Heavy Rubber Research Articles

Conveyor belt modelling in extrusion flow simulation

Abstract Technical rubber or polymer profiles are often extruded while dragging them into a water bath. However, complex or heavy profiles may require additional guiding tools. For example, geometrically complex profiles, such as PVC-window frames, require the use of calibrators for satisfying severe geometric requirements, while heavy rubber profiles, such as D-shape fenders or tire treads, require a conveying belt mainly for being able to achieve the process. Within the context of numerical simulation of extrusion flows, such a guiding tool brings an additional downstream constraint to the kinematic equation which dictates the shape of the extrudate surface. In the present paper, we propose a simple engineering approach for modelling a conveyor belt used in rubber tire tread extrusion, and we apply it to the simulation of the extrusion flow for a 3D non-symmetric profile of a viscoelastic material.

Comparative Study of Water-Blasting Equipment for Airfield Surface Decontamination

Runway rubber removal is a maintenance function employed to ensure safe landing areas for aviation operations. Rubber deposits accumulate on runway areas where aircraft tires touchdown and braking occurs. This tire-rubber build-up occludes pavement microtexture and macrotexture, causing a significant loss in available skid resistance during wet conditions. Reduction of available pavement microtexture in a wet environment prevents the development of adhesional friction, which can result in viscous hydroplaning. Reduction of pavement macrotexture prevents the removal of bulk water from the tire–pavement contact area and also prevents the development of the hysteresis frictional component. To restore friction to safe levels for aircraft operations, rubber must be periodically removed. Several techniques for rubber removal are available. Water-blasting is a proven surface decontamination technique which employs the use of high-pressure or ultra-high-pressure water (UHPW) to blast rubber deposits from the runway surface. This effort provides a performance-based comparison between three commercially available UHPW water-blasting systems. The evaluation was conducted on an ungrooved portland cement concrete (PCC) runway with heavy rubber contamination along the touchdown and breaking zones. Several types of testing equipment such as a circular track meter (CTM) and dynamic friction tester (DFT) were used to characterize the surface properties of the runway before and after rubber removal. The measurements were used for statistical pairwise comparative analysis of International Friction Index (IFI), speed constant and mean profile depth (MPD). Treatment effect analysis of premeasured and postmeasured data revealed that UHPW systems improved the surface texture properties by at least 40% regardless of the decontamination equipment.

Research on Structural Damage Diagnosis Based on Strain Modal

The damage diagnosis theory and method of engineering structure is one of the hot issues concerned by the engineering circles at present. Based on the strain modal analysis theory, it expounds the connection among displacement mode, strain mode and curvature mode, with a heavy rubber as the material to make a cantilever beam, and establishing the different damage conditions of the cantilever beam, studying about dynamic structural damage identification under the incentive, which provides the theoretical basis and technical support for the research on damage detection of large engineering structure.

Laboratory assessment of the effect of heavy rubber glove thickness and sizing on effort, performance and comfort

Powerline maintainers often work hands-on with live electrical circuits wearing rubber gloves of considerable thickness. The gloves interfere with touch, object manipulation and extra effort is required during manual work. A laboratory study was performed with twenty naïve participants to document the effort required to use gloves of different sizes and thicknesses. The electrical activity (EMG) of seven forearm muscles was measured whilst performing a set of standardized tasks. Ratings of effort, performance times and ratings of comfort, fit and dexterity were also made. Large and statistically significant differences were observed as glove thickness increased: Performance decreased, effort and EMG amplitude increased and self rated comfort, fit and overall rating decreased. Even to make an aperture prior to grasping, a substantial effort was required, especially for the extensor muscles of the forearm. When moving from the bare hand to the thickest glove, the rating of perceived exertion and muscle activity approximately tripled. The ratings of effort and performance time were not different for the three glove sizes but ratings of comfort and fit favoured the correct size. Relevance to industry The rapid increase in the gloves’ effects with thickness argues that selection of the thinnest glove consistent with the task and safety demands is important.

A guide to the productive poking, prodding and injection of cells

![Figure][1] Microinjection: Methods and Applications (Methods in Molecular Biology Vol. 518) Edited by David J. Carroll Humana Press (2009) 224 pages, ISBN 978-1-58829-884-3, $99.50 (hardback) This is just the type of book I would have liked to have had read before I began my own

Subjective evaluation of low-frequency impact sounds on floor-ceiling assemblies.

