Modeling in the quality by design environment: Regulatory requirements and recommendations for design space and control strategy appointment

2017 ◽  
Vol 533 (2) ◽  
pp. 346-356 ◽  
Author(s):  
Jelena Djuris ◽  
Zorica Djuric
2008 ◽  
Vol 3 (2) ◽  
pp. 60-68 ◽  
Author(s):  
Thomas Garcia ◽  
Graham Cook ◽  
Roger Nosal

2019 ◽  
Vol 166 ◽  
pp. 326-335 ◽  
Author(s):  
Riccardo Deidda ◽  
Hermane T. Avohou ◽  
Roberto Baronti ◽  
Pier Luigi Davolio ◽  
Benedetta Pasquini ◽  
...  

Author(s):  
James R. Coleman ◽  
John A. Robson ◽  
John A. Smoliga ◽  
Cornelia B. Field

2020 ◽  
Author(s):  
Sijie Zhang ◽  
Linlin Wu ◽  
Xiaoping Wang ◽  
Xingchu Gong ◽  
Haibin Qu

Abstract Background Ginkgo biloba leaf extract (EGBL) is one of the most commonly used and most studied herbal medicines around the world. Taking into account that previously reported HPLC-ELSD methods for terpene trilactones determination in EGBL are time-consuming with complicated sample preparation, it is reasonable and meaningful to developing a simple, sensitive and robust HPLC-MS method based on a novel analytical quality by design (AQbD) approach. Methods Firstly, analytical target profile (ATP) and systematic risk analysis were carried out to identify potential critical method attributes (CMAs) and critical method parameters (CMPs). Secondly, CMPs were identified using a standard partial regression coefficient method. Thirdly, Box-Behnken design (BBD) was employed to establish the quantitative relationship between CMAs and CMPs. Fourthly, the Monte Carlo simulation method was used to build hypercube design space. Then, the verification experiments were performed. Fifthly, the optimized method was validated and utilized. Finally, the paired t test was used to compare the developed method with HPLC-ELSD. Results After the screening experiments, flow rate of mobile phase, the proportion of formic acid in the mobile phase, gas flow rate and gas temperature were identified as CMPs. Models to quantitatively describe the relationship between CMAs and CMPs were built. The operational hypercube design spaces of the HPLC-MS method for terpene trilactones analysis in EGBL were successfully calculated and found to be robust, which led to the analytical control strategy. The verification experiments were successfully performed within the design space and model was found to be accurate. The method had been successfully used for quality analysis of development batches of EGBL and obtained almost identical results to data determinated using HPLC. Conclusions In this work, an analytical control strategy for HPLC-MS method for terpene trilactones analysis in EGBL was developed using AQbD concepts, which is promising for application to other Chinese medicines. The developed HPLC-MS method is an alternative method for quantification of terpene trilactones in commercial EGBL and will be applicable throughout the life cycle of the product.


TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 295-305
Author(s):  
Wesley Gilbert ◽  
Ivan Trush ◽  
Bruce Allison ◽  
Randy Reimer ◽  
Howard Mason

Normal practice in continuous digester operation is to set the production rate through the chip meter speed. This speed is seldom, if ever, adjusted except to change production, and most of the other digester inputs are ratioed to it. The inherent assumption is that constant chip meter speed equates to constant dry mass flow of chips. This is seldom, if ever, true. As a result, the actual production rate, effective alkali (EA)-to-wood and liquor-to-wood ratios may vary substantially from assumed values. This increases process variability and decreases profits. In this report, a new continuous digester production rate control strategy is developed that addresses this shortcoming. A new noncontacting near infrared–based chip moisture sensor is combined with the existing weightometer signal to estimate the actual dry chip mass feedrate entering the digester. The estimated feedrate is then used to implement a novel feedback control strategy that adjusts the chip meter speed to maintain the dry chip feedrate at the target value. The report details the results of applying the new measurements and control strategy to a dual vessel continuous digester.


2014 ◽  
Vol 9 (4) ◽  
pp. 792 ◽  
Author(s):  
Anna Pinnarelli ◽  
Giuseppe Barone ◽  
Giovanni Brusco ◽  
Alessandro Burgio ◽  
Daniele Menniti ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 452
Author(s):  
Dongwei Guo ◽  
Zibing Hou ◽  
Zhiqiang Peng ◽  
Qian Liu ◽  
Jianghai Cao

The statistical correlation was applied to analyze the specific and quantitative correlation relationship between the solidification structure and central segregation along the casting direction in carbon steel billet. On this basis, the segregation formation mechanism of the solute element and related control strategy were investigated. It is found that the equiaxed crystal zone fluctuation along the casting direction determines the fluctuation degree of central segregation. At the same time, the central segregation at a certain position is mostly affected by the equiaxed crystal zone width at the hysteretic position. Moreover, the casting speed can influence the columnar to equiaxed transition (CET) fluctuation along the casting direction by affecting the flow of molten steel in the billet. Overall, the segregation mechanism of solute elements along the casting direction can be summarized into two aspects: First, with the growth of columnar crystals in the initial stage, the segregated solutes are continuously enriched and distributed in the equiaxed crystal zone after CET. The fluctuation of the equiaxed crystal zone will affect the distribution of the enriched solute in the billet and cause the fluctuation of the central segregation. Second, due to the solidification shrinkage at the end of solidification, the solute-enriched liquid phase at the hysteretic position is pumped to the solidification endpoint and forms the central V-shaped segregation. Meanwhile, the stable solidification structure (columnar crystal length or equiaxed crystal zone width) along the casting direction and control measures preceded equiaxed crystal zone formation are beneficial to reduce the central V-shaped segregation.


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