In the present study, a computational investigation into acoustic and tribological performances in journal bearings is presented. A heterogeneous pattern, in which a rough surface is engineered in certain regions and is absent in others, is employed to the bearing surface. The roughness is assumed to follow the sand-grain roughness model, while the bearing noise is solved based on broadband noise source theory. Three types of heterogeneous rough/smooth journal bearings exhibiting different placement and number of the rough zone are evaluated at different combinations of eccentricity ratio using the CFD method. Numerical results show that the heterogeneous rough/smooth bearings can supply lower noise and larger load-carrying capacity in comparison with conventional bearings. Moreover, the effect on the friction force is also discussed.

It is a well-known fact that incorporating a slip boundary into the contact surfaces improves bearing performance significantly. Regrettably, no research into the effect of slip on the behavior of journal bearing systems operating with non-Newtonian lubricants has been conducted thus far. The main purpose of this work is to explore the performance comparison of Newtonian and non-Newtonian fluid on a heterogeneous slip/no-slip journal bearing system. The tribological and acoustic behavior of journal bearing is investigated in this study using a rigorous program that combines CFD (computational fluid dynamics) and two-way FSI (fluid–structure interaction) procedures to simulate Newtonian vs. non-Newtonian conditions with and without slip boundary. The numerical results indicate that irrespective of the lubricant type (i.e., Newtonian or non-Newtonian), an engineered heterogeneous slip/no-slip pattern leads to the improvement of the bearing performance (i.e., increased load-carrying capacity, reduced coefficient of friction, and decreased noise) compared to conventional journal bearing. Furthermore, the influence of the eccentricity ratio is discussed, which confirms that the slip beneficial effect becomes stronger as the eccentricity ratio decreases. It has also been noticed that the Newtonian lubricant is preferable for improving tribological performance, whereas non-Newtonian fluid is recommended for lowering bearing noise.

Distribution and inventory are two major components that causes total cost of the product become high. Those two components are not categorized in to the process that added value to the product. This research use Distribution Requirement Planning (DRP) to find the right quantity and short replenishment time in inventory decision that manufacture industries faced to supply their own Distribution Centers and Warehouses in food Company. DRP giving the lower total distribution cost than actual cost. It is because DRP supply products at each Distribution Centers and Warehouses in a minimum quantity using Economic Order Quantity. It also using the similar concept with Material Requirement Planning to find the right delivery time so that it can minimize the total inventory time in The supply chain. DRP can be used to solve the inventory and distribution problem in multi echelon supply chain. From this research, using historical data, DRP gave the minimum total distribution and inventory cost than the initial scenario that company used. Based on DRP result, The total Inventory and Distribution Cost from January to December 2019 is 481.251.325,4.

Removal of Mg 2+ , K +, and SO4 -2 ions in seawater has been successfully done by precipitation in a mixing tank method. This study aims to remove the content of magnesium ions (Mg + ), potassium (K + ) and sulfate (SO4 -2 ) in sea water with the addition of chemicals disodium phosphate (1.2 % volume), calcium chloride (2 % volume) and sodium hydroxide (2% volume). Stirring is performed at 100 rpm and the pH solution is adjusted to 9. Disodium phosphate serves to bind magnesium ions and potassium, CaCl2 serves to bind the sulfate ion, while sodium hydroxide is used to adjust the pH of the solution mixture and also reacted with magnesium ions. In total, the removal efficiencies of Mg 2+ , K + and SO4 -2 ions in seawater were 97%, 96%, and 92%, respectively. The precipitated solids contains component of PO4 -(14.5%), Mg 2+ (13.8%), SO4 2-(28.2%), Ca 2+ (24.1%) and K + (1.9%) ions.Keywords: sea water, disodium phosphate, calcium chloride, precipitation, removal ions INTRODUCTIONThe average waters of the world's oceans contain 3.5% dissolved salts, 96.5% water and average salinity is about 35 g/kg. When salts dissolve in water they usually react with water and dissociate (break apart) into ions, positively and negatively charged atoms or groups of atoms. These ions are either negatively charged anions, or positively charged cations. Six major ions make up > 99% of the salts dissolved in seawater: four cations sodium (Na + ), magnesium (Mg 2+ ), calcium (Ca 2+ ), and potassium (K + ); and two anions: chloride (Cl -) and sulphate (SO4 2-). These six ions and the five next most common ones make up the major constituents of seawater and comprise 99.99% of dissolved materials. Sodium chloride (NaCl), makes up 86% of dissolved ions in seawater. Many other elements (trace elements) are dissolved in seawater in concentrations less than one part per million (ppm). The molar concentration of magnesium in sea water is about five times higher than calcium. In fact, both magnesium and calcium are in a delicate equilibrium where slight charge in alkalinity and carbon dioxide tension may cause precipitation (Irving, 1926). Jijun et al, (2012) developed the precipitation of calcium and magnesium from seawater using CO2. Mg ion can rarely incorporate into the solid precipitates, compared, for example, to calcium salts. The rate of Mg phosphates nucleation is several orders of magnitude lower than that of Ca phosphates, at the same values of pH and total phosphate concentration (Golubeva, 2001). The removal rate of Ca is higher than the removal rate of Mg in pH value between 8.0 and 9.0. In the Mg-free seawater system the removal rate is high enough in pH value between 8.0 and 9.0. Meanwhile, in the Ca-free seawater system there is no precipitation between pH 8.0 and 8.3 (Jijun et al, 2012). Precipitation of phosphate is high enough in pH range from 8 to 10. However, it decreased as pH is increased from 10 to 12, probably because of competition between phosphate and hydroxyl OH − ions (Liu and Warmadhewanti, 2009

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