To investigate meaningful ratings and criteria for the acoustical performance of building partitions, it is necessary to understand the subjective judgments of listeners when hearing transmitted or radiated sounds. Impact sounds on floors caused by footstep noise (walking, running, etc.) are particularly bothersome and are not well characterized. A series of recordings of the sound radiated into the room below a floor-ceiling test assembly when an impact occurs on the topside of the assembly (floor surface) is ongoing. The primary impact sources considered are real adult walkers, and a heavy rubber ball, standardized in JIS A 1418-2. The binaural recordings are presented to listening test participants, who rate subjective attributes of the sounds such as annoyance. In this way the floor-ceiling test assembly is rated (and can be ranked) subjectively, and metrics derived from purely physical measurements can be assessed and interpreted. Preliminary results from measurements on a range of lightweight wood framed assemblies are discussed.

Eaten alive on the Net

According to the ProMED-mail list, The Morbidity and Mortality Weekly Report (4 Jan. 2002) of the US Centers for Disease Control and Prevention described two cases of severe encephalitis in children caused by Baylisascaris procyonis, one in Chicago and one in Los Angeles, one ending in severe brain damage and the other in death. Most racoon populations are infected with this intestinal parasite, and children are particularly at risk because they may transfer soil into their mouths that are contaminated with racoon faeces containing the eggs of B. procyonis. Many people like racoons and feed them or allow them to share dog or cat food with household pets. After 3–4 weeks outside, the eggs become infective and when ingested by young racoons, they develop into migrating larvae, which settle in the small intestine as adults, which can reach 14–18 cm long. Eating an intermediate host such as a mouse, squirrel or bird infected with the larvae often infects older racoons. In accidentally infected intermediate hosts (e.g. dogs or humans), larvae could migrate through the eye or the brain and cause extensive damage through a secondary inflammatory response. People are advised to treat decks, patios and other potentially contaminated surfaces with boiling water to reduce the risk of infection.Craig Stephen, a vet from the University of British Columbia, Canada, remarked that not only children are at risk: other animals in wildlife rehabilitation centres could acquire ‘nosocomial’ infections (those favoured by a hospital environment). He cited two cases, that of a dove and a squirrel, which had been housed in cages used for racoons previously; both developed fatal central nervous system disease.Another contributor pointed out that thorough cleaning was not enough and sent information from three websites (http://www.tc.umn.edu/∼devo0028/zoonos2.htm#15; http://www.wildcare.com/disinfect.htm; http://www.hrschicago.org/rabbitfr.html), which emphasize how long the eggs can survive and how tough they are. Decontamination procedures recommended include ‘autoclaving, flaming with gasoline, propane, or fuel oil, boiling in lye water…or boiling in Lysol’ and wearing a ‘ mask over the nose and mouth, disposable clothing, disposable gloves and heavy rubber boots that can be cleaned with boiling water’. Finally, Richard Montali (Smithsonian National Zoo, Washington DC, USA) said read the wonderful chapter on the ascarid by K.R. Kazacos in the 2nd edition of Parasitic Diseases of Wild Animals (2001, Chapter 11, pp. 301–341, Iowa State University Press).[This nematode was mentioned here once before, when a vet warned a student very firmly of the dangers involved in handling B. procyonis eggs in the lab; see Parasitol. Today (1998) 14, 478.]

Medical Waste in the Environment

Comment: Once upon a time, we all used the heavy rubber tubing, that is, back in the 1970s, and it worked quite well. Most of us abandoned it, not just because of the concern for infection but also because of the toxicity of the resterilization process and the waste gases and ethylene oxide emitted from that resterilization process. Although this study addresses some of the issues in recycling, it clearly does not address all of them, such as the cost of a local resterilizing program collection and delivery of the resterilized goods as well as pollution of the environment. It would be nice to see a more complete and balanced study conducted.

Soil grinding mill

A laboratory soil grinding mill capable of unattended pulverizing and sieving of soils for testing purposes, has been developed by the Materials and Research Branch of the Manitoba Department of Transportation. The cylindrical aluminum mills contain one or more steel rollers which are encased in heavy rubber tubing. A screened door on the mills allows crushed soils particles to escape when they have reached the required sieve size. The mills are driven by two rollers and the ground and sieved soil is collected in a pan beneath them. The mills can be operated unattended.

SURF-HARD

Abstract SURF HARD is a nitriding alloy steel designed for those applications requiring exceptionally hard wear resistant surface and a tough core, such as heavy duty gears, spline shafts, rubber and paper mill rolls, cylinder liners, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-246. Producer or source: Atlas Alloys Division, Rio Algom Corporation.

