Belts see V-belts


The heart, a double pump consisting of four chambers (Fig. 2), drives the circulatory system. The atria are the upper two chambers which act as receiving chambers the much larger lower two ventricles serve as propulsion chambers. After the blood deUvers oxygen, it returns to the heart via the venous side of the system which ends up in the venae cavae prior to entering the right atrium. Continuing its flow progression, the blood moves into the right ventricle which pumps it out to the pulmonary arteries and on to the lungs. After the blood enters the lungs, disposes of carbon dioxide, and picks up fresh oxygen, it returns via the pulmonary veins to the left atrium of the heart and hence to the left ventricle which is the largest of the heart s pumping chambers. The blood starts its journey over again when it is propelled from the left ventricle to the aorta and from there throughout the body via the peripheral arteries.  [c.178]

Feed purification. Impurities that enter with the feed inevitably cause waste. If feed impurities undergo reaction, then this causes waste from the reactor, as already discussed. If the feed impurity does not undergo reaction, then it can be separated out from the process in a number of ways, as discussed in Sec. 4.1. The greatest source of waste occurs when we choose to use a purge. Impurity builds up in the recycle, and we would like it to build up to a high concentration to minimize waste of feed materials and product in the purge. However, two factors limit the extent to which the feed impurity can be allowed to build up  [c.282]

During the optical coat work stress examination method the upper plate of the head of some of the bolts was covered with an optical coat work (Fig. 4). On the head of some other bolts strain gauges were stuck which measured the plain biaxial stress state in the middle of the top surface of the head of the bolt (3.5 x 3 mm). The magnetic probe detected average stresses up to 0.1 mm depth in an area of 14 mm diameter in the middle of the head of the bolt.  [c.7]

However, this probe design is dedicated to a special turbine blade type and a special inspection task on this blade. But similar probe types and probe holders can be provided also for other engine types and for other inspection tasks like wall thickness measurement and crack detection in other zones of a blade.  [c.762]

The globular proteins albumin in eggs and fibrinogen in blood are converted to insoluble forms by modification of their higher-order structure. The process is called denaturation and occurs, in the systems mentioned, with the cooking of eggs and the clotting of blood.  [c.21]

Some scales are fixed in position and the material to be weighed is brought to the scale. Higher capacity floor scales, tmck scales, and railroad-track scales are typically fixed in position these scales should be located where they are convenient for the weighing operation, but are not subjected to unnecessary abuse from through traffic. Scales are often built into fixed material handling or processing equipment so that material can be weighed as it is being moved, eg, as in the cases of conveyor, tank, and hopper scales. Scales can be built into tanks or silos used for storage, either for inventory control or for controlling the discharge of these materials.  [c.332]

Endless belt percolation extractors (Fig. 5) such as the uncompartmented de Smet belt extractor and the compartmented Lurgi frame belt extractor are similar in principle and closely resemble a belt filter, and are probably the simplest type of percolation extractor from a mechanical point of view. These are fitted with a slow-moving perforated belt. The belt is made from steel mesh cloths when the soHds are fine, or coarser screens when the soHds are larger, and is attached to chains which pass over sprockets at each end of the extractor. The soHd is fed from a hopper at one end of the extractor to the moving belt, and the bed height is controlled by an adjustable damper at the oudet of the feed hopper. The two side walls of the extractor provide support for the bed on the moving belt. Fresh solvent is fed by spraying it onto the bed close to the discharge end of the belt, but leaving sufficient distance for adequate drainage of the bed prior to discharge. MisceUa draining from the bed is collected in a pan below the belt and circulated back to be sprayed onto the bed at a point closer to the soHds-feed end of the belt this process is repeated to achieve extraction operating with a countercurrent flow. The top of the bed is scraped by a hinged rake which has two functions (/) it prevents a layer of fine soHds from accumulating at the top of the bed thereby reducing permeabihty, and (2) it form a soHds pile which helps to prevent intermingling of misceUa from different feed points at the surface of the bed. The belt is effectively washed twice once by fresh solvent just after the soHds discharge point, and then at the other end of the belt return by misceUa. The extraction time and percolation rate determine the belt speed and the amount of drainage area, and hence linear length of belt, requited. These parameters control the plant capacity as the bed height is fixed by the mechanical design of the extractor.  [c.92]

