N Chakpitak

P Loahavilai

K Dahal

A Bouras

Knowledge Management on Asset Management for End of Life Products

Keywords: Knowledge Management, Asset Management, Reliability Centered Maintenance, End-of-life Product, Factory Relocation

Because of considerable high labor cost in developed countries particularly Japan and Korea, the end of life products required manual or semimanual processes have been relocated to developing countries. In addition, the relocation creates an immediate financial profit on old asset sale while it is revalued to 30% of its initial value in the new relocated factory. The relocation is not only production location change but also the experience in operation and maintenance process to its Foreign Direct Investment affiliate. Since the old product and process are both nearly at their end of life, it needs to extend the life as long as the product still exists in the market. In order to immediately launch the operation as well as to retain the knowledge, therefore, the asset management and new maintenance modes are proposed at all product, process and people aspects to improve reliability of the old asset and to minimize maintenance cost. The research in this paper was carried out on a Korean relocated electronic factory in Thailand. The result clearly shows that the reliability, quality, cost and intellectual capital are significantly improved.

Introduction

There has been a significant rapid increase in Foreign Direct Investment (FDI) outflow to developing countries in Asian, Latin America since the late of 1980's. [START_REF] Velde | Foreign Direct Investment and Development-An historical perspective[END_REF] Normally, FDI transfer tangible assets and intangible assets to the FDI overseas, where it provides some potential benefit. [START_REF] Mishra | Inward FDI and firm-specific advantages of Indian manufacturing industries[END_REF] For other reason, FDI may need to protect its cost competitiveness advantage through the transfer. [START_REF] Lipsey | Home-and Host-Country Effects of Foreign Direct[END_REF] The FDI from East Asian countries also invest in developing countries in Asia. Most of Japanese FDI moves their production to a new location where the production costs were lower. [START_REF] Urata | The Role of Foreign Direct Investment in East Asian Economic Development[END_REF] Anyhow, the Korean FDI invests aboard to utilize the lower labor cost and to reconstruct the less competitive domestic industries. [START_REF] Kim | Korea Economic Relations with Southeast Asia[END_REF] At the early stage, the motive frequently is driven by the cost competitiveness. The old equipment, which is running beyond its engineering designed life, the life cycle cost of machine replacement shall be a significant financial burden. Because the life cycle cost includes not only the acquisition costs, but also the ownership costs and the disposal costs. [START_REF] Enparantza | A Life Cycle Cost Calculation and Management System for Machine Tools[END_REF] Moreover, it needs a considerable decision to invest in the production of the old 'sunset' product in the industry of high precision or high manufacturing technology.

It is not justified to invest on new machinery for the old products, which normally have no market growth or a declining market. Therefore, the retrofit of a company's equipment with the shift of the maintenance system for a longer profitable period is the most appropriate solution. [START_REF] Sundberg | Management aspects on Condition Based Maintenance-the new opportunity for maritime industry[END_REF] Even the old products cannot make a lot of profit, but the product owner company can keep the market as well as spare part service to customers. The product has no longer investment cost, and the production equipment is still available. Moreover, the production technology is nearly obsolete or requires unskilled labor. In the developed countries, the labor cost is much more expensive.

This research uses a case study of a FDI who loses their cost competitiveness in an old location in a developed country. The FDI chooses to relocate the old machinery to the cheaper operation cost location in a developing country.

Literature Review

In this relocation scenario, new technology should be employed in order to save the cost of unskilled labor. Therefore, the old technology production line has to be replaced by a new one, and then, relocate the old one to developing countries. The knowledge in operation and maintenance for the equipment should be transferred from the old plant in the developed country to a new factory in developing country. [START_REF]UNCTAD World Investment Report[END_REF] Finally the new plant tries to keep running the production as long as possible until it has no longer customers or its production cost is not justified. Therefore, its corrective, preventive, and inspection maintenance should be changed into condition based, reliability based and risk based maintenance respectively. Thus, the experience in operation and maintenance is needed to be utilized in order to extend its operational life. [START_REF] Moubry | Maintenance Management-A New Paradigm[END_REF] The weak points of the equipment can be identified from its historical corrective maintenance records. Some equipment's running conditions should be timely monitored. Moreover, the preventive maintenance schedule should more focus on its unreliable parts. [START_REF] Bertling | A Reliability-Centered Asset Maintenance Method for Assessing the Impact of Maintenance in Power Distribution Systems[END_REF] The periodic inspection maintenance should concentrate on some major parts. The deterioration mechanism of the major parts should be followed up properly.

From an asset management's historical perspective, the learning processes of a factory on the operation and maintenance are develop through the operation and maintenance activities. [START_REF] Sherwin | A review of overall models for maintenance management[END_REF] The learning model is based on experience collectively gained over a period of time. Anyhow, it is a time consuming process with many staffs involved to develop best practices. Hence, it requires a step-by-step development from breakdown to proactive maintenance. [START_REF] Legutko | Modern approach to machines operation maintenance[END_REF] In the breakdown maintenance scheme, equipment is disassembled and assembled to get the basic knowledge in plant installation and commissioning. Corrective maintenance scheme represents knowledge on diagnosis when failures occur. In preventive maintenance scheme, most activities involve resource scheduling to avoid unplanned outages. Predictive maintenance scheme indicates the abilities of the knowledge workers to foresee the future faults and events based on the present condition of equipment. [START_REF] Ahuja | Total Productive Maintenance: Literature Review and Directions[END_REF] Finally, with more knowledge gained over an operating period, the proactive maintenance indicates abilities of the knowledge workers to assess the asset lifetime as well as its' parts that consequently assists the utilities in the decision making on the replacement or the refurbishment. Furthermore, the associated costs and risks can be reduced from the experience of maintenance while more knowledge has increasingly been gained over a period of time.

Methodology

A Korean FDI relocated electronic factory in Thailand has been selected as a case study. The asset management is introduced to improve the factory preventive maintenance scheme. The asset management procedure includes three stages;

Fig. 1. Stages of the methodology

Firstly the asset survey shall be conducted. Each asset in the factory needs to be evaluated for its replacement cost. Normally the replacement cost can be received from its manufacturer for brand new equipment. But in some cases, equipment has already been no longer manufactured. Then the replacement cost can be assumed as the price when it was initially purchased. The prioritization should be done from the most expensive replacement cost to the least one. Top three expensive assets should be in a short list under consideration. Later, the aged profile curve should be plotted for high priority equipment. Normally, an individual machine that is beyond 20 years should be focused. The further focus should be given to the too old ones. Then, performance including availability and reliability of the old assets should be evaluated.

Secondly, Knowledge Management shall be applied in Asset Study. The risk assessment should be done on the targeted assets by using risk assessment matrix, and the knowledge acquisition should be done on its design versus operation, maintenance history and deterioration mechanism.

Finally, based on the acquired knowledge, the suitable maintenance method such as Risk Based Inspection, Reliability Centered Maintenance or Instrumental Protective Function for particular equipment is then selected to improve the traditional preventive maintenance procedure.

4

Analysis and Results

Replacement cost

In evaluating the replacement cost, it is required to classify the overall asset. This asset is classified into 3 categories which are; -Class A, the main machinery which directly affect to the production capability -Class B, the supporting machinery to the main machinery -Class C, instrument which does not need maintenance service In this study, only machinery in class A shall be identified the replacement cost. The replacement cost is evaluated at the new purchasing price of machinery from the existing manufacturers. The example of replacement cost of Bonding and Molding machinery that their life are over than 5 years, are evaluated as following Fig. 2 and Fig. 3.