A General Mobile Processing Tank

Some five years ago, during the development of the new and enlarged Department of Radiology at St. Joseph Hospital (Fort Worth, Texas), the desirability of exposing and processing radiographs in various parts of the hospital became apparent. Particularly in the orthopedic and urologic operating rooms was the need of immediate processing facilities evident. Financially, however, the provision of fixed developing tanks in closets adjacent to these rooms was impractical. Various types of portable processing equipment were checked but, because of weight, limitation of film size, and other considerations, none were thought feasible. The design of a mobile tank that would answer the varying needs of these departments was therefore undertaken. The tank was designed with the advice of Mr. M. B. Thompson of Eastman Kodak Company and Mr. H. O. McKenzie of the General Electric Company X-Ray Department. The Reliance Engineering and Manufacturing Company in San Antonio worked out the details and undertook the construction. The tank has now been in use for some four years, and has been found very satisfactory. When the same need was encountered at the Harris Memorial Hospital, another tank with certain modifications was built. This new tank has been in service for a year and has proved satisfactory in every respect. The tank is a standard 5-15-5 splashproof type. It measures 21 × 21 inches, is 45 1/2 inches high, and will handle any standard size hanger. It is mounted on 6-inch casters and covered with a stainless-steel top, having a heavy rubber liner, which is clamped on with trunk-type locks. When locked, this liner seals the five-gallon inserts to prevent the splashing or mixing of chemicals in transportation. The force expended in moving the tanks is less than that necessary for a small mobile x-ray machine. Heating is by electric elements in stainless-steel inserts in the lower part of the water chamber. A thermostat is located in the mid-portion in the wall of the tank, at the same distance from the water as the solutions, in order that a uniform temperature may be maintained. Indicator lights with small red and amber jewels, at the lower right hand front, show red when the tank is heating and amber when it is at the desired temperature. Storage compartments are available under the tank for film boxes and cassettes of various sizes. On the right side of the tank is a towel ring; on the left side are hooks to carry the desired number of film hangers. On the left hand front is a valve connected to a polyethylene tube, which can be put in a floor drain and used to drain the solutions and clean the tank. An adjustable safe light in the right rear of the tank, with a sixty-second interval timer attached, is used in the processing of films. While in storage, this tank can be plugged in at all times, the thermostat maintaining any desired temperature. With the top clamped on, there is practically no oxidation or heat loss.

Oxygen Capacity of Lizard Bloods

The oxygen capacity of bloods from nineteen species of lizards representing eight genera and three families were determined. Mean values obtained for these species ranged from 7.7 to 12.6 vol %. Oxygen capacity was found to be uncorrelated with the extent of heat resistance characterizing the various species. Likewise no correlation was evident between oxygen capacity and the altitude at which the lizards had existed prior to study, whether the analysis was concerned with populations within a single species (Sceloporus jarrovi), species within a single genus (Sceloporus), or with the entire array of species studied. The values reported for this study fall within t'he general range previously established for reptiles by other authors. The upper portion of this range overlaps the lower portion of that for oxygen capacities of birds and mammals. This overlap suggests that the demands upon respiratory transport created with the intensification of metabolism in the evolution of homeothermy have been met primarily through such means as augmentation of cardiac output rather than through any major increase in the transport capacities of the blood. We have undertaken this study of oxygen capacity of lizard bloods as an initial step in the analysis of respiratory transport in this group. Bloods of nineteen species from southwestern United States, representing eight genera and three families have been analyzed. Acknowledgments. -We are extremely grateful to Dr. Mont A. Cazier, the Director of the Southwestern Research Station, for the numerous courtesies extended to us during our work in Arizona, and to Harvey F. Pough for the assistance rendered in the capture and maintenance of lizards. We also wish to thank Dr. Wilbur W. Mayhew of the University of Calilfornia at Riverside for supplying us with desert iguanas, Dipsosaurus dorsalis. This study was supported in part by grants from the National Science Foundation (G-2096 and G-9238) and from the Horace H. Rackham School of Graduate Studies, The University of Michigan. MATERIALS AND METHODS A majority of the lizards used in this study were obtained in extreme southeastern Arizona and southwestern New Mexico, within 25 miles of the Southwestern Research Station, near Portal, Arizona. Sceloporus poinsetti and Crotaphytus collaris were obtained in Hidalgo County, New Mexico. Sceloporus jarrovi, S. undulatus virgatus (designation of subspecies has been made only where two or more conspecific forms occur within the same county), S. clarki, Uta stansburiana, Holbrookia texana, Phrynosoma modestum, P. cornutum, P. douglassi, Cnemidophorus inornatus, C. sacki, and C. tigris, were obtained in Cochise County, Arizona. Lizards which could be approached closely were captured with a noose connected to the end of a trout pole. More wary animals were obtained by stunning them with a heavy rubber band Present address: Department of Zoology, Yale University.