The vane-axial fan wheel has short, stubby airfoil blades mounted on a hub which may be as large as 75% of the wheel diameter. The air leaving the axial-flow wheel has an appreciable rotational component which can be converted to static pressure ia a suitably designed set of stationary straightening vanes. The straightening vanes are shaped to pick up the air leaving the wheel blades without shock. Although straightening vanes of airfoil cross section are theoretically desirable, vanes formed of pressed heavy sheet metal are less expensive. The motor is enclosed ia a housiag having the same diameter as the hub and has either a rounded cap or a bullet-shaped tail to reduce eddy losses. The straightening vanes surround the motor housiag and can serve as stmctural supports for the housiag. GeaeraHy, the number of guide vanes exceeds the number of propeller vanes by one, with the numbers selected so that there is no common divisor for the number of hub vanes and guide vanes. This minimises flow pulsation and noise. Siagle-stage fans can develop pressures to 1.5 kPa (6 ia. of water) with some desigas going as high as 2.25 kPa (9 ia. of water). Standard designs are available either belt-driven or directly connected to motors with speeds as high as 3450 rpm. In addition, two-stage units have been developed that produce considerably higher pressures but have received Httle iadusttial use. Performance curves show a dip to the left of the pressure peak (Fig. 10). Whereas vane-axial-flow fans can be designed that do not have such dips, those that do have dips should be operated to the right of the pressure peak. The principal advantage of the vane-axial fan is compactness and convenience of use ia inline ducts, plus its better efficieacy whea carefully desigaed. The higher manufacturiag precisioa required geaeraHy eliminates any cost savings that might result from its smaller size.  [c.111]

A problem common to animals consuming a high energy diet or lush, immature legume vegetation is increased susceptibiUty to bloat. Bloat is a condition where mminal fermentation occurs too rapidly, leading to excess gas buildup in the mmen. This gas is not expelled owing to heavy foam production in the mmen. Antifoaming agents available to prevent bloat include siUcones, detergents, vegetable oils, animal fats, animal mucins, and Hquid paraffins (31). Poloxalene [9003-11-6] is an example of a commonly used surfactant developed primarily to prevent bloat on pasture.  [c.157]

Perfluorinated compounds are also potentially useful as inert reaction media, particularly when one of the reactants is gaseous. The high solubiHty of oxygen and carbon dioxide in perfluorinated Hquids has allowed their use as blood substitutes (41) and as oxygenation media for biotechnology (42). One product, Fluosol DA (43) (Green Cross Corp.), has been commercialized, and there is an abundant patent art in this area (see Blood, artificial).  [c.299]

Blood and urine are most often analyzed for alcohol by headspace gas chromatography (qv) using an internal standard, eg, 1-propanol. Assays are straightforward and lend themselves to automation (see Automated instrumentation). Urine samples are collected as a voided specimen, ie, subjects must void their bladders, wait about 20 minutes, and then provide the urine sample. Voided urine samples provide the most accurate deterrnination of blood alcohol concentrations. Voided urine alcohol concentrations are divided by a factor of 1.3 to determine the equivalent blood alcohol concentration. The 1.3 value is used because urine has approximately one-third more water in it than blood and, at equiUbrium, there is about one-third more alcohol in the urine as in the blood.  [c.486]

Full details of this work were pubHshed (6) and the processes, or variants of them, were introduced in a number of other countries. In the United States, the pharmaceutical industry continued to provide manufacturing sites, treating plasma fractionation as a normal commercial activity. In many other countries processing was undertaken by the Red Cross or blood transfusion services that emerged following Wodd War II. In these organisations plasma fractionation was part of a larger operation to provide whole blood, blood components, and speciaUst medical services on a national basis. These different approaches resulted in the development of two distinct sectors in the plasma fractionation industry ie, a commercial or for-profit sector based on paid donors and a noncommercial or not-for-profit sector based on unpaid donors.  [c.526]

