Large Amount Of Air Research Articles

Catastrophic failure of an ammonia/air mixer

Kemira B.V. operates a 1200 metric tpd (100%) high pressure nitric acid plant in Rozenburg, the Netherlands since 1968. Until the incident described here occurred, operation had always been uneventful. In August 1993, however, the ammonia/air mixer suddenly burst open, releasing large amounts of air and ammonia to atmosphere. Two persons working in the plant miraculously missed being hit by the gas jet and flying debris. This paper describes the incident, its cause and measures taken to prevent reoccurrence.

Dry Mechanical Dispersion of Submicron Particles

AbstractConcerning the use of air classifiers with cut sizes in the micron range and lower, it is necessary to disperse the feed material properly in an air flow to avoid agglomerates larger than the desired cut size. Commonly used dispersing devices such as injectors use large amounts of air. To reduce the size and costs of the subsequent air classifiers, two new types of dispersing systems were developed, one design being related to a brush feeder and the other to a pin mill. Both apply mechanical rather than fluid mechanical forces in the dispersion process. The brush disperser achieves the same size distributions as the pin mill disperser with much less machinery. Its properties as a feeding and dispersing system are shown and its ability to disperse particles in the submicron range is confirmed by two independent particle size analysis systems: a new diffraction spectrometer and an impactor.

Air entrainment in two-dimensional turbulent shear flows with partially developed inflow conditions

In plunging jet flows and at hydraulic jumps, large quantities of air are entrained at the intersection of the impinging flow and the receiving body of water. The air bubbles are entrained into a turbulent shear layer and strong interactions take place between the air bubble advection/diffusion process and the momentum shear region. New air-water flow experiments were conducted with two free shear layer flows: a vertical supported jet and a horizontal hydraulic jump. The inflows were partially developed boundary layers, characterized by the presence of a velocity potential core next to the entrapment point. In both cases, the distributions of air concentration exhibit a Gaussian distribution profile with an exponential longitudinal decay of the maximum air content. Interestingly, the location of the maximum air content and the half-value band width are identical for both flow situations, i.e. independent of buoyancy effects.

The stratospheric polar vortex and sub-vortex : fluid dynamics and midlatitude ozone loss

It has been suggested on the basis of certain chemical observations that the wintertime stratospheric polar vortex might act as a chemical processor, or flow reactor, through which large amounts of air - of the order of one vortex mass per month or three vortex masses per winter - flow downwards and then outwards to middle latitudes in the lower stratosphere. If such a flow were to exist, then most of the air involved would become chemically ‘activated’, or primed for ozone destruction, while passing through the low temperatures of the vortex where fast heterogeneous reactions can take place on polar-stratospheric-cloud particles. There could be serious implications for our understanding of ozone-hole chemistry and for midlatitude ozone loss, both in the Northern and in the Southern Hemisphere. This paper will briefly assess current fluid-dynamical thinking about flow through the vortex. It is concluded that the vortex typically cannot sustain an average throughput much greater than about a sixth of a vortex mass per month, or half a vortex mass per winter, unless a large and hitherto unknown mean circumferential force acts persistently on the vortex in an eastward or ‘spin-up’ sense, prograde with the Earth’s rotation. By contrast, the ‘sub-vortex’ below pressure-altitudes of about 70 hPa (more precisely, on isentropic surfaces below potential temperatures of about 400 K) is capable of relatively large mass throughput depending, however, on tropospheric weather beneath, concerning which observational data are sparse.

Ozone loss in middle latitudes and the role of the Arctic polar vortex

There have been a number of different suggestions as to the cause of the observed ozone decline over middle latitudes. Here, the particular impact of polar processes on the middle latitude lower stratosphere is discussed. Recent studies suggest that air, recently activated and then torn from the edge of the polar vortex, contributes to the observed ozone decrease. For example, observational and modelling studies both indicate that there is an important role for filaments of vortex air being stripped away from the vortex edge. However, there appears to be little support for the idea of the vortex as a massive ‘flowing processor’ through which large quantities of air, primed for ozone destruction, are transported.

Modelling of air ingress and pressure distribution in ladle shroud system for continuous casting of steel

The pressure distribution and fluid flow profiles whithin the slide gate and shroud nozzle for the continuous casting of steel have been investigated using a full scale water model and a CFD (computational fluid dynamics) model. The water modelling has shown that a large quantity of air can be drawn into the liquid stream if there is any breakdown of the seals in the vicinity of the slide gate. The 3‐dimensional numerical solution for highly turbulent flow has predicted the pressure distribution and velocity profile within the slide gate and shroud. Based on the experimental and numerical modelling, it has been shown that cavitation can occur near the slide gate during ladle teeming. This can be a source for erosion of the refractories. Improvements to the design of the ladle shroud system are recommended.