Fig. 2. Replacement Cost of Bonding Machinery by Product

Aged profile development

Aged profile shows the investment in replacing machinery according to their ages. The life extension of these machineries is considered and expected to provide at least 15 years extension. The aged profile of three main machineries is shown in Fig. 4, 5 and 6. According to the age categories in this study, there are 4 recovery operations for 4 age levels, aiming at recapturing value from its End of Life as follows, -Recycling the breakdown and low performance machine which its life is more than 20 years. The purpose is to reuse parts by various separation processes and reusing them in the other machine. -Repairing and reusing the breakdown machine but still in a good performance which its life is from 10 years in order to return it service in working order by changing parts. -Reviewing the maintenance plan of the machine that its life is from 5 years by increasing PM or applying Reliability Centered Maintenance (RCM), Risk Based Inspection and Monitoring only the Instrumental Protective Function in order to protect the low service performance. -Relying on the manufacturing manual to maintain the operation function of machine which its life is less than 5 years

Performance evaluation

The factors to evaluate the Service Performance of the machinery include 12 variables (See Table 1.). From the normalization graph of variable number 5 to 12, it is found that SOT-XXX production line possesses the overall highest performance among three production lines (See Fig. 7.). It is suggested that the production line of TO-XX and TO-XXX product should decrease the Preventive Maintenance. Some machines should be recycled or refurbished. The running capacity of these two production lines is still lower than the acceptable ratio, so there is an opportunity to build a stock of regularly ordered product.

Risk Assessment

Risk Assessment Matrix is used to assess the risk of each machine. It requires the participation of knowledge workers and the experienced technicians. This is needed to assess the possibility to be breakdown and the seriousness of problem and assess risk into three levels (High -Medium -Low) together with its part's lifetime while providing the subsequent action needed of each part. (see Fig. 8)

Risk

Asset Study: Engineering design, History and Deterioration Mechanism

After assessment and collecting the lifetime of each part of the machine by the risk assessment matrix, the experienced technicians shall examine the machinery engineering design, its operation, maintenance history and parts deterioration mechanism in order to understand and plan its maintenance mode. See the sample of the asset study of the Back Inline System (BIS) machine in Fig. 9.

Fig. 9. Engineering design, operation and maintenance history study

The machine part is classified into 5 categories; Static equipment, Rotating/Moving Equipment, Instrumentation, Instrumental Protective Function (IPF) and Static Equipment which identifies its lifetime. The Deterioration Mechanism study of each part in 5 categories is shown in Fig. 10.

After studying the asset, which is based on the acquired knowledge of machinery engineering design, its operation, maintenance history and parts deterioration mechanism; the maintenance mode shall be suitable and selective according to its design and deterioration mechanism. There are three selective maintenance modes, Risk Based Inspection (RBI), Reliability Centered Maintenance (RCM) and Instrumental Protective Function (IPF), proposed for individual equipment, which is described in Table 2.

Integration of new maintenance mode to existing maintenance system

Through the process of asset survey and study, a new maintenance mode is introduced but it should be applied with the existing maintenance system in the firm. This Korean FDI already has its own maintenance system, but it focuses on the Preventive maintenance, which may lead to the excessive maintenance cost. Therefore, the RCM, RBI and IPF maintenance mode shall reduce the over-maintenance cost. The new maintenance mode integrating with the existing maintenance system can be illustrated in Fig. 11. The old PM system provided a PM master plan based on machine manufacturer recommendation. The technician took an action on daily monitoring, cleaning, lubricating and changing parts and report in the PM, then, input the report in CMMS.

After RCM integrating, the technicians study machine deterioration mechanism and PM history, then, make Risk Assessment (RAM) and RBI (Risk Based inspection) based on their experience. The technicians use RAM data to build a maintenance Mode instruction and, together with their experience, make a Machine Life Time Justification manual. After input to CMMS, then, the RBI plan for old machine and PM plan for new machinery, which is not over 5 years old, are scheduled. Later technician maintain the machine according to the prior designed maintenance mode.

Finally, the problem in the maintenance work is discussed and feedback to the maintenance team for improvement.

Reliability and Quality Improvement

There is an indicator showing that after applying the new selective maintenance mode, in the middle of 2011, the process reliability is improved. Considering the record of Outgoing Quality Control (OQC) of all products after the production line applied the new maintenance mode. The number of OQC reject caused by machine failure at the end of 2012 was significantly reduced 81% from the first half 2011, See Table 3.

Maintenance Cost Improvement

There is also a record of maintenance expense that shows a big improvement in maintenance cost before and after the application of new maintenance mode. (See Table 4.) Initially, they generate the Preventive Maintenance cost plan at the beginning of the fiscal year. The first half of 2011, before the application of new selective maintenance mode, they spent 94% of the annual budget. But after the application of new maintenance mode, the cost of maintenance was reduced to 37% of the budget.

Emerging of Knowledge Retention

Prior to the research's commencing, most of the experienced technicians with current average 13 years working as senior technicians never externalize their tacit knowledge in any kind of media. Many of them left the firm without knowledge retention. But through the process of asset study, they had used their experience to justify the machine risk with the risk assessment matrix, as well as the risk based inspection and part life time. Their knowledge was elicited and documented online to share to the technician community. The knowledge was delivered to other maintenance members in the form of books (a Machine Part Lifetime Justification book and a Machine Risk Inspection book). The knowledge is also retained within the organization. . The knowledge retention, then, was activated and delivered to the less experienced junior technicians. The process of knowledge capturing and retention is illustrated in Fig. 12.

Conclusion

Since the core manufacturing factors are people, process and product, therefore the management of the end-of-life product manufacturing also requires the improvement of those three factors. A new financial strategy of the obsolete product should be applied to stretch its intellectual capital. The asset management plan should be applied to improve the manufacturing process. And the knowledge management should be applied to improve the knowledge of manufacturing technical people. These can make extra corporate value including stock market value and customer satisfaction. Therefore, the problem of product and process end of life can be solved by the shift of maintenance system with knowledge management. The case study in this paper also showed the explicit improvement of reliability, quality and product cost. Moreover, it also retains the knowledge of the experienced technicians before their retirement or resignation. The whole process of Asset management could help the firms to endure their product life cycle.

Fig. 3 .

 3 Fig. 3. Replacement Cost of Molding Machinery by Product

Fig. 4 .Fig. 5 .Fig. 6 .

 456 Fig. 4. Aged Profile by the Replacement Cost of Bonding Machinery Group

Fig. 10 .

 10 Fig. 10. Machine part's Deterioration Mechanism

Fig. 13 .

 13 Fig. 13. Tangible and intangible performance

Table 1 .

 1 Service performance evaluation

	Fig. 7. Service Performance of 7 variables

Table 2 .

 2 Maintenance mode selection

			Type of Equipment	Maintenance Mode	How to Maintain
					Monitoring its corrosion,
		1 Static Equipment		erosion,wearing and
					fouling condition
		2 Rotating/Moving Equipment	RCM	Monitoring,doing Preventive Maintenance
					and Lubricating
		3 Instrumentation		Testing, Calibrating and Cleaning
			Instrumental Protective
		4	Function (Safeguard	IPF	Testing its operation
			Equipment)
		5	Static Equipment which prescribed its lifetime	RBI	Checking Integrity (Specification) and Inspection its function
	6	Discussion

Table 3 .

 3 OQC rejected by machine failure in 2011-2012

	OQC Reject Caused	2011	2012
	By Machinery	1st Half	2nd Half 1st Half	2nd Half
	T arget (T ime)	42	42	24	24
	Actual (T ime)	47	25	14	4
	% to target	112%	60%	58%	17%
	% to Last Period	100%	53%	30%	9%

Table 4 .

 4 Maintenance Cost in 2011-2012

  After implementing the RCM as the knowledge based maintenance, the actual financial and intellectual capital performances of relocated machinery had been observing for 2 years from 2012 to 2013. It can be seen that both performances were significantly increased. The researchers had further made a calculation model and forecasted the 5-year performance from 2014 to 2018. The result shows significant ratios that the relocated machinery possesses a competitive advantage in intellectual capital. During 7 years from 2012 to 2018, Human Capital is 9 times of Human Asset. Total market capital is $431 Million USD, with the intellectual capital 59% ($254 Million USD) and financial capital is 41% ($ 177 Million USD) as exhibited in fig.13.