Bullet-resistant glass products are tested according to UL 752 (18). The test specifies that three shots are fired from 4.6 m and impacting within 100 mm of each other in a triangle, and that there is no penetration of the projectile nor any glass embedded in the cormgated board. The level of approval is determined by the velocity and energy level of the bullet at the muzzle of the firearm. Additional tests required include impacts 38 mm apart and tests over temperature ranges of 13—35°C for indoor use and —31.7 to 49°C for outdoor use.  [c.526]

The cross-belt separator is one of the oldest types of separators (10). The feed flows over a conveyor belt, and the magnetics are picked up by another belt perpendicular to the feed belt and moving over the sharp edged upper poles of an electromagnet. The lower poles are situated below the belts and are flat. The disk separator is a modification of the cross-belt and consists of a series of disks containing concentrating grooves and revolving above the feed belt. Electromagnets are used to magnetize the concentrating grooves by induction. This design lends itself to excellent control, sharpness of separation, and selectivity. It is capable of producing a separate middlings product.  [c.410]

AT-11 exerts a wide range of physiological effects on the cardiovascular, renal, and endocrine systems, and the peripheral and central nervous systems. The main physiological effects of angiotensin are to increase blood pressure and heart rate and to cause retention of salt and water. The effects derive from a direct vasoconstrictor and myocardial effect of angiotensin, its abiUty to release other vasoconstrictors from endocrine and neuroendocrine tissues, and its abiUty to release sodium and water-retaining hormones, primarily aldosterone and vasopressin. In the brain, angiotensin 11 eUcits a diversity of responses including an increase in blood pressure and water intake, stimulation of natriuresis and salt appetite, and secretion of pituitary hormones.  [c.528]

The development of easy-to-use assays for determining theophylline blood levels afforded a handle on maintenance of effective but nontoxic levels. The relatively good availabihty of such assays in the United States probably contributed to the historical preference for theophylline treatment by U.S. physicians. Careful titration of the dose must be done on a patient-by-patient basis because individual rates of metaboHsm vary widely. Most ( 85%) of an oral dose of theophylline is metabolized by Hver microsomal enzymes. As a result many dmgs, eg, cimetidine [51481-61-9], anticonvulsants, or conditions, eg, fever, cigarette smoking, Hver disease, which affect Hver function alter theophylline blood levels.  [c.440]

In 1980, the National Heart, Lung and Blood Institute of NIH estabHshed goals and criteria for developing heart devices and support techniques in an effort to improve the treatment of heart disease. This research cuHninated in the development of both temporary and permanent left ventricular-assist devices that are tether-free, reHable over two years, and electrically powered. The assist devices support the failing heart and systemic circulation to decrease cardiac work, increase blood flow to vital organs, and increase oxygen supply to the myocardium. The newer ventricular assists are required to have no external venting, have a five-year operation with 90% reHabiHty, pump blood at a rate of 3—7 L/min into the aorta at a mean arterial pressure of 90 mm Hg (12 kPa) when assisting the human left ventricle, and have a specific gravity of 1.0 for the implantable ventricular assist device.  [c.183]

Magnetic pulleys are available ia diameters from 152 to 1524 mm and ia widths that match the conveyor belt width. The material burden on the belt, belt speed, and type of tramp iron expected to be encountered are all considerations ia magnetic pulley selections.  [c.420]

Selection. The magnetic pulley width should match that of the belt. The face width is normally 51 mm wider than the belt width up to 1067 mm wide, and 76 mm on widths ia excess of 1219 mm. The speed of operation of the conveyor belt should be determined by calculating the maximum capacity to be handled. Using this iaformation, the diameter of the pulley required to handle the capacity can be determined (Table 2). The operating belt speed must be acceptable for the diameter selected. If the recommended belt speed is exceeded, the pulley diameter that can handle the belt speed must be used.  [c.420]

