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Cooking process is one of the most energy and time consuming steps in the edible oil extraction factories. The main goal of this study was cottonseed oil extraction by microwave radiation and elimination of any heat treatment of cottonseeds before extraction. The effect of cooking process on the physicochemical properties of extracted oil from two varieties of cottonseed (Pak and Sahel) was evaluated by free fatty acid content, melting point, smoke point and refractive index. Our results didn't show any significant differences between cooked and uncooked samples (P>0.05) regarding physicochemical characteristics. From GC analysis of extracted oils, it was found there is no significant difference in fatty acid composition of cooked, uncooked and control (conventional extraction) samples. The thermal stability (Rancimat) analysis of oil samples showed the cooking process could cause a slight increase in the stability of oils for both varieties (about 40 min). The cooking process also increased total extracted phenolic compounds and considerably decreased total gossypol content of the cottonseed oil; but the extraction efficiency didn't change considerably after elimination of the cooking process. It can be concluded that microwave rays can destroy the structure of oil cells during process and facilitate the oil extraction without any heat treatment before extraction.

The friction and cohesion forces take an important place in fiber processing. The friction force defines the sliver and rover strength and, up to a certain level, the yarn strength also. Many works deal with the measuring of the inter-fiber friction force using different methods. Some of these studies concern the measure of the frictional force on one single fiber. Basu et al.[1] measured the variation in the frictional forces developed between a straight-edge probe and a single Egyptian cotton fiber under a range of some normal loads. Postle and Ingham [2] measured the frictional force during the withdrawing of a wool fiber from a compressed pad. Lindberg and Gralen [3] measured the frictional force between two fibers twisted together. Lord [4] studied the frictional force developed during the relative motion of two identical fiber fringes. The method of El Mogahzy and Gupta and El Mogahzy and Broughton [5,6] is very similar to Lord's, but their apparatus was more precise. They studied theoretically the friction phenomena and tried to explain Howell's equation.The friction may be approached by the drafting force. Martindale [7], Kamarov et al. [8] and Cavaney and Foster [9] tried to measure the drafting force for cotton and rayon. They showed its dependence on the draft, the input sliver count, the compactness, the sliver direction, the distance between the drafting cylinders (ratch), the front roller speed and the fiber length. Oslen [10] later used the device of Martindale, performing the measurement precision by using an electric force sensor. Brook and Hannah [11] measured the force developed during the extension of twisted wool roving at the same magnitude speed as the normal drafting. Grishin [12] and Hannah [13] tried to explain theoretically the drafting force. There are some other methods for measuring inter-fiber frictional behavior, as in the method of Baratlett et al. [14]. They studied the behavior of yarn withdrawn at a constant speed and tension, in contact with a short portion of a music wire, a yarn or other flexible objects. 1 There are few methods for measuring frictional forces in yarn. King [15] and Morrow [16] measured frictional Abstract The friction and cohesion forces are some of the most important parameters that affect the yarn spinnability and tenacity. A new and simple device was carried out in order to quantify the friction and cohesion forces during a quasi-static fiber slippage in a sliver. This device was composed of two identical small carriages. One of them was fixed, whereas the second was moving on a linear guide. A piece of sliver was put down in the carriage channel in zero-gage position. The sliver was compressed with the upper carriage sides, where two identical weights were loaded. This apparatus was tested under different loads, sliver counts and speeds. The results were analyzed in order to check out the parameters which characterized the friction force during inter-fiber slippage.

Fiber surface properties have a significant effect on yarn spinning. The frictional behavior of fibers greatly influences their processing, their performance and the performance of the final product. In order to investigate the effect of fiber surface properties and inter-fiber friction during spinning process, card slivers are taken and subjected to three drawing passages. Card and drawing frame slivers are then tested by the Static Friction Tester (SFT), which has been developed earlier. Fiber fineness, maturity and fiber length are measured by using different testing instruments. Hook content is calculated by utilizing fiber length data. The statistical analysis of results shows the same trend for the different cotton fibers tested.

One of the effective forces in the textile process is friction. A new and simple device is developed in order to quantify the friction forces during a quasi-static fibre slippage in sliver. The device is composed of two identical clamps, one of which is fixed and the other moving through a linear guide. A piece of sliver was maintained under controlled pressure in the zero gage position of the two clamps. The frictional force during the fibre slippage in the sliver was measured using three different speeds, eight different normal loads and three different sliver counts. Five replications were preceded for each factorial combination. In general, the frictional force increased with the speed, but the analysis of variance of the data indicated that the effect was not significant, whereas the effect of the normal load on frictional force was positive and highly significant. A statistic model based on these results is proposed with respect to sliver count and normal load. Following this model, the effects of the normal load and sliver count on the frictional force were not linear.