Diffuse subcutaneous emphysema, pneumomediastinum, and pneumothorax after dental extraction

Subcutaneous emphysema, pneumomediastinum, and pneumothorax may result from surgical procedures and trauma and usually do not present a diagnostic dilemma. We present a case of subcutaneous emphysema, pneumomediastinum, pneumothorax, and pneumoretroperitoneum after a dental procedure with an air-and-water-cooled turbine burr drill. This allowed air and water under pressure to be driven into the field and track through the fascial planes. Although this is a common occurrence, these patients frequently go undiagnosed or misdiagnosed as allergic reactions to locally administered anesthetic agents. If a large amount of air is injected, it may track into not only the subcutaneous tissues but also the mediastinum, pleural space, and retroperitoneal space. Patients with significant amounts of air must be admitted, observed for airway compromise, and be provided IV antibiotics and hydration.

Air under the Diaphragm in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis (CAPD)

To understand the significance of pneumoperitoneum in patients undergoing continuous ambulatory peritoneal dialysis (CAPD), we reviewed 110 upright x-rays of 33 patients. Only 3 x-rays belonging to 2 patients displayed large amounts of air under the diaphragm. One patient had documented colonic perforation and the other patient used a faulty technique that introduced air into the abdomen. Five additional asymptomatic patients showed minute amounts of air. We conclude that large amounts of air, as defined radiographically by an air shadow of more than 5 mm in height, is unusual in CAPD patients and should be taken seriously as suggestive of bowel perforation until proven otherwise.

A CASE OF BLUNT DUODENAL INJURY WITH AVULSION OF THE PAPPILA OF VERTER WHICH CAUSED EMPHYSEMA OF MESOCOLON AND GREATER OMENTUM

We report a case of peforation of the duodenum by blunt trama in which abdominal X-ray film disclosed a retention of soap bubble like gas in the omentum (omental bubble sign). A 19-year-old female who sustained abdominal trauma was admitted. Abdominal X-ray showed the above mentioned finding and there was an emphysema at the upper abdomen on CT. No free air was seen, Moreover, after oral intake of water soluble contrast medium, pyelogram was positive, suggesting a perforation at the G1 tract. Laparotomy performed 13hrs after the admission revealed a complete avulsion of the duodenum at Vater's pappila with bile leakage in the retroperitoneum. In addition, a large amount of air was seen in the omentum. Pancreaticoduodenectomy was performed. The subsequent hospital course was satisfactory and she discharged on 84th day after the admission. Emphysema in the transverse mesocolon and greater omentum are very important findings for the diagnosis of retroperitoneal perforation of the duodenum. As the course of these air leakages, different two pathways were guessed: (1) via transverse mesocolon and (2) via gastrocolic mesenterium. Pyelogram after the oral intake of water soluble contrast medium is an important finding to diagnose a perforation at the digestive tract.

Removal of air from liver specimens via vacuum.

Fresh liver specimens have been ultrasonically imaged in vitro in order to evaluate specimen air content before the acquisition of ultrasonic waveform data for tissue characterization studies. It was found necessary to expose liver slices to vacuum for about 16 h in order to remove enough air to acquire waveform data from air-free regions of interest in these slices. Larger portions of liver, and whole liver, were found to retain large amounts of air even after 16 h of exposure to vacuum.

Air entrainment in mortars and concrete: The effect of superplasticizer/salt combinations

The use of salt-saturated solutions in mixing super plasticized mortars and concretes will sometimes lead to the entrainment of large quantities of air (in excess of 20 per cent, often as high as 50 per cent). The author describes a test to quantify the potential of various superplasticizers to entrain air when used in salt-containing mortars and concrete. A solid form of a sulphonated naphthalene formaldehyde condensate (SNFC) was mixed with saturated brine solution, with and without defoaming agents, and the level of foaming was measured. The test was repeated using 20 per cent active liquid sulphonated melamine formaldehyde condensate (SMFC) in place of SNFC. In the case of SNFC, reaction with the salt produced a large amount of relatively stable foam, only partially controlled by defoamers. In the case of SMFC there is less foaming and it can be effectively controlled with a defoamer. The test described is a simple one which allows quick determination of the potential for foaming. (TRRL)

Technique of Coughing

To the Editor.— I am subject to attacks of allergic asthma complicated by bronchitis. I discovered a technique for coughing that has served me well in clearing large numbers of mucus plugs. The technique consists of exhaling as completely as possible (really forcing the air out), coughing hard a couple of times (with all the air completely expelled), taking in a small amount of air, coughing again a couple of times, taking in a little more air, coughing again, taking in still more air, coughing again, and so on, until I was taking in large amounts of air and coughing in the usual way. As I was doing this, I could feel the secretions moving up my bronchi and being coughed out. This technique may already be described or be in widespread use, but I have never heard of it.