The chilled surface drying process is similar to atmospheric drying, with the cooling process being driven by a chilled surface as opposed to air flow through a tall tower. The wet soap is superheated in high pressure, nonboiling heat exchangers. Drying is achieved by the release of steam when this superheated soap is introduced into a chamber with a slight negative pressure, which is commonly referred to as a flash chamber. The resulting hot, dry soap melt is cooled through the formation of a thin film on a chilled surfaced, commonly in the form of a roU (rotating cylinder). The hot dry soap falls into the small gap ( 10 50 fiTo) formed at the interface between a large chilled roU and a smaller, temperature-controlled (may be heated or cooled) apphcator roU that aids in uniform film formation. As the chilled roU rotates, the dry, cold soap is removed via scraping with a doctor blade and emerges in the form of flat flakes. The amount of soap drying is governed by the temperature at which the soap is introduced and the air flow in the flash chamber. This process is exceptionally good for modem synthetic surfactant containing formulations because it is amenable to more sticky in-process materials. This drying approach can also be achieved using a chilled belt in place of the chilled roU.  [c.156]

The success of thrombus lysis depends mainly on how large the thrombus is and whether any blood flow stiU remains. The outcome is better the larger the surface of the entire thrombus exposed to the thrombolytic agent. As the clot ages, the polymerization of fibria cross-linking and other blood materials iacreases and it becomes more resistant to lysis. Therefore, the eadier the thrombolysis therapy starts, the higher the frequency of clot dissolution. Thrombolytic agents available are Hsted ia Table 7 (261—276).  [c.143]

Take-Ups. A take-up is requited on a belt conveyor to ensure the proper belt tension at the drive pulley and along the conveyor, as weU as to ensure the proper troughing contour between idlers. A take-up is also needed to compensate for changes in belt length caused by elastic stretch during start-up, and any elongation characteristics of the belt that occur over a period of time.  [c.155]

Belt Cleaning. Idlers and snub pulleys on the return mn support the belt on the material carrying surface of the belt and, therefore, are exposed to any material that may cling to the surface of the belt. This material is then transferred to the surface of the return idler roUs and snub pulleys and can adversely affect the training and control of the belt path. Cleaning sticky materials from the surface of a belt is difficult. There are available a variety of single and multiple-blade belt scrapers having spring or counterweighted supports, motor driven or belt powered blade, or bmsh cleaners. Each has had varying success in thoroughly cleaning the belt surface. A variety of self-cleaning idlers constmcted using mbber-disk, spinal, and beater roUs for use on the belt return mn have been moderately successhil in dislodging material from the belt surface.  [c.155]

Loading and discharge points on belt conveyors need to accommodate several factors. Figure 2 -Aa shows details for one type of rubber seal on a metal sldrt plate. It is particularly important that material be loaded onto the belt in its center and in the direction of its travel, preferably with lumps falling on a layer of fine material. Fines can be delivered to the Belt first by notching the feed chute or instalhng a screen sec tion or grizzly bars. Figure 21-4Z shows a heavy-duty loading-section design using not only rubber idler rolls but an additional short pad belt. Mass-flow bins and/or bin-flow-assisting devices are often used to minimize segregation of fines and to assure a uniform feed from a hopper onto a conveyor belt.  [c.1918]

One of the first successful techniques for selectively removing solvent from a solution without losing the dissolved solute was to add the solution dropwise to a moving continuous belt. The drops of solution on the belt were heated sufficiently to evaporate the solvent, and the residual solute on the belt was carried into a normal El (electron ionization) or Cl (chemical ionization) ion source, where it was heated more strongly so that it in turn volatilized and could be ionized. The moving belt system had some mechanical problems and could be temperamental. It can still be found in some laboratories, but the more recent, less-mechanical inlets such as thermospray and electrospray have replaced it. Thermospray alone gives poor ion yields, but thermospray with the help of an electrical discharge (plasmaspray) gives excellent ion yields. Thermospray alone is now obsolete, having given way to plasmaspray (atmospheric-pressure chemical ionization, APCI) and electrospray.  [c.71]

