Index Terms—-professional diving; breathing gas compression chambers to investigate the causes of this optimization; dive profile optimization sickness and how it can be prevented.
    [Show full text]
  • Nitrogen Narcosis
    WHAT IS IT? A reversible alteration in consciousness that occurs while at depth (usually noticeable around 30 meters or 100 ft) Caused by the anesthetic effect of certain gases at high pressure NITROGEN NARCOSIS Depths Beyond 100 Feet! Individual Variability Day-to-Day Variability Signs and Symptoms of N2 Narcosis Impaired performance mental/manual work Dizziness, euphoria, intoxication Overconfidence Uncontrolled laughter Overly talkative Memory loss/post-dive amnesia Perceptual narrowing Impaired sensory function Loss of consciousness > 300 ft Deep Scuba Dives Breathing Air YEAR DIVER DEPTH 1943 Dumas 203 feet 1948 Dumas 307 feet 1967 Watts 390 feet 1968 Watson 437 feet 1989 Gilliam 452 feet Prevention of Nitrogen Narcosis Restrict diving depth to less than 100 fsw If affected, return immediately to surface Plan dive beforehand − Max time to be on bottom − Any decompression required − Minimum air required for ascent − Emergency action in event of accident Breathe helium/oxygen mixture How to Beat Narcosis (Francis 2006) Be sober, no hangover and drug free Be rested and confident Use a high quality regulator Avoid task loading Be over trained Approach limits gradually Use a slate to plan dive Schedule gauge checks and buddy checks Be positive, well motivated and prudent Oxygen Characteristics: − Colorless − Odorless − Tasteless Disadvantage: − Toxic when Oxygen is the only gas excessive amounts metabolized by the human body are breathed under pressure Too much or too little oxygen is dangerous! Oxygen Toxicity
    [Show full text]
  • Code of Federal Regulations GPO Access
    4±23±97 Wednesday Vol. 62 No. 78 April 23, 1997 Pages 19667±19896 Briefings on how to use the Federal Register For information on briefings in Washington, DC, see announcement on the inside cover of this issue. Now Available Online Code of Federal Regulations via GPO Access (Selected Volumes) Free, easy, online access to selected Code of Federal Regulations (CFR) volumes is now available via GPO Access, a service of the United States Government Printing Office (GPO). CFR titles will be added to GPO Access incrementally throughout calendar years 1996 and 1997 until a complete set is available. GPO is taking steps so that the online and printed versions of the CFR will be released concurrently. The CFR and Federal Register on GPO Access, are the official online editions authorized by the Administrative Committee of the Federal Register. New titles and/or volumes will be added to this online service as they become available. http://www.access.gpo.gov/nara/cfr For additional information on GPO Access products, services and access methods, see page II or contact the GPO Access User Support Team via: ★ Phone: toll-free: 1-888-293-6498 ★ Email: [email protected] federal register 1 II Federal Register / Vol. 62, No. 78 / Wednesday, April 23, 1997 SUBSCRIPTIONS AND COPIES PUBLIC Subscriptions: Paper or fiche 202±512±1800 Assistance with public subscriptions 512±1806 General online information 202±512±1530; 1±888±293±6498 FEDERAL REGISTER Published daily, Monday through Friday, Single copies/back copies: (not published on Saturdays, Sundays, or on official holidays), by the Office of the Federal Register, National Archives and Paper or fiche 512±1800 Records Administration, Washington, DC 20408, under the Federal Assistance with public single copies 512±1803 Register Act (49 Stat.
