Large Amount Of Air Research Articles

Microelectrophoresis with Alternating Electric Fields

Electrophoretic mobility of microscopically visible particles is measured from photographs of their oscillatory migration in a low frequency electric field. The measurements are inherently free of gravitational or thermal-convective drifting. Many measurements may be made from one photograph. An automatic timing circuit insures reproducibility and determines the sign of the particles' charge.

Wind Penetration Through Fabric Systems—Part II

The earlier study of spaced double windbreak layers was extended to determine the decrease in effectiveness of such systems when porous materials are used in the inter vening space to insure positive separation of layers. It was shown that mesh spacers caused little decrease in the efficiency of the system. Lower values of heat transfer coefficients were obtained by keeping the air penetration through the outer windbreak within the air handling capacity of the space than by letting large quantities of air into the space and blocking further penetration with an inner windbreak of low permeability. Where there was little penetration of the outer windbreak layer, the still air in the air space increased the insulation over that where the layers were unspaced. Results with loose-fitting systems were found to be similar to those for tight-fitting systems, provided that penetration of the inner windbreak was not excessive. Finally, the laboratory findings were cbrroborated by a field study of clothing incorporating the spaced-windbreak principle.

A comparison of magnox A 12 and ZA alloys as canning materials for nuclear reactors

The properties of the magnesium alloys ZA and A 12 are compared for their use as fuel element canning materials in power reactors of the Calder Hall type. It is concluded that ZA shows more resistance to grain growth than A 12 and also possesses superior mechanical properties in that ZA has a higher rupture ductility, is free from grain boundary cavitation effects, has a higher fatigue strength and a resistance to creep at high temperatures as good as that of A 12. The resistance to oxidation in CO2 is similar in both alloys but in gross fault conditions in which large amounts of air are included in the coolant at high temperatures, then A 12 is more resistant to severe attack. The ignition temperatures of A 12 are slightly higher than those of ZA. Despite the more attractive mechanical characteristics of ZA, fuel elements clad in A 12 have performed satisfactorily whereas ZA canned elements in the Calder Hall and Chapelcross reactors have had to be discharged at low burn-ups. This has been shown to be due to the diffusion of plutonium through the ZA can walls, while A 12 presents an excellent barrier to such diffusion at current fuel element temperatures. Les propriétés des alliages de magnésium ZA et A 12 sont comparées au point de vue de leur emploi comme matériaux de gaînage d'éléments combustibles dans les réacteurs de puissance du type “Calder Hall”. On en conclut que ZA montre plus de résistance à la croissance du grain que A 12 et aussi possède des propriétés mécaniques supérieures en ce sens que ZA a une ductilité à la rupture plus élevée, est exempt d'effets de cavitation aux joints de grains, possède une résistance à la fatigue plus élevée et une résistance au fluage à haute température aussi bonne que celle de l'alliage A 12. La résistance à l'oxydation dans le gaz carbonique est similaire dans les deux alliages mais dans des conditions accidentelles oú de grandes quantités d'air sont introduites dans le fluide de refroidissement à hautes températures, alors l'alliage A 12 est plus résistant à une attaque sévère. Les températures d'inflammation de A 12 sont légèrement plus élevées que celles de ZA. En dépit des caractéristiques mécaniques plus attractives de ZA, les gaines en A 12 des éléments combustibles ont donné des performances satisfaisantes tandis que les éléments gaînés en ZA dans les réacteurs de Calder Hall et Chapelcross ont dû être défournés après un faible taux de combustion. On a montré que ceci était dûà la diffusion du plutonium à travers les parois de la gaîne en ZA tandis que l'alliage A 12 présente une excellente barrière à une telle diffusion aux températures couramment utilisées pour l'élément combustible. Die Eigenschaften der Magnesium-Legierungen ZA und A 12 wurden verglichen im Hinblick auf Ihren Gebrauch als Umhüllungsmaterial für Spaltstoffelemente von Kraftwerksreaktoren des Calder Hall-Typs. Es konnte festgestellt werden, dass die Legierung ZA einen grösseren Widerstand gegen Kornwachstum aufweist gegenüber der Legierung A 12. Sie besitzt ausserdem bessere mechanische Eigenschaften wie z.B. eine höhere Dauerstandsfestigkeit und Kriechfestigkeit bei hohen Temperaturen und ist frei von Korngrenzen-Kavitationseffekten. Der Widerstand gegen Oxydation in CO2 ist in beiden Legierungen ähnlich. Jedoch ist unter Versuchsbedingungen, in welchen ein grosser Anteil von Luft im Kühlmittel bei hohen Temperaturen eingeschlossen ist, die Legierung A 12 gegen Korrosionsangriffe widerstandsfähiger. Die Entzündungstemperatur von A 12 ist etwas höher wie die von ZA. Ungeachtet der besseren mechanischen Charakteristik der Legierungen von ZA zeigten Spaltstoffelemente mit einer Umhüllung von A 12 befriedigende Ergebnisse. ZA-umhüllte Elemente in Calder Hall und im Chapelcross Reaktor wurden dagegen bei niedrigen Ausbränden entnommen. Das Ergebnis lieferte Hinweise auf die Diffussion von Plutonium durch ZA-Wände, während A 12 eine hervorragende Barriere für solche Diffusionserscheinungen bei den Betriebstemperaturen der Spaltstoffelemente darstellt.

