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Ultrasonics in medicine
June, 1954.]
CURRENT TOPICS
Handrails will move at the same speed as the belt and passengers will be able to step on and off as if it were an escalator. The belt will move in whichever direction the traffic is heavier. The General Electric reversing starter and totally-enclosed 1200 rpm. fan-cooled motor are both rated at 20 hp., 220-volts, 3-phase, 60 cycles. The thrustor brake is fated at 600 lb. feet continuous and 800 lb. feet intermittent. Distillation of Sea Water.--Thermocompression distillation of sea water into drinking water at island and desert military bases will be accomplished more rapidly and economically as a result of investigations recently completed by the Engineer Research and Development Laboratories, Fort Belvoir, Va. The investigations have determined the most effective means of controlling scale formation in equipment. Until now this has been the greatest obstacle to economical distiUation. In the thermocompression method, steam from boiling sea water is compressed and recycled to maintain the boiling action. As the latent heat is transferred to sea water the steam condenses to form pure salt free distillate. Scale deposited by the boiling brine on evaporator tube surfaces has in the past doubled the cost of distillation due to lost capacity and efficiency, and the additional labor and materials required. Frequent descaling with citric acid, which may be accomplished while distillation is in progress, will permit indefinite maintenance of production by field units. A simple procedure has been devised which minimizes the corrosion hazards of acid, time out for cleaning and other interferences. In addition, the investigation established that descaling may be reduced to a minimum in permanent or semi-
529
permanent installations by means of brine stabilization equipment designed for the predetermined conditions of the location on the basis of essential engineering data. The brine stabilizing method which provides a stabilizer of suspended solids on which the greater part of the scale is deposited has in some instances increased unit production twenty times. The investigation included laboratory work at the E R D L Sanitary Engineering Branch at Fort Belvoir, Virginia, and field work at the former E R D L Distillation Test Station, Fort Story, Virginia, the Boston Army Base, Boston, Massachusetts, and Kindley Air Force Base, Bermuda. Basic investigations on the equilibria of scale-forming compounds in boiling concentrated sea water were carried out at the University of California. The University also conducted a series of tests at Oakland Army Base, Oakland, California. Ultrasonics in Medicine.--The use of electronically generated high frequency sound vibrations in the treatment of cancer and in lieu of brain surgery were two topics discussed at the recent I R E convention. How ultrasonic vibrations have been used in the treatment of cancer in mice was discussed by Earl H. Newcomer of the University of Connecticut who presented a paper on the effects of ultrasound on living cell structure. Although it was reported that half the mice were killed by the treatment because of injury to vital organs caused by the high intensity vibrations, those which survived treatment were characterized by a complete regression of the tumor. High frequency, high intensity sound has been used in the treatment of mental patients in lieu of surgery according to a report made to the engi-
530
CURRENT TOPICS
neers by Dr. P. Lindstrom of the Veterans Administration Hospital of Pittsburgh, who stated that a technique has been developed which will cause minial lesions in the deeper layers of the frontal lobes. Dr. Lindstrom pointed out that in lobotomies a part of the brain is either cut, removed or otherwise destroyed which can lead to unpredictable hemorrhages and side effects such as epilepsy, loss of bladder control and mental deterioration. Utilizing ultrasound techniques, Dr. Lindstrom continued, most patients improved mentally or obtained pain relief. Minor lesions caused by ultrasound, it was reported, could only be seen in a microscope. D e t e c t i o n of F i l m s on Electrical
C o n t a c t s . - - T h e mystery of why certain metal surfaces on wires and contacts fail at times to conduct electricity even though they are physically joined is being solved in many cases with the aid of a tiny platinum wire one-thirtieth as thick as a human hair. Formed into a loop by scientists at the General Electric Research Laboratory, the thin wire can be used to detect finger prints and other films built up by oxidation or tarnishing. Even invisible films can frequently be detected. When compressed against a surface, the resilient platinum probe ferrets out films on the most highly buffed and machined surfaces. Measurement of the pressure exerted with a micrometer suggests the type of film present and its electrical strength. Details about films are studied through measurement of voltage that must be applied through the fine probe in order to break down the film, and by observation of the probing operation through high-powered microscopes. Developed by Robert H. Savage and Dr. Donald G. Flom, the probe has
[J. F. I.
