John R. Clarke (scientist)

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John R. Clarke
John Clarke.png
Born (1945-11-20) November 20, 1945 (age 78)
Fort Smith, Arkansas, U.S.
Allegiance Flag of the United States.svg United States of America
Service/branch United States Army Reserve
Years of service11
Rank Captain
Other work United States Navy Experimental Diving Unit, University of Wollongong

John R. Clarke [1] (born November 20, 1945) [2] is an American scientist, private pilot and author. He is currently the Scientific Director at the United States Navy Experimental Diving Unit (NEDU). Clarke is recognized as a leading authority on underwater breathing apparatus engineering.

Contents

Background

Clarke is the youngest of four children; his siblings are now deceased.

In 1969, Clarke volunteered for the United States Army Reserves. He was promoted to first lieutenant in 1974 then Captain in 1979. Clarke was honorably discharged in September 1980.

While at Georgia Tech in 1965, Clarke earned his scuba diving certification. He later participated in the NOAA/ Navy Scientist in the Sea program in 1972. He then went to the Navy Dive School in 1980. Clarke has remained an active scuba diver throughout his career. [3]

Clarke received his private pilot license in 1974 and instrument rating in 1978. [4] He currently owns a Piper Arrow [5] and volunteers as a pilot for Angel Flight Southeast.

Education

Clarke graduated from Shawnee Mission East High School in Prairie Village, Kansas in 1964. He received a BS degree in applied biology (1969), and an MS degree (1971) from Georgia Tech. His master's thesis studied the impact of pressure on Sacchromyces cerevisiae. [6]

Physiology continued to drive Clarke and in 1976 he completed his Doctor of Philosophy by evaluating changes in physiology and pharmacology in bivalve molluscs hearts at Florida State University (FSU). [7]

Academic career

While completing his doctorate at FSU, Clarke worked as instructor and director of development in the Department of Biological and Physical Sciences at Thomas County Community College from 1975 to 1976. [2]

Later in 1976, Clarke assumed a position as instructor and research associate in the Department of Physiology at Case Western Reserve University School of Medicine. [2]

In 1977, Clarke left Case Western for a two–year Parker B. Francis Foundation Fellowship in the Department of Physiology at the University of Florida College of Medicine. [2] The fellowship is named after the founder of Puritan Bennett and supports pulmonary research. [8]

While working for the US Navy, Clarke accepted an appointment as an Adjunct Assistant Professor with Graduate Advisory Status for the Uniformed Services University of the Health Sciences from 1984 to 1990. [2]

Clarke accepted an appointment as a Visiting Principal Fellow at the University of Wollongong in April 1998 to advise on a doctoral project. [2] As of 2015, Clarke has served on five thesis committees from various institutions. Advisees have included Margie E. Bolton, [9] Elizabeth Jane McCarthy, [10] Rungchai Chaunchaiyakul, [11] Erich C. Frandrup, [12] and Adam J. Smith. [13]

US Navy career

In 1979, Clarke joined the team at the Naval Medical Research Institute (NMRI), now called the Naval Medical Research Center in Bethesda, Maryland. He was the head of the Respiratory Physiology Branch of the Physiology Division in the Diving Medicine Department. When Clarke left NMRI in 1991, he was the Diving Life Support Equipment Program Director GM-14.

Clarke led a team of researchers, scientists and engineers while at NMRI. The projects included work on diving equipment and physiology that included high frequency ventilation experiments.

From 1983 to 1991, Clark served as a National Research Council mentor for PhD research fellows. [2] Clarke also mentored students from the Research Science Institute with some students winning the nationwide Westinghouse science competition. [2]

Since 1991, Clarke has served as the Scientific Director GM-15 at the United States Navy Experimental Diving Unit (NEDU) in Panama City, Florida.

At NEDU, Clarke provides scientific oversight over engineering and physiological studies RDT&E for US Navy diving operations. He also serves as an advisor for Naval Sea Systems Command policy regarding technical challenges. [14] This work includes equipment evaluations [15] [16] and physiology experimentation. [17] [18]

Writing

Clarke's interest in writing began early. [19] He published his first scientific article at age fifteen. [20] While an undergraduate engineering student, he was paid for two of his articles in the Georgia Tech Engineer. [19]

Clarke assisted his writing mentor, author Max McCoy, with a chapter taking place at NEDU in McCoy's 2004 book Moon Pool. [19]

Middle Waters

In 2014, Clarke published his first novel, Middle Waters. It deals with two divers that set out to rescue aliens stranded on their spacecraft at the bottom of the sea. The government is aware of their presence and very interested in the alien technology. The divers soon find themselves caught between the alien civilization and their own government as they work to avert disaster while unknowingly competing with their friends in the recovery.