Laboratory Teaching of Space Biology

1. Demonstration of the effects of decompression. As man and other animals are decompressed, they experience progressive augmentation of respiratory and heart function, ebullism (the boils as popular writers say), and ultimately collapse. Each of these may be dramatically demonstrated with equipment already available in almost any laboratory. (1) The equipment list reads as follows: filter pump (or vacuum pump), mercury manometer, bell jar or vacuum flasks, heavy rubber tubing, thermometer, beaker, mouse, and frog. Connect the filter pump to a bell jar and a mercury manometer as shown in Fig. 1. The mercury manometer is assembled in a few minutes by taping a strip of Tygon tubing to a meter stick, then putting the tube into a bottle of mercury. The bottle is placed adjacent to the meter stick such that the mercury meniscus corresponds to the pressure at your altitude. Put a mouse, a frog, and a beaker of water heated to 40 or 500C inside the bell jar. Keep a thermometer in the beaker of water. The demonstration now begins. Turn on the tap water through the filter pump. The mercury gradually rises as air is withdrawn. The mouse and frog do quite well at first, but between 500 and 400mm Hg (i.e., about 10,000 to 15,000 feet as shown on Table 1) the mouse breathes more rapidly. Continue the ascent at about 100mim Hg/min. Should you exceed this, the mouse may scratch his ears as though the pressure is too much for his middle ear to compensate. At 25,000 to 30,000 feet the frog remains practically normal, but the mouse is obviously disquieted and will soon fall unconscious. Shortly before the mouse faints, I suggest that the pressure be lowered and the animal saved for future experiments. The class now has witnessed the reaction of a homeotherm undergoing decompression, reactions not unlike that of astronauts in the event of structural failure of their cabin or meteor penetration. You might point out, however, that unconsciousness occurs much faster during explosive decompression. Human volunteers have collapsed in 10 to 15 seconds under such circumstances, the duration it takes for a column of oxygenated blood to pass from the lungs to the brain. In such a total vacuum, all blood is deoxygenated as it enters the lungs. Continue again with the frog and the beaker of warm water. Decompress to about 40mm (65,000 feet) if the water pressure in your tap permits. The frog does not appear distressed, and in fact will continue to live at this altitude for many hours. This probably reflects the low oxygen requirements of poikilotherms (hibernators perform similarly). But what of the beaker of water? 100

From Heavy Water, Heavy Rubber

From Heavy Water, Heavy Rubber

Infusion treatment of shock; alkali and acid in shock treatment.

The existing situation in the fluid therapy of shock has been accurately summarized by Wiggers. 1 It is generally suspected that the beneficial effects of sodium chloride do not depend solely or largely on its ability to restore plasma volume. It must be due to the action of the sodium or chloride ions or of the NaCl molecule. Illustrative of the first sentence is the superiority of saline over plasma 2-5 or dextran solution. 6 The problem of the second sentence is explored in the present paper. Methods Tourniquet shock, which was first standardized in rats, 2 was produced in dogs by tight constriction of both hindlegs as high as possible with heavy rubber bands or 6 mm. tubing. Anesthesia was induced with pentobarbital (Nembutal) intravenously or intraperitoneally. The animals were awake toward the end of the ligation period, when the limbs had lost sensation. Such constriction for five hours

AN APPARATUS FOR DETERMINATION OF VITAL CAPACITY OF INFANTS

Since infants cannot cooperate, the apparatus shown in figure 1 was devised to determine their vital capacity. It consists of a 5 gallon (22.7 liter) closed container, similar to a milk can, of sufficiently heavy gage metal so that the walls are rigid. A water manometer is connected to measure the pressure within the container, which is connected by heavy walled rubber tubing with a Marriott face mask. 1 The container is calibrated by pouring measured amounts of water into it. As shown in figure 2, the pressure increases 1 mm. for each 4.8 cc. of water added to the container, or 0.23 mm. per cubic centimeter. The vital capacity of an infant is measured by placing the face mask quickly and tightly over his mouth and nose at the end of a full inspiration. The maximum of several determinations is taken as the vital capacity. If the infant draws