been used at times to replace difficult chemical means for analyzing such films. Such chemical techniques, it was pointed out, often destroy or damage the surface, while the delicate probe does not affect it. Savage said that these explorations, though just in the beginning stages, already have detected insulating films on many electrical contacts that otherwise might continue to plague technicians working with them. The tiny loop recently helped scientists at the laboratory to detect permanent high-resistant areas on silver contacts that had been polished with a high-speed buffer. They found that the same surfaces, when machined, developed only temporary insulating films which could be removed with solvents. Phenolic F o a m . - - A remarkable buoyant plastic material which transforms itself from a liquid resin to an expanded light weight cellular solid state in two or three minutes is being used to replace balsa wood to fill the voids of small carriers. Balsa imparted buoyancy to the ship and prevented listing in the event the hull was damaged by shells. Phenolic foam is also being used for low temperature and acoustical insulations, structural reinforcements for tail sections of airplanes, buoyancy media for boats of all types and for packaging materials. The cost of the liquid resin (unfoamed) is about 50 cents per pound, making this material one of the least expensive foams available. The Navy's first introduction to plastic foams came with the surrender of the German heavy cruiser Prinz Eugen. At the end of the war further knowledge was gained concerning the great military and commercial utilization of vinyl resins in the German war economy. Samples
CURRENT TOPICS
Handrails will move at the same speed as the belt and passengers will be able to step on and off as if it were an escalator. The belt will move in whichever direction the traffic is heavier. The General Electric reversing starter and totally-enclosed 1200 rpm. fan-cooled motor are both rated at 20 hp., 220-volts, 3-phase, 60 cycles. The thrustor brake is fated at 600 lb. feet continuous and 800 lb. feet intermittent. Distillation of Sea Water.--Thermocompression distillation of sea water into drinking water at island and desert military bases will be accomplished more rapidly and economically as a result of investigations recently completed by the Engineer Research and Development Laboratories, Fort Belvoir, Va. The investigations have determined the most effective means of controlling scale formation in equipment. Until now this has been the greatest obstacle to economical distiUation. In the thermocompression method, steam from boiling sea water is compressed and recycled to maintain the boiling action. As the latent heat is transferred to sea water the steam condenses to form pure salt free distillate. Scale deposited by the boiling brine on evaporator tube surfaces has in the past doubled the cost of distillation due to lost capacity and efficiency, and the additional labor and materials required. Frequent descaling with citric acid, which may be accomplished while distillation is in progress, will permit indefinite maintenance of production by field units. A simple procedure has been devised which minimizes the corrosion hazards of acid, time out for cleaning and other interferences. In addition, the investigation established that descaling may be reduced to a minimum in permanent or semi-
529
permanent installations by means of brine stabilization equipment designed for the predetermined conditions of the location on the basis of essential engineering data. The brine stabilizing method which provides a stabilizer of suspended solids on which the greater part of the scale is deposited has in some instances increased unit production twenty times. The investigation included laboratory work at the E R D L Sanitary Engineering Branch at Fort Belvoir, Virginia, and field work at the former E R D L Distillation Test Station, Fort Story, Virginia, the Boston Army Base, Boston, Massachusetts, and Kindley Air Force Base, Bermuda. Basic investigations on the equilibria of scale-forming compounds in boiling concentrated sea water were carried out at the University of California. The University also conducted a series of tests at Oakland Army Base, Oakland, California. Ultrasonics in Medicine.--The use of electronically generated high frequency sound vibrations in the treatment of cancer and in lieu of brain surgery were two topics discussed at the recent I R E convention. How ultrasonic vibrations have been used in the treatment of cancer in mice was discussed by Earl H. Newcomer of the University of Connecticut who presented a paper on the effects of ultrasound on living cell structure. Although it was reported that half the mice were killed by the treatment because of injury to vital organs caused by the high intensity vibrations, those which survived treatment were characterized by a complete regression of the tumor. High frequency, high intensity sound has been used in the treatment of mental patients in lieu of surgery according to a report made to the engi-
530
CURRENT TOPICS
neers by Dr. P. Lindstrom of the Veterans Administration Hospital of Pittsburgh, who stated that a technique has been developed which will cause minial lesions in the deeper layers of the frontal lobes. Dr. Lindstrom pointed out that in lobotomies a part of the brain is either cut, removed or otherwise destroyed which can lead to unpredictable hemorrhages and side effects such as epilepsy, loss of bladder control and mental deterioration. Utilizing ultrasound techniques, Dr. Lindstrom continued, most patients improved mentally or obtained pain relief. Minor lesions caused by ultrasound, it was reported, could only be seen in a microscope. D e t e c t i o n of F i l m s on Electrical
C o n t a c t s . - - T h e mystery of why certain metal surfaces on wires and contacts fail at times to conduct electricity even though they are physically joined is being solved in many cases with the aid of a tiny platinum wire one-thirtieth as thick as a human hair. Formed into a loop by scientists at the General Electric Research Laboratory, the thin wire can be used to detect finger prints and other films built up by oxidation or tarnishing. Even invisible films can frequently be detected. When compressed against a surface, the resilient platinum probe ferrets out films on the most highly buffed and machined surfaces. Measurement of the pressure exerted with a micrometer suggests the type of film present and its electrical strength. Details about films are studied through measurement of voltage that must be applied through the fine probe in order to break down the film, and by observation of the probing operation through high-powered microscopes. Developed by Robert H. Savage and Dr. Donald G. Flom, the probe has
[J. F. I.
been used at times to replace difficult chemical means for analyzing such films. Such chemical techniques, it was pointed out, often destroy or damage the surface, while the delicate probe does not affect it. Savage said that these explorations, though just in the beginning stages, already have detected insulating films on many electrical contacts that otherwise might continue to plague technicians working with them. The tiny loop recently helped scientists at the laboratory to detect permanent high-resistant areas on silver contacts that had been polished with a high-speed buffer. They found that the same surfaces, when machined, developed only temporary insulating films which could be removed with solvents. Phenolic F o a m . - - A remarkable buoyant plastic material which transforms itself from a liquid resin to an expanded light weight cellular solid state in two or three minutes is being used to replace balsa wood to fill the voids of small carriers. Balsa imparted buoyancy to the ship and prevented listing in the event the hull was damaged by shells. Phenolic foam is also being used for low temperature and acoustical insulations, structural reinforcements for tail sections of airplanes, buoyancy media for boats of all types and for packaging materials. The cost of the liquid resin (unfoamed) is about 50 cents per pound, making this material one of the least expensive foams available. The Navy's first introduction to plastic foams came with the surrender of the German heavy cruiser Prinz Eugen. At the end of the war further knowledge was gained concerning the great military and commercial utilization of vinyl resins in the German war economy. Samples