		450	Million $USD.
				Total Market Capital 431
		400		-Intellectual capital 254 (59%) -Financial capital 177 (41%)
		350			Structural Capital
				(Internal & External),
					187
		300
		250
					Individual
		200			Competence (Human Capital), 68
						Total Revenue 167
		150
		100	Ratio: HA to HC = 1:9	Ratio:	Financial Capital, 177	Product Cost, 115
				HA+Dprecistion to
			Individual	Profit = 1:5.8
		50	Competence (Human	Profit, 43
			Physical Net Asset, 9 Capital), 68	Maintenance Mode Depreciation Cost, 9	Online Document	Depreciation Cost, 9 Profit, 43
		Tacit Knowledge Human Asset, 7 Action RAM, RBI -Asset after Relocation and Knowledge (2012-2018) Worker RCM implementation	RBI Mode RCM Mode Human Asset, 7 Profit and Relocated cost (2012-2018)	Machine Part Life Capital Performance time Justification Book (2012-2018)	Knowledge Explicit Business Performance (2012-2018)
				IPF Mode	RBI Schedule Plan
			Experienced	Low Skilled and	Knowledge
			Technicians	new Technicians	Worker
			Fig. 12. Process of knowledge capturing and retention
	6.5	Intellectual capital growth

Commented [b1]: You mean "reflects"??


Frédéric Noël
email: frederic.noel@grenoble-inp.fr

Dov Dori
email: dori@ie.technion.ac.il

Towards 3D visualization metaphors for better PLM perception

Keywords: Virtual reality, PLM, Object-Process Methodology, conceptual modeling

PLM tools mainly refer information systems based on a wide graph representing linked information. Such a PLM model is compatible with a metamodel often expressed in UML. UML graphics diagrams are paradigms to support sharing and understanding the concepts and relationships that must be supported by the PLM tool. Nevertheless instance diagrams contain so many objects that it is hard to present them in a holistic view that can be easily shared by collaborators. This paper presents a 3D approach to visualize an Object-Process Methodology (OPM) model, which provides a single holistic view of a complex system and supports sharing among collaborating parties. This approach has been applied to managing the complex information related to VISIONAIR -a European visualization infrastructure project, successfully enabling the management of 123 simultaneous projects.

Introduction

Product lifecycle management (PLM) integrates the theories and technologies to create, optimize and manage a holistic view of a product throughout its life cycle. Maintaining information coherence is a major PLM issue. Tools have been developed and commercialized to integrate information from the various domains involved in the various product life cycle stages. Such tools require detailed product models as well as the engineering processes to produce it. Models are often formalized through Unified Modeling Language (UML). The complexity of the modeled domain leads to huge class diagrams which represent the conceptual model of PLM. Some object diagrams are used to visualize the instantiation of the conceptual model, but they are seldom practiced because the complexity of relationships leads to very large, entangled graphs that cannot be understood. Hence, such diagrams are usually limited to small examples. Some user interface is needed to access information in models of real life products. Web-based user interfaces are currently practiced, leading to a large amount of tables linked together. A standard user accesses the system through a profile area, with a table of projects and products with which she or he are concerned. Selecting a project or product, he gets access to new tables providing specialized information. Each table is a partial view of the complete information system. Overall comprehension of the product life cycle requires navigating through a big set of tables and building a mental view of the product evolution or its related processes.

While PLM claims to provide a holistic management of the product life cycle, it fails to offer simple, user-friendly views. We present a new way to access needed PLM information. Using a 3D visualization framework, we take advantage of the third dimension to augment perception capacity.

In the next section we discuss various product and process models which were proposed to measure the PLM complexity. Section 3 focuses on Object Process Methodology (OPM) and the OPM-based presentation, which combines the processes and the object being processed, yielding a set of conceptual 2D object-process diagrams (OPDs). Section 4 presents the use case concerning the management of more than 120 projects simultaneously in the VISIONAIR FP7 European project. A main objective of the VISIONAIR project was to invite guest users to one of the 29 research institute laboratories participating in the VISIONAIR consortium. We created a conceptual view of VISIONAIR processes in an OPM model. Then, a 3D projection of the instantiation model was used to simultaneously visualize the status of various projects. This 3D approach is presented in Section 5. The paper concludes with the discussion about the added value of this visualization for process management.

PLM conceptual models

A wide literature covers PLM models. Design is mainly concerned with the product and the definition of its engineering processes via activity/process models or by product data management models which often integrate the product and its manufacturing processes. PLM also address models of customers (CRM), enterprise resources planning (ERP), and many other aspects. Some authors propose integration of these aspects. In this section we provide a rapid overview of product and activity models.

Product Models

The product breakdown structure is often used as a decomposition of the product for short-term projects. Indeed, this provides a local bill of materials, which was extended as the core model of product data management (PDM) systems. The bill of materials is a tree of articles, mainly corresponding to an assembly decomposition into sub-assemblies or components. It becomes quickly complex when every representation of article may be released and the corresponding versions are saved in the same data base. Moreover, various views, such as design view, manufacturing view, etc., are attached to the product life state. The bill of materials is a structure decomposition of the product, which provides reference to identify parts of complex products and to access a set of representations or views. Indeed the bill of materials is a structure decomposition of the product.

The structure decomposition does not provide a complete description of the product. Gero [START_REF] Gero | The situated function behaviour structure framework Design Studies[END_REF] highlighted the cognitive dimensions of product analysis as the function, behavior and structure descriptions (FBS). Many models were developed to integrate functional and behavioral representations of the products. The Core Product Model was an attempt to propose an extensible standard model. Its kernel definition was expressed by Fenves [START_REF] Fenves | A core product model for representing design information[END_REF][START_REF] Sudarsan | A product information modeling framework for product lifecycle management[END_REF] through a UML class diagram (Figure 1). Bond-graphs were proposed to focus on function and behavior representations [START_REF] Paynter | Analysis and design of engineering systems[END_REF]. The product part of IPPOP (Integration Process Product for Performance Optimization) model focused on establishing links between FBS dimensions [START_REF] Noël | The PPO design model with respect to digital enterprise technologies among product life cycle[END_REF]. The FBS-PPRE model claimed to integrate manufacturing processes and resources to the FBS model [START_REF] Labrousse | Proposition d'un modele conceptuel unifié pour la gestion dynamique des connaissances d'entreprise[END_REF]. All these models fail in describing product behavior which remain a polysemous concept [START_REF] Noël | A dynamic multi-view product model to share product behaviours among designers: how process model adds semantic to the behaviour paradigm[END_REF]. No model succeeded in becoming the standard. A recent effort has been to extend UML to SysML by arguing that the product is a system and adding requirements and parametric diagrams [START_REF] Johnson | Integrating models and simulations of continuous dynamic system behavior into SysML[END_REF], including to functional and behavior diagrams.

STEP is a special case which is often reduced to an exchange standard, but initially it was built to model the overall life cycle of a product [START_REF] Urban | Integrated product data environment: data sharing across diverse engineering applications[END_REF]. Indeed the norm the EXPRESS language acts as an editor of conceptual models [START_REF] Goh | An integrated environment for product development using STEP/EXPRESS[END_REF], which is similar to the UML diagram class. As in UML, an EXPRESS diagram is a set of relationships between concept classifiers which have basic attributes. A diagram is a conceptual view of a partial domain as it will be modeled and exchanged through the standardized files, but it could be also directly used as a modeling data structure. The various chapters of the STEP standard define partial views of PLM aspects. STEP fails to provide a coherent holistic view for PLM, because the various parts were defined separately and intersection concept may differ with respect to the corresponding chapters. Moreover STEP releases are too often late and lag after commercial innovations, making STEP obsolete.

Indeed, product models are presented as 2D diagrams, and when they are instantiated to show all the actual instances of one or more object classes, perception of and interaction with the model becomes a real challenge.