The definition of biologies versus dmgs continues to evolve. Assignment is made on a case by case basis (25). Section 351 of the PubHc Health Service Act defines a biologic product as "any vims, therapeutic semm, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, or analogous product... appHcable to the prevention, treatment, or cure of diseases or injuries in man." Biologies are subject to licensing provisions that requite that both the manufacturing faciHty and the product be approved. AH Hcensed products are subject to specific requirements for lot release by the FDA. In comparison, dmgs are approved under section 505 of the FD C act (21 USC 301—392), where there is not lot release by the FDA except for insulin products. Insulin, growth hormone, and many other hormones have been treated as dmgs, whereas erythropoietin (EPO), which also fulfiHs the criteria of a hormone, was reviewed in the biologic division of the FDA. Insulin is derived from a bacterial fermentation EPO is obtained from mammalian ceH culture. Hormones, for the most part, are expected to be reviewed as dmgs.  [c.46]

Haemonetics apheresis technology utilizes a discontinuous flow method, eg, countercurrent separation, to collect blood components such as plasma, single-donor platelets, lymphocytes, and stem cells. Anticoagulated blood from a donor enters the bowl via the inlet port and feed tube, as shown in Figure 5. At the end of the feed tube, the blood meets the base of the bowl and fluid is accelerated to the angular velocity of the bowl, ie, oJ = 4800 rpm (540 rad/s). As a result of the centripetal force, blood migrates into the separation chamber, ie, the space between the body and outer core. In this separation chamber, blood separates into layers according to the mass density of the components. When the separation chamber is full, plasma is forced out of the separation chamber into the upper assembly where it contacts the effluent tube that is not rotating. The bowl has a unique rotating seal which maintains steriUty of the bowl contents while allowing for rotation of the bowl. Plasma leaves the bowl through the effluent tube and outlet port into the effluent line, which leads to the collection bags.  [c.522]

History. Methods for the fractionation of plasma were developed as a contribution to the U.S. war effort in the 1940s (2). Following pubHcation of a seminal treatise on the physical chemistry of proteins (3), a research group was estabUshed which was subsequendy commissioned to develop a blood volume expander for the treatment of military casualties. Process methods were developed for the preparation of a stable, physiologically acceptable solution of alburnin [103218-45-7] the principal osmotic protein in blood. Eady preparations, derived from equine and bovine plasma, caused allergic reactions when tested in humans and were replaced by products obtained from human plasma (4). Process studies were stiU being carried out in the pilot-plant laboratory at Harvard in December 1941 when the small supply of experimental product was mshed to Hawaii to treat casualties at the U.S. naval base at Pead Harbor. On January 5, 1942 the decision was made to embark on large-scale manufacture at a number of U.S. pharmaceutical plants (4,5).  [c.526]

P. R. Foster and B. Cuthbertson, ia R. Madhok, C. D. Forbes, and B. L. Evatt, eds.. Blood, Blood Products and HIV, 2nd ed.. Chapman and Hall, London, 1994, pp. 211-251.  [c.538]

The efficacy of treatment regimens is gauged by the lack of symptoms and monitoring of blood chemistries, including blood glucose and glycosylated hemoglobin levels. The latter tests have revolutionized the approach to diabetic therapy. Blood glucose values can be monitored multiple times each day by the patient, with the goal of maintaining values as close to normal as possible. Various methods available for home blood glucose monitoring, including colorimetric dipsticks and electronic meters, require a small drop of blood newer, less invasive methods for blood glucose monitoring are under development. Hemoglobin in circulating red blood cells undergoes a nonenzymatic glycosylation to produce what is referred to as glycosylated or glycated hemoglobin, also known as hemoglobin A. This reaction takes place continuously over the life of a red blood cell, and its rate is governed by blood glucose concentrations. Therefore, the amount of glycosylated hemoglobin present at a given time reflects an averaged level of blood glucose control over the preceding 6—8 weeks. Taken together, home blood glucose monitoring and determination of glycosylated hemoglobin levels provide extremely useful parameters for assessing the efficacy of treatment.  [c.338]

