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Some factors affecting crude protein balance (CPB), as a measure of efficiency, were studied using 2824 records of 501 lactating Holstein cows. The CPB (kg d-1) was calculated as crude protein (CP) intake (kg) minus CP yield (kg). Two different statistical methods including principal components (PCs) and general linear model analyses were used to study the effects of different factors. Crude protein balance had a moderate correlation with PCs 1 (-0.206), 2 (0.318) and 3 (-0.281), which accounted for 65.6% of total variations. Age, parity, lactation stage, pregnancy stage, dry matter intake (DMI), milk yield (MY), fat corrected milk yield (FCM), milk fat percentage (F%), milk lactose percentage (L%), milk fat yield (FY), milk protein yield (PY), milk lactose yield (LY), dietary levels of net energy for lactation (NEL), CP, ruminally undegradable protein (RUP), neutral detergent fiber (NDF) and ether extract (EE) and income over feed cost (IOFC) were correlated to CPB, at least, in one of PCs 1, 2 or 3. In general, linear model analysis CPB was significantly affected by parity and lactation stage and had significant partial linear regression coefficients on DMI (kg d-1), F%, FY (kg d-1), PY (kg d-1), NEL (Mcal kg-1) and dietary levels of CP (%), RUP (%), NDF (%) and EE (%). The quadratic partial regression coefficients of CPB on NEL, CP, RUP and NDF were also significant. The estimates for optimum dietary levels of NEL, CP and RUP for minimizing CPB in the studied population were 1.49 Mcal/kg, 11.29% and 7.58%, respectively. In comparison to NRC’s estimates, it seems that, more NEL, RUP and NDF and less CP are needed to minimize protein balance in lactating dairy cows.

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The purpose of this research is to examine and explain the mechanisms of the forming process called ‘line heating’ and to develop numerical tools for efficient calculation and prediction of its behavior. The forming process consists of heating at a (steel) plate in a predetermined pattern of lines by means of a gas torch so that the plate assumes a certain‚ curved shape. Today this method which is widely applied in the production of ship hull shell plate and construction is an alternative or supplement to other forming methods such as pressing and rolling. Considering a rational method for the determination of heating line patterns and heating among would be very beneficial. Much research is carried out in industry and at universities to achieve technology of this method‚ as the potential economic benefit is obvious. In this paper, experimental test and numerical simulation of Line Heating method has been done on naval plate- Grade E. Thermal and mechanical finite element analysis has been done separately. Experimental test results shows that with using Oxy-Acetylene gas heat we can make smooth curvature on plate. Effect of heat input and increasing of heating lines studied in this research. Results shows that increasing two heating lines on plate will increase maximum stress 6% and increasing heat input will enhance bending effect.