Activity Models

Similar to product models, activity models have also been proposed in the PLM domain. A simple and comprehensive activity model widely used in industry for short term projects is the work breakdown structure (WBS) [START_REF] Tausworthe | The Work Breakdown Structure in Software Project Management[END_REF]. WBS seems to be very efficient, because it is easily understood by any engineer. Yet, it is just a tree decomposition of a task. Such decomposition was widely adopted in most activity models starting by the series of IDEFx process models or within project management tools, such as Microsoft Project. Several UML diagrams convey activity: state machines, activity diagrams, sequence diagrams, and even use case diagrams. Business Process modeling Notation (BPMN) was proposed in 2006 by the Object Management Group (OMG). These activity models propose diagram representations that make them quite intuitive, as illustrated by the BPMN diagram in Figure 2.

Fig. 2. An example of a BPMN model [12]

Activity models usually present an a priori model of the expected process. The major problems with these representations concern three aspects:

• These representations are not easy to update, share and create on the fly; they lack agility. • They are seldom reused and almost every project leads to a definition of a new model. Moreover, the model is supposed to fit all its instances. • Complexity is poorly managed, as decomposition is hardly undertaken.

Every non-trivial activity has to be decomposed into sub-activities, and this recursive process must be stopped whenever the right balance between modeling need and model comprehension efficiency is reached.

Complex information systems and user interfaces

A model is not an end in itself, rather, it is expected to support some human expert activity. Individuals should be able to extract, edit, and share information while maintaining a coherent model. This idealized view has not been reached, and therefore partial solutions are provided to support human experts as they advance along the PLM process:

• Groupware is widely used to share models. To support coherence, the most popular solution has been a check-out/check-in protocol, which enables users to protect potentially modified data and inform collaborators that they are doing so. Synchronization solutions exist, but they are mainly practiced in software development projects. Application of such solutions to a wider range of domains have been investigated [START_REF] Bricogne | Towards PLM for mechatronics system design using concurrent software versioning principles, Product Lifecycle Management. Towards Knowledge-Rich Enterprises[END_REF] but only partly realized. • Mapping to an expert view: expert dedicated models are produced either by manual reconstruction from scratch or by and by hand, by extraction and conversion of common models to a dedicated view. A mapping to a 3D model is a usual practice within product development, because it fits the physical view of a real product. This approach is used obviously in CAD systems, but also for manufacturing simulators and many other behavior analysis systems, such as finite elements method. Such mappings provide a metaphor to visualize and interact with a partial view of PLM and help resolve interoperability issues. Interoperability and Groupware are the major ways to create connections across a huge data set, and providing a more complete and holistic information PLM model. The research question in this regard is how to enable a holistic understanding of a complex information system? The assumption of this study is that a 3D model may be used to extend the capacity to present instances of object classes in an information system even if the information does not have an obvious 3D physical metaphor.

The next section presents a conceptual model of a real use case supported by a process-driven information system. A 3D representation of an instance of this process is then introduced and tested on various 3D viewers to assess how the 3D presentation helps manage this complex information.

An infrastructure project with a complex 4.1 VISIONAIR activities

VISIONAIR is a European infrastructure for research in visualization technologies, which operated between 2011 and 2015. The project acronym means "VISION Advanced Infrastructure for Research". The 25 partners involved in the project operate 29 high-level visualization and interaction facilities that share a technologyoriented vision. The 29 facilities were associated to four technological domains:

1. Augmented collaborative environments, including holography, were supported to enable local or remote collaboration of actors. 2. Ultra-high definition and networking facilities provided ultra-high definition (UHD) displays (4K and 8K, even in 3D), including streaming the corresponding content on networks.

Virtual reality (VR) facilities included immersive environments such as

CAVEs, where the user is immersed in virtual scenes. 4. Scientific visualization facilities were dedicated to the navigation and understanding of results of data output by high performance computing or from physical observation.

The infrastructure hosted external research projects. A call for projects was launched and any European research could apply for a Trans-National Access (TNA) project. A process, described in detail in the sequel, was designed to evaluate project proposals in order to accept or reject them. An information system was created to manage the 230 TNA applications received over the project's four years and ensure the realization of 122 of them, enabling projects that cover a wide spectrum of disciplines, including the following: This long list demonstrates the variety of projects managed within VISIONAIR and the difficulties associated with gaining control and managing the projects. Obviously, we implemented information systems to support both the evaluation of the proposals and the collaboration with the applicant. This use case is a service deployment rather than a product design activity and thus the corresponding "product model" is much simpler. In the following sections, we present the OPM conceptual framework to model this process.

OPM conceptual model

Object-Process Methodology (OPM) is an approach and a language for modeling complex systems using a compact set of concepts [START_REF] Dori | Object-Process Methodology -A Holistic Systems Paradigm[END_REF]. It is a holistic graphical and textual paradigm for the representation and development of complex systems in a formal framework. OPM is a tool for system engineers and it enables representing systems simply in a single model, expressed in both graphics and equivalent natural language.

By using a single holistic hierarchical model for representing structure and behaviour, clutter and incompatibilities can be significantly reduced even in highly complex systems, thereby enhancing their comprehensibility. OPM has proven to be better in visual specification and comprehension quality when it was used for representing complex reactive systems compared to the standard in the field of systems engineering.

One major benefits of OPM is the combination of the product model through object definition and the activity process which consume an object in a given state and produce objects in a new state. The three concepts of the FBS paradigm are joined in a single 2D diagram: Structure is related to objects, Functions are related to activities and Behaviour is related to object states. This combination makes it ideal for collaborating and communicating knowledge and ideas, via visualization-based platform.

An OPM diagram is composed of 3 main symbols plus links:

• Objects are represented by rectangles. The name of the rectangle identifies the concept, which is either an actor or an object. Within Figure 3, a "Research group", a "Visionair consortium", a "Project" are objects managed through the process.

• Object States are represented by rounded rectangles placed in the object rectangle. One object has a single active state and is identified with its current state. The "research group" in Figure 3, may have several states: "unaware", "aware", "waiting for feedback", "project rejected" and "project approved" • An activity is represented by an ellipsis. An activity is decomposed in several activities by drawing ellipsis inside the father ellipsis. There is no recursive decomposition on a single diagram. If a sub-activity must be decomposed this second level of decomposition will be drawn in a secondary diagram. • Several links are available:

• consumption, and production link:

• control link • inheritance link: the traditional specialization link of concept • link

These concepts are presented in Figure 3. Through a first draft model of the transnational project activity process.

3 OPM description of VISIONAIR TNA process

Object-Process Methodology, OPM [START_REF] Dori | Object-Process Methodology -A Holistic Systems Paradigm[END_REF][START_REF] Peleg | The Model Multiplicity Problem: Experimenting with Real-Time Specification Methods[END_REF] is a systems modeling paradigm that represents the two things inherent in a systems: its objects and processes. OPM, which has become ISO 19450 Specification in Aug. 2014 [16], is an ideal visual-textual platform for not just engineering systems and managing human knowledge, but also for extending and evolving it by combining disparate facts within a formal, intuitive, consistent, reliable, and evolvable OPM model.

OPM is fundamentally simple; it builds on a minimal set of concepts: stateful objects-things that exist, and processes-things that happen and transform objects by creating or consuming them or by changing their states. Another fundamental advantage of OPM is that it represents the system simultaneously in graphics and natural language, and the two are completely interchangeable. OPM enables clear representation of many important features of a system at various levels of detail. OPM semantics was originally geared towards systems engineering, as it can model information, hardware, people, and regulation.

OPM was selected for modeling the TNA process because of the the clear conceptual overview of the process it porvides. Basically, a TNA process involves an external "Research Group" which is supposed to apply for a project. VISIONAIR consortium members are in charge to support this Research Group. First a Review Committee is organized for assessing the proposed "Project" and a "Host Facility" technically supports the project if and when it is accepted.

Objects are denoted in OPM by rectangles and the states of an object are denoted by rounded-corner rectangles inside the object. Examples of states of the object Host Facility are expecting an incoming project, preparing the execution of the project, hosting the Research Group, and finally completed experiment (see Figure 3).

