PPC System Research Articles

Removal mechanism and quantitative control of trichloroethylene in a post-plasma-catalytic system over Mn–Ce/HZSM-5 catalysts

The optimization of the TCE degradation process was achieved and the TCE degradation pathway in the PPC system was proposed.

Post-plasma-catalytic degradation of toluene using atmosphere double dielectric barrier discharge combined MnOx-based catalysts

Post-plasma catalytic system with Mn-based has shown potential performance in terms of air pollution degradation, in which Ce was induced into MnOx/Al2O3 mixed with 1:1 weight ratio by the impregnation method to increase the capacity of toluene degradation. The catalytic ability of prepared catalysts was analyzed by characterizations of XRD, SEM, XPS, and BET. The effects of the SIE and initial concentration on toluene and CO2 production were discussed in this work. The results showed that the toluene removal efficiency and CO2 selectivity increased with the promotion of SIE. With the addition of 15% Ce1Mn1/A2O3, the PPC system displayed the potential performance in the enhancement of toluene conversion and CO2 generation, and suppression of ozone and NO2 compared with plasma alone. At the SIE level of 504 J/L, the system showed better performance in terms of toluene removal efficiency (90.1%), CO2 selectivity (67.3%), O3 suppression (79.3%), and NO2 prohibition (61.8%). Also, the organic by-products generated by the PPC system were discussed.

Integrated Concept for Acquisition and Utilization of Production Feedback Data to Support Production Planning and Control in the Age of Digitalization

Abstract Digitalization is changing industrial production and is offering huge potential for producing companies. One effect resulting from the increasing presence of information and communication technology in production is the increasing quantity and quality of production feedback data. However, only collecting large amounts of data of data does not lead to high logistical performance and low logistical costs. It is essential to acquire the right data with as little operating expenses as possible, to analyze the acquired data target-oriented and to present the results user-oriented, so that concrete actions can be derived. In practice, this is a challenge for producing companies. To demonstrate the opportunities in this field of action, a concept was developed at the Institute of Production Systems and Logistics (IFA) (Hannover, Germany) and, furthermore, implemented in the IFA learning factory. This paper starts with a short introduction of the IFA learning factory. After that, the paper presents the developed concept in detail, describing the PPC system, the data acquisition using RFID, an order processing support system using ESL and the (real-time) data analysis. In the end a summarizing conclusion is given underlining the importance of an integrated concept for data acquisition and utilization.

Abatement of mixed volatile organic compounds in a catalytic hybrid surface/packed-bed discharge plasma reactor

In this study, post plasma-catalysis degradation of mixed volatile organic compounds (benzene, toluene, and xylene) has been performed in a hybrid surface/packed-bed discharge plasma reactor with Ag-Ce/g-Al2O3 catalyst at room temperature. The effect of relative air humidity on mixed VOCs degradation has also been investigated in both plasma-only and PPC systems. In comparison to the plasma-only system, a significant improvement can be observed in the degradation performance of mixed VOCs in PPC system with Ag-Ce/γ-Al2O3 catalyst. In PPC system, 68% benzene, 89% toluene, and 94% xylene were degraded at 800 J·L–1, respectively, which were 25%, 11%, and 9% higher than those in plasma-only system. This result can be attributed to the high catalytic activity of Ag-Ce/γ-Al2O3 catalyst to effectively decompose O3 and lead to generating more reactive species which are capable of destructing the VOCs molecules completely. Moreover, the presence of Ag-Ce/γ-Al2O3 catalyst in plasma significantly decreased the emission of discharge byproducts (NOx and O3) and promoted the mineralization of mixed VOCs towards CO2. Adding a small amount of water vapor into PPC system enhanced the degradation efficiencies of mixed VOCs, however, further increasing water vapor had a negative impact on the degradation efficiencies, which was primarily attributed to the quenching of energetic electrons by water vapor in plasma and the competitive adsorption of water vapor on the catalyst surface. Meanwhile, the catalysts before and after discharge were characterized by the Brunauer-Emment-Teller and X-ray photoelectron spectroscopy.

Event-driven Production Planning and Control Based on Individual Customer Orders

Manufacturing companies have to increase their flexibility to obtain their competitive advantage in the future. Therefore it is necessary for companies to become adaptable and to be able to react on changing events immediately. In a large number of cases, a quick dissemination of information is prevented by the human factor. The usage of new possibilities in technology enables manufacturing processes to meet problems resulting from imperfect information sharing, cooperation and coordination. For example, the planning and control of production systems is still subject to human decisions and every production order requires the release of the responsible employee. In case of order changes, an optimized order release is prevented due to a lack of information in human centered PPC. Several approaches deal with different strategies of order releases such as autonomous or decentralized PPC. This paper introduces an event driven PPC system in order to shorten the reaction time and increasing the utilization of work load in production systems. A special focus is set on the bill of material. Traditionally, only parts and their quantitative composition are listed. If this traditional structure is extended with physical information for each part, the system will be able to derive specific actions according to the production process for the respective part autonomously. A simulation visualizes the feasibility of the approach by using an exemplary production program and the extended bill of material of individual customer orders.