Award winning author and physician Rachel Scott suggested readers not "start this read at bedtime, if you plan to get any sleep!". [21]

Max McCoy, author for the Indiana Jones franchise from 1995 on, claimed that Middle Waters was a book he had wished he'd written and would read over and over again. [21] This was based partially on the fact that the main character is a diving scientist, a role that Clarke knows well and expertly conveys his knowledge to the reader.

Professional societies and service

Clarke is a member of the American Academy of Underwater Sciences, [18] the American Physiological Society, Sigma XI, and the Undersea and Hyperbaric Medical Society (UHMS). [2] He served as the Chair of UHMS's Membership Committee from 1989 to 1991 and was elected as a member at large to their executive committee, serving in that role from 1998 to 2001. [2]

Clarke also serves as a reviewer for research journals including the Journal of Applied Physiology, Ergonomics, Undersea Biomedical Research, and Annals of Biomedical Engineering. [2]

Diving safety is a passion and Clarke volunteers as an advisor to the National Association of Underwater Instructors Rebreather Advisory Committee [22] and Florida State University Diving Control Board. [23] Clarke also lectures to the general diving public about issues impacting diver safety. [18] [24]

Awards

In 1998, Clarke was selected as a Naval Sea Systems Command Spring 1998 trainee for "Leadership for a Democratic Society" course at the Office of Personnel Management's Federal Executive Institute in Charlottesville, Virginia. [2]

Clarke won first place in the 2010 "best first line in a comic vampire novel" contest held by the Ozark Creative Writers' Conference in Eureka Springs, Arkansas. [25]

Bibliography

Book chapters

  • Morrison JB, Clarke JR (2008). "Diving Physiology: free diving, breathing apparatus, saturation diving". In: Eds., NAS Taylor, H Groeller, Physiological Bases of Human Performance During Work and Exercise.
  • Clarke JR (2003). "Future of US Navy Diving". In: Naval Forces Under the Sea – A Look Back, A Look Ahead: 3–90 to 3–94.
  • Clarke JR, Flook V (1999). "Respiratory Function at Depth". In: The Lung at Depth, ed. CEG Lundgren and J Miller. In Series, Lung Biology in Health and Disease, ed. Claude Enfant. New York, Marcel Dekker: 1–71.
  • Clarke JR (1999). "Underwater Breathing Apparatus". In: The Lung at Depth, ed. CEG Lundgren and J Miller. In Series, Lung Biology in Health and Disease, ed. Claude Enfant. New York, Marcel Dekker: 429–527.
  • Clarke JR (1996). "Measurement of average resistance in underwater breathing apparatus". In: Book III, Drilling & Production Economics: 227–230.
  • Clarke JR (1992). "Diver tolerance to respiratory loading during wet and dry dives from 0 to 450 msw". In: Lung Physiology and Divers' Breathing Apparatus. Ed. V. Flook and A.O. Brubakk., BPCC-AUD, Aberdeen: 33–40.
  • Clarke JR (1992). "Impedance and power measurements in the testing of closed circuit UBA". In: Lung Physiology and Divers' Breathing Apparatus. Ed. V. Flook and A.O. Brubakk., BPCC-AUD, Aberdeen: 85–93.
  • Clarke JR, Joye D (1989). "Formal descriptions of elastic loads encountered in the use of underwater breathing systems". In: Lundgren and Warkander, Eds. UHMS Workshop, Physiological and Human Engineering Aspects of Underwater Breathing Apparatus, Buffalo, NY, Undersea and Hyperbaric Medical Society, Bethesda: 59–76. Archived from the original on February 23, 2015.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR, Survanshi S, Thalmann ED, Flynn ET (1989). "Limits for mouth pressure in underwater breathing apparatus (UBA)". In: Eds. Lundgren and Warkander, Physiological and Human Engineering Aspects of Underwater Breathing Apparatus. Undersea and Hyperbaric Medical Society, Inc. Bethesda, MD. Archived from the original on February 23, 2015.{{cite journal}}: CS1 maint: unfit URL (link)
  • Casey L, Clarke JR, Fletcher J, Ramwell P (1982). "Cardiovascular, Respiratory, and Hematologic Effects of Leukotriene D4 in Primates". In: Samuelsson and Paoletti, Eds. Advances in Prostaglandin, Thromboxane, and Leukotrien Research Series, Vol. 9, Leukotrienes and Other Lipoxygenase Products. Raven Press, New York. 9: 201–10. PMID   6211952.