Processes, denoted as ellipses, transform objects by ( 1) consuming them, (2) producing them, or (3) changing their state. The TNA process is comprised of the following main subprocesses: first promotion was made by the review committee and projects were solicited. An interested Research Group creates an account and can apply for a project. Then it waits for the results of the Reviewing process, which produces the informatical object Review Outcome. Depending on this outcome, the project may be rejected, accepted, or modifications may be requested. The acceptance activity notifies the Host Facility and the Research Group, which collaborate for remote preparation, then for co-located set of one or more experiments (see Figure 3). The 2D diagram in Figure 3 provides an overall view of the process, but the number of arrows gives an idea of the complexity of the managed process. Each object "knows" its current state and can clearly identify the process that should be processed next. As soon as a project was submitted, the Research Group knows that it must wait for review outcome. Every process may be split into sub-processes via OPM's in-zooming mechanism, but in this paper we do not make use of this refinement mechanism.

While each single actor (object) knows its current state and activity opportunities, the complete management of all the simultaneous projects, the corresponding research groups and host facilities remains a real challenge, as one needs to be on top of all the simultaneously occurring projects. to figure out which research groups and host facilities are concerned, or rapidly get the list of projects in a given state. We produced a database system that reflects the TNA project process. Only humans can achieve a holistic picture by integrating several partial results from querying the database. In the next section we present tour 3D metaphor for improved management of the TNA process.

3D visualization of the TNA process

A few works investigated the potential of visualization for information system. Bihanic and al. [START_REF] Bihanic | Visualisation de Systèmes d'Information Complexes. Une approche par « points de vue étendus[END_REF] proposed various way to visualize graph data. Hayka and al. [START_REF] Hayka | Heteregenous PLM Environments with Grid Computing and Virtual Reality Applications[END_REF] developed new metaphors for multitouch tables to visualize a PDM bill of materials. Sadeghi investigated the management of models for project reviews [START_REF] Sadeghi | Visual and interactive tool for product development process enhancement: towards intuitive support of co-located project review PLM[END_REF]. The current work is a new step in these investigations.

3D metaphor

As argued, the OPM 2D diagram provides an efficient conceptual view of the process but it cannot visualize a set of object instances. The core idea of the 3D metaphor is to take advantage of the third dimension, which is available with current visualization technologies. The third dimension is used to list the instances concerned an object state. We then wish to assess the benefit of improved process control as a result of using the third dimension. An interaction behavior was encoded. A trackball system was designed to support free navigation in 3D over the scene. When selecting an object in a certain state, the list of object instances are drawn along an axis orthogonal to the diagram plane. Figure 4 shows a specific view where the "Host Facility" was selected at the state of "preparing a project". The projects which were accepted show up on the right column, identified by their index, e.g., Project #75 at the top, while the host facilities are listed by their name and (in parentheses) the number of projects that the Host Facility is preparing to host.

With this single view, a user gets a clear picture of the concerned facilities and projects in response to his or her graphics-driven query. By selecting an instance from one the two lists, additional information can be printed in an information window. For a project, one can get the project name, the Research Group, dates of submissions and of state change, etc. Depending on the working mode, selecting an instance may visualize the related items. For example, if a specific Project is selected, the relevant instances of the object classes Research group, Host Facility, Review Committee with their current state are presented. This visualization provides the system executives and operators with a clear view and rapid understanding of all the information related to a given project.

Projection on various device

Our 3D metaphor was tested on several devices. First, we used a stnadard 2D desktop. Figure 4 and Figure 5 were produced this way. To test for information overload, in Figure 5 several states of the Research Group object were selected, and indeed, as Figure 5 shows, there is too much information and the added value of the 3D instance presentation is lost.

We then used a 3D active stereoscopic full HD display with a Crystie back video projector on a wall 3 meters wide and 2 meters high. As Figure 6a shows, the OPD is oriented from top to bottom.

The metaphor was also tested on a powerwall. As Figure 6b shows, the powerwall is made of 9 Samsung © LCD 55" panels with very narrow, 5mm sides between any two adjacent displays.

Finally, the metaphor was tested on a head-mounted display (HMD) Oculus © DK2. This technology is both affordable and can be easily installed on standard desktop computers. However, interaction with this device is not convenience, and some dizziness may appear due to loss of contact with real space. In our case, such uncomfortable feelings due to large displacement are not an issue, since the global scene may be really to avoid large head movements. Since interaction with HMD is challenging, a mouse was used, which required some training.

Overall perception

The assessment focused on the overall subjective display perception rather than on interaction issues. While we did not have a large enough sample to allow for statistical analysis, the differences in perception were very obvious. Three factors appear to be significant:

• Dimensionality: a traditional 2D desktop and the power-wall were used for projecting the 3D scene on a 2D display. The HMD and the stereoscopic back projection systems are referred to as 3D spaces. • Resolution: the tested 2D desktops were either at very high resolution 4K or Full HD. Both the 3×3 power-wall and the stereoscopic back projection system have Full HD resolution. The HMD is a Full HD display used in side-by-side mode, so each eye has half full resolution in the horizontal direction.

• Brightness: all the displays have high brightness, but the brightness of the power-wall is video projector. An important usage issue is text readability. Low resolution is a drawback, and this deficiency increases with stereoscopy, where even a small alinement defect hinders text readability, making it unusable for information systems. Thus, HMD is currently still an immature technology, while systems with higher resolution are preferred. The 3D superposition of text in on 2D displays makes them hardly readable. The 3D spaces are more adequate to perceive 3D superposition of text, but on the other hand, resolution in 2D displays is better, so the power-wall provides better rendering of text with 3D superposition.

The immersion in 3D space allows putting the diagram on a horizontal plane and perceiving the instances as being lists perpendicular to that plane. The object states far from the observer on the horizontal plane are the initial states and the closest states are easily perceived as the final states, making the project time line clearly aligned from far (origin, past) to close (destination, future). With full immersion and tracking, the observer can overcome the difficulties arising with text superposition in 2D desktops. However, the projection of text in 3D is at a lower resolution, making it less readable. When a lot of text is projected the user loses the ability to focus on the text, and some of it also occludes other text. Higher resolution is needed for this approach to be implemented in a valuable tool.

With respect to interaction comfort, using HMD, traditional desktop, and 2D power-wall, the user can sit down. We have not implemented 3D interaction at this stage and used a 2D mouse in this first test. 3D stereoscopic back projection system appears to better fit a clear perception of 3D, as navigation becomes easier, but resolution must improve for better text readability.

Conclusion

Among existing conceptual modeling approaches and diagram kinds, OPM has proved to be very efficient, because it combines both processes and state-full objects -the only two building blocks in the universal OPM ontology. In our application we, have found it to be a clear and nice tool to collaborate about the conceptual definition and management of the complex trans-national access process. Since, like any other diagram kind, OPMs are not adapted to the description of instances, as soon as more than a single instance is running under the process, a new approach is in order.

The complexity of the VISIONAIR EU FP7 Project, in which more than 200 projects were simultaneously managed in 29 Host Facilities by one Review Committee, called for designing and assessing new management metaphors.

Using the 3D representation metaphor, we have demonstrated a clear advantage. Additional research and development must take place in order to formalize this approach and take advantage of the opportunities opened by this study.

The various rendering technologies and devices must also be assessed. Obviously, real immersion in the 3D model with ultra-high definition will provide higher added value than the devices we have tested.

The current state-of-the-art and expected trends promote usage of HMDs, which are becoming affordable and easier to deploy in an office environment. We plan to extend this work by implementing and surveying new devices, improving the 3D metaphor, and designing and assessing new interaction systems.

In any case this study opens widely new perspectives towards the usage of virtual environments in the PLM area.

Fig. 1 .

 1 Fig.1. The Core Product Model[START_REF] Fenves | A core product model for representing design information[END_REF]

Fig. 3 .

 3 Fig. 3. First draft of a TNA Project Process

Fig. 4 .

 4 Fig. 4. 3D Presentation of instances

Fig. 5 .

