Failure behaviour of two types of adhesively bonded joints (composite-to-metal, metal-to-metal) has been studied under failure modes (Mode I: double cantilever beam (DCB) and Mode II: three-point end notch flexures (3-ENF)) using acoustic emission (AE) technique. The bonded specimens were prepared using two types of adhesive bond materials with three variations of adhesive bond quality. The effect of the presence of interfacial defects along the interface on the residual strength of the joint has also been studied. It was possible using the maximum AE amplitude method to select the AE events of mechanical significance. However, it proved difficult to propose a definitive AE trait for the mechanical phenomena occurring within specific AE event signals, for all adhesive types, bond qualities, and substrate configurations; therefore, all specimen combinations. There was a notable shift in spectral energy proportion as the AE source of mechanical significance varied along the specimen length for specimen combinations. However, it was difficult to confirm this distinctive trait for all specimen combinations due to difficulty in confirming the location and exact mechanical source. The proposed measurement technique can be useful to assess the overall structural health of a bonded system and may allow identification of defects.

No abstract

at Duiikirk, Saskatchewan, and tlic liorsc Shoe Lake .\lining Co., near Ormiston, Saskntchewan. The last-named coinpnny is owned and opcratcd by tho International Nickel Co. of Canada, and tlic reason for its existonce provides an interesting story of the rngirics of chemical industry.In sinelting the nickel coppcr orcs of the Sudbury district as carried out by thc lntcrnational Nickel, nitrc cakc is required at one stagc of the operation. The dcrelopmcnt of the synthetic ammonia proccss and the animonia osidntion method of producing nitric acid rcplaccd alinost cntircly the oldcr proccss of niniiufncturing nitric acid froiii sodium nitratc and consequently rcinovcd the sourcc of by-product iiitrc cakc, but had no effect irhatcvcr on tlic desire of Ziiternatioiinl Nickel to usc it in thcir siiicltiiig opcmtioiis. A sourcc of siipply was nssurcd by working the IIorsc Shoe Lake deposit for sodium sulphate which is shipped to Copper Cliir, \diere Canndian I ndustrics, Ltd., fuse it with sulphuric acid t o pro(liicc the rcqiiircd iiitrc ciikc. no lougcr a hy-product but one of priiiiary inlporta1icc.The clicniicnl proccsscs wliicb lia\*c been dcvelopcd arouiitl the siiicltcr of the Coiisolidntcd Jliuiiig SC SiiicltiiigCo. at Trail, 13.C., provide nil oiitstaiitling esninplc in the utilizrition of slncltcr funics protliicctl \vIicii sincltiiig sulpliidc orcs. Alcntioii has alrciiily been iixidc of thc siilpliuric acid plant a t this location. 111 :itltlitioii a syiitlietic rinirnoriiu plant using tlic Fiiuscr process opcratcs on hydrogen from ;in elcctrolytic phiit and using iuiported pliosplinte rock i~ coiiiplctc line of :iniiiioiiiuin phosphate fcrtilixcrs is prodiiccd :is ~vcll as ninnioiiiiini sullilintc.A more rccciit addition is a pliiiit to produce elenicntary sulphur from these fuuics. tl w r y ingenious proccss of coiiccntratioii of sulphur diosidc lias bccii workcd out at this plant. Sincc aninionin is :ivnilnblc which was later neutralized w i d sulphuric acid it is very siniplc chciiiicully to convert it Erst to aiuiiioniuiii sulphitc by scrubbing fluc gases with its water solution. On trciitincnt with sulphuric acid auiiiionium sulphat r, aiid stroug sulphur diosidc gas :ire produccd. Tliis strong gns is rcducccl with cokc giving eleincntary sulphur.Othcr fertiliecrs proiluccd for Ciiniidi:in coiisuniption are thc various grndcs of superpliosphatc which nrc manufactured by thc Obcr proccss :it Cnnntlinn In-dustries plants t i t 13cloei1, Quebec, and IIamilton. Ontario. Calciuin cyniiainidc is also manufactured by the North dnierican Cyanamide Co. a t Xiagarti Palls, Ontario. Otlicr products :it this plant arc sodium cpinide for use in tlic niiniiig industry and sodium silicnte glass which is produced in an electric furnace. This paper has been prepared as a Ilricf description of the heavy cheniical iildustry in Canada in which statistics ham been studiously avoided. There are, ho\vever, two figurcs wliich iiicnii considerably iiioro than tlic usiinl run of statistics. 7'he figures nvailablc nrc for tlic ...

Some twenty five years ago Dr. A.H. Stuart established a private research laboratory for the investigation of certain industrial problems which were then being brought to his notice. These problems ranged over a wide area but in recent years those connected with lubrication have been much in evidence. Some of them have lead to an intensive study of the physical properties of graphite. In addition to a large number of private reports to engineering firms, he has published over 400 papers and articles on this work. Dr. Stuart has served on a number of research committees and panels of examiners and is the author of six books on applied mathematics. In the following article he discusses the value of colloidal graphite for lubrication at high temperatures and pressures, for running‐in new machinery and its application to resin‐bonded fabric bearings.

The friction characteristics of dry films formed on the surface of metals by natural or artificial means has been investigated in some detail, both in this country and in the U.S.A. for some years past. The work is of more than academic interest and has been stimulated by an ever increasing number of industrial problems which call for dry film lubrication in their solution.