VPLS Based Quality and Cost Control for Tennessee Eastman Process

Product quality and operation cost control obtain increasing emphases in modern chemical system engineering. To improve the fault detection power of the partial least square (PLS) method for quality control, a new QRPV statistic is proposed in terms of the VP (variable importance in projection) indices of monitored process variables, which is significantly advanced over and different from the conventional Q statistic. QRPV is calculated only by the residuals of the remarkable process variables (RPVs). Therefore, it is the dominant relation between quality and RPV not all process variables (as in the case of the conventional PLS) that is monitored by this new VP-PLS (VPLS) method. The combination of QRPV and T2 statistics is applied to the quality and cost control of the Tennessee Eastman (TE) process, and weak faults can be detected as quickly as possible. Consequently, the product quality of TE process is guaranteed and operation costs are reduced.

Optimization of Quality Control Method and Ethanol Extraction Process of Psoralen and Bergapten in Ficus pandurata

[Objectives]To establish a qualitative identification and content determination method for psoralen and bergapten in the roots and leaves of Ficus pandurata,and the multi-indicator scoring method to optimize the ethanol extraction process for the effective parts of F.pandurata.[Methods]Qualitative identification was carried out by thin-layer chromatography(TLC)and content determination was made by high-performance liquid chromatography(HPLC);the content of psoralen and bergapten and extract yield were used as indicators,to investigate the effects of ethanol volume fraction,solid-to-liquid ratio,extraction time and extraction times on the ethanol extraction process of F.pandurata;multi-indicator scoring method was adopted,orthogonal test method was designed to optimize the extraction process,and verification test was performed.[Results]TLC chart of F.pandurata shows clear spots and good separation;the detected concentrations of psoralen and bergapten in the roots are in the range of 1.02-32.64μg/mL and shows a good linear relationship with the peak area(r=0.9997);these components have not been detected in the leaves,and the precision,RSD of stability and repeatability test is less than 2%;the average recovery rate was 99.8%-100.2%,and the RSD value is 1.12%-1.13%(n=6);the optimized extraction process is to use 50%ethanol as the extraction solvent,the solid-to-liquid ratio of 1∶10,reflux extraction of 3 times,and 1.5 h each time;the results of the three batches of verification tests show that the content of the two indicator components obtained is high,and the average value of the total amount is 0.34 mg/g(RSD=0.30%,n=3).[Conclusions]The established quality control method for F.pandurata is simple,easy,accurate and reproducible;the preferred extraction process is stable and feasible,suitable for the extraction and purification of coumarin effective parts in F.pandurata roots,so it is expected to provide references for further development of F.pandurata.

Study on Quality and Safety Trust Early Warning of Dairy Products Based on Statistical Process Control

In order to solve such problems as lack of dynamic evaluation system in evaluation of quality and safety trust of dairy products,and weak awareness of prevention,it is necessary to introduce the statistical process control into the quality and safety trust evaluation system of dairy products,and establish quality and safety trust early warning model for dairy products,so as to determine the control limit of control chart and carry out early warning according to eight criteria. According to the empirical results,the statistical process control is helpful for finding the hidden process risks and providing the necessary basis for enterprises taking positive measures to raise the confidence of consumers.

Application of Statistical Process Control for Setting Action Thresholds as Quality Assurance of Dose Verifications in External Beam Radiotherapy

Purpose: To test the concept of Statistical Process Control (SPC) as a Quality Assurance (QA) procedure for dose verifications in external beam radiation therapy in conventional and 3D Conformal Radiotherapy (3D-CRT) treatment of cervical cancer. Materials and Methods: A study of QA verification of target doses of 198 cervical cancer patients undergoing External Beam Radiotherapy (EBRT) treatments at two different cancer treatment centers in Kenya was conducted. The target doses were determined from measured entrance doses by the diode in vivo dosimetry. Process Behavior Charts (PBC) developed by SPC were applied for setting Action Thresholds (AT) on the target doses. The AT set was then proposed as QA limits for acceptance or rejection of verified target doses overtime of the EBRT process. Result and Discussion: Target doses for the 198 patients were calculated and SPC applied to test whether the action limits set by the Process Behavior Charts could be applied as QA for verified doses in EBRT. Results for the two sub-groups of n = 3 and n = 4 that were tested produced action thresholds which are within clinical dose specifications for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. Conclusion: Action thresholds set by SPC were within the clinical dose specification of ±5% uncertainty for both conventional AP/PA and 3D-CRT EBRT treatment techniques for cervical cancer. So the concept of SPC could be applied in setting QA action limits for dose verifications in EBRT.