Cerebral air embolism in the dog.

The problem of air embolism has attracted the attention of many investigators. The literature contains numerous reports of severe neurologic damage or unexpected death occurring during some types of thoracic or abdominal diagnostic and therapeutic procedures.2,4,5,8,21more recently, operations in the neck during cordotomy, laminectomy, and thyroidectomy have been blamed for air embolization with subsequent neurologic deficits or death.19-21Obstetricians and gynecologists also have encountered the problem in patients during postpartum kneechest exercises.28Interest in the danger of air embolism has increased since the advent of open-heart surgery and the use of the artificial oxygenator.24 Experimentally, the effects of air emboli differ greatly, depending on whether they are venous (injection usually in femoral or jugular vein) or arterial (injection in carotid artery or pulmonary vein). In the case of venous embolization, large amounts of air are tolerated by experimental animals, perhaps because of the filtering effect

CLINICAL CONFERENCE

Thorough familiarity with normal variations and insignificant anatomic deviations is essential to the practice of clinical pediatrics. Through constant observation and experience differentiation from disease becomes possible. In radiology this same problem exists and is probably more significant, as roentgenograms record only the situation as of a particular moment-an inherent weakness of the method. In radiology many standard procedures are established so that results may be duplicated and progress of disease evaluated. Deviations from standard procedures often simulate disease. In addition to this pitfall, there are many anatomic variations to plague the radiologist at the time of interpretation. The following are examples of roentgenograms which have simulated disease but upon investigation proved to be normal: 1. The gaseous pattern in the infant differs from the adult. Ordinarily, we are taught that gas in the small bowel suggests obstructive ileus. In the infant under 2 years of age, gas in the small bowel is normal. After this age or after the child begins to walk the gas in the small bowel disappears and its presence then assumes significance. Improved intra-abdominal circulation, better co-ordination of diaphragmatic movements is responsible for greater absorption of gas in the small bowel after this age (Fig. 1). Large amounts of air in the stomach are not necessarily due to obstruction. A very hungry baby will swallow huge amounts of air to a point of distending the abdomen. We know this occurs and is without significance, as we use this phenomenon for diagnostic pyelography. In this procedure, the ravenously hungry child is given a bottle of formula after the intravenous or intramuscular injection of contrast material is administered.

Condensation Processes for the Extraction of Radioactivity from Air

A NUMBER of natural and artificial radioactive elements are known to exist in the atmosphere. The active atoms, other than those which form gases, get attached to aerosols present in the air and can be collected on filters capable or retaining the aerosols. The filters generally used for this purpose are: (1), mechanical and (2), electrostatic. Mechanical filters, if made efficient for retaining fine aerosols (of dimensions 0.01µ), have large resistance to air flow; hence it is difficult to process large amounts of air and therefore to measure weak activities. Electrostatic filters have negligible resistance to air flow and are efficient for retaining fine particles up to ∼ 0.01µ. Their efficiency for still smaller sizes decreases because of the difficulty of charging very fine aerosols.