 5 Fig. 5. 2D Desktop visualization of several states of the same object A 3D viewer was used to visualize the OPM diagram. The original OPM diagram, called Object-Process Diagram (OPD), was simply drawn on a plane and thus remains unchanged with the same semantic.An interaction behavior was encoded. A trackball system was designed to support free navigation in 3D over the scene. When selecting an object in a certain state, the list of object instances are drawn along an axis orthogonal to the diagram plane. Figure4shows a specific view where the "Host Facility" was selected at the state of "preparing a project". The projects which were accepted show up on the right column, identified by their index, e.g., Project #75 at the top, while the host facilities are listed by their name and (in parentheses) the number of projects that the Host Facility is preparing to host.With this single view, a user gets a clear picture of the concerned facilities and projects in response to his or her graphics-driven query. By selecting an instance from one the two lists, additional information can be printed in an information window. For a project, one can get the project name, the Research Group, dates of submissions and of state change, etc. Depending on the working mode, selecting an instance may visualize the related items. For example, if a specific Project is selected, the relevant instances of the object classes Research group, Host Facility, Review Committee with their current state are presented. This visualization provides the system executives and operators with a clear view and rapid understanding of all the information related to a given project.

Fig. 6 .

 6 Fig. 6. Testing the metaphor on various displays

•

  Improvement of engineering processes: interacting with fluid dynamics simulations, weather forecast, new style design, extended vision and perception of technical 2D drawings, manufacturing process analysis or simulation, augmented tools for manufacturing, manufacturing plant layout arrangement, and training on assembly and disassembly of products. • Remote collaboration: remote physical feedback by handling haptic devices from a long distance, co-working with shared 4K panels, co-organisation of nurse schedule, surgery tele-operation, and remote collaborative concerts involving musician and dancers located in various countries and participating in a same concert within a virtual environment. • New tools and methods for medical applications: ergonomic analysis to support sport analysis activities, training gun fighters, analysing rugby and basketball gestures, and enabling new protocols of remote interconnections between athletes and coaches. 3D ultra-high definition quality with low bandwidth and low latency over networks to support this kind of remote collaboration was demonstrated. • Museum applications: storytelling and reconstruction of fragile historical sites for patrimony conservation and archeological studies. • Virtual visit: visits of faraway planets with data incoming from observatories, exploring seas and animals scanned from tomography, and other applications including studies about virtual environment perceptions and psychology, etc.

Table 1 .

 1 Qualitative comparison of displays

	Device	2D Desktop	HMD	Tracked Stereoscopy PowerWall
	Text Readability	+++	+	++	++++
	Project timeline	+	++	+++	++
	Text superposition	+	+	+	++
	Interaction comfort	++	++	+++	+++

Acknowledgments. This paper was written within the scope of the VISIONAIR infrastructure project. VISIONAIR was lead by Grenoble INP, 46 avenue Felix Viallet, F-38 031 Grenoble cedex 1, FRANCE. This project is funded by the European Commission under grant agreement 262044. This work has also been partially supported by the LabEx PERSYVAL-Lab(ANR-11-LABX-0025-01) and by the Gordon Center for Systems Engineering at Technion, Haifa 32000, Israel.


Michal Kozderka
email: mkozderka@unistra.fr

Bertrand Rose
email: bertrand.rose@unistra.fr

Doc. Ing Vladimír Kočí

Prof Emmanuel Caillaud

Prof Nadia Bahlouli
email: nadia.bahlouli@unistra.fr

High impact polypropylene recycling -Mechanical resistance and LCA case study with improved efficiency by preliminary sensitivity analysis

Keywords: LCA, lack of data, data quality, Polypropylene, recycling

Life Cycle Inventory is one of the longest part of the LCA and yet we cannot always get all the necessary data. This study is a methodological point of view on getting a quality results from a case study of polypropylene recycling, based on an intersection of currently used methods of benchmarking the unavailable data, using the sensitivity analysis and the good practices in LCA. The principle is in classification of unavailable data based on their relevance to the results and to the goal and scope definition. The goal is to let the analysts focus on the most important parameters before spending resources on the least relevant missing data. The approach was realized on a case study of High Impact Polypropylene (HIPP) recycling. The LCA study is completed with study of impacts on the mechanical properties of the HIPP.

Introduction

Practitioners of the Life Cycle Assessment (LCA; ISO 14040, 2006) [START_REF]ISO 14040: Environmental Management -Life Cycle Assessment -Principles and Framework[END_REF] find themselves unfortunately often in a confusing situation. In the same time the best available data are required for all applications [START_REF]ISO 14040: Environmental Management -Life Cycle Assessment -Principles and Framework[END_REF], [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF] but the data available in databases are not entirely representative and the data quality vary in different LCI databases. [START_REF] Lasvaux | Influence of simplification of life cycle inventories on the accuracy of impact assessment: application to construction products[END_REF] Different common impact assessment methodologies do not give the same results although their intended use is alike or the same [START_REF] Pizzol | Eco-toxicological impact of 'metals' on the aquatic and terrestrial ecosystem: A comparison between eight different methodologies for Life Cycle Impact Assessment (LCIA)[END_REF]- [START_REF] Reap | A survey of unresolved problems in life cycle assessment[END_REF] and neither do even LCA modelling programs. [START_REF] Herrmann | Does it matter which Life Cycle Assessment (LCA) tool you choose? -a comparative assessment of SimaPro and GaBi[END_REF] But LCA and LCA-based methodologies still remains the most efficient way of environmental impact assessment method [START_REF] Gaussin | Assessing the environmental footprint of manufactured products: A survey of current literature[END_REF]- [START_REF] Commission | COMMISSION RECOMMENDATION of 9 April 2013 on the use of common methods to measure and communicate the life cycle environmental performance of products and organisations[END_REF] and with systems like The EPD International or PEF, an objective tools for product's environmental impact assessment, allowing comparison of equivalent product. [START_REF] Commission | COMMISSION RECOMMENDATION of 9 April 2013 on the use of common methods to measure and communicate the life cycle environmental performance of products and organisations[END_REF], [START_REF] Minkov | Type III Environmental Declaration Programmes and harmonization of product category rules: status quo and practical challenges[END_REF] If a LCA practitioners struggled always for the best data possible, they would have to update their data once they finished getting them because the first ones would be already outdated. But every study have some deadline and practitioners need to organize their work in order to work the most efficiently possible.

This Work have two objectives: a. Describe an approach to help with the difficult data The idea is to sort the unavailable data in order to put the most energy in the most important missing data. The method is demonstrated on a LCA of a simple plastic product, typical in the automotive industry. b. Give the results of a case study we used to test the approach.

We have studied recycling of High Impact Polypropylene, typical for the automotive industry. The LCA study is completed with a study of mechanical properties in function of number of recycling of the one given product.

State of the art and Objectives of the research

The LCA is one of the most complete tools for environmental impact assessment, but its use is usually expensive and time consuming. [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF] Certainly, from the beginning, when a LCA lasted years and has cost millions of dollars it came a long way and actually the duration of LCA is usually counted in months (depending on complexity of the studied product and on the scope of the study) and costs thousands of dollars.

The development in LCA in the last years is not any more focused on the methodology itself, but more on the data quality [3]- [START_REF] Herrmann | Does it matter which Life Cycle Assessment (LCA) tool you choose? -a comparative assessment of SimaPro and GaBi[END_REF], [START_REF] Guo | LCA data quality: sensitivity and uncertainty analysis[END_REF], [START_REF] Zhou | An improved life cycle impact assessment (LCIA) approach for assessing aquatic eco-toxic impact of brine disposal from seawater desalination plants[END_REF] better assessment in the categories of impact in toxicology and ecotoxicology [START_REF] Van De | USEtox -The UNEP-SETAC toxicity model: Recommended characterisation factors for human toxicity and freshwater ecotoxicity in life cycle impact assessment[END_REF] and on advanced systems based on Product category rules (PCR), allowing to compare equivalent products. [START_REF] Kirana Chomkhamsri | Analysis of Existing Environmental Footprint Methodologies for Products and Organizations: Recommendations, Rationale, and Alignment[END_REF], [START_REF] Minkov | Type III Environmental Declaration Programmes and harmonization of product category rules: status quo and practical challenges[END_REF] Quality of the LCA methodology is already proved by thousands of studies. Latest development on the field of the LCA methodology itself is composed of studies of smaller scale, while the growing field is rather in the PCR-based systems. But improving of the methodology and studies of improvement of efficiency, quality and completeness of LCA are still going on.