Assessing the Awareness and Usage of Quality Control Tools with Emphasis to Statistical Process Control (SPC) in Ethiopian Manufacturing Industries

Introduction: The present work was devoted to assess the awareness and usage of quality control tools with the emphasis on statistical process control in Ethiopian manufacturing industries. Semi structured questionnaire has been employed to executive and technical managers of manufacturing industries of various size and specialism across the country. Stratified random sample method by region was used to select sample industries for the study. The samples used for this study are industries mainly from Oromiya, Addis Ababa, Tigray, Amara, SNNP and Diredawa regions proportional to their size of the available industries. Methods: Exploratory method and descriptive statistics was used for data analysis. Available documents and reports related to quality control policy of the selected companies were investigated. Results and Discussions: The number of manufacturing industries involved in this study was 44. Of the sampled manufacturing industries about 60% are from Oromiya and Addis Ababa regions. It has been reported that 100% of the respondents said that the importance of quality control tools is very important to their organizations’ productivity and quality improvement (Figure 3). Quality control professionals were also asked the extent to which quality control system is working in their industry and majority of the respondents (45%) have indicated that quality control system is working to some extent in their respective industries (Figure 18). Conclusions and Recommendations: Most of the quality department of the industries did not fully recognize the importance of statistical process control as quality control tools. This is mainly due to lack of awareness and motivation of the top managements, shortage of man power in the area, and others together would make it difficult to apply quality control tools in their organization. In general, the industries in Ethiopia are deficient in vigor and found to be stagnant hence less exposed to a highly competitive market and don’t adopt the latest quality control techniques in order to gain knowledge about systems to improve quality and operational performance. We conclude that quality management system has to be established as an independent entity with a real power and hence the quality control department which is responsible for quality can make an irreversible decision with respect to quality of any given product. Moreover, the concerned bodies (government and ministry of industries) should give attention and work together with universities to ensure how these statistical process control techniques could be incorporated in a curriculum of the universities at higher levels in degree and masters programs. Furthermore, different trainings which could improve quality and efficiency of their respective management system should be given as short and long term to the employees including top and middle managers found in various industries relevant to their process.

Water Quality Microbiological Inspection and Quality Control Technology

People’s lives are strongly linked to the quality of their drinking water.The quality of drinking water can be successfully ensured by testing microorganisms in water quality samples and examining their unqualified variables.Many urban residents’drinking water contains a variety of microorganisms,which will have a direct impact on the quality of the water,and all microorganisms will offer a health risk.As a result,steps should be taken to eliminate germs.As a result,the focus of this article is on water quality microbiological inspection and quality control technology.

Multivariate Statistical Process Monitoring and Control: Recent Developments and Applications to Chemical Industry

Multivariate statistical process monitoring and control (MSPM&C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares (PLS) are surveyed in this paper. The four-step procedure of performing MSPM&C for chemical process, modeling of processes, detecting abnormal events or faults, identifying the variable(s) responsible for the faults and diagnosing the source cause for the abnormal behavior, is analyzed. Several main research directions of MSPM&C reported in the literature are discussed, such as multi-way principal component analysis (MPCA) for batch process, statistical monitoring and control for nonlinear process, dynamic PCA and dynamic PLS, and on-line quality control by inferential models. Industrial applications of MSPM&C to several typical chemical processes, such as chemical reactor, distillation column, polymerization process, petroleum refinery units, are summarized. Finally, some concluding remarks and future considerations are made.

Multi-objective quality control method for cold-rolled products oriented to customized requirements

To deal with the increasing demand for low-volume customization of the mechanical properties of cold-rolled products, a two-way control method based on mechanical property prediction and process parameter optimization(PPO) has become an effective solution. Aiming at the multi-objective quality control problem of a company's cold-rolled products, based on industrial production data, we proposed a process parameter design and optimization method that combined multi-objective quality prediction and PPO. This method used the multi-output support vector regression(MSVR) method to simultaneously predict multiple quality indices. The MSVR prediction model was used as the effect verification model of the PPO results. It performed multi-process parameter collaborative design and realized the optimization of production process parameters for customized multi-objective quality requirements. The experimental results showed that, compared with the traditional single-objective quality prediction model based on support vector regression(SVR), the multi-objective prediction model could better take into account the coupling effect between process parameters and quality index, the MSVR model prediction accuracy was higher than that of the SVR, and the optimized process parameters were more capable and reflected the influence of metallurgical mechanism on the quality index,which were more in line with actual production process requirements.