Integration of the CAD/CAPP/PPC systems

The necessary condition that must be performed in order to ensure full functional integration of the computer aiding systems of technical and organizational production preparation is utilisation of the coherent product model. Utilisation of feature method for representations of the construction and the technological process elements is a key factor for integration of design and technological process planning—CAD/CAPP integration model. The availability of alternative process plans plays the main role in the CAPP/PPC system integration. The main advantage of the accessibility of alternative process plans for product is that we may fast react on a disturbance in the course of the manufacturing process by help of the reactions knowledgebase—one of the module of proposed PPC system. This paper describes a methodology for integration CAD/CAPP/PPC systems in detail.

3-Sigma PPC - A Holistic Approach for Managing the Logistic Performance of Production Systems

Recent developments have led to substantial improvements of production planning and control systems. Despite this, manufacturing companies still have difficulties in meeting their logistic performance objectives and the logistic performance requirements of customers. In order to solve this problem, the 3-Sigma PPC approach introduced in this paper proposes two important innovations. Firstly, 3-Sigma PPC takes a holistic view of PPC systems. It considers the effects that the logistic models, the organisational structure and the decisions of actors of a PPC system have on its logistic performance. Secondly, 3-Sigma PPC comprehensively transfers quality management principles to the context of production management.

Backlog Control Design for a Closed Loop PPC System

In this paper a discrete dynamic model of a single workstation is used to design and analyse control algorithms for closed-loop PPC that improve performance, especially response to disturbances such as rush orders and periodic fluctuations in capacity, while ensuring that dynamic behavior remains favorable and robust. The presence of delays in adjusting capacity presents challenges in both dynamic analysis and control algorithm design that are addressed in the paper. Methods of control engineering, such as transfer function and frequency response analysis, are used to make analysis of fundamental system properties tractable and to improve control of dynamic behavior.

Design and Analysis of a Closed-Loop Single-Workstation PPC System

Methods at control engineering can be integrated with methods of production engineering to improve robustness and performance of production systems, while making dynamic analysis tractable and improving understanding of complex behavior. In this paper a discrete, dynamic model of a single workstation is developed, including characteristic equations of transfer functions that are useful in choosing control parameter values according to desired dynamic performance and response. Nonlineartties such as dependence of capacity on WIP and delay in adjusting capacity due to work rules are modeled and incorporated into the dynamic analysis. Examples are presented of control parameter selection and resulting performance.

Control-Theoretic Analysis of a Closed-Loop PPC System

An analysis of a production planning and control system with closed-loop control of backlog and work-in-progress is presented in this paper, illustrating integration of methods of control engineering with methods of production engineering. The architecture of the system is described and a control-theoretic dynamic model is developed that includes uncertainties in capacity and work input that result from equipment failures, rush orders, etc. Transfer function analysis is used to model dynamic relationships between system inputs and variables including backlog and work-in-progress. The results are used to select control laws for desired system performance and to calculate system response.

Control of the state of orders on machines

Many computer-aided production and control (PPC) systems are available on the market and these systems have to be integrated into existing information systems. Experience has proven that commercial PPC systems do not provide the expected results because they do not have a closed production planning and control feedback loop. This article proposes that the basic PPC system model be expanded so as to include a system which enables control, co-ordination and management of the state of orders on machines. Detailed description is given regarding the general production control procedure, which is based on the Deming circle of continuous improvements, and the corresponding procedure for implementation of control of the state of orders, which wait on the treated machines during the selected interval. To implement the practical continuous control of the state of orders a computer software product CONTROL has been developed.

Exploiting logistic potentials with a simulation-aided test of PPC methods

In order to guarantee company competitiveness, the cost-effectiveness and efficiency of the production process must be continuously enhanced. In practice, PPC systems are implemented for this purpose, but frequently do not meet expectations. Reasons may be an inadequate selection of PPC methods as well as an unsuitable configuration of PPC parameters. By making use of a simulation-aided test bed it becomes possible to check and reconfigure a PPC system with regard to its specific application in a company. This gives access to logistic potentials which have remained unused so far. The paper introduces the concept of a simulation-based PPC tester and describes one application of the system in a medium-sized mechanical engineering company. An example taken from that investigation shows how to generate warehouse logistics operating curves with the help of simulation and how this knowledge could be used to select suppliers and to determine the 'appropriate' stock-on-hand level.