In this study we connect three approaches to bring a way of improving the resource efficiency in the Life Cycle Inventory (LCI) stage: a. use of sensitivity analysis as a tool to sort unavailable data according to the result's sensitivity to them [START_REF] Steen | On uncertainty and sensitivity of LCA-based priority setting[END_REF] b. complete model of sensitivity analysis considering multiple impact categories [START_REF] Björklund | Survey of approaches to improve reliability in lca[END_REF] c. qualitative approach common in LCA methodology [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF].

The objective is to let the LCA practitioner simply sort the unavailable parameters according to their relevance to the desired results and let him distribute his resources on data collection efficiently.

Methods

Preliminary sensitivity analysis

As a method we have chosen the sensitivity analysis. Its role is basically to verify quality of used parameters, [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF] but its ability to sort importance of unavailable data is often overlooked. The principle is in analyzing estimations of unavailable parameters. Then the sensitivity analysis can give us an order of parameters depending on their influence to the LCA results. The idea of the method comes from the LCA's iterativity. Normally we perform the sensitivity analysis in the end of the study in order to find parameters that could easily influence the study and eventually we have to come back and precise the most important parameters. This time we only make a step forward and test an estimations of missing parameters before trying to get the real numbers. Such model helps to understand the role of missing parameters and especially it allows performing the sensitivity analysis itself. A similar method is used as proposed by Bengt Steen (1997), [START_REF] Steen | On uncertainty and sensitivity of LCA-based priority setting[END_REF] for a single impact category approach. In our case we combined the method with the sensitivity analysis model proposed by [START_REF] Björklund | Survey of approaches to improve reliability in lca[END_REF] [START_REF] Björklund | Survey of approaches to improve reliability in lca[END_REF] to enlarge to a multiple impact category use. The inconvenience of iterativity in this approach is that every time we change any input data, the result of the sensitivity analysis will change too. This is why improvement of several important parameters at once is advantageous. Contrary to the original method we do not compare only the results mentioned in the goal of the study, but all the absolute results. The borders of our approach are given by the scope of the study and the goals of the study define only a group of parameters with higher priority. So in addition to the original methods, to be sure not to overlook any important aspect of the study, we review the goal and scope definition to find a restrictions that would make us adjust the final priority order of unavailable data or parameters. Because of large number of possible goals and uses of LCA, every case study needs probably a unique approach. In our case study the scope is defined as all the relevant processes and energies, neglecting maintenance of machines, activities of employees and their facilities and construction and energy consumption of buildings. No matter the results of the sensitivity analysis, the data inside the scope definition should not be neglected. The goal of the study is to search for the differences between scenarios with virgin and recycled High Impact Polypropylene. Therefore we should give priority to the data participating on the goal of the study. Two categories of results will then appear. The parameters participating on the goal of the study and a complementary parameters. The objective of the preliminary sensitivity analysis is not to neglect as much processes as possible. Even estimated flows of constant value in a comparative study can help to understand the role of eventual difference of impacts between the two studied solutions, as proposed by Gehin, Zwolinski and Brissaud for a brick LCI model. [START_REF] Gehin | Integrated design of product lifecycles-The fridge case study[END_REF] a. The first step is then modelling the scenario with estimation of all difficult data. b. The second step is to review the goals and scope and take actions to prevent any violation of goal and scope definition of the whole study. This step is different for every case study. In our case it was a precaution of not neglecting any data inside the scope definition and giving priority to all missing parameters, related to the goal of the study -difference between impacts of virgin and recycled HIPP product. c. The third step consists of a preliminary sensitivity analysis itself.

For an arbitrary level of significant sensitivity, usual choice is 5 or 10 percent, we will get the results in two forms. Absolute and relative, where x will be the estimated parameter value, xc a critical value of the parameter that would increase or decrease any impact category over the level of significant sensitivity and ∆x will be a relative parameter variance, useful for the parameter classification as proposed by Bengt Steen (1997), [START_REF] Steen | On uncertainty and sensitivity of LCA-based priority setting[END_REF].

LCA

The study of environmental properties was done as a classical comparative LCA study, according to ISO 14040 ( 2006) [START_REF]ISO 14040: Environmental Management -Life Cycle Assessment -Principles and Framework[END_REF]. The desired results are the differences between environmental impacts of virgin HIPP and HIPP with different ratios of recycled matter. The goal of the LCA study then was: Identify the changes in environmental impacts between products made of virgin and recycled HIPP. The only available product to be studied was a testing rod. Not a typical part, used in the automotive industry. After consultation with a car body parts producer, it was decided to keep studying the testing rod, as its lifecycle was similar to the most HIPP parts that he produces. That means rather regional plastic and part producers, transports by a truck and shredding of used parts to produce parts of the same or similar purpose which is defined as a closed loop recycling. [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF], [START_REF] Gehin | Integrated design of product lifecycles-The fridge case study[END_REF]. Ideally, the results should be applicable not only to the studied product, but for mostly simple PP injected parts. The lifecycle of the testing rod was similar, but not exactly the same as for the most car parts.

During the study we decided to add two complementary hypothetical scenarios in order to simulate more closely a serial production. For the Lifecycle impact assessement (LCIA) we chose the ready-made methodology CML, which is well adapted to the production industry [START_REF] Henrikke | The Hitch Hiker's Guide to LCA[END_REF] and widely used in the automotive industry. [START_REF] Fluence | Life Cycle Assessment[END_REF]- [START_REF]Life cycle Environmental Certificate for the S 400 HYBRID[END_REF] The choice of the CML methodology was verified in comparison with several other available methodologies, ReCiPe (midpoint and endpoint approach), I02+ v2.1 and EDIP 2003/1997. In similar impact categories we observed the difference between the virgin HIPP and mix of 50% virgin and 50% recycled HIPP. The results of a recycled HIPP scenario in all Lifecycle Impact Assessment (LCIA) methodologies are expressed relatively to the results of virgin HIPP, where virgin HIPP represents 100% impact. Figure 1 shows a good coherence between LCIA methodologies in categories of fossil fuels depletion, global warming potential (GWP), acidification, eutrophication, ozone depletion, photochemical ozone creation, particulate matter formation and ionizing radiation. Contrary, in the categories of abiotic or metal depletion, human toxicity, terrestrial and freshwater ecotoxicity the LCIA methodologies does not even agree whether the use of recycled HIPP has a positive or negative impacts. We decided to keep CML, which remains between the highest and the lowest results in all the categories except for the human toxicity, where the CML result is the highest.

Figure 1 Comparison of LCIA methodologies on an intermediate scenario (truck transports) In all categories virgin material represents 100% of the impact, while the other columns represent the relative impact of 50% recycled material, calculated with various LCIA

Mechanical behavior

The material was reprocessed 0, 3, 6, 9 and 12 times and two characterizations was observed. From the material point of view -Molecular weight and rheological characterization and from the mechanical point of view -Tensile behavior in small and large stress specter. An unfilled high impact polypropylene was used. Referenced as SABIC®PP, grade 108MF97, composed by a PP matrix containing 22% of ethylene propylene rubber (EPR) particles. A low amount of talc was also detected (<0.5%), thus the material is assumed as a two phases material.

experimentation

The product lifecycle was modelled according to a practice of an important producer of plastic car body parts. The result is a closed loop scenario where the recovered HIPP is used to produce the same product, or at least the same type of product. See the model on the Figure 2.

The case study was modelled and assessed in a software tool GaBi V4. Originally it was supposed that choice of the LCA software wouldn't have any consequences to the results. However, the latest studies show that the results can be influenced due to a minor errors in the programs. [START_REF] Herrmann | Does it matter which Life Cycle Assessment (LCA) tool you choose? -a comparative assessment of SimaPro and GaBi[END_REF] During the LCI phase we fell on 5 undocumented processes, see table 1. Even if all the production processes are available, some parameters may remain hidden. In our case, even if we had concerned machines at disposition, we didn't have any measure instruments for energy consumption of a medium voltage machines. Other cases are retailers who don't give out origin of the goods, because they consider them as a strategic information, or transport societies who simply do not collect data for a specific journeys.