GAS EXCHANGE IN THE ROOTS OF MANGROVES

ALONG THE southern and western coasts of the Florida peninsula occurs one of the greatest developments of mangrove swamp in the world. Rhizophora mangle L., the red mangrove, perching on its arched stilt roots, is the dominant species and the most marine. Another important component is Avicennia nitida Jacq., the black mangrove, which is restricted to the tidal zone and reaches its most luxuriant development on intertidal mud flats in more sheltered inland localities. Both species have a considerable tolerance for fresh water (Davis, 1943). Familiar to anyone who has visited the mangrove region are the air roots which protrude in great numbers from the mud under and around Avicennia bushes or trees. A single tree may produce several thousand of these air roots, usually 20-30 cm. high and a centimeter thick, soft and spongy, and studded with little whitish lenticels. In the mud they connect to radially-running main roots, which are also soft and spongy and contain large amounts of air (fig. 1). The vertical air-roots are often referred to as pneumatophores because it is believed that they may have the function of aerating the root system which lies buried in the mud. If one of the arching stilt roots of Rhizophora is dug out of the mud it is found to terminate in a bunch of long, spongy, finger-thick, and air-filled roots (fig. 2). The stilt root has a conspicuous development of lenticels, and one may wonder whether these might serve as ventilating ports for the mud roots. If they do, one might ask by what process the ventilation takes place, as it seems almost incredible that the voluminous roots down in the mud could be effectively ventilated by simple diffusion alone, through little lenticels high up on the stilt roots. One might also wonder how such a system, which gets its oxygen from the air, avoids getting jammed with nitrogen. However, before worrying over how the ventilation comes about one must first establish that such ventilation does take place, and this is the object of the present investigation. GAS EXCHANGE IN SUBMERGED ROOTS OF VARIOUS PLANTS.-Several investigators have analyzed the gases in roots of plants growing in water or mud which is poor in oxygen. In general these roots have been found to be aerated; how is usually not clear. Conway (1937), in a series of experiments on the sedge Cladium mariscus R. Br., found that air spaces were continuous from the leaves down into the roots. The gas connections were particularly free

SOME INVESTIGATIONS INTO THE BATCH PROCESS OF MILK STERILIZATION

SummaryBacteriological aspects of the batch‐sterilizing process as practised in one dairy, based on meso‐phile and thermophile spore counts and an analysis of subsequent spoilage, have been examined. The results from the commercial process have been compared with those from processes on a pilot scale giving treatments of 100°C. for 90 min. and 113°C. for 35 min. The treatment at 100°C. gave unsatisfactory bacteriological results: 20% of the treated bottles showed mesophile spoilage within 7 days, while almost all the bottles gave thermophile spoilage. The 113°C. treatment gave milk which was free from mesophile spoilage after 10 weeks, while the thermophile spoilage was reduced to 29%. The colour of the milk was affected considerably by this treatment.After treatment by the normal process in one of the dairy sterilizers, no spoilage occurred due to growth of thermophiles during the long cooling period. Slow cooling appeared to encourage subsequent mesophile growth slightly. Mesophile spoilage was 12 times as great for bottles treated at the bottom of the sterilizer than for those treated at the top. This was due to temperature variations throughout the sterilizer, caused by large amounts of air in the steam. The effect of efficient air removal on the temperature distribution is shown, and the influence of sterilizer operation on potential spoilage is discussed.The number of mesophile spores in the milk as received was normally below 5 per 100 ml. The number of thermophile spores in this milk was of the same order, but increased as the milk passed through the plant, particularly towards the end of the day's run. The filler was found to be the main source of this thermophile contamination.Preliminary results are given on the browning of whole milk during sterilization. At normal processing temperatures it is difficult to produce effectively sterile milk without undesirable brownness.

Air embolism in pneumoperitoneum.

