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APPENDIXSix rats were fed for 6 days a diet containing 16% of casein as the sole protein. For the last 3 days they were kept in metabolism cages, and the urine and faeces for each day were collected.They show that data based upon the nitrogen intake and excretion for one day indicate the state of nitrogen balance as well as those based upon figures for 3 days.The results of a study of the nitrogen balance are shown in the table. Ranges, avevages, and standard deviations Values for six rats for three separate days Daily N intake, mg. 203-244, 2373=16*7 232-244, 242 f 4 ' 9 223-244, 241 +8.G Daily N excretion, mg. 121-187, 17Oh 25'4 127-190. I70 5 23.6 I 30-202, 173525.4 N balance yo of ingested (positive), mg. N retained 6 7 5 1 1 . 1 29 f 6.6 54-105. 22-41. 7 ' i 19.3 2 9 5 7 . 2 42-93, 17-42. 57-82, 23-40, 68f18.9 2 9 f 8 . 9 Values for six rats for three days combined 219-244, I 26-190, 54-93, 22-41, 240h10.2Custard apple pulp, when exposed to air, turns pink due to peroxidase activity and becomes bitter when heated above 55", whch renders preservation by heat treatment inapplicable. To preserve the pulp, it is necessary to add 1% of citric acid together with 0 .

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The results are presented of an investigation of the yield and total solids content of the latex obtained in successive tappings of papaya fruit and of the yield and activity of the crude papain obtained from the latex samples by sun-and vacuum-drying. The effect of the addition of metabisulphite, with and without thymol, on the activity of th'e dried products is described. IntroductionStudies on the preparation of papain have been conducted by several w,orker~,l-~ but little information is available in the literature regarding the yield and total solids content of the latex and the yield and activity of crude papain in different individual tappings, except for papers from workers in Cey1on.j These points have now been investigated, with a study of drying conditions and chemical treatment of papaya latex in a pilot-plant investigation on the development of an integrated process for the preparation of crude papain and pectin* from raw papaya.

Tribological behaviour of Ti-6Al-4V alloy sliding against WC-Co was evaluated by employing WS 2 nanoparticles blended in a cutting fluid used for machining of this alloy. Pin-on disk tests were carried out under boundary-lubricated condition using a cutting fluid (70% water and 30% oil) blended with WS 2 nanoparticles (CF + WS 2 ). When a cutting fluid with ≥ 0.5 wt.% WS 2 was used, the COF of the tribosystem was reduced compared to CF + 0%WS 2 . The lowest COF of 0.05 was obtained when 1.0 wt.% WS 2 was used. Low and stable COF values were accompanied by the formation of a tribolayer incorporating WS 2 and WO 3 on the WC-Co surfaces. During orthogonal machining of Ti-6Al-4V using CF + 1.0%WS 2 , a tribolayer with the similar composition was formed on the cutting edge of the WC-Co tool and the average cutting force was reduced by 35% compared to cutting with CF + 0%WS 2 . Machining with CF + 1.0%WS 2 produced thinner chips. Other improvements in machining performance attained using CF + 1.0%WS 2 included reduction of adhesive wear on the tool and a lower roughness of the machined surface.