Refereed Journals

Non-Refereed Journals and Reports

  • Clarke JR, Ferris V (2012). "The Use of One-Sample Prediction Intervals for Estimating CO2 Scrubber Canister Durations". Navy Experimental Diving Unit Technical Report 12-03.
  • Clarke JR (2007). "Review of MARCORSYSCOM operational requirements for Enhanced Underwater Breathing Apparatus (EUBA) using simulation software". Navy Experimental Diving Unit Technical Report 07-11 (Classified).
  • Clarke JR, O'Connor PE (2004). "Testing of a prototype Special Operations gas mask". Navy Experimental Diving Unit Technical Report 04-27(Classified).
  • Clarke JR, Schultz B, Crepeau L, Lowe M (2003). "Evaluating the effects of high-dose melatonin on mental and somatic status of normal subjects". Navy Experimental Diving Unit Technical Report 03-20. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR (2003). "Gas flows supporting umbilical diving – requirements and measurements". Navy Experimental Diving Unit Technical Report 03-09. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Warkander DE, Clarke JR (2002). "Method for estimating the remaining capacity of the carbon dioxide scrubber in the Hyperbaric Oxygen Treatment Pack". Navy Experimental Diving Unit Technical Report 02-13. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR (2002). "The analysis of sodalime granule size distributions". Navy Experimental Diving Unit Technical Report 02-08. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Naggiar ER, Sanchack KE, Clarke JR (2002). "Comparison of Draeger Divesorb Pro to Sofnolime 812 in the MK 25 Mod 2 SEAL Delivery Vehicle, MK 16 Mod 0, and Viper VSW canisters". Navy Experimental Diving Unit Technical Report 02-02 (Classified).
  • Clarke JR (2002). "Evaluation of the pre-production model self-contained operational utility tank (SCOUT) high pressure air system. Navy Experimental Diving Unit Technical Report 02-01 (Classified)".{{cite journal}}: Cite journal requires |journal= (help)
  • Clarke JR (2001). "Evaluation of the Self-Contained Operational Utility Tank (SCOUT) high pressure air system". Navy Experimental Diving Unit Technical Report 8-01 (Classified).
  • Clarke JR (1999). "Statistically Based CO2 Canister Duration Limits for Closed-Circuit Underwater Breathing Apparatus". Navy Experimental Diving Unit Technical Report 2-99. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Crepeau L, Clarke JR (1998). "Recommended canister limits for the Draeger LAR V/MK 25 UBA using 408 L-grade and 812 D-grade Sofnolime". Navy Experimental Diving Unit Technical Report 9-97 (Classified).
  • Clarke JR, Thompson LD, Godfrey RJ (1998). "Lot variability of Sofnolime 408 carbon dioxide absorbent when tested in the cold". Navy Experimental Diving Unit Technical Report 1-98. Archived from the original on July 1, 2012. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Morgan KR, Cowgill DE, Clarke JR (1997). "MK 24 Full face mask diaphragm retainer shroud modification with the EBS I and II". Navy Experimental Diving Unit Technical Report 11-97. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Crepeau L, Clarke JR (1997). "CBR protective respirator-induced performance decrements during Navy-relevant operational tasks". Navy Experimental Diving Unit Technical Report 2-97 (Classified).
  • Clarke JR, Maurer J, Southerland DE, Junker DL (1997). "Evaluation of the Diving Systems International EXO-26 BR full face mask". Navy Experimental Diving Unit Technical Report 1-97 (Classified).
