Entire Operating Cycle Research Articles

Growing of the Business Too Fast Resulting Overtrading: How to Overcome Using Pareto Principle

This project report investigates overtrading, which is the result of an expansion rate that is too high in relation to a particular business’s structure. It often results in cash flow Problems. The phenomenon of overtrading is described considering the current situation of one of the biggest trading and manufacturing companies in Sri Lanka. In this study, I basically focused on the excessive investment on inventory and poor product management techniques due to non compliance with the 80-20 rule known as Pareto principle. As a result of this non compliance, it was identified that company faces severe cash flow problems especially in last three years.The study reveals that the concerned company has overtraded and their rapid expansion was the main reason for this situation. Basically as a result of excessive investment of inventory, the entire operating cycle has been badly affected. The study was able to identify the reasons, repercussions and solutions for the overtrading situation of the company and necessary recommendations have been given to the Board of Management for proper implementation.

Packaging Related Failure Modes of Microelectronic Components

Today's electronics development is governed by two trends: miniaturization of size and increase of power, which both contribute to significantly higher operation temperatures of the components and assemblies. Additionally, with the establishment of the RoHS standards, also the assembly process takes place at temperatures which are significantly higher than some few years ago. Therefore the package needs to protect the component against higher and higher temperatures during the entire component live time, from assembly through the entire operation cycle. The packaging design engineer disposes of a large number of parameters to optimize each packaging for its individual application. Even in the “simple” case of just a small silicon die in a small package, the specific composition of the mould compound may make the difference between an “easy-to-solder” package and one with repetitive failure issues during soldering and/or product operation. It is immediately clear that the situation is even much more complicated in case of highly evolved MEMS components. Modern type cavity based sensor packages need to be designed for minimum component warpage during the entire product live time, a task which is particularly challenging for the 260 °C top temperature the component may face during assembly. In the present paper we will apply our TDM (Topography and Deformation Measurement) system to monitor the warpage behavior of various components during temperature cycles which are either typical for the solder process, or for the components operation conditions. Simultaneously with heating or cooling the components, high resolution ( μm range) topographies will be obtained on the components packaging. These topography and deformation maps will be used to analyze potential packaging related failure modes. An example will be presented how to optimize a MEMS packaging process only by carefully adjusting the assembly conditions, without any variation of the packaging materials or design.

Cyclic steady thermal response of rapidly switchedfixed-bed heat regenerators in counterflow

An analytical solution of the counter current thermal regenerator problem when its cyclic steady-state is established is given. It takes account of the flushing phase, i.e. of that part of the blow involved in removing the residue of fluid from a previous blow. In fact, it is possible for some gas particles to remain always within the regenerator, without exiting either end. The proposed analytical approach is based on a Lagrange frame of reference for evaluating the fluid temperature during an entire operation cycle. This temperature is obtained as a function of the time and location within the regenerator and its profile depends on two dimensionless parameters: the reduced length and the flushing ratio. The method allows the matrix temperature profile to be obtained, too. The knowledge of the gas and matrix dimensionless temperature profiles in a graphical form allows a complete estimation of the dimensionless heat exchanged between gas and matrix during a semi-period at a given location.

Fraction Collector for Distillation Columns Operating at Reduced Pressure

A fraction collector for distillation columns operating at reduced pressure is described. With the apparatus, fractions of known volume can be automatically collected in collecting vessels closed with serum caps under controlled atmosphere or under vacuum. The collecting vessels are accessible at all times for further analysis of the distillate. The design is based on the use of a piston pump that ejects collected fractions into the collecting vessels via a pressure-relief valve and a needle and septum connection. Operating power for the pump is derived from a pneumatic ram. The entire operating cycle of the apparatus is controlled by feedback mechanisms.