Continuous Prediction Model of Carbon Content in 120 t Converter Blowing Process

A continuous prediction model of carbon content of 120 t BOF is established in this paper. Based on the three-stage decarburization theory and combined with the production process of 120 t converter, the effects of oxygen lance height and top blowing oxygen flow rate are also considered in the model. The explicit finite difference method is used to realize continuous prediction of carbon content in the converter blowing process. The model parameters such as ultimate carbon content in molten pool are calculated according to the actual data of 120 t BOF, which improves the hit rate of the model. Process verification and end-point verification for the continuous prediction model have been carried out, and the results of process verification indicate that the continuous prediction model established in the paper basically accords with the actual behavior of decarburization. Moreover, the hit ratio of the continuous prediction model reached 85% for the prediction of end-point carbon content within a tolerance of ±0.02%.

Optimization of the installation sequence for the temporary fasteners in the aircraft industry

Riveting and bolting are common assembly methods in aircraft production. The fasteners are installed immediately after hole drilling and fix the relative tangential displacements of the parts, that took place. A proper fastener sequence installation is very important because a wrong one can lead to a “bubble-effect”, when gap between parts after fastening becomes larger in some areas rather than being reduced. This circumstance affects the quality of the final assembly. For that reason, the efficient methods for determination of fastening sequence taking into account the specifics of the assembly process are needed. The problem is complicated by several aspects. First of all, it is a combinatorial problem with uncertain input data. Secondly, the assembly quality evaluation demands the time-consuming computations of the stress-strain state of the fastened parts caused by sequential installation of fasteners. Most commonly used strategies (heuristic methods, approximation algorithms) require a large number of computational iterations what dramatically complicates the problem. The paper presents the efficient methods of fastener sequence optimization based on greedy strategy and the specifics of the assembly process. Verification of the results by comparison to commonly used installation strategies shows its quality excellence.

Recommended Best Practices for Lyophilization Validation 2021 Part II: Process Qualification and Continued Process Verification

This work describes the lyophilization process validation and consists of two parts. Part one (Part I: Process Design and Modeling) focuses on the process design and is described in the previous paper, while the current paper is devoted to process qualification and continued process verification. The goal of the study is to show the cutting edge of lyophilization validation based on the integrated community-based opinion and the industrial perspective. This study presents best practices for batch size determination and includes the effect of batch size on drying time, process parameters selection strategies, and batch size overage to compensate for losses during production. It also includes sampling strategies to demonstrate batch uniformity as well as the use of statistical models to ensure adequate sampling. Based on the LyoHUB member organizations survey, the best practices in determining the number of PPQ runs are developed including the bracketing approach with minimum and maximum loads. Standard practice around CQA and CPP selection is outlined and shows the advantages of using control charts and run charts for process trending and quality control. The case studies demonstrating the validation strategy for monoclonal antibody and the impact of the loading process on the lyophilization cycle and product quality as well as the special case of lyophilization for dual-chamber cartridge system are chosen to illustrate the process validation. The standard practices in the validation of the lyophilization process, special lyophilization processes, and their impact on the validation strategy are discussed. Graphical Abstract

Recommended Best Practices for Lyophilization Validation—2021 Part I: Process Design and Modeling

This work describes lyophilization process validation and consists of two parts. Part I focuses on the process design and is described in the current paper, while part II is devoted to process qualification and continued process verification. The intent of these articles is to provide readers with recent updates on lyophilization validation in the light of community-based combined opinion on the process and reflect the industrial prospective. In this paper, the design space approach for process design is described in details, and examples from practice are provided. The approach shows the relationship between the process inputs; it is based on first principles and gives a thorough scientific understanding of process and product. The lyophilization process modeling and scale-up are also presented showing the impact of facility, equipment, and vial heat transfer coefficient. The case studies demonstrating the effect of batch sizes, fill volume, and dose strength to show the importance of modeling as well as the effect of controlled nucleation on product resistance are discussed.

Diagnostic possibilities and limitations of urgent intraoperative pathologicanatomical studies in oncogynecology