  • Clarke JR, Maurer J, Junker DL (1996). "Evaluation of the SIVA 55 (S-55) semi-closed underwater breathing apparatus". Navy Experimental Diving Unit Technical Report 14-96 (Classified).
  • Clarke JR, Junker DL, Rainone M (1996). "Evaluation of the US Divers Nordic SCUBA regulator for use in cold water". Navy Experimental Diving Unit Technical Report 11-96. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR, Knafelc M, Junker DL, Allain SC (1996). "Evaluation of the Fullerton Sherwood S-24 (SIVA) semi-closed underwater breathing apparatus". Navy Experimental Diving Unit Technical Report 9-96 (Classified).
  • Clarke JR, Knafelc M, Junker DL, Allain SC (1996). "Evaluation of the Draeger LAR V Nitrox (LAR 7) semi-closed underwater breathing apparatus". Navy Experimental Diving Unit Technical Report 8-96 (Classified).
  • Clarke JR, Knafelc M, Junker DL, Allain SC (1996). "Evaluation of the Draeger Extreme semi-closed underwater breathing apparatus". Navy Experimental Diving Unit Technical Report 7-96 (Classified).
  • Clarke JR, Junker DL, Allain SC (1996). "Evaluation of the US Divers DC-55 semi-closed underwater breathing apparatus". Navy Experimental Diving Unit Technical Report 5-96 (Classified).
  • Clarke JR, Rainone M (1996). "Evaluation of the Scuba Pro MK 10 and MK 20 SCUBA regulators for use in cold water". Navy Experimental Diving Unit Technical Report 1-96. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR, Rainone M (1995). "Evaluation of the Poseidon Odin SCUBA regulator for use in cold water". Navy Experimental Diving Unit Technical Report 14-95. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Baiss D, Southerland DG, Clarke JR (1995). "MK 3 Mod 0 Lightweight Dive System (LWDS) air flow capacity". Navy Experimental Diving Unit Technical Report 12-95 (Classified).
  • Clarke JR, Rainone M (1995). "Evaluation of Sherwood SCUBA regulators for use in cold water". Navy Experimental Diving Unit Technical Report 9-95. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR (1994). "US Navy Unmanned Test Methods and Performance Goals for Underwater Breathing Apparatus". Navy Experimental Diving Unit Technical Manual 01-94. Archived from the original on February 23, 2015. Retrieved 2015-02-23.{{cite journal}}: CS1 maint: unfit URL (link)
  • Clarke JR, Russell K, Crepeau L (1993). "MK 16 canister limits for SDV operations". Navy Experimental Diving Unit Report 2-93.
  • Clarke JR (1989). "Formulation of elastic loading parameters for studies of closed-circuit underwater breathing systems". Navy Medical Research Institute Technical Report 89-89, Bethesda.
  • Clarke JR, Homer LD, Flynn ET (1983). "Efficiency of high frequency ventilation as determined by nitrogen washouts: a model study". Navy Medical Research Institute Technical Report 83–09.
  • Clarke JR, Mints Jr WE, Bradley ME (1981). "An improved method of compensating whole body plethysmographs". Navy Medical Research Institute Report 81-10.
  • Clarke JR (1979). "Smoking and Diving". Public Information Brochure for Florida Sea Grant. MAFS 7.
  • Clarke JR (1968). "Holography the crystal ball of sound". Georgia Tech Engineer. 25 (4): 26–29.
  • Clarke JR (1967). "The Depth Challenger glass spheres for use in research submersibles". Georgia Tech Engineer. 29 (6): 12–17.

