الفهرس 
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Abstract
Thread greases have a great importance due to the tremendous pro-gress achieved by the mechanical industries of machines and engines of various types and uses, and the accompanying progress in terms of the increase in the amount of production. Nowadays, the international
energy organizations are expecting the depletion of crude oil;
therefore, the search for alternatives from renewable resources
become necessary. On the other hand, sugarcane bagasse is one of the environmental problems because the most used method for dis-posing of sugarcane bagasse is burning it in the air, which considers a burden on the environment. Accordingly, this study aims to maximize the utilization of some renewable resources, such as used cooking oils, sugarcane bagasse, and polymerized jojoba oil, in the preparation of the thread biogreases.
Physicochemical properties, identification and characterization of the purified waste cooking oil and jojoba oil were carried out using ASTM/IP standard methods analysis. These include density, refractive index, and Kinematics viscosity at 100 oC, Dynamic viscosity at 50 oC, molecular weight, total acid number and iodine value. In addition, fatty acid composition of Purified waste cooking oil and jojoba oil were determined using GC. The obtained acids from GC in Purified waste cooking oil are Capric, Lauric, Tridecanoic, Myristic, Pentadecanoic, Palmitic, Palmitoleic, Heptadecanoic, Stearic, Oleic and Linoleic with percentage, 0.66, 0.43, 0.28, 19.30, 4.96, 22.94, 8.29, 8.63, 4.95, 0.66 and 0.43 respectively. And the fatty acid composition of jojoba oil Myristic acid, Palmitic acid, Oleic acid, , Palmitoleic acid, Stearic acid, Eicosenoic acid, Erucic acid and Lignoceric acid with percentage 0.3, 2.05, 12.3, 0.6, 0.53, 57.13, 11.63, 2.0.
On the meantime, the rheological properties of PWCO and jojoba oil are studied at different temperatures, 30oC, 50oC and 70oC. It was found that the both oils showed Newtonian behavior.
Torrefaction process of sugarcane bagasse was carried out in autoclave 2 L at temperature 250oC for 2 hours. The total yield was determined by the difference between the weight of sample before and after the torrefaction experiment. Mass yield of torrefied bagasse was ranging 65% and 75%.
The partial thermal decomposition (torrefaction process) of sugarcane bagasse was carried out using an autoclave bar in isolation from air and in the presence of nitrogen gas. The effect of thermal decomposition temperatures and contact time of sugarcane bagasse were tested. It found that the conditions that give the highest yield of torrefied bagasse are temperature of 250 degrees Celsius and contact time of two hours. It was grinded, the particle size was determined and it was found to be 282 nm; the ultimate analysis of raw sugarcane bagasse and torrefied bagasse were determined. The results showed that the torrefied bagasse consists mainly of carbon by 52.70, hydrogen by 3.80, oxygen by 43.22 and nitrogen by 0.28. This reveals that the possibility and importance of using the resulting torrefied bagasse as a thickening and filling agent for the thread biogreases under investigation.
Jojoba oil undergoes polymerization in microwave at different time to produce different grades with different Molecular weight PJ1, PJ2 and PJ3, The physico-chemical properties for the produced polymers were determine; tribological properties of the prepared polymers were determined using four ball tester, it was found that PJ1 with lowest molecular weight ,1230, has lowest friction coefficient and wear scare diameter . This indicates that the PJ1 (oligomer with low molecular weight from jojoba oil) is considerable as an additives So, PJ1 is the best type to be used as an additives to the prepared thread biogrease under investigation.
In addition, Multiple-objective optimization software (LINDO, version 17) is used to perform the required optimization, aiming to minimize both FCO and WSD. The limits for the affecting variables minimum WSD and FCO are 309 and 0.003 respectively. This could be achieved at 196 N, 600 rpm and 1.2 hr.
In this respect, five grades of thread biogreases were prepared, name-ly G1, G2, G3, G4 and G5, in which G1 is without PJ1, but G2, G3, G4 and G5 with PJ1 in concentrations of 1%, 3%, 5% and 6%, respectively. The physicochemical, tribological and chemical corrosion properties of the prepared greases were determined.
In general, the results showed that the grease prepared using
polymerized jojoba oil PJ1 is better than the grease prepared without PJ1.Comparing the prepared greases in the presence of different
concentrations of PJ1, it was found that the physicochemical and
tribological properties improve with increasing the concentration of PJ1.
The study is showed that the use of biomass (sugarcane bagasse and waste cooking oil) can be used in the preparation of thread biogrease, in addition to using the polymerized jojoba oil with a molecular weight of 1230 as improver.