Assay method for quality control and stability studies of a new antimalarial agent (CDRI 99/411)

CDRI compound no. 99/411 is a potent 1,2,4-trioxane antimalarial candidate drug under development at our Institute. An HPLC method for determination of CDRI 99/411 with its starting material and intermediates has been developed and validated for in process quality control and stability studies. The analytical performance parameters such as linearity, precision, accuracy, specificity, limit of detection （LOD） and lower limit of quantification （LLOQ） were determined according to International Conference on Harmonization ICH Q2（R1） guidelines. HPLC separation was achieved on a RP-select B Lichrosphere~ column （250 mm x 4 ram, 5 lam, Merck） using water containing 0.1% glacial acetic acid and acetonitrile as the mobile phase in a gradient elution. The eluents were monitored by a photo diode array detector at 245 and 275 nm. Based on signal to noise ratio of 3 and 10 the LOD of CDRI 99/411 was 0.55 μg/mL, while the LLOQ was 1.05 μg/mL. The calibration curves were linear in the range of 1.05- 68 μg/mL. Precision of the method was determined by inter- and intra-assay variations within the acceptable range.

Frame Design and Reality of On-line Quality Control System for CNC Machining Center Based on Microcomputer

After giving a short review of the methods used for detecting and monitoring in general systems, this paper describes the way of communication between computer and Computer Numerical Control (CNC) Machining Center (MC). Based on these, the paper addresses the means of performing in cycle measurement for manufacturing quality, provides an approach of improving the state of manufacturing process by achieving the real time change of control parameters according to the level of manufacturing process, and discusses the technique of implementing in process dimensional errors compensation corresponding to the in cycle measurement. The results of the experiments show that the frame design is successful and the operation is reliable. The system is taking shape nowadays.

Advances in Process Control for Refractory Production

This paper reviews main problems of domestic refractories, in terms of the structure, principle, performance and new theory of automatic control, such as modern control, fuzzy control, artificial neural network, and expert system. Advanced equipment used in Rill Dalian Plant is introduced, as well as quality control and guarantee in Europe. Some topics to upgrade Chinese refractory industry are discussed.

Dynamic estimation and reliability control of quality assurance for bored piles

A systematic method was proposed to estimate the occurrence probability of defective piles(OPDP) from a site according to quality assurance inspection. The OPDP was firstly suggested as the criterion to weight the performance of a pile foundation. Its prior distribution and updating distribution were deduced to follow Beta distributions. To calibrate the OPDP, a dynamic estimation model was established according to the relationships between prior mean and variance and updating mean and variance. Finally, a reliability-control method dealing with uncertainties arising from quality assurance inspection was formalized to judge whether all the bored piles from a site can be accepted. It is exemplified that the OPDP can be substantially improved when more definite prior information and sampling formation become available. For the example studied herein, the Bayesian estimator of updating variance for OPDP is reduced from 0.0037 to 0.0014 for the first inspection, from 0.0014 to 0.0009 for the second inspection, and with less uncertainty by incorporating experience information.

System Control Research of Multi-link Fructus Trichosanthis Quality

It could not guarantee the quality of medicinal materials and decoction pieces to purely make quality standard of traditional Chinese medicine and carry out quality control. For the problems existed in each process and link of traditional Chinese medicine production,control techniques and measures of guaranteeing and improving quality should be proposed,thereby forming process control system for quality of each traditional Chinese medicine. Based on systemic research on Fructus Trichosanthis which is common traditional Chinese medicine more than30 years,the concept of establishing process control system of Fructus Trichosanthis quality is proposed firstly in this paper. The research aims to find quality problems from 10 processes and links( plant variety,cultivation and propagation,field pest control,fruiting and maturity degree of fruit,storage,regulator,chemical ingredient,quality standard,limited index and circulation),and form feasible techniques and measures solving problems in each process and link,thereby systemically guaranteeing the quality of Fructus Trichosanthis medicinal material and decoction pieces. It guarantees and improves clinical efficacy of Fructus Trichosanthis in Chinese medicine,and could provide reference for establishing process control system of quality of other traditional Chinese medicines.

Development and Application of Quality Control System for Highway Subgrade Construction

The compaction quality of the subgrade is directly related to the service life of the road. Effective control of the subgrade construction process is the key to ensuring the compaction quality of the subgrade. Therefore, real-time, comprehensive, rapid and accurate prediction of construction compaction quality through informatization detection method is an important guarantee for speeding up construction progress and ensuring subgrade compaction quality. Based on the function of the system, this paper puts forward the principle of system development and the development mode used in system development, and displays the development system in real-time to achieve the whole process control of subgrade construction quality.