Patents

See also

Related Research Articles

Nitrox refers to any gas mixture composed of nitrogen and oxygen. This includes atmospheric air, which is approximately 78% nitrogen, 21% oxygen, and 1% other gases, primarily argon. In the usual application, underwater diving, nitrox is normally distinguished from air and handled differently. The most common use of nitrox mixtures containing oxygen in higher proportions than atmospheric air is in scuba diving, where the reduced partial pressure of nitrogen is advantageous in reducing nitrogen uptake in the body's tissues, thereby extending the practicable underwater dive time by reducing the decompression requirement, or reducing the risk of decompression sickness.

<span class="mw-page-title-main">Trimix (breathing gas)</span> Breathing gas consisting of oxygen, helium and nitrogen

Trimix is a breathing gas consisting of oxygen, helium and nitrogen and is used in deep commercial diving, during the deep phase of dives carried out using technical diving techniques, and in advanced recreational diving.

The timeline of underwater diving technology is a chronological list of notable events in the history of the development of underwater diving equipment. With the partial exception of breath-hold diving, the development of underwater diving capacity, scope, and popularity, has been closely linked to available technology, and the physiological constraints of the underwater environment.

<span class="mw-page-title-main">Deep diving</span> Underwater diving to a depth beyond the norm accepted by the associated community

Deep diving is underwater diving to a depth beyond the norm accepted by the associated community. In some cases this is a prescribed limit established by an authority, while in others it is associated with a level of certification or training, and it may vary depending on whether the diving is recreational, technical or commercial. Nitrogen narcosis becomes a hazard below 30 metres (98 ft) and hypoxic breathing gas is required below 60 metres (200 ft) to lessen the risk of oxygen toxicity.

<span class="mw-page-title-main">Oxygen toxicity</span> Toxic effects of breathing oxygen at high partial pressures

Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures. Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lungs, and eyes. Historically, the central nervous system condition was called the Paul Bert effect, and the pulmonary condition the Lorrain Smith effect, after the researchers who pioneered the discoveries and descriptions in the late 19th century. Oxygen toxicity is a concern for underwater divers, those on high concentrations of supplemental oxygen, and those undergoing hyperbaric oxygen therapy.

<span class="mw-page-title-main">Scuba diving</span> Swimming underwater, breathing gas carried by the diver

Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives.

Diving disorders, or diving related medical conditions, are conditions associated with underwater diving, and include both conditions unique to underwater diving, and those that also occur during other activities. This second group further divides into conditions caused by exposure to ambient pressures significantly different from surface atmospheric pressure, and a range of conditions caused by general environment and equipment associated with diving activities.

<span class="mw-page-title-main">Edward D. Thalmann</span> American hyperbaric medicine specialist and decompression researcher

Capt. Edward Deforest Thalmann, USN (ret.) was an American hyperbaric medicine specialist who was principally responsible for developing the current United States Navy dive tables for mixed-gas diving, which are based on his eponymous Thalmann Algorithm (VVAL18). At the time of his death, Thalmann was serving as assistant medical director of the Divers Alert Network (DAN) and an assistant clinical professor in anesthesiology at Duke University's Center for Hyperbaric Medicine and Environmental Physiology.

<span class="mw-page-title-main">Breathing performance of regulators</span> Measurement and requirements of function of breathing regulators

The breathing performance of regulators is a measure of the ability of a breathing gas regulator to meet the demands placed on it at varying ambient pressures and temperatures, and under varying breathing loads, for the range of breathing gases it may be expected to deliver. Performance is an important factor in design and selection of breathing regulators for any application, but particularly for underwater diving, as the range of ambient operating pressures and temperatures, and variety of breathing gases is broader in this application. A diving regulator is a device that reduces the high pressure in a diving cylinder or surface supply hose to the same pressure as the diver's surroundings. It is desirable that breathing from a regulator requires low effort even when supplying large amounts of breathing gas as this is commonly the limiting factor for underwater exertion, and can be critical during diving emergencies. It is also preferable that the gas is delivered smoothly without any sudden changes in resistance while inhaling or exhaling, and that the regulator does not lock up and either fail to supply gas or free-flow. Although these factors may be judged subjectively, it is convenient to have standards by which the many different types and manufactures of regulators may be objectively compared.

<span class="mw-page-title-main">United States Navy Experimental Diving Unit</span> The primary source of diving and hyperbaric operational guidance for the US Navy

The United States Navy Experimental Diving Unit is the primary source of diving and hyperbaric operational guidance for the US Navy. It is located within the Naval Support Activity Panama City in Panama City Beach, Bay County, Florida.

CUMA is a make of rebreather underwater breathing set designed and made in Canada for the Canadian Armed Forces by Fullerton Sherwood Engineering Ltd to replace the Royal Navy CDBA.

Capt. Willard Franklyn "Bill" Searle Jr. USN (ret.) was an American ocean engineer who was principally responsible for developing equipment and many of the current techniques utilized in United States Navy diving and salvage operations.

The Lambertsen Amphibious Respiratory Unit (LARU) is an early model of closed circuit oxygen rebreather used by military frogmen. Christian J. Lambertsen designed a series of them in the US in 1940 and in 1944.