In modem practice, topsoil is first stockpiled for later appHcation. The overburden, ie, sand, gravel, clay, etc, is then removed and the exposed coal is removed by bucket-wheel excavators, bucket-chain dredges, or draglines and shovels. Excavators having daily capacities of 2 x 10 m of overburden or coal have been built in Germany. These machines are 83 m high, 220 m long, and weigh 13,000 t. Plans for the Hambach mine near Cologne call for reaching a depth of about 500 m with an overburden coal ratio of more than 6 1. The bucket-wheel excavator works with a stacker of similar capacity to move overburden. The coal usually is moved by a conveyor belt and later by electric locomotives in 2000 t lots (27).  [c.154]

Wet chemistry methods for analysis of body analytes, eg, blood glucose or cholesterol, requite equipment and trained analysts (see Automated instrumentation). In contrast, dry chemistry systems can be used at home. Millions of people with diabetes check thein blood glucose levels and are able to obtain results in a matter of a few minutes. An insulin deUvery system that can respond to changes in the blood glucose level is not available. Injected insulin does not automatically adjust, and therefore the dose requited to mimic the body s response must be adjusted daily or even hourly depending on diet and physical activity. Self-monitoring of blood glucose levels, essential for diabetics, has become possible owing to the advent of dry chemistry systems (1—8) (see Insulin and other antidiabetic drugs). By regular and accurate monitoring of her blood glucose level by dry chemistry, an expectant diabetic mother can have a normal pregnancy and give binth to a healthy child. Athletes with diabetes can self-test thein blood glucose to avoid significant problems. Dry chemistry systems are usefiil not only to diabetics, but also to patients having other medical problems. These systems are also used in animal diagnosis, food, fermentation, agriculture, and environmental and industrial monitoring.  [c.38]

Noniu ueous Costings Since the 1970s, dry reagent coatings have been exclusively water-borne because of the behef that enzymes function only in aqueous medium. Nonaqueous enzymatic coatings for dry chemistries have been researched, developed, and refined, however (24,30) red blood cells do not adhere to such coatings. Additionally, quick end points are obtained. These coatings give superior thermostabiUty. Furthermore, these coatings can be easily ranged by antioxidants, whereas water-borne coatings are difficult to range. Nonaqueous hydroxylated acryflc polymers have been synthesized which have good hydroplulicity and hydrogel character. The enzymes GOD and POD are insoluble in organic solvents but become extremely rigid and can be dispersed with ease. Dispersions of less than 1 )Tm were made using an Attritor mill or a ball mill. To prepare nonaqueous coatings, polymer solution, TMB, mica, surface modifiers, and solvents were added to the enzyme dispersion and slightly mixed on a ball mill. Ranging compound can be post-added. The composition of a typical nonaqueous coating useful for low range blood glucose measurement, gram basis, is 33.29 hydroxyethyl methacrylate—butyl methacrylate—dimethylaminoethyl methacrylate (65 33 2) polymer (40% sofld), 2.38 TMB, 1.17 GOD, 2.68 POD, 3.28 sodium dodecyl benzene sulfonate [25155-30-0] 26.53 xylene, 26.53 1-methoxypropanol, and 1.96 cosmetic-grade C-4000 ultrafine mica. Many surfactants and surface modifiers that eliminated RBC retention were investigated. Antioxidants that function as ranging compounds in these nonaqueous systems include 3-amino-9-(aminopropyl)-carbazole dihydrochloride, butylated hydroxy toluene [128-37-0] (BHT), and a combination of BHT—propyl gaHate. These ranging compounds are effective in a ranging compound-to-TMB indicator molar ratio of 1 2.5—1 20.  [c.43]