Table 1: Estimated unavailable parameters

To save time and work most efficiently possible, we needed to sort the data according to their relevance to the study. This sorting was performed on two levels. Qualitative and quantitative.

In the first time, we looked at the goal definition and at the lifecycle model on the qualitative level. The goal of the study is to find out if recycled HIPP is better than the virgin HIPP. Therefore we search for the difference between these two materials.

In the model we searched for all the processes that can have any influence on the difference between the two studied materials. In other words we needed to search for processes that changes between the virgin and recycled scenarios. This research was based on the nature of modelled processes and verified by comparing the inputs and outputs between scenarios. See the distribution of processes and flows on Figure 2.

Between the undocumented processes and flows, only the transport from the producer of HIPP granulate was found as a process, participating on the defined goal. The dimensions of the other undescribed processes did not change in any way between scenarios with different ratio of recycled HIPP.

In the second step we performed a sensitivity analysis on an estimation of unknown data. The first line in bold correspond to a parameter that was identified as a contributor on the goal of the study. This parameter gets priority before the other complementary parameters. However, the sensitivity analysis shows that the study is not very sensitive to this parameter. In the target country the distance couldn't rise over 1500 km and therefore it could never reach the critical variance and any impact could never rise or decrease above the significant level of 5%.

The same situation appears for the distance from the transport society stock to the customer. Therefore it can be roughly estimated without doing any harm to the study. But we should be more careful with the electric energy and lubricating oil consumptions. Even if they do not directly participate on the goal of the study, they do put the results in a real circumstances, showing how important is the difference between virgin and recycled HIPP, compared to their entire lifecycle.

Results

Preliminary sensitivity analysis

The timesaving is difficult to account for due to variability of the LCA applications, we could never know how much time we would spend on a parameter we eventually did not try to search for. In our case, we found one complementary parameter that could never reach the level of significant change in any impact category. The practitioner might then make a quick estimation based on his own experience with goods distribution, without doing any harm to the study. Stress strain test and lubricating oil consumption was clearly identified as processes that need more research, while electric energy consumption of milling, that have the relative critical variance higher than 100% gives some space for substitution or estimation. Iterativity, which is often perceived as an unpleasant quality that makes the studies longer, gives a precious advantage in the preliminary sensitivity analysis. Whenever we get any precisions to the unavailable parameters, the sensitivity of the whole study to these parameters can be quickly reviewed and help to decide if we need to continue with more precisions or if the current knowledge is sufficient to stop the research and put more energy to the research of another unknown parameter. The most interesting result is probably the critical variance of distance from the HIPP granulate producer to the part production unit. The combination of our qualitative and quantitative approach seems ambiguous. One says that the parameter should get priority before the other parameters, the other says that no matter the choice this parameter could never make a significant change of the results. This is a case where the qualitative criteria works as a protection of the good practices in LCA. The goal of the study is a translation of the reason why the study is done. Any other information given by the study are complementary, so even if the parameter may seem unimportant in the sensitivity analysis, we should privilege the quality of the data contributing on the goals of the study. The quantitative result would be just a comforting argument if the parameter really could not be found and we had to make an estimation. The preliminary sensitivity analysis is not any more valid for the final results, as the parameters get more precise and the results are represented for different ratios of recycled matter, while the preliminary sensitivity analysis was composed only of two scenarios with 0% and 50% of recycled HIPP. But the approach is the same for both, preliminary sensitivity analysis and sensitivity analysis of final results, so the tables and data prepared in the beginning of the study can be reused.

LCA

In the most impact categories, the recycled HIPP got better results than the virgin one. Figure 3 shows that the impacts evolution in function of recycled content ratio is close to a linear function.

According to our LCIA methodology testing (Figure 1) we get different results in function of LCIA methodology choice in the categories of abiotic depletion, human toxicity and ecotoxicities. In these categories we cannot make a proper conclusion whether recycling is better or not. But in the other categories, fossil fuels depletion, global warming potential, acidification, eutrophication, ozone depletion, photochemical ozone and particulate matter formation all the available methodologies (CML, ReCiPe, I02 and EDIP) show the same tendency and more or less also the same quantities. The CML methodology does not have ionizing radiation impact category. However, all the other methodologies agree on higher impact with higher ratio of recycled plastic. The only CML impact category in which the recycled HIPP is worse than the virgin granulate, seems to be ozone depletion. The biggest contributor on this category is an electric energy conversion -primary source of energy for the recycling technologies. In the same time, according to CML 2001-09 normalization for EU-25, the contribution of all scenarios on the European pollution in category of ozone depletion is one of the least important, see Figure 4. Comparison of the real scenario with the two hypothetical scenarios confirms the hypothesis that with cleaner production and transports the importance of virgin HIPP granulate is growing. See Figure 4. The difference between virgin and recycled plastics is always the same, speaking in absolute values, but relatively it grows on importance when the rest of the scenario gets cleaner. We can see that even in the real scenario with aircraft transport and milling operation the difference between 0% and 100% recovery makes 20% to 40% in every impact category. That may be an important argument in decision making.

Mechanical properties

The material exhibit a classical mechanical behavior under tensile loading [START_REF] Bahlouli | Mechanical behavior of composite based polypropylene: Recycling and strain rate effects[END_REF] after a linear elastic response, a small viscoelastic response appears before the yielding point. After this point, materials deform plastically. (Figures 56) For the yield stress and the yield strain respectively, it can be observed that the recycling process decreases the yield stress. (Figures 78) It is observed that the variations of the Young modulus values are of the same order of magnitude than the experimental errors. It could be concluded that a slight effect can be detected between on the virgin material and its respective 12 times recycled derivatives. (Figure 10) It can be observed that the failure stress decreases linearly with the degradation by the several cycles. At the same time the failure strain is also pretty affected by the different recycling cycles with the same tendency. On all the tested samples, no necking was observed. However a white zone appeared at the sample's center since relatively low strain. This zone grew until the failure of the specimen. As often mentioned, this is characteristic of a significant amount of cavitation [START_REF] Addiego | Characterization of volume strain at large deformation under uniaxial tension in high-density polyethylene[END_REF], [START_REF] Fond | Localisation des déformations et mécanismes d'endommagements dans les polymères multiphasés[END_REF] caused by the plastic deformation of polymers near the yield point. This phenomenon corresponds to the evolution of the initial porosity and the initiation of crack type damage.

Conclusion and perspectives

LCA remains an expensive part of product development and its use is growing slowly in the production industry. More efficient combination of currently used methods is therefore always a useful step forward. In the eventual continuation of this research, including the uncertainty analysis may be a good direction.

Most companies currently using LCA or LCA-based approaches, managed to develop their own timesaving and efficient product category rules and practices. The proposed method can be mostly useful for studies of new product or for new users, especially for more complicated studies with higher numbers of unknown processes.

Every study is different and it is impossible to calculate a universal ratio of time saving with the preliminary sensitivity study. Further work could focus on definition of a precise methods for different product types for example following the CPA/NACE codes in order to improve the efficiency in the systems like The EPD International or PEF/OEF.

Figure 2 :

 2 Figure 2: Product lifecycle scenario. Processes and flows in black do change between scenarios, processes and flows in grey remain constant. Flows are scaled according to their weigh. Consumption and production of electric energy are represented only by their direction, not scale.

Figure 3 :

 3 Figure 3: Midpoint trend evolution -initial scenario

Figure 4 :Figure 6 :

 46 Figure 4: CML 2001-nov.09 normalized -comparison of all three scenarios

Figure 10 :

 10 Figure 10: Poisson ratio Figure 9: Young modulus

Table 2

 2

	show the results:

Table 2 :

 2 Sensitivity analysis results. As a border significant sensitivity we chose 5% change of any midpoint impact category.