Smooth Material Flow Research Articles

EFFECT of PULPER‐FINISHER OPERATION ON QUALITY of TOMATO JUICE and TOMATO PUREE

ABSTRACTPreliminary tests were done on the performance of an existing pulper finisher design with two unadjustable blades. Quality parameters such as consistency index and yield were determined at screen sizes of 0.5, 1.0, 1.5 mm and speeds: 100, 300, 500 and 700 rpm. Design modifications were made on the pulper finisher by addition of another blade and slide tapering of blades to allow smooth flow of material on one direction. Quality parameters such as consistency index, pulp/serum ratio, particle size distribution, total solids and total yield were evaluated.A maximum quality index in terms of total solids, pulp/serum, consistency, particle size distribution was achieved at screen size 1.0 mm and a speed of 700 rpm. Maximum yield of tomato juice however, was obtained with screen size of 1.5 mm and a speed of 700 rpm. Results of the comparative tests done on existing and modified pulper finisher showed that quality and quantity of tomato juice and puree from the modified unit is better and higher. A 3% increase in yield was observed from the modified unit.

The behavior of manufacturers' inventories: 1967–1986

Although inventory investment is one of the more volatile components of aggregate demand, there is yet no satisfactory theory of inventory behavior. Estimated inventory models consistently yield implausible results such as very slow speeds of adjustment. This paper generates stylized facts on manufacturing inventory behavior in order to form a basis for an alternative theory of inventory investment. Inventories are categorized according to durable versus nondurable manufacturing sectors and stage of fabrication. One of the main results is that the persistence of inventories is not alleviated by accounting for the stage of fabrication distinction and inventory interaction among stages. As a result, inventory levels lag demand by a year or more, while inventory investment is coincidental. The conclusion for modelling is that greater attention should be paid to institutional constraints that prevent the smooth flow of materials through the firm.

A simulation analysis for a transtainer-based container handling facility

The efficiency of a marine cargo terminal depends primarily upon a smooth and orderly flow of material during the container loading process. It has been observed that the transtainer operation is the bottleneck in the loading process due to the frequent container rehandles and its speed. Past attempts at improving port operations have concentrated on the computerization of the load planning function and the efficient warehouse of the outbound containers. These attempts have, to some extent, been successful but have not been able to significantly eliminate the unproductive movements of the material handling equipment during the load operation. This study proposes a methodology of utilizing a buffer space as a method to increase the utilization of the material handling equipment and reduce the total container loading time. A stimulation model using a graphics simulation system is developed to compare the proposed methodology with the current practice at the Port of Portland. The results from 96 simulation runs show that the use of a buffer space significantly improves the flow of material during the loading operation, resulting in an average of 4% reduction in the total loading time. The methodology proposed in this study can be evaluated and implemented for any transtainer-based container port operation, and is anticipated to make considerable contribution to the plannig of future container port design.