    [Show full text]
  • Leonardo User Manual
    Direction for use Computer Leonardo ENGLISH cressi.com 2 TABLE OF CONTENTS Main specifications page 4 TIME SET mode: General recommendations Date and time adjustment page 31 and safety measures page 5 SYSTEM mode: Introduction page 10 Setting of measurement unit and reset page 31 1 - COMPUTER CONTROL 3 - WHILE DIVING: COMPUTER Operation of the Leonardo computer page 13 FUNCTIONS 2 - BEFORE DIVING Diving within no decompression limits page 36 DIVE SET mode: DIVE AIR function: Setting of dive parameters page 16 Dive with Air page 37 Oxygen partial pressure (PO2) page 16 DIVE NITROX function: Nitrox - Percentage of the oxygen (FO2) page 18 Dive with Nitrox page 37 Dive Safety Factor (SF) page 22 Before a Nitrox dive page 37 Deep Stop page 22 Diving with Nitrox page 40 Altitude page 23 CNS toxicity display page 40 PLAN mode: PO2 alarm page 43 Dive planning page 27 Ascent rate page 45 GAGE mode: Safety Stop page 45 Depth gauge and timer page 27 Decompression forewarning page 46 Deep Stop page 46 3 Diving outside no decompression limits page 50 5 - CARE AND MAINTENANCE Omitted Decompression stage alarm page 51 Battery replacement page 71 GAGE MODE depth gauge and timer) page 52 6 - TECHNICAL SPECIFICATIONS Use of the computer with 7 - WARRANTY poor visibility page 56 4 - ON SURFACE AFTER DIVING Data display and management page 59 Surface interval page 59 PLAN function - Dive plan page 60 LOG BOOK function - Dive log page 61 HISTORY function - Dive history page 65 DIVE PROFILE function - Dive profile page 65 PCLINK function Pc compatible interface page 66 System Reset Reset of the instrument page 70 4 Congratulations on your purchase of your Leo - trox) dive.
    [Show full text]
  • Preventing Breathing- Gas Contamination
    RESEARCH, EDUCATION & MEDICINE // SAFETY 101 Preventing Breathing- STEPHEN FRINK Gas Contamination BY BRITTANY TROUT ncidents involving bad breathing gas — be it Recommendations for Compressor Operators air, nitrox, trimix or another mixture — are Compressor operators can help prevent gas rare, yet they do occur. Health effects on divers contamination and mitigate the risk of dive accidents vary depending on the contaminant breathed. in several ways. Among the most severe symptoms of breathing Attentive compressor maintenance. Proper contaminated gas are impaired judgment and loss of compressor maintenance helps ensure breathing-gas consciousness, both of which may be deadly underwater. quality as well as extends the life of the compressor. ISources of contamination include hydrocarbons Breathing-gas contamination is less likely in well- from compressor lubricants, carbon monoxide (CO) maintained and properly functioning compressors. from engine exhaust (or overheated compressor oil) If maintenance is neglected and the compressor and impurities from the surrounding environment such overheats, the lubricating oil may break down and as methane and carbon dioxide (CO2). Dust particles produce CO and other noxious byproducts. in breathing gas can also be hazardous, potentially Effective procedures. A fill checklist can help ensure impairing respiratory function or damaging diving safety procedures are remembered when cylinders equipment. Excessive moisture can cause corrosion are filled. Before starting to fill tanks, the operator in scuba cylinders and other dive gear and may cause should inspect the compressor’s filters for damage regulators to freeze due to adiabatic cooling (heat loss and note the presence of contaminants such as subsequent to increased gas volume). cigarette smoke, paint fumes or engine exhaust near the intake.
    [Show full text]
  • Special Operations Rebreathers
    Special Operations Underwater Life Support Systems INTRODUCTION TO JFD JFD is the world leading underwater capability provider facilitating the commercial and defence diving industries by offering innovative diving, submarine rescue and subsea technical solutions. JFD has a well-established history in the development of advanced and innovative diving and submarine rescue systems spanning over 30 years. Our systems continue to set the president in terms of capability and performance and JFD is relied upon by divers worldwide across both the defence and commercial sectors. Our products and services have been delivered to a large number of countries across all continents. With in-service support established in many of these locations and tailored Integrated Logistics Support (ILS) packages, JFD is able to provide high customer equipment availability, rapid technical support and tailored training packages. 2 | Introduction JFD offers two highly capable underwater life support systems to meet the full mission profile of today’s Special Operations diver. A modular approach enables customisation of the life support system in response to demands across the full operational spectrum. SHADOW ENFORCER The solution for extended duration and deeper diving The lightweight solution for short duration mission mission profiles. profiles. 3 | Offering A common life support platform facilitates a multi-mission capability offering numerous operational and logistic benefits that include: ENHANCED MISSION EFFECTIVENESS • Front and back mount options • Oxygen