Air embolism is a dramatic and often catastrophic complication of pneumoperitoneum. It follows the entrance of large quantities of air into the pulmonary venous system through a systemic vein. Fortunately, its incidence is rare, but it occurs more frequently than the occasional report in the literature would seem to indicate. 1 The growing popularity of pneumoperitoneum in the treatment of pulmonary tuberculosis and its ease of administration seem certain to increase the frequency with which an embolism is met by the general practitioner as well as the phthisiologist. The purpose of this report is to add three more cases of air embolism to the literature and stress the clinical application of the observations of Durant 2 and his coworkers, who have provided a simple effective method for coping with this emergency. REPORT OF CASES Case 1.— C. A. P., a white man aged 24, was discovered to have pulmonary tuberculosis

Traumatic Pneumocephalus

Prior to the advent of radiologic diagnosis, only one case of traumatic pneumocephalus had been reported. Extracranial pneumatocele, characterized by the dissection of air through the subaponeurotic tissues of the scalp, has long been recognized, but its intracranial counterpart, following fracture of the paranasal sinuses or mastoids, was not so accessible to the usual methods of diagnosis. Since the report of Luckett in 1913, many cases of pneumocephalus have been recorded, and major contributions such as those of Dandy and Lewis have appeared. The following case presents evidence of the immediate development of pneumocephalus following skull fracture, a somewhat unusual finding. A well developed white male was attacked by thieves as he stopped to change a tire early in the morning of April 10, 1948. He evidently was struck about the head and face by some blunt object. He was found unconscious on the street shortly after the beating and was brought immediately to Wesley Memorial Hospital. Films of the skull and facial bones taken probably four or five hours after injury were not entirely satisfactory because of the patient's disoriented condition. They revealed, however, various linear fractures in the vault, chiefly on the left, with multiple fracture lines entering the base of the skull in the region of the sphenoid yoke and the cribriform plate. Fracture of the lateral wall of the right maxillary sinus, with dense clouding of this sinus, was also observed. A large amount of air was seen within the subarachnoid space, both in the basal cisterns and surrounding the cerebral convexities. The lateral ventricles were well delineated by air (Fig. 1). Air was also present in the subdural space about the falx (Fig. 2). Physical examination on entry to the hospital showed edema and ecchymosis of the periorbital tissues. The left pupil was larger than the right, and there was no evidence of light perception by the left eye. A large hematoma was present over the left temporal bone, and there were a few small lacerations, the largest involving the left ear. Dry blood was seen in the nasal cavity, but no cerebrospinal fluid rhinorrhea or otorrhea was observed at this time. There were no cranial nerve motor changes, and generally the reflexes were normal; no signs of meningeal irritation were present. Blood pressure was 130/78. Laboratory findings were not significant. By April 11 the patient was fully conscious. He received penicillin and sulfonamides from the time of admission to April 18. Parenteral fluids were discontinued after the first two days, after which time he took nourishment by mouth. The blood pressure ranged from 120 to 140 systolic and from 68 to 90 diastolic. The temperature, which rose to 103° F. on April 12, subsided rapidly and remained under 99.4° to the time of discharge. Ophthalmologic examination on April 14 revealed complete blindness of the left eye, and it was concluded that the left optic nerve had been severed.

An examination of the lighter constituents of air

This research was undertaken with the object of ascertaining whether a large quantity of air, if systematically fractionated, would yield any consti­tuent lighter than helium. It has been stated that “coronium” has revealed its presence in the gases emitted from the Solfatara of Pozzuoli by a line of wave-length 531·5—531·6; and that from some of the Vesuvian fumaroles gases have been obtained which give rise to new lines not coincident with any important lines in the neon or helium spectra. Again, it has been stated by Dewar in a lecture delivered at the Royal Institution (April 11, 1902), that in the most volatile part of the atmosphere “a vast number of rays, generally less brilliant, are distributed through the whole length of the visible spectrum. The greater part of these rays are of, as yet, unknown origin.” A subsidiary object of the present research was to form a new estimate of the proportion of free hydrogen in air by the method of fractionation. The most important estimations have been made by Gautier, Rayleigh, and Dewar. Gautier, using the method of passing air over red-hot copper oxide, found 19·5 volumes of free hydrogen in 100,000 volumes of air, i. e. , about half as much free hydrogen as carbon dioxide. Rayleigh discussed and, in part, repeated the work of Gautier; he considered three parts per 100,000 as a maximum estimate, but regarded the question as still unsettled. Dewar, in the lecture mentioned above, stated that “air contains as a minimum not more than 1/100000th of free hydrogen.”