<span class="mw-page-title-main">Underwater breathing apparatus</span> Equipment which provides breathing gas to an underwater diver

Underwater breathing apparatus is equipment which allows the user to breathe underwater. The three major categories of ambient pressure underwater breathing apparatus are:

<span class="mw-page-title-main">Decompression (diving)</span> Pressure reduction and its effects during ascent from depth

The decompression of a diver is the reduction in ambient pressure experienced during ascent from depth. It is also the process of elimination of dissolved inert gases from the diver's body which accumulate during ascent, largely during pauses in the ascent known as decompression stops, and after surfacing, until the gas concentrations reach equilibrium. Divers breathing gas at ambient pressure need to ascend at a rate determined by their exposure to pressure and the breathing gas in use. A diver who only breathes gas at atmospheric pressure when free-diving or snorkelling will not usually need to decompress, Divers using an atmospheric diving suit do not need to decompress as they are never exposed to high ambient pressure.

Human physiology of underwater diving is the physiological influences of the underwater environment on the human diver, and adaptations to operating underwater, both during breath-hold dives and while breathing at ambient pressure from a suitable breathing gas supply. It, therefore, includes the range of physiological effects generally limited to human ambient pressure divers either freediving or using underwater breathing apparatus. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, the effects of breathing gases at raised ambient pressure, effects caused by the use of breathing apparatus, and sensory impairment. All of these may affect diver performance and safety.

<span class="mw-page-title-main">History of scuba diving</span> History of diving using self-contained underwater breathing apparatus

The history of scuba diving is closely linked with the history of the equipment. By the turn of the twentieth century, two basic architectures for underwater breathing apparatus had been pioneered; open-circuit surface supplied equipment where the diver's exhaled gas is vented directly into the water, and closed-circuit breathing apparatus where the diver's carbon dioxide is filtered from the exhaled breathing gas, which is then recirculated, and more gas added to replenish the oxygen content. Closed circuit equipment was more easily adapted to scuba in the absence of reliable, portable, and economical high pressure gas storage vessels. By the mid-twentieth century, high pressure cylinders were available and two systems for scuba had emerged: open-circuit scuba where the diver's exhaled breath is vented directly into the water, and closed-circuit scuba where the carbon dioxide is removed from the diver's exhaled breath which has oxygen added and is recirculated. Oxygen rebreathers are severely depth limited due to oxygen toxicity risk, which increases with depth, and the available systems for mixed gas rebreathers were fairly bulky and designed for use with diving helmets. The first commercially practical scuba rebreather was designed and built by the diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. His self contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with an estimated 50–60% oxygen supplied from a copper tank and carbon dioxide scrubbed by passing it through a bundle of rope yarn soaked in a solution of caustic potash. During the 1930s and all through World War II, the British, Italians and Germans developed and extensively used oxygen rebreathers to equip the first frogmen. In the U.S. Major Christian J. Lambertsen invented a free-swimming oxygen rebreather. In 1952 he patented a modification of his apparatus, this time named SCUBA, an acronym for "self-contained underwater breathing apparatus," which became the generic English word for autonomous breathing equipment for diving, and later for the activity using the equipment. After World War II, military frogmen continued to use rebreathers since they do not make bubbles which would give away the presence of the divers. The high percentage of oxygen used by these early rebreather systems limited the depth at which they could be used due to the risk of convulsions caused by acute oxygen toxicity.

The science of underwater diving includes those concepts which are useful for understanding the underwater environment in which diving takes place, and its influence on the diver. It includes aspects of physics, physiology and oceanography. The practice of scientific work while diving is known as Scientific diving. These topics are covered to a greater or lesser extent in diver training programs, on the principle that understanding the concepts may allow the diver to avoid problems and deal with them more effectively when they cannot be avoided.