    [Show full text]
  • (Medical and Mechanical) Treatment of Erectile Dysfunction
    130 SOP Conservative (Medical and Mechanical) Treatment of Erectile Dysfunctionjsm_12023 130..171 Hartmut Porst, MD,* Arthur Burnett, MD, MBA, FACS,† Gerald Brock, MD, FRCSC,‡ Hussein Ghanem, MD,§ Francois Giuliano, MD,¶ Sidney Glina, MD,** Wayne Hellstrom, MD, FACS,†† Antonio Martin-Morales, MD,‡‡ Andrea Salonia, MD,§§ Ira Sharlip, MD,¶¶ and the ISSM Standards Committee for Sexual Medicine *Private Urological/Andrological Practice, Hamburg, Germany; †The James Buchanan Brady Urological Institute, The Johns Hopkins Hospital, Baltimore, MD, USA; ‡Division of Urology, University of Western, ON, Canada; §Sexology & STDs, Cairo University, Cairo, Egypt; ¶Neuro-Urology-Andrology Unit, Department of Physical Medicine and Rehabilitation, Raymond Poincaré Hospital, Garches, France; **Instituto H.Ellis, São Paulo, Brazil; ††Department of Urology, Section of Andrology and Male Infertility, Tulane University School of Medicine, New Orleans, LA, USA; ‡‡Unidad Andrología, Servicio Urología Hospital, Regional Universitario Carlos Haya, Málaga, Spain; §§Department of Urology & Urological Reseach Institute (URI), Universiti Vita Saluta San Raffaele, Milan, Italy; ¶¶University of California at San Francisco, San Francisco, CA, USA DOI: 10.1111/jsm.12023 ABSTRACT Introduction. Erectile dysfunction (ED) is the most frequently treated male sexual dysfunction worldwide. ED is a chronic condition that exerts a negative impact on male self-esteem and nearly all life domains including interper- sonal, family, and business relationships. Aim. The aim of this study
    [Show full text]
  • Nitrox Recreational Mode - Perdix
    Nitrox Recreational Mode - Perdix User Manual Shearwater Perdix Nitrox Recreational Mode 8. System Setup+ ...........................................................18 Table of Contents 8�1� Dive Setup ��������������������������������������������������������������������������������������������������������� 18 Mode �������������������������������������������������������������������������������������������������������� 18 Table of Contents �����������������������������������������������������������������������������������������������������2 Salinity ����������������������������������������������������������������������������������������������������� 18 Conventions Used in this Manual �����������������������������������������������������������������������3 8�2� Deco Setup ������������������������������������������������������������������������������������������������������� 19 1. Introduction .................................................................. 4 Conservatism ������������������������������������������������������������������������������������������� 19 1�1� Features ���������������������������������������������������������������������������������������������������������������4 Safety Stop ���������������������������������������������������������������������������������������������� 19 8�3� Bottom Row ����������������������������������������������������������������������������������������������������� 19 2. Modes Covered by this Manual ................................. 5 8�4� Nitrox Gases ����������������������������������������������������������������������������������������������������
    [Show full text]
  • The Lookout Winter 2018
    The Lookout Winter 2018 THE LOOKOUT MANIFEST A Message From the Wheelhouse GUE Fundamentals 2018 Diving Highlights Wreck Profile: Reliance SAS_11 Exploration Report News & Updates THE LOOKOUT Published by: Northern Atlantic Dive Expeditions, Inc. https://northernatlanticdive.com A Message From the Wheelhouse [email protected] Thanks for checking out Issue #11 of The Lookout, our annual newsletter covering wide ranging topics that are historical, Editors-in-Chief: technical, and relevant to our diving community in Massachusetts. This issue includes articles on our GUE Heather Knowles Fundamentals class, and trips to Florida, Kingston, Alexandria David Caldwell Bay and Truk Lagoon! We revisit an oldie, but goodie with a wreck profile on the Reliance. We also share an exploration Copyright © 2018 Northern Atlantic Dive update on our project, the unidentified vessel, SAS_11. Expeditions, Inc. We’d like to thank all our customers and crew for your All Rights Reserved continued support and participation aboard Gauntlet. The 2019 diving season will be an exciting one. We hope that you’ll join us on our adventures whether you are looking for training or just some great wreck diving off the coast of New England! We hope you enjoy this issue of The Lookout! Heather and Dave Issue 11 !1 The Lookout Winter 2018 GUE Fundamentals: Never Too Late! Training pathways for divers entering technical diving used to be straightforward. Most divers progressed through open circuit (OC) technical training beginning with advanced nitrox and decompression procedures courses, followed by trimix training through the two or three levels. With the mainstream market entry and growth of closed-circuit rebreathers (CCR), many open circuit trimix divers moved over to this technology, continuing to dive at their highest level after learning the basic foundational skills of the CCR.
    [Show full text]