Other Membrane Separation Techniques. The six membrane separation processes described above represent the bulk of the industrial membrane separation industry. A seventh process, dialysis (qv), is used on a large scale to remove toxic metaboUtes from blood in patients suffering from kidney failure (93). The first successful artificial kidney was based on cellophane (regenerated cellulose) membranes and was developed in 1945. Many changes have been made since then. In the 1990s, most artificial kidneys are based on hoUow-fiber modules having a membrane area of about 1 m. Cellulose fibers are stiU widely used, but are gradually being displaced by fibers made from polycarbonate, polysulfone, and other polymers, which have higher fluxes or are less damaging to the blood. As shown in Figure 43, blood is circulated through the center of the fiber, while isotonic saline, the dialysate, is pumped countercurrentiy around the outside of the fibers. Urea, creatinine, and other low molecular weight metaboUtes in the blood diffuse across the fiber wall and are removed with the saline solution. The process is quite slow, usually requiring several hours to remove the required amount of the metabohte from the patient, and must be repeated one to two times per week. Nonetheless, 100,000 patients use these devices on a regular basis.  [c.88]

If the laydown belt is moving and filaments are rapidly traversed across this direction of motion, the filaments are deposited in a zigzag or sine wave pattern on the surface of the moving belt. The effect of the traverse motion on the coverage and uniformity of the web have been described mathematically (28,29). The relationships between the collecting belt speed, period of traverse, and the width of filament curtain being traversed determine the appearance of the formed web upon the laydown belt. Figure 6 illustrates the laydown for a process where the collecting belt travels a distance equal to the width of the filament curtain x, during one complete period of traverse across a belt widthjy. If the belt speed is and the traverse speed is the number of layers deposited, is calculated by the formula, 2 = (V %)- h can be seen that if the traverse speed is twice the belt speed and if x andjy are equal, then a  [c.166]

A20 pigments, one of the oldest and most diverse group of pigments, comprise two types. One type consists of pigments that ate iasoluble ia the aqueous reaction medium ia which they are synthesized, eg, Hansa and diaryUde yellows and oranges, or aryUde reds and maroons. Most of the pigments show poor bleed characteristics, but relatively good acid and alkah resistance. They show acceptable lightfastness ia deep shades but poor tint lightfastness. The second type are laked or precipitated azo pigments derived from components substituted with sulfonic and/or carboxyhc acid groups. The pigments ate rendered iasoluble by precipitation as calcium, barium, strontium, or manganese salts. Among the commercially important laked pigments are Lithol Red and Lithol Rubiae [5281-04-9] Lake Red C [5160-02-1/, Red 2B, and more recendy iatroduced yellows based on pyrazolone sulfonic acid derivatives. These pigments are characterized by good to excellent bleed resistance, poor acid and alkah resistance, fair to good lightfastness ia deep shades, and poor tint lightfastness. Also available are special azo pigments which show very good overall properties and therefore find appHcations ia fairly demanding systems.  [c.25]

One successful total artificial heart is ABIOMED s electric TAH. This artificial heart consists of two seamless blood pumps which assume the roles of the natural heart s two ventricles (Fig. 7). The pumps and valves are fabricated from a polyurethane, Angioflex. Small enough to fit the majority of the adult population, the heart s principal components are implanted in the cavity left by the removal of the diseased natural heart. A modest sized battery pack carried by the patient suppHes power to the drive system. Miniaturized electronics control the artificial heart which mns as smoothly and quietly as the natural heart. Once implanted, the total artificial heart performs the critical function of pumping blood to the entire body (6).  [c.183]

BloodSa.lva.ge, In a growing awareness that a patient s own blood is the best to use when blood is needed, newer techniques are reducing the volume of donor blood used in many cardiovascular and orthopedic surgeries. Surgical centers have a device, called the CeU Saver (Haemonetics), that allows blood lost during surgery to be reused within a matter of minutes, instead of being discarded. This device coUects blood from the wound, mns it through a filter that catches pieces of tissue and bone, then mixes the blood with a salt solution and an anticoagulant. The device then cleanses the blood of harmful bacteria. Subsequently the blood is reinfused back to the same patient through catheters inserted in a vein in the arm or neck, eliminating the worry of cross-contamination from the HIV or hepatitis vimses (see Blood, coagulants and anticoagulants Eractionation, blood).  [c.183]