Use of Quality Control Circles-A Fad or Need

Different techniques including Quality Control Circles, Business Process Reengineering and Statistical Process Control （SPC）, Total Quality Management have been in use to reduce waste in the industry. Waste is considered as necessary evil and there are many types of waste in the industry. There are many ways and means to reduce waste but the less costly is to use Quality Control Circles technique effectively and efficiently. In quality control circles human resources that consist of small groups of employees are selected, who voluntarily meet at regular intervals to identify, analyze and solve quality and other problems in their work areas. In the Quality Control Circles different techniques of the quality improvement and total quality management are utilized which could be numeric or nonnumeric such as statistical quality control techniques and fish bone diagram or brain storming respectively. This article discusses that how reduction of waste in Pakistan industry is possible by using Quality Control Circles implementation.

Application of Non-Destructive Testing Technology in Quality Testing and Control of Water Conservancy Projects

In view of social development,the demand for water conservancy engineering applications continues to increase.The number and scale of water conservancy projects in China have been in a state of continuous expansion in recent years.As a result,how to achieve efficient testing and effective control of the quality of water conservancy projects has always been a topic of discussion in the field of water conservancy engineering in our country.This paper summarizes the application of non-destructive testing technology in the quality testing and control of water conservancy projects.On the basis of explaining the connotation and application advantages of non-destructive testing technology,the non-destructive testing application strategies for concrete strength,steel corrosion and shallow cracks in water conservancy projects were studied.

The development of Fructus corni quality standard considering the effects of processing

The quality standards for Fructus Comi have been established based on the effects of the manufacturing processes.Three critical process parameters(CPPs)of extraction,filtration,and concentration to prepare Fructus Comi concentrate were identified by Plackett-Burman design with a single batch of Fructus Corni,which were heating medium temperature,extraction time,and water addition.Morroniside yield,loganin yield,and dry matter yield were process critical quality attributes(CQAs).CPPs arranged with a Box-Behnken design were applied to treat different batches of Fructus Comi After constructing a model that included CPPs,material propertie s,and process CQAs,loganin content was found to be the critical material attribute(CMA).The design space was calculated with a probability method.According to the limits of process CQAs,the minimum content of loganin in Fructus Corni was calculated with an error propagation method,which was 6.92 mg·g^(-1).When the content of loganin in Fructus Corni reaches up to 6.92 mg·g^(-1),the material is considered high-quality and is most suitable for the process.High-quality material can be used for production of Fructus Comi concentrate.This method can also be used to set material quality standards for other Chinese medicines.

A novel dynamic call admission control policy for wireless network

To address the issue of resource scarcity in wireless communication, a novel dynamic call admission control scheme for wireless mobile network was proposed. The scheme established a reward computing model of call admission of wireless cell based on Markov decision process, dynamically optimized call admission process according to the principle of maximizing the average system rewards. Extensive simulations were conducted to examine the performance of the model by comparing with other policies in terms of new call blocking probability, handoff call dropping probability and resource utilization rate. Experimental results show that the proposed scheme can achieve better adaptability to changes in traffic conditions than existing protocols. Under high call traffic load, handoff call dropping probability and new call blocking probability can be reduced by about 8%, and resource utilization rate can be improved by 2%-6%. The proposed scheme can achieve high source utilization rate of about 85%.

A NOVEL CALL ADMISSION CONTROL SCHEME IN CELLULAR/WLAN INTEGRATION AND PERFORMANCE ANALYSIS

In order to achieve the Quality of Service(QoS) provisioning and efficient resource utili-zation in cellular network and Wireless Local Area Network(WLAN) integration,an Integrated Ser-vice-Based Call Admission Control(ISB-CAC) scheme is proposed in this paper.The integrated network is modeled by using multi-dimensional Markov chains.The numerical analysis is presented to evaluate the important performance measures such as the blocking probability of originating calls,the dropping probability,and the average transfer time,etc.The steady-state probabilities of the multi-dimensional Markov chains are obtained by using an iterative approach,and the CAC pa-rameters are optimally designed.The analytical model is validated by the computer simulation.It is shown that compared with the conventional WLAN-First Call Admission Control(WF-CAC) scheme,the proposed ISB-CAC scheme not only provides better QoS for mobile users but also utilizes the bandwidth resources more efficiently.