Multiple injection units

Co-injection molding involves injecting two or more different materials into a mold, generally in sequence. To accomplish this, molding machines are fitted with multiple injection units (Figure 14-53). Two-shot molding, the most common version, often utilizes an indexing mold. In this process, the mold is rotated 180° after the first shot fills a portion of the cavity, then the second shot finishes the part... 

Multi-shot processes, as the name implies, require multiple shots of material to make a single component. For each one of these materials an injection unit is required. To mould these multiple shots also requires special tooling and equipment. Multi-shot capability can be built either into the injection tool or controlled by the injection moulding machine. To enable multi-shot, multiple injection units can be arranged to feed machines in a number of ways as the next section will explain. 

Multiple injection units can be arranged aroimd the clamping units as combinations of horizontal and vertical units in piggy back or right angle configurations. Some examples are shown in Figure 10.27. 

If the mass spectrometer is equipped with an LC system, then fast fingerprint MS analyses can be performed by injection of a series of different samples by the autosampler unit. This system will allow automated operation of a large series of samples. In addition, it is possible to utilize the flexibility that lies in the use of different mobile phases and the fast variation between them. The LC-MS system is simply operated as an ordinary LC-MS system, but without an analytical column. Typical injection volumes would be between 0.1 and 3 pL, and mobile phase flows between 0.1 and 0.2 mlV min. With this flow, a chromatographic peak will appear between 0.3 and 0.8 min after injection. Total time per analysis will be 1-2 min per injection. With a scan range of m/z 65-1500, a sufficient number of scan spectra (>15 spectra) will be captured for further data processing. Normally, it is preferred to perform multiple injections from the same sample, and the number of injections could be from 3 up to 10, depending on the study. With multiple injections, the precision of the analytical system can be controlled directly from the score plots and, of course, be evaluated relatively to the differences between the samples. 

Reaction-injection-molded PU offers a solution for the rapid production of complex plastic parts directly from low-viscosity monomers (single chemical unit) and oligomers (chain of multiple chemical units). These liquids are combined by impingement mixing as they enter the mold. 

The dosing system for liquid silicone rubber, which was described previously, is designed for only one machine. In order to save costs on space and investments, central material supply units are also available. Here, multiple injection moulding machines are supplied from one dosing system. Modem material conveyance systems operate on the concept of central material supply with a decentralised supply by volume at every injection moulding machine. Figure 7.8 depicts this type of system in a schematic overview. 

Flare noise (roar of combustion) is the most serious because it is elevated and the sound carries. The flare can be located at a remote distance from the operating unit or surrounding community. Noise of steam injection into the burner can be reduced by using multiple no22les. Furnace noise from air intake, fuel systems, and combustion blower forced draft/induced draft (FD/ID) fans can be reduced by acoustics. The plot plan should be evaluated for noise generation and to find the means of alleviating or moving noise to a less sensitive area. 

A notable difference between the newer large machines and the somewhat smaller units is the use of multiple, reverse-flow can combustors configured annulady. Because the individual cans are relatively small, they reportedly lend themselves well to laboratory experimentation with various fuel types, including reduced-heat value synfuels (see Fuels, synthetic). A dry, low NO version of the can combustors has been developed for both gas and hquid fuel firing. NO emissions can reportedly be held below 25 ppm when firing gas fuel. By employing water injection, NO emissions can be held below 60 ppm for oil-fired units. 

A more simplified description is a unit that combusts materials in the presence of oxygen at temperatures normally ranging from 800 to 1650°C. A typical configuration of an incinerator is shown in Figure 9. Typical types of incineration units that are discussed herein are catalytic oxidation, fluidized beds, hquid injection, multiple hearth furnaces, and rotary kiln. Thermal desorption is also discussed. However, an overview of the main factors affecting incinerator performance is presented first, below. 

A maximum latency of 50 seconds was allowed to prevent tissue damage and to enable multiple testing. Drugs were given by cumulative IV injections at 42-minute intervals up to a maximum dose one unit below the dose which produced rotarod failure. 

Intramuscular injections have been shown to produce elevations in serum enzyme activities presumably due to either inflammatory areas in the muscle or actual breakdown of cells and release of enzyme. In one study, preinjection values of creatine phosphokinase were in the normal range of 24-100 units. Multiple intramuscular injections of penicillin, diuretics, and narcotics every 6 hours caused the creatine phosphokinase values to rise to levels between 160 to 240 units, or up to 2.5 times the upper limit of normal. When the injections were stopped, the creatine phosphokinase values returned to normal within 48 hours (B7). Similar observations of aspartate aminotransferase activities were made in patients receiving intramuscular injections of penicillin every 4 hours. Activities rose to values as high as 200 units. Other workers have reported injection related serum creatine phosphokinase elevations following intramuscular administration of chlorpromazine and suxamethonium (HIO, M11,T6). 

Injection 1,000, 5,000, 10,000, and 20,000 units/mL (multiple-dose vials) (Rx) Various, Liquaemin Sodium (Organon)... 

Primary axillary hyperhidrosis (Botox only) The recommended dose is 50 units per axilla. Define the hyperhidrotic area to be injected using standard staining techniques (eg. Minor s Iodine-Starch Test). Botulinum toxin type A is reconstituted with 0.9% nonpreserved sterile saline (100 units/4 mL). Using a 30-gauge needle, 50 units of botulinum toxin type A (2 mL) is injected intradermally in 0.1 to 0.2 mL aliquots to each axilla evenly distributed in multiple sites (10 to 15) approximately 1 to 2 cm apart. 

Even if a medication is available in multiple formulations and dosage forms, the prescriber must consider the absorption and distribution differences between adult and pediatric patients. Blood supply at injection or infusion site, available blood supply for unit muscle mass, and skeletal muscle mass relative to body mass vary with patient age and size, causing drug absorption to vary, as well. A rapid intravenous bolus in a pediatric patient might result in acute toxicity a slow intravenous infusion, often required in neonates, can cause erratic, unreliable drug delivery in an older child. In addition, the volume of fluid tolerated for intravenous delivery varies significantly with the age and size of the patient. The blood supply and blood flow to and from the injection site are of prime importance since a gradual decrease in blood supply per unit muscle mass is seen with maturation. In addition, the skeletal muscle mass relative to... 

Dosage form Pitocin is available in a 1 ml ampule, a 1 ml prefilled syringe, a 1 ml vial, and a 10ml multiple-dose vial. Each preparation contains oxytocin 10 units/ml. Oxytocin Solution for Injection (Eon, Fujisawa) is supplied as a 1 ml ampule or vial and a 10 ml vial each contains oxytocin 10 units/ml. Oxytocin for injection also contains oxytocin 10 units/ml. 

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