Blood Oxygena.tors, The basic constmction of an oxygenator involves any one of several types of units employing a bubble-type, membrane film-type, or hoUow-fiber-type design. The most important advance in oxygenator development was the introduction of the membrane-type oxygenator. These employ conditions very close to the normal physiological conditions in which gas contacts occur indirectiy via a gas-permeable membrane. Blood trauma is minimised by the use of specialized biomaterials such as PTFE, PVC, and cellophane, although lately siUcone mbber and cellulose acetate have predominated. A siUcone—polycarbonate copolymer, ethylceUulose perfluorobutyrate, and poly(aIkyl sulfone) were introduced in the mid-1980s, and tend to dominate this field.  [c.184]

The cross-belt separator has been used to concentrate such high value minerals as ihnenite, wolframite, mona2ite, xenotime, columbite, and tantaUte. The use of a lift action provides a high degree of selectivity and a minimum amount of entrapped nonmagnetic minerals. Because the accumulation of magnetics at the high intensity point creates a buildup across the belt width, the cross-belt magnet widths are limited to a maximum of 610 mm. The feed is, at most, a few particles deep and accordingly feed rates are limited to about 2 MTPH/m of feed belt width. Lower capacities are required for the cleaning of very weaMy magnetic minerals.  [c.430]

A method for determining a sample s total hemoglobin content was developed ia 1929. A tube of whole blood was ceatrifuged, packing the red cells at the bottom of the tube, and the percentage of total sample volume occupied by the RBC was deterroiaed by dividing the height of the packed cells by the total height of the sample. This perceatage was called packed cell volume (PCV) or hematocrit (HCT). Ia combination with RBC measuremeats, the hematocrit provided a sample s mean red blood cell volume (MCV) (3).  [c.400]

Arvin [9046-56-4] is a purified fraction from the cmde venom of Agkistrodon rhodostoma (48). The action of this venom fraction is selectively specific for fibrinogen and can rapidly deplete fibrinogen in vivo safely from the ckculating blood. Blood without fibrinogen cannot undergo clot formation.  [c.178]

OC- and P-Adrenoceptor Blocking Agents. Labetalol possesses both a- and p-adrenoceptor blocking effects, blocking both p - and P2-adrenoceptors, but only a -adrenoceptors (234,235). It also possesses P2-adrenoceptor agonistic (vasodilatory) effects, and produces significant reduction in blood pressure and a slight decrease in heart rate. It is efficacious in nuld, moderate, and severe hypertension. The cardiac output is maintained because of an increase in stroke volume. Exercise-induced blood pressure increases are blunted and the heart rate is reduced. In chronic treatment, PRA is reduced. Labetalol does not influence the blood cholesterol, triglyceride, orflpoproteins. The side effects are gastrointestinal discomfort and dizziness.  [c.141]

Calcium channel blockers reduce arterial blood pressure by decreasing calcium influx, resulting in a decrease in intracellular calcium (236,237). The arterial smooth muscle tone decreases, thereby decreasing total peripheral resistance. The increase in vascular resistance in hypertension is found to depend much on calcium influx. Calcium channel blockers reduce blood pressure at rest and during exercise. They decrease the transmembranous calcium influx or entry that lead to a net decrease of intracellular calcium and therefore the vascular tone falls, as does blood pressure.  [c.141]

In the pipe conveyor, patented by the Japan Pipe Conveyor Company, the belt is ia a flat position as it passes over the tail pulley to be loaded. It then passes through a transition section where it is transformed iato a tubular shape with the belt edges ovedappiag to form a seal. The belt is constrained ia this position by special multiroll idlers, spaced at iatervals along the length of the conveyor. The belt is opened at the head pulley to discharge the material, and then reformed iato the tube-shape as it continues back on the return mn. The tubular belt configuration encloses the material, and thereby eliminates the need for weather and dust enclosures used on conventional belt conveyors. A further advantage is that the material handling surface of the belt never touches the idler surfaces, thereby eliminating the problem of return idler contamination. The diameter of the pipes formed by the belt range from 100 to 900 mm. An example is shown ia Figure 3b.  [c.156]


See pages that mention the term Belts see V-belts : [c.283]    [c.465]    [c.203]    [c.277]    [c.143]    [c.34]   
Plant Engineer's Handbook (2001) -- [ c.0 ]