OCCUPATIONAL LEUKODERMA

In May 1939 an insurance company requested the examination of a group of men employed in a tannery near Chicago. These men had instituted suit against the tannery, claiming that a peculiar depigmentatiori of the skin, which had developed on their forearms and hands, was the result of wearing a certain type of rubber glove. A visit was made immediately to the tannery, and on the first day 20 of these men were examined. All of them showed this unusual type of depigmentation, some more than others. Thirteen of them were Negroes, 3 were Mexicans and 4 were white. In 7 of the Negroes and in 2 of the Mexicans the depigmentation was especially evident, extending over the backs of the hands and up the forearms, ending in an abrupt line halfway up the forearms. The involved areas corresponded with those covered by a heavy rubber gauntlet type of glove

Mixing and Moulding without Mastication

Abstract The preliminary experiments described indicate the remarkable potentialities of the injection method of moulding rubber articles, whether produced from mixes of powdered or masticated rubber. Employing rubber powder made by the Stam process, intimate mixing with vulcanizing ingredients and fillers is essential, and may conveniently be achieved with simple apparatus by ball milling the ingredients. The necessity for heavy rubber machinery of the orthodox type is eliminated. It is desirable to employ an accelerator of relatively low activity, or a delayed action ultra-accelerator. With very fast accelerators, vulcanization begins either during mixing of the powder or while being forced from the injection cylinder to the mould. Such premature vulcanization leads to serious distortion. It is believed that the stresses to which a compressed rubber powder compound is subjected during the process of injection moulding are sufficient to rupture the individual rubber particles, to ensure cohesion, and promote satisfactory dispersion of compounding ingredients. It is confidently asserted that results superior to those instanced herein could be achieved with an injection moulding device designed to facilitate uniform heating of both top and bottom of the mould cavity. It is also felt that a careful study of the effect of changing the injection pressure and the size of the injection orifice might yield valuable information. The success attending these early experiments warrants extending the investigation to new types of rubber powder (cf. Rubber Age, 19, 335 (1938)).

Prevention and treatment of postoperative thrombophlebitis

Summary No satisfactory routine procedure has been devised for the prevention of postoperative thrombophlebitis. Certain measures have been discussed which will help to minimize the three essential factors of local vein injury, slowing of venous blood flow and alteration in the coagulability of the blood. Postoperative thrombophlebitis Inay be successfully treated in the acute stage by adequate elevation of the limb and the use of extensive hot wet packs locally. It is advisable to get the patient up as soon as the temperature has been normal for three days, swelling below the knee has subsided and local tenderness in the involved veins has disappeared. As soon as the patient is out of bed it is necessary to equip him with an adequate leg support and for this a heavy pure rubber bandage is recommended. The bandage can usually be discarded in from three to twelve months without the subsequent appearance of any signs or sy-nlptoms of chronic venous insufficiency. Once the clinical picture of acute postoperative femoral or iliac thrombophlebitis has appeared, the danger of fatal pulmonary embolism is small.

Chart for the Estimation of Equivalent Cures

Abstract IN ALL heavy rubber articles the temperature conditions which obtain during curing are very different from those existing in light articles. Heat penetrates thin rubber sheets so quickly that they may be said to cure at constant temperature. Heavy articles, however, are heated very slowly, so that their cure may generally be divided into periods of rising temperature, approximately constant temperature, and falling temperature. During August, 1926, the writer developed a method of evaluating and comparing cures made under such variable temperature conditions. The principle is applicable to all cases of variable temperature cures???as, for instance, shoe-curing schedules, etc. Two papers presenting methods of estimating the curing effect of variable temperature schedules have recently appeared. Sheppard and Wiegand have developed equations and charts whereby curing effect may be calculated and expressed mathematically. Their method is based on the empirical relation that the intensity of curing action doubles with every rise in temperature of A° F., where A is a selected constant (in the example given, 15° F.). The method is therefore limited, in exact application, to compounds for which the temperature interval (A) during which the rate of cure (corresponding to intensity of curing action of the schedule) doubles is actually constant. Tests show that for many stocks the interval is not constant over the range of curing temperatures. The procedure is also limited to schedules where the rate of rise of temperature is constant.