Theoretically Estimating the Performance of Gas Turbines Under Varying Atmospheric Conditions

It is well known that the performance of internal combustion engines is affected by varying atmospheric conditions, namely by the atmospheric temperature, pressure, and humidity. However, except for variable-speed gas turbines, performance correction formulas have not been established for gas turbines as they have for reciprocating engines. Although performance correction formulas, based on dimensional analysis, have been proposed for variable-speed gas turbines, these formulas are not applicable to the constant-speed gas turbines which are commonly used to drive generators. The correction quantities of gas turbines must be obtained experimentally. But, in general, a gas turbine, compared to a reciprocating engines, consumes such a large amount of air that conducting experiments at various atmospheric conditions in an environmental laboratory is hardly feasible. Therefore it is necessary to establish highly accurate performance correction formulas theoretically. The purpose of this paper, as a basic study in the development of correction formulas, is to analyze theoretically the effects of atmospheric conditions on the performance of gas turbines. For the purpose of analysis, the following concepts are introduced: (1) the use of moist air in place of dry air as the working medium, thus enabling one to estimate the effects of humidity; (2) the idea of “the specific output per unit volume” in addition to the specific output per unit mass and the thermal efficiency; (3) the effect of air temperature on the pressure ratio and the efficiency of the compressor. In the performance analysis, the following two methods are adopted: first, the changes in the efficiencies of the components are neglected while varying atmospheric conditions; second, as a more precise method, the changes in the efficiencies of the components are also considered. Finally, in order to confirm the validity of the assumptions and the calculation methods, the theoretical values obtained are compared with actual gas turbine data. As the result of this paper, the effects of varying atmospheric conditions on the performance of gas turbines are described quantitatively, so that the resultant change in performance can be estimated without experiment.

Another Idea Regarding SIDS

The large number of pediatricians and investigators who have a great interest in the sudden infant death syndrome (SIDS) should read the recent paper by Kadlub and Kadlub. They propose a theory that adds a new concept to the many theories which have been proposed, many of which have been already discarded. They state "this is a disease which does not make sense" and "the very first symptom of this condition is death." True. They believe that the infant who swallows large amounts of air along with his food, who has not been allowed to belch, and who lies flat in his crib, perhaps right after feeding, may expel an enormous amount of air in his sleep from the position in which he sleeps and with which his epiglottis, nasopharynx, and nasal passage are inadequate to deal.

A Laboratory Investigation of Fire-Water Flooding

Abstract The results of a systematic investigation of the parameters of fire-water flooding are reported. The parameters of fire-water flooding are reported. The results were obtained from a series of 131 combustion-tube tests. Experimental equipment and procedures were developed to minimize heat-transfer procedures were developed to minimize heat-transfer problems and transient effects at the inlet of the problems and transient effects at the inlet of the tube. The tests were performed with water/air injection ratios from 0 to 13 cu ft/Mscf, using crudes with gravities from 10 degrees to 48 degrees API, in waterflooded and nonwaterflooded sands at pressures of 0, 1,000, and 2,000 psig. The air requirements for fire-water flooding were reduced by more than 50 percent in some cases. Similar results were obtained with various crudes. Introduction The greater demand for crude oil, the increased difficulty of discovering new reservoirs, and the desire to reduce dependence on imports have emphasized the need for enhanced recovery methods capable of economically producing the crude remaining in known reservoirs. Numerous methods have been proposed and tested in laboratories and field pilots, and some have been used in commercial applications. Fire flooding is one enhanced recovery method that has been technically successful in many field applications. Some of these projects have been economically successful, but many are only marginally so. The high cost of air compression for fire flooding is one of the major factors that influence the economics. Large quantities of air are required per unit reservoir volume swept, especially for heavy crude, because all the residual material remaining in the sand immediately ahead of the combustion zone must be consumed. Only a portion of the heat generated is necessary for maintaining the movement of the combustion zone, and the remainder is left behind in the depleted sand. Fire-water flooding is a recovery technique that was conceived to improve the economics of dry fire flooding. In this process, water is injected along with the air to recover some of the heat remaining behind the combustion zone. At low water injection rates, the heat is transported through the combustion zone by superheated steam to where it can be utilized for preheating the reservoir. At higher water injection rates, the water partially quenches the combustion, reducing the maximum temperature to the steam-plateau level, and heat is transferred through the combustion zone as saturated steam. The air requirement is lower with water injection because the amount of hydrocarbonaceous material deposited on the sand grains is less and because all of this fuel is not necessarily consumed. At a constant air injection rate, the oil may be produced faster with water injection than without because of the more rapid combustion-zone movement, the increased utilization of energy, and the increased volume of fluid injected. Fire-water flooding has been investigated in several different laboratories with combustion-tube experiments. The feasibility of partially quenched combustion, the reduced air requirements, and the improved utilization of heat with water injection have been confirmed. However, the results of only a few experiments have been reported by each investigator, and only a limited amount of experimental information is available on the relationships of the fire-waterflooding parameters. in addition, it has been suggested that be results of wet combustion tests may be misleading because of experimental limitations. In this paper, the results of a systematic investigation of the parameters of fire-water flooding are reported. The results were obtained from combustion-tube tests. The equipment was designed to minimize heat-transfer problems, and operating procedures were developed that reduced the procedures were developed that reduced the transient effects at the inlet of the tube. SPEJ P. 537

