Error chain analysis-an effective method for tighter manufacturing process control
PRODUCTION PLANNING & CONTROL
Authors: Dockree, James; Wang, Qian; Frei, Regina
Abstract
One of aims of manufacturing quality control is to ensure that products are made free from defects according to specifications without unnecessarily increasing time and cost of production. Over-control of a process can be as detrimental to a manufacturer as under-control. It is common in industry that operators use their personal knowhow and intuition to decide where to implement process verification, and where to tighten it when processes are not meeting specifications. This is partially because there is little scientific guidance that can assist operators in making a decision on levels of quality control of a process at varying stages. To remedy this, a new method for manufacturing quality control, namely Error Chain Analysis (ECA), is introduced and its application is illustrated in this article. ECA is capable of statistically analysing the quality of a multi-stage manufacturing process based on existing control measures, and it enables to indicate where added or tighter control may need to be effectively implemented. For testing its applicability, ECA was built into a user-friendly tool that was subsequently used to analyse data gathered from a large manufacturing company in the UK.
Side-to-Side Superficial Temporal Artery to Middle Cerebral Artery Bypass Technique: Application of Fourth Generation Bypass in a Case of Adult Moyamoya Disease
OPERATIVE NEUROSURGERY
Authors: Lang, Michael J.; Kan, Peter; Baranoski, Jacob F.; Lawton, Michael T.
Abstract
BACKGROUND: Moyamoya disease (MMD) is a rare cause of cerebral hemorrhage and ischemia. Spontaneous development of collateral supply from the external carotid artery (ECA) may limit the use of donor arteries used in standard direct bypass techniques. OBJECTIVE: To identify the technical feasibility of side-to-side (S-S) superficial temporal artery to middle cerebral artery (STA-MCA) bypass and demonstrate the application of fourth generational bypass techniques in the treatment of MMD. METHODS: S-S bypass was performed in order to maintain distal outflow in the donor STA. Fourth generation bypass techniques, including atypical anastomosis construction and intraluminal suturing were utilized. RESULTS: The novel S-S STA-MCAbypass was performed, with patent flowin both recipient MCA and endogenous ECA-ICA collaterals supplied by the distal STA. Technical nuances, including proper alignment of donor vessel, tension reduction, and S-S anastomosis construction with intraluminal suturing technique are essential for successful bypass. Unique flow properties of this bypass were identified, resulting in flow augmentation to the recipient territory compared to standard end-to-side (E-S) techniques. CONCLUSION: Fourth generational bypass techniques can be successfully applied to MMD, allowing for novel bypass construction. S-S anastomosis can result in potentially beneficial flow properties compared to standard E-S constructions.