Pin-holing

This procedure is used to separate crystallized product from solvent or to remove crap and solids from a liquid. Figure 8 shows the proper apparatus to use. The collecting flask is called a side arm flask and to that extended nipple (tee heel) is attached a vacuum source. The thing that is shoved through the rubber stopper is called a Buchner funnel and is usually made of white porcelain or, preferably, PP. The Buchner funnel, when viewed from above, can be seen to have lots of pin holes in the bottom surface of its reservoir. Over this surface is layered a single sheet of rounded filter paper or paper towel. 

The most significant commercial product is barium titanate, BaTiO, used to produce the ceramic capacitors found in almost all electronic products. As electronic circuitry has been rniniaturized, demand has increased for capacitors that can store a high amount of charge in a relatively small volume. This demand led to the development of highly efficient multilayer ceramic capacitors. In these devices, several layers of ceramic, from 25—50 ]lni in thickness, are separated by even thinner layers of electrode metal. Each layer must be dense, free of pin-holes and flaws, and ideally consist of several uniform grains of fired ceramic. Manufacturers are trying to reduce the layer thickness to 10—12 ]lni. Conventionally prepared ceramic powders cannot meet the rigorous demands of these appHcations, therefore an emphasis has been placed on production of advanced powders by hydrothermal synthesis and other methods. 

When selecting a particular paster adhesive, coating material, and coating process for sohd fiber packaging, the fact that sohd fiberboard lacks the open-flute stmcture (to facihtate exit of moisture from internal phes of paperboard) should be considered. It is generally desirable to minimize the amount of process water added with the adhesive or coating with sohd fiber products. Moisture trapped in the filler phes can result in pin holes or bhsters in the coating and/or warp of the sheet (15). 

High purity 75% ferrosihcon containing low aluminum and calcium can be used in continuously cast heats where nozzle blockage is a problem. In iron melting, this ahoy is desirable to minimize buildup on refractory faces in the furnace or on stopper rods or nozzles. Low aluminum ferroshicons can also help reduce hydrogen pin holes in castings poured in green-sand molds. 

Quite often problems arise when instruments for normal seiwice are subjected to low temperature use. Since some metals become brittle at low temperatures, the instrument hteraUy falls apart. Elastomeric gaskets and seals contract faster with decreasing temperatures than the surrounding metal parts, and the seal often is lost. Even hermetically sealed instruments can develop pin holes or small cracks to permit ciyogenic liqmds to enter these cases with time. Warming the instrument causes the trapped hquid to vaporize, sometimes generating excessive gas pressure and failure of the case. 

The sheet may also be inspected for the quality of welding and checked for pin-holes by a weld-hole detector before it is finally cut into lengths or wound onto rolls. 

As discus.sed earlier, puny filling is generally not advisable unless the surface is poor, uneven or has pin holes. If is advisable to use primer surfacer, which provides a thicker coal and helps to fill such surfaces. The epoxy primer is thicker and may do this job in most cases. 

A new nose eone was obtained and initial maehining performed by die repair faeility. The nose eone is supported by six radial pins. The nose eone and inlet easing were sent to die main plant to ensure die pin hole loeations were properly positioned. Here, die inlet easing was assembled and oversized pin holes were drilled and reamed in die pieees. Pins made to fit die holes were also maehined. Repau maehining... 

Assuming that an adequate transition fit is speeified for both the pin hole and eoupling bore, the pin is in double pure shear with the bore of the eoupling, and so the shear stress, L, is given by ... 

A Tube Furnace.—Various forms of furnace are used. Those which are heated on the principle of the Lothar Meyer hot-air furnace by a number of pin-hole gas jets are easily regulated, and can be raised to a high temperature. The Gattermann furnace, shown in the diagram (Fig. 20), is a very convenient form. 

Check the seal rotary unit and make sure the drive pins and spring pins are free in the pin holes or slots. 

High-voltage coating-testing equipment When cathodic protection is applied to a structure which has a protective coating, the current required is proportional to the bare metal area on the structure. Thus whenever a protective coating is applied it should be of good quality, with very few failures or pin holes in it, so that the cathodic-protection system may be economic. 

It is quite necessary that the welding of the tank is perfect and free from pin holes. Leaks frequently appear where the tubes are welded in the top of the tank. These may be eliminated by brazing the joints. A less satisfactory way is to use a cement of litharge and glycerol. This cement may also be used with success on leaky valves. Occasionally leaks occur in the rubber tubing or its connections with the bottle or tank, but these are unusual. 

Mercury. Double distilled mercury is usually recommended for polarographic work. The re-distilled mercury of commerce is generally satisfactory for most determinations it should be filtered through a filter-paper cone with a small pin-hole in the tip (or through a sintered-glass funnel) before use in order to remove any surface oxides or dust. 

Clinker treatments are additives designed to reduce the amount of clinkering formations that takes place in boilers fired by bark, bagasse, and similar low-calorific-value fuels. These fuels can give rise to considerable amounts of noncombustible deposits that must be continuously or regularly removed from the furnace area. Clinker treatments are formulated for use with various types of furnace, including slant, pin hole, and chain grate furnaces. 

The biggest challenge to produce an ultra-thin (about 1 nm) overcoat is to make the coating free of pin-holes while maintaining the durability and tribological properties. In an HDD system, pin-holes can cause much more contaminants from all sources, such as outgas compounds from polymeric foam components, pressure sensitive adhesives, ionic residues from improperly cleaned components and ambient pollutants, which can be detrimental to the tribology and durability of the HDD. Therefore, efforts have been made mainly on the improvement of carbon film [4-7]. 

Figure 4.6 Block diagram of the apparatus for the fluorescence depolarization measurement. The dashed and solid arrows indicate the light paths ofthe excitation pulse and the fluorescence from the sample. OBJ microscope objective, M mirror, L lens, DM dichroic mirror, LP long-pass filter, PH pin-hole, PBS polarizing beam splitter, P polarizer, PMT photomultiplier.

The speed of burning of fast igniter cord depends on the speed of burning of the blackpowder-coated yarns and this depends in turn on the gas channels left in the construction of the fuse. The remainder of the fuse is also combustible, so that there is no pressure build up due to lack of venting. Should a minor pin hole or break in the outside layers be produced and water enter, the incendiary composition will continue to burn so that the fuse will not fail, although it will slow down for the distance of the damage. 

Dip 20nm-50pm Complex and irregular shapes can be coated, can be a continuous process, very simple Thickness variations, voids, and pin holes Insulating polymer layers, electronic parts, and assemblies... 

Common defects that are observed in this coating technique are voids, pin holes, thickness variations, and wavy surfaces. Voids and pinholes are caused by air entrapment in the film, surface contamination, or dust particles. 

Cylindrical lead collimators with 10 mm thick walls and a clear aperture of about 10 mm diameter were placed between the pin-hole and the X-ray output window of the main chamber to reduce scattered photon noise inside the vacuum chamber. Also, a set of magnets (with typical magnetic field strength of about 1 T) were placed inside each tube to stop high-energy electrons. All these measures were adopted to reduce as much as possible X-rays produced... 

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