IS THE INJECTION OF AIR IN HYPODERMIC MEDICATION A SOURCE OF DANGER?

In concluding a paper on "The Cause of Sudden Death after Antitoxin," Seibert and Schwyzer (American Pediatric Society, May 24, 1896) say: "We here express our firm opinion that the sudden deaths reported after antitoxin injections were caused by injected air and not by antidiphtheritic serum." I believe that this conclusion is without any justification whatever. It has been shown over and over again that relatively large quantities of air could be injected directly into the circulation in the lower animals without serious consequences. Senn, Hare, Adamkiewicz and others have reported experiments in this line with the conclusions that the danger from air injections is small indeed. Nevertheless, it is believed by most practitioners that the accidental injection of even a small bubble of air may be followed by very severe consequences. Many of the older books teach this. The experiments and conclusions of Drs. Seibert and Schwyzer have been

Rare Animal at the Manchester Aquarium

AMONG the numerous new accessions brought together to swell the list of special attractions for the throngs of Whit-week visitors at the Manchester Aquarium, one of the latest arrivals is especially deserving of notice in these columns. This is an example of the so-called “Congo Snake” (Murænopsis tridactvla), from the neighbourhood of New Orleans, a singular eel. or snake-like animal, belonging, nevertheless, to neither of the classes represented by those two types, but rather to the true Amphibia. Judging from its shape, proportions, and colour, the uninitiated would certainly pass it as an ordinary eel, from which, on closer examination, it will be found to differ in possessing no fins, small bead-like eyes a mere puncture in the place of the ordinary gill-operculum, though more especially in having stationed at each extremity of the attenuated body a pair of feeble little legs, and each leg furnished with three slender toes. These legs may be described as almost rudimentary, but they are at the same time used by the animal, and with more marked effect than might be presupposed, when crawling over the ground at the bottom of its tank. Rising into the midst of the water, it can further swim with great rapidity, progressing then by rapid undulations of its body from side to side, after the manner of a true snake. The length of this specimen is about two feet six inches; greatest diameter, in the centre of the body, one inch and a half, tapering off from the posterior pair of legs into an attenuate and slightly compressed tail. The colour closely resembles that of an ordinary eel, being slate-grey on the dorsal surface and sides down to the lateral line, and below this, ash colour. Along the lateral line is a double row of minute punctures, the orifices, no doubt, of mucous glands similar to those obtaining in true fishes. The animal has to repair to the surface of the water to breathe, but this is at distant intervals, a large quantity of air being drawn through the nostrils into the lung-pouch by a singular inflation of the throat, repeated several times in succession. This specimen is exhibited in one of the octagon table tanks in the centre of the saloon, eighteen inches in depth, so that when taking in its supply of air it does not altogether leave the ground, but raises itself in a semi-erect position until the head touches the surface of the water. With the head just an inch or two below the surface, and standing, as it were, upon its posterior legs, with the anterior pair held out helplessly in the water, is a very favourite attitude with this creature, though at the same time an essentially grotesque one, reminding the observer of the somewhat similar attitude and general appearance, on a colossal scale, of the larva of Ourapteryx or other of the Geo-metria moths. In its native swamps the “Congo Snake” is reputed by the black population to be highly venomous, an injustice to the poor creature as great as when applied by our own benighted countrymen to the harmless Newt or Triton of English ponds and streams, and of which it is merely a highly interesting and most extraordinary exotic type.

20. Chronic Arteritis—Consecutive Aneurisms—Rupture of an Aneurism in the Trachea—Passage of a large quantity of Air into the Circulatory System—General Emphysema—Sudden Death.

20. Chronic Arteritis—Consecutive Aneurisms—Rupture of an Aneurism in the Trachea—Passage of a large quantity of Air into the Circulatory System—General Emphysema—Sudden Death.

20. Chronic Arteritis—Consecutive Aneurisms—Rupture of an Aneurism in the Trachea—Passage of a large quantity of Air into the Circulatory System—General Emphysema—Sudden Death.

20. Chronic Arteritis—Consecutive Aneurisms—Rupture of an Aneurism in the Trachea—Passage of a large quantity of Air into the Circulatory System—General Emphysema—Sudden Death.