Trepanning

To obtain a clear picture of larger, more complex, offline WT boilers, in addition to visual inspections, it is common practice to trepan or cut sections out of some of the tubes. The deposits found are weighed, reported as a weight per unit surface area, and analyzed. Repairs are then made to the tubes. 

The cellular reaction product consisted of alternating plates of C03W lamellae in a solute-depleted Co matrix (eCo). Ffomogenized ingots were cut into slices 1 mm thick and then heat-treated. Spark erosion was used to trepan 3 mm diameter discs which were then jet electropolished to form thin foils for TEM examination in a Philips EM 430 STEM instrument operating at 300 kV in the nanoprobe mode with a probe size of 5 to 10 nm. 

Antiquity. The treatment of what we now call schizophrenia probably dates back to prehistoric times. In early cnltures, madness was usually believed to result from some malevolent external force that invaded the person and took possession of the individnal. Treatment efforts would then be directed at enticing or driving out these evil spirits. This would explain the rise of shamanistic exorcisms that existed in a variety of cnltnres and remain prevalent today. In addition, it may be that trepanation (removing a piece of the skull) practiced by Stone Age peoples may have been the hrst psychosnrgery used to allow the evil sprits an avenue of escape. 

The big diameter LK was first introduced in the year 2000 by Vajpayee [50] for a use in the surgical treatment of sequelae due to comeal bums. Vajpayee has recorded the results of nine ocular operations. The intervention begins with a conjunctival peritectomy over 360°. The conjunctiva is reclined backwards. The recipient cornea is trepanned to a 12-13 mm diameter and to a 300 pm depth. The lamellar graft is sampled via a trepanation at 1.5 mm back to the limbus in order to include LSC. It is then sutured by 24 10/0 nylon stitches. Despite the limbus allograft, no immunosuppressive therapy has been prescribed. The operation was practiced about 30 months after the occurrence of the bum. Results are recorded after a 7.4 month observation. The visual acuity has improved in six cases. No recurrence of the comeal neovascularization and no... 

In animals of the control and experimental groups after eye treatment with 0.5% dicain solution, a mechanical trauma in the central part of the cornea was produced by a trepan. Wound depth achieved was half of the corneal thickness diameter was 4 mm. 

S.K. Chark, P.V. Rao Trepanning of A1203 by electro-chemical discharge machining (ECDM) process using abrasive electrode with pulsed DC supply. International Journal of Machine Tools Manufacture 47 (2007), pp. 2061-2070. 

V.K. Jain, S.K. Chak Electrochemical spark trepanning of alumina and quartz. Machining Science and Technology 4 (2000), pp. 277-290. 

The original specification for the thickness of steel plates used in the manufacture of the hull was 11 mm. Core samples were taken by trepanning and the thickness of the metal remaining was measured. The results ranged from 9.0 down to 2.5 mm, with the bow section having experienced the most severe corrosion. In certain areas, the steel had completely corroded with gaping holes clearly visible. This illustrates the wide variation in corrosion rates experienced by the submarine as it lay for some 70 years on the seabed. 

Drilling Trepanning cutter large round hole... 

Twist drill Spade drill Trepanning cutter Center drill Combination drill Countersink Counterbore... 

The tumour was implanted by stereotactical implantation. The rats were anaesthetized with 0.1ml Equithesin/lOOg body weight. A skin incision was made, and the skull was trepanned using a dental drill 2.5mm in diameter. 40,000 cells (20,000 cells/pl cell suspension) was injected with a Hamilton syringe with a cone-tipped 0.7mm needle at a depth of 2.5mm. The protocol was approved by the Norwegian State Comission for Animd Experimentation. 

Laser Beam Machining, Fig. 5 Process approaches for single pulse, percussion, and trepanning drilling (a-c) as well as machining (d) with focused laser beams... 

Polyurethane adhesives in neurosurgery. KL-3 has been widely used in the following surgical situations [421] recovery of potency of cerebral arteries with saccular anemysms that cannot be eliminated from the circulation plasty of cerebral fistulas in the anterior cranial fossa the closing of defects in the dura mater plasty of trepanation holes fixation of bone fragments in craniotomic defects and sealing of extra- and intracranial anastomoses. 

Fig. 99. A viscoelastic pillow in the anterior chamber serves as deposit for the donor cornea in the trepanation opening...

Where large-diameter holes are required in sheet metal, they can be conveniently cut using a trepanning tool. Fig. 8.17(a). 

The arm can be adjusted to any diameter within the range of the trepanning tool, which may be as large as 300 mm. The cutting tool can be ground to any angle to suit the material being cut. 

Large holes in sheet material can be produced using a trepanning tool. 

The total number of charge location sleeve bolts in two reactors is 800. Four have been sampled by trepanning and 13 by the ultrasonic test rig. None have yet exhibited a defect. 

This bolt was subsequently trepanned out and did not exhibit a defect on Initial Inspection. Detailed analysis of this bolt Is not yet available. 

Table 7.5 Range of average chemical analyses (wt%) from Trawsfynydd RPV trepanned welds 1, 2, 3 and 4 compared with mean values from surveillance and vessel cut-outs ...

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