Control Charts for One-sided Capability Indices

Chen, Kuen‐Suan; Huang, Hsin-Yi; Huang, Chiao-Tzu

doi:10.1007/s11135-006-9013-y

Cited by 19 publications

(13 citation statements)

References 12 publications

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“…Resultados semelhantes quanto à viabilidade da utilização do controle de qualidade foram encontrados por CHEN et al (2007), que afirmaram, após estudar a capacidade do processo para medidas unilaterais, que esse índice, utilizando gráficos de controle, pode ser usado não somente para monitorar a estabilidade do processo, mas também para monitorar a qualidade do mesmo, acompanhando índices de especificação e avaliando sua estabilidade.…”

Section: Resultsunclassified

Índice de capacidade do processo na avaliação da irrigação por aspersão

2010

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RESUMO:Analisar a qualidade da irrigação, além de avaliar seu bom funcionamento, é uma forma de verificar a viabilidade de sua implantação e operação. Como a uniformidade de distribuição é um dos parâmetros mais utilizados para essa avaliação, este trabalho objetivou utilizar técnicas de engenharia de qualidade, usando o índice de capacidade do processo (C pl ) para avaliar a uniformidade de distribuição de água em um sistema de irrigação por aspersão convencional. Os ensaios foram conduzidos no Núcleo Experimental de Engenharia Agrícola, UNIOESTE, com dois aspersores modelo Super10, marca NAANDAN, espaçados 9 m entre si, durante 25 irrigações de 1 h cada. Os dados climáticos foram coletados a cada 10 min, por uma estação meteorológica sem fio. Encontraram-se um CUC médio de 79,72% e velocidade do vento média de 1,85 m s -1 . Foram aplicados os testes de controle de qualidade, elaborando os gráficos de controle de Shewhart e calculado o índice de capacidade do processo (C pl ), sendo que os resultados obtidos permitem afirmar que a utilização do índice de capacidade do processo torna-se uma ferramenta poderosa para classificar sistemas de irrigação em função de sua uniformidade de distribuição. PALAVRAS-CHAVE:Controle de qualidade, velocidade do vento, uniformidade de distribuição. PROCESS CAPACITY INDEX IN THE UNIFORMITY EVALUATION OF SPRINKLER IRRIGATION ABSTRACT:Analyzing the irrigation quality, besides evaluating its good operation, is a form of verifying the viability of its implantation and operation. As the distribution uniformity is one of the most used parameters for that evaluation, this work aimed to use techniques of quality engineering, by using the process capacity index (C pl ) to evaluate the uniformity of water distribution in overhead irrigation by sprinkler. The research was carried out at the Experimental Center of Agricultural Engineering, UNIOESTE, with 2 sprinklers Super10 model, NAANDAN, spaced 9m between themselves, during 25 irrigations with 1 h each. The Weather data were collected every 10 min. by a wireless weather station. It was found a medium CUC of 79.72% and a medium wind speed of 1.85 m s -1 . It was applied quality control tests, elaborating SHEWHART control charts and it was calculated the process capacity index (C pl ). The obtained results allow us to affirm that the use of the process capacity index becomes a powerful tool to classify overhead irrigations in function of distribution uniformity.

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Section: Resultsunclassified

Índice de capacidade do processo na avaliação da irrigação por aspersão

2010

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“…CHEN et al (2007) assume that one-sided ratios can be used to not only stability monitoring, but also to quality, following specification ratios and evaluating the stability. In the present research, upper one-sided capability ratio was applied (C ps ) because used parameters, except for pH, presents only maximum limits (upper) of launching onto water body.…”

Section: Methodsmentioning

confidence: 99%

Shewhart's control charts and process capability ratio applied to a sewage treatment station

et al. 2014

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ABSTRACT:The current study used statistical methods of quality control to evaluate the performance of a sewage treatment station. The concerned station is located in Cascavel city, Paraná State. The evaluated parameters were hydrogenionic potential, settleable solids, total suspended solids, chemical oxygen demand and biochemical oxygen demand in five days. Statistical analysis was performed through Shewhart control charts and process capability ratio. According to Shewhart charts, only the BOD (5.20) variable was under statistical control. Through capability ratios, we observed that except for pH the sewage treatment station is not capable to produce effluents under characteristics that fulfill specifications or standard launching required by environmental legislation.

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“…Thus, the process meets the requirements for the Low Limit specification (LIE) in the nominal flow studies of the evaluated system. Feasibility results of using quality control were found by CHEN et al (2007) state that after studying the process capability for unilateral measures, this index using control charts, can be used not only to monitor the stability of the process but also to monitor their quality, following specification indexes and assessing its stability. S1(0.6 dS m …”

Section: Process Capability Indexmentioning

confidence: 99%

Evaluation of Self Compensating Emitters Irrigating With Saline Water: Part Ii: Process Capability Index

et al. 2016

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ABSTRACT:The use of tools such as process capability index for irrigation aims to observe how this irrigation is adequate in terms of quality. The aim of the study was analyzing the Christiansen uniformity coefficient and the flow of a drip irrigation system with self-compensating emitters under water different salt concentrations, using the process capability index. The research was conducted in a greenhouse at the Federal University of Campina Grande (UFCG). The experimental design was a randomized block in a factorial 5 x 2 with three replications, the factors consisted of five levels of irrigation water salinity (CEw) (0.6, 1.5, 2.5, 3.5 and 4.5 dS m -1 at 25°C) and two running times (0 and 350 hours of operation). The Christiansen uniformity coefficient (CUC) for new and used emitters was greater than 90%, in different salt concentrations studied. The flow of emitters is maintained within the statistical quality control, since management and maintenance operations are made after 350 hours of operation. The potential process capability index for the Christiansen uniformity coefficient was higher than recommended for new and used emitters, being the process within the required specifications.

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Control Charts for One-sided Capability Indices

Abstract: process capability indices, yield, specification limit, control charts,

Cited by 19 publications

References 12 publications

Índice de capacidade do processo na avaliação da irrigação por aspersão

Índice de capacidade do processo na avaliação da irrigação por aspersão

Shewhart's control charts and process capability ratio applied to a sewage treatment station

Evaluation of Self Compensating Emitters Irrigating With Saline Water: Part Ii: Process Capability Index

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