Morphology of the three anterior pairs of spiracles of Belostoma and Ranatra (aquatic Heteroptera: Belostomatidae, Nepidae)

When totally submerged beneath the surface of the water, Belostoma and Ranatra respire by means of air stores which adhere to their bodies and which communicate with the spiracles. The mesothoracic spiracle lies between the prothorax and mesothorax; the metathoracic and first abdominal spiracles lie posteriorly in the mesothorax and metathorax, respectively. All three spiracles possess a cuticular sieve-plate with a network of trabeculae. The mesothoracic and metathoracic sieve-plates have an inner membrane which appears to limit their permeability, especially in Ranatra. The first abdominal sieve-plate, in contrast, lacks the inner membrane and is penetrated by large lacunae in both genera; this spiracle is probably capable of exhaling and inhaling large amounts of air. The mesothoracic and metathoracic spiracles appear to be of less respiratory importance. The amount of air which can pass through their sieve-plates and (or) open ecdysial scars is limited in Belostoma and may well be negligible in Ranatra.

PNEUMATIC BARRIERS FOR OIL CONTAINMENT UNDER WIND, WAVE, AND CURRENT CONDITIONS

ABSTRACT An experimental laboratory study of the pneumatic barrier has recently been completed at Texas ?&M University (sponsored by the U S. Coast Guard). Both the fluid mechanics of air-bubble generated currents and their effectiveness for containing oil under wind, wave, and current loadings were investigated. The bubble-generated current has been found to provide an effective means of containing oil on water. However, under strong currents (2 knots) or breaking wave conditions, large quantities of air are required and the substantial increase in power requirements which results may prove the system uneconomical for some applications. Consequently, use of the pneumatic barrier to prevent oil spreading on water is recommended for protected areas with low (below 1.0 knot) currents.

The treatment of the air pollution problem within the chemical industry of West Germany.

Abstract

Tonsillar Hypertrophy, Airway Obstruction, Alveolar Hypoventilation, and Cor Pulmonale in Twin Brothers

Twin brothers suffering from severe alveolar hypoventilation secondary to tonsillar hypertrophy are presented. The ventilatory abnormalities were more severe in the child with greater degree of upper airway obstruction. Pulmonary hypertension and right ventricular failure developed only in the latter twin thus confirming a cause-effect relationship between upper airway obstruction and the cardiac complications. The cardiac abnormalities were completely relieved after tonsillectomy, but not after adenoidectomy in the child who had both procedures. The procedure of cardiac catheterization was complicated by considerable respiratory difficulty and cardiac arrest in the twin with larger tonsils. When the right heart catheter was left open to air for a short time, large quantities of air were sucked into the heart causing near fatal air embolism. This danger should be kept in mind when patients with upper airway obstructions are catheterized. There seems to be a definite place for tonsillectomy when the tonsils are sufficiently large to interfere with ventilation.

Stratospheric Tapping by Intense Convective Storms: Implication for Public Health in the United States

The observation of a cloud-free vortex in the top of a violent convective storm over Oklahoma suggests a mechanism whereby large quantities of air may be brought directly from the lower stratosphere to the lower troposphere in the central part of such storms. That this mechanism, in combination with the torrential rains frequently generated by these systems, is capable of producing radioactive "hot spots" on the ground is pointed out. Climatological considerations and observations of accumulated strontium-90 in soils support the hypothesis that the Plains States are peculiarly subject to heavy contamination compared to other middle-latitude areas because of this mechanism.