Pressure infiltration, application

Studies reviewed herein have demonstrated the potential ability of several new approaches to control enzymatic browning in fruit and vegetable products the use of novel AA derivatives, polyphosphates and (5-cyclodextrin as browning inhibitors the application of browning inhibitors to cut fruits and vegetables by pressure infiltration and the use of cvs. having a low tendency to brown. It is likely that one or more of these approaches will be useful as an alternative to sulfites to control browning in affected commodities. 

Table 1—Application of Browning Inhibitors to Delicious Plugs by Pressure Infiltration vs Dipping...

Infiltration rate. This is the rate at which air moves through a window system as a result of pressure differences between the inside and the outside. Infiltration rates are expressed as airflow rates—cubic meters per hour or cubic feet per minute per square foot of window. An infiltration rate below 0.3 cfm/sq ft is recommended in all applications. 

The risk of adverse reactions is low, and includes mainly vaso-vagal reactions, which can partly be prevented by the patient lying down in connection with the application. The vaso-vagal reaction is characterized by a fall in blood pressure, bradycardia, pallor and, rarely, loss of consciousness and convulsions. Infiltration of larger amounts of anaesthetics, e.g. in a fracture hematoma, increases the risk of systemic toxic reactions with paraesthesias, metal taste and visual disturbances. The infiltration should be stopped when there are such symptoms, which could precede the more serious reactions (loss of consciousness and convulsions). 

As the anesthetic agent is absorbed and thus removed from the site of application, its local action ceases, and its systemic and toxic effects start. Because most of these drugs, especially cocaine, are rapidly destroyed in the body, the systemic toxicity increases with the rapidity of absorption. It is therefore desirable and often necessary to delay the absorption. This may be done by restricting the local circulation. Cocaine itself tends to do this by producing a local vasoconstriction, an action that is not shared by its substitutes. This vasoconstriction should be reinforced by the addition of epinephrine. More dilute solution may thus be used, and the anesthetic effect is much more prolonged. With intracutaneous infiltration, the pressure and edema also result in ischemia. In suitable situations, the circulation may be slowed by bandages, or arrested by temporarily clamping the arterial blood supply. 

Infiltration occurs due to capillary attraction within the fiber preform and can be undertaken at atmospheric pressure by passing a continuous tow through a bath of molten metal, but is practical only if the molten alloy wets out the carbon fiber [161-168]. A plated coating used to aid wetting must not be too thin otherwise it will be dissolved completely before infiltration has been completed. The application of pressure aids infiltration, but if the preform is compressed too much, then infiltration is prevented, limiting the fiber fraction to about 30 vol%. Composites with Pb alloy matrix can be prepared by an infiltration technique... 

The Lanxide Corporation (now intellectual property within MSE Inc.) have patented the PRIMEXTM pressureless metal infiltration process and the PRIMEX CASTTM foundry process, which are able to infiltrate ceramic reinforcements with molten metals without application of pressure or vacuum and it is believed that the processes can be used with carbon fiber. 

Materials successfully applied as a contact surface include boron nitride coated graphite, alumina, and quartz. Each possesses a smooth surface that does not react with the metal sample in a high temperature environment. Contact pressure was applied by either thermally compressing the stack or applying a weight. To compress a stack by thermal means, an inconel rod was placed at either end of the stack between the end sample and crucible wall. When the inconel rod lengthens due to thermal expansion, a compressive force is applied to the stack. This can be seen in Figure 3 where a setup is shown post-infiltration. Note the lateral face application of the contact surfaces and the placement of the stilts into the pool of bronze. 

Figure 3. Experimental Setup for Contact Infiltration Using Thermally Induced Pressure Application... 

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