References

  1. "John Clarke Online: About". JohnClarkeOnline.com. 6 August 2011. Archived from the original on 31 October 2018. Retrieved September 9, 2018. John R. Clarke, Ph.D.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 "John R. Clarke, PhD". Curriculum Vitae[ full citation needed ]. December 28, 2014.
  3. Clarke, John (28 February 2015). "After the Heart Attack – The Healing Power of Athletic Passions". Archived from the original on 2015-04-02. Retrieved 2015-02-28.
  4. Clarke, John R. "Personal communication with Gene Hobbs on Feb 18, 2015 at 7:34 PM".{{cite web}}: Missing or empty |url= (help)
  5. Clarke, John R. (26 April 2011). "Me and My Arrow". JohnClarkeOnline.com. Archived from the original on 2015-01-22. Retrieved 2015-02-22.
  6. Clarke, JR (1971). "The Effect of High Pressure on the Permeability of Sacchromyces cerevisiae to Vital Dye". Georgia Institute of Technology.{{cite journal}}: Cite journal requires |journal= (help)
  7. Clarke, JR (1976). "The Effect of High Pressure on the Physiology and Pharmacology of Hearts of Bivalve Molluscs". Florida State University.{{cite journal}}: Cite journal requires |journal= (help)
  8. "Parker B. Francis Fellowship Program History". Archived from the original on 2015-04-03. Retrieved 2015-02-18.
  9. Bolton, ME (1979). "Diving habits and obstetric course of pregnant scuba divers". Master's Thesis Presented to the University of Florida. Archived from the original on February 23, 2015.{{cite journal}}: CS1 maint: unfit URL (link)
  10. McCarthy, Elizabeth Jane (1985). "The effects of Gas Density on Gas Transport During High Frequency Oscillation" (PDF). Doctoral Thesis Presented to the Uniformed Services University of the Health Sciences. Archived (PDF) from the original on 2015-02-23. Retrieved 2015-02-23.
  11. Chaunchaiyakul, Rungchai (2000). "Thoraco-Pulmonary Mechanics: Interaction of Age and Habitual Physical Activity". Doctoral Dissertation Presented to University of Wollongong, Dept. Of Biomedical Science. Archived from the original on 2015-02-23. Retrieved 2015-02-23.
  12. Frandrup, Erich C. (2003). "Exploration of Impedance and Resistance in a Simple Underwater Breathing Apparatus". Masters Thesis Presented to Dept. Of Mechanical Engineering and Materials Science, Graduate School of Duke University.
  13. Smith, Adam J (2008). "Resting Oxygen Consumption Rates in Divers Using Diver Propulsion Devices". Masters of Science in Biomedical Engineering Presented to Department of Chemical and Biomedical Engineering, College of Engineering, University of South Florida. Archived from the original on 2015-02-23. Retrieved 2015-02-23.
  14. "2nd Annual Multi-Agency Contaminated Water Diving Workshop Report on Proceedings" (PDF). Navsea-Supsalv. 1 June 2007. Archived (PDF) from the original on 2015-09-24. Retrieved 2015-02-22.
  15. Barlow, Rich. "Future gear". SCUBA Diving. Archived from the original on 2015-01-09. Retrieved 2015-02-22.
  16. Tang, Kay (26 March 2014). "The Best Cold-Water Scuba Diving Regulators". Livestrong Foundation. Archived from the original on 2015-02-23. Retrieved 2015-02-22.
  17. Svitil, Kathy A (1 July 2000). "Future Tech: Rebreathers are rapidly making scuba gear look like the underwater equivalent of a windup watch". Discover . Archived from the original on 2015-02-23. Retrieved 2015-02-22.
  18. 1 2 3 Pollock, Neal W. "AAUS Rebreather Colloquium" (PDF). E-Slate. 6 (10). Archived (PDF) from the original on 2015-02-23. Retrieved 2015-02-22.
  19. 1 2 3 "About John Clarke Online". JohnClarkeOnline.com. 6 August 2011. Archived from the original on 2015-02-19. Retrieved 2015-02-22.
  20. Clarke, John R. (1960). "Light spectra and glucose relationships in plants". Proceedings of the Kansas Academy of Science.
  21. 1 2 "Middle Waters Reviews". Archived from the original on 2015-02-23. Retrieved 2015-02-22.
  22. "NAUI Rebreather Advisory Board". National Association of Underwater Instructors. Archived from the original on 2014-05-31. Retrieved 2015-02-22.
  23. The Florida State University Diving Control Board (2006). "The Florida State University Coastal and Marine Laboratory Standards for Scientific Diving and Operation of the Scientific Diving Program" (PDF). Archived (PDF) from the original on 2015-02-23. Retrieved 2015-02-22.
  24. Menduno, Michael (7 May 2012). "PCO2: The Dark Matter of Rebreather Diving". DIVER Magazine. Archived from the original on 2015-02-23. Retrieved 2015-02-22.
  25. Clarke, John (16 January 2015). "Blood, as a Delicacy, Is Underrated". johnclarkeonline.com. Archived from the original on 2015-02-23. Retrieved 2015-02-19.