Introduction. One of the variants of intravital pathological and anatomical diagnostics is intraoperative pathological and anatomical ("urgent") examination, which serves for tumor process verification. Urgent intraoperative pathological and anatomical examination is widely used when there are certain differential diagnostic difficulties and limitations of instrumental methods of examination.The purpose of the study — to analyze the possibilities, limitations and the accuracy of "urgent" pathologic and anatomical diagnostics in oncogynecological diseases. Materials and methods. We retrospectively analyzed medical records of 378 inpatients treated in the gynecologic oncology department of CHOKZO and NM for the period from January 2016 to January 2021. Results and discussion. Urgent histological examination was used to diagnose ovarian tumors (82%, n=310); to evaluate the extent of a tumor process in uterine body cancer, ovarian cancer, cervical cancer (peritoneal carcinomatosis, ingrowth into adjacent tissues and organs) (15%, n=57); less often to evaluate resection margin ablation in cervical cancer, uterine body cancer (3%, n=11). In a comparison of conclusions after urgent morphological examination and conduction of material, discrepancies were registered only in hypodiagnostic ovarian tumors (in 5.8% of all "urgent" ovarian tumor studies, n=18), when the question about the malignancy potential of a process cannot be reliably decided. The reliability of intraoperative morphological verification of the process is 94.2%. The sensitivity is 96%, specificity is 97%, which is consistent with the results of other studies. Conclusions. Intraoperative morphological diagnosis is a highly specific and highly sensitive method of investigation. There are limitations of this diagnostic method depending on the volume of tissue material, quality of cryostat sections, as well as tumor features (e.g., ovarian masses) consisting of heterologous morphological areas. A compliant, multidisciplinary approach is required to successfully meet the challenges of intraoperative examination.

Process Analytical Technology Tools for Monitoring Pharmaceutical Unit Operations: A Control Strategy for Continuous Process Verification

Various frameworks and methods, such as quality by design (QbD), real time release test (RTRT), and continuous process verification (CPV), have been introduced to improve drug product quality in the pharmaceutical industry. The methods recognize that an appropriate combination of process controls and predefined material attributes and intermediate quality attributes (IQAs) during processing may provide greater assurance of product quality than end-product testing. The efficient analysis method to monitor the relationship between process and quality should be used. Process analytical technology (PAT) was introduced to analyze IQAs during the process of establishing regulatory specifications and facilitating continuous manufacturing improvement. Although PAT was introduced in the pharmaceutical industry in the early 21st century, new PAT tools have been introduced during the last 20 years. In this review, we present the recent pharmaceutical PAT tools and their application in pharmaceutical unit operations. Based on unit operations, the significant IQAs monitored by PAT are presented to establish a control strategy for CPV and real time release testing (RTRT). In addition, the equipment type used in unit operation, PAT tools, multivariate statistical tools, and mathematical preprocessing are introduced, along with relevant literature. This review suggests that various PAT tools are rapidly advancing, and various IQAs are efficiently and precisely monitored in the pharmaceutical industry. Therefore, PAT could be a fundamental tool for the present QbD and CPV to improve drug product quality.

The research on precise forming technology of “λ” type composite skin

With the application of “ λ” type composite skin becoming more and more extensive and diversified, its precise forming technology is also widely concerned. This article mainly solves the quality problems of “ λ” type corner area, such as delamination dispersion and surface wrinkle, which exist in reality commonly in the manufacturing process. The prepreg is heated along the corner area of the tooling to solve the problem that prepreg is difficult to be compacted due to the large modulus of carbon fiber in “ λ” type corner area. Furthermore, two precompaction tests are creatively increased at 16 layers (middle layer) and 32 layers (last layer) for the thick structure, respectively, to ensure the compaction effect of the blank. In addition, combined with the characteristics of highly elastic rubber and carbon fiber-reinforced materials, a new type of soft mold structure with proper flexibility and good stiffness is proposed innovatively through the reasonable placement of carbon fiber-reinforced materials and the setting of exhaust holes according to the structure characteristics of “ λ” type root skin. Through further process verification, it is shown that the improved process has effectively solved the problems of wrinkles and internal delamination at the sharp corners of parts and realized zero-defect manufacturing of “ λ” type root skin for the first time.

Process mining approach to formal business process modelling and verification: a case study

Purpose The need for assuring correctness of business processes in enterprises is widely recognised in terms of business process re-engineering and improvement. Formal methods are a promising approach to this issue. The challenge in business process verification is to create a formal model that is well-aligned to the reality. Process mining is a well-known technique to discover a model of a process based on facts. However, no studies exist that apply it to formal verification. This study aims to propose a methodology for formal business process verification by means of process mining, and attempts to clarify the challenges and necessary technologies in this approach using a case study. Design/methodology/approach A trading company simulation model is used as a case study. A workflow model is discovered from an event log produced by a simulation tool and manually complemented to a formal model. Correctness requirements of both domain-dependent and domain-independent types of the model are checked by means of model-checking. Findings For business process verification with both domain-dependent and domain-independent correctness requirements, more advanced process mining techniques that discover data-related aspects of processes are desirable. The choice of a formal modelling language is also crucial. It depends on the correctness requirements and the characteristics of the business process. Originality/value Formal verification of business processes starting with creating its formal model is quite new. Furthermore, domain-dependent and domain-independent correctness properties are considered in the same framework, which is also new. This study revealed necessary technologies for this approach with process mining.