ANAEROBIC DIGESTION STABILITY TEST BY SHEWHART CONTROL CHART

Quality monitoring in thyroid surgery by Shewhart control chart

Introduction The outcome of thyroid surgery is usually assessed according to two major complications: recurrent laryngeal nerve paralysis and hypoparathyroidism. The purpose of the study was to monitor the outcomes of thyroid surgery using Shewhart control charts, and then to identify possible ways to improve quality by exploring the special causes of variation in the observed complication rate...

ANAEROBIC DIGESTION Monitoring and Control

Anaerobic digestion is an old biological wastewater treatment process, having first been studied more than a century ago. It is a multistep process in which organic matter is degraded into a gas mixture of methane and carbon dioxide by microorganisms. It thus reduces the Chemical Oxygen Demand (COD) of the influent and produces valuable energy (methane). The biological scheme involves several m...

Combined Shewhart-cusum control chart for improved quality control in clinical chemistry.

We describe the adaptation of the decision limit cumulative sum method (cusum) to internal quality control in clinical chemistry. With the decision limit method, the cusum is interpreted against a numerical limit, rather than by use of a V-mask. The method can be readily implemented in computerized quality-control systems or manually on controls charts. We emphasize the manual application here ...

Influence of Reliability on the Traditional Control Charts: a “reliable Shewhart Control Chart”

− The traditional control charts are based on the assumption that the measurement data relating to the average of each subgroup of the parameters under observation of a specific quality characteristic of product, process, system or service, are reported regardless of time stability of its own parameters. This condition is generally not verified in real cases, where we should take into account t...

Anaerobic digestion