Tolerance Limit-based Estimation of the Proportion of Non-conforming Parts in a Multiple Stream Process

The conventional way to characterize the proportion of non-conforming parts in a process is to calculate process capability indices and transform them into a ratio. These widely used indices are able to give digestible information about the ratio of non-conforming parts if some assumptions are fulfilled. A correct estimation method should be based on the output distribution of the process, and the uncertainty of the parameter estimates should be considered, as well. In this article, a special case of the output distribution is examined: a mixture of normal distributions is considered. In practice, this output distribution appears if a multiple stream process is investigated. The novelty of this study is to apply the tolerance interval-based estimation method for the proportion of non-conforming parts in a case study of a multiple stream process and to qualify the limitations of the proposed estimation method. A simulation study is performed to investigate the bias, mean square error, and root mean square error of the estimates from the two estimation methods (process performance index-based and tolerance interval-based) for different sample sizes for each stream (N ). It was found that, if it may be assumed that the speed of the streams is equal in the case of the sample sizes investigated (N = 25, 50, 100 per head), the proposed (tolerance interval-based) method overestimates the proportion of non-conforming parts while the conventional (process performance index-based) method underestimates it. The tolerance-limit based estimation method has asymptotically better properties than the process performance index-based estimation method

Acute Ecotoxicological Effects of Bauxite Residue Addition on Mortality and Motion-frequency of Dendrobaena veneta and Enchytraeus albidus (Annelida) in Three Types of Soils

The bauxite residue is produced in high amount all over the world. This industrial waste is a possible soil-ameliorant material. Although the material has been producing in high amount, it is not frequent to reuse it. We investigated its ecotoxicological effects on two annelid species: Dendrobaena veneta and Enchytraeus albidus. Two forms of bauxite residue (BR: S – untreated; G – dried, filter pressed and gypsum neutralized) and three natural soils (NH: Nagyhörcsök, NY: Nyírlugos, OB: Őrbottyán) were examined. To determine the safe concentration in short term, the acute mortality and sublethal behavior tests (peristaltic motion-frequency) were performed. The bauxite residue addition (< 5/10 %) raised the pH and water holding capacity level of soils. Both types of the bauxite residue increased the motion-frequency of the worms. The untreated type had an acute mortality effect (> 25 %). Both species refused the higher concentration soils (≥ 10 %) of both types of bauxite residue. Slight bauxite residue addition may improve the life circumstances of annelids in acidic sandy soils because of the pH level and water holding capacity potential rise

Acute Ecotoxicological Effects of Bauxite Residue Addition on Mortality and Motion-frequency of Dendrobaena veneta and Enchytraeus albidus (Annelida) in Three Types of Soils

The bauxite residue is produced in high amounts all over the world. This industrial waste is a possible soil-amendment material. Although the material has been produced in high amounts, it is not frequently reused. We investigated its ecotoxicological effects on two annelid species: Dendrobaena veneta and Enchytraeus albidus. Two forms of bauxite residue (BR: S – untreated; G – dried, filter pressed, and gypsum neutralized) and three natural soils (NH: Nagyhörcsök, NY: Nyírlugos, OB: Őrbottyán) were examined. To determine the safe concentration of bauxite residue in soil on the short, acute mortality and sublethal behavioral tests (peristaltic motion-frequency) were performed. The bauxite residue addition (<5/10%) raised the pH and water holding capacity level of soils. Both types of the bauxite residue increased the motion-frequency of the worms. The untreated type had an acute mortality effect (>25%). Both species refused the soils containing both bauxite residue types at higher concentrations (>10%). Slight bauxite residue addition may improve the life circumstances of annelids in acidic sandy soils because of the potential rise of the pH level and water holding capacity