Fernando A Bortuluzi

Feni Agostinho
email: feniagostinho@gmail.com

Cecília M V B Almeida

Silvia Bonilla

Biagio F Gianetti

Exploring Alternatives of Accounting for Environmental Liabilities in the Company's Balance Sheet

Keywords: emergy accounting, integrated report, Petrobras S.A., oil spill

Environmental concerns have recently reached the stock market, in which investors want analyze the company's related-risks in causing environmental damages. Usually, the Company's Balance Sheet (CBS) is summarized, disallowing a clear interpretation of environmental issues. Moreover, methods used to valuate environmental liabilities are often subjective, which create communication problems. The aims of this work are (i) to explore alternatives for CBS structural presentation to clearly represent environmental liabilities, which allow efficient communication with society and investors, and (ii) to assess a methodological alternative of valuating environmental liabilities under economical terms. The "Petrobras" S.A. Brazilian Oil Company is taken as a case study by accounting its oil spill related-incidents occurred in 2000 yr. Results show an improved CBS structure that could be used to represent the company's environmental related-issues. Additionally, emergy accounting appears as a powerful alternative to replace contingent valuation in quantifying environmental liabilities.

Introduction

History has many examples of companies that passed from successful to failure examples, such as the American Company Enron in the 90's, and, recently, the American Lehman Brothers and the Brazilian EBX group. These examples expose a similar problem: the weakness of the current model to represent the Company's Balance Sheet (CBS). Since 2010, the top-100 worldwide companies are discussing the creation of a new CBS structure, considering an integrated thinking and a more holistic perspective. This proposal is being labeled as Integrated Report (IR) [1], which goal is to clearly represent the company's targets at long term and the strategies to get there. In this sense, several important aspects as human, natural, and intellectual capitals are also being considered instead of exclusively financial results. The IR, which intends to be in harmony with sustainable development, is severely criticized in some studies [START_REF] Deegan | The accounting will have a central role in saving the planet… really? A reflection on "green accounting and green eyeshades twenty years later[END_REF] due to the difficulties in integrating biophysical accounting with the many existing cores of financial accounting conventions.

Similarly to IR, some studies [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF] have already argued that provisioning for environmental damages should be present in the CBS, otherwise, distorted information is obtained in which the liabilities are undervalued and equity overvalued. Not accounting for liabilities at the same year of occurrenceusually due to judicial delaycan also affect the company's future performance and result in economical losses; and investors will not have in traditional CBS enough indicators for the efficient evaluation of the company's economical performance, especially regarding to judge risks on investing in the company.

The traditional financial accounting techniques are unable to measure resources and services provided by biosphere, as well as all the environmental impacts caused by releasing high concentrated wastes on natural environment. This accounting limitation is due to a lack of market value of environmental goods and services. Some studies [START_REF] Cormier | Investors' assessment of implicit environmental liabilities: An empirical investigation[END_REF] have warned about the need for developing and standardizing trustable methodologies to quantify the environmental performance of companies. The valuation of environmental liabilities, for a long time, is realized under subjective approaches, which do not represent real values for repair or substitution [START_REF] Odum | Environmental accounting -emergy and environmental decision making[END_REF]. In this sense, the environmental liabilities must be objectively quantified (i.e. under biophysical approaches) to be included into the CBS. Efforts were made to quantify liabilities by using eMergy methodology [START_REF] Whoite | Emergy analysis of the T/V Exxon Valdez oil spill and alternatives for oil spill prevention[END_REF], and to integrate eMergy with bookkeeping techniques [START_REF] Ortega | Combining bookkeeping techniques and emergy analysis[END_REF][START_REF] Campbell | Financial accounting methods to further develop and communicate environmental accounting using emergy[END_REF]. However, none of them have explored the inclusion of the quantified liabilities into the CBS in a way they can be accessible to interested pubic and clearly represented by scientifically accepted methods.

This work explores alternatives for representing the environmental liabilities into the CBS, focusing on an efficient communication about the company's economical performance for the general society and investors. For this, raw data from [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF] is used considering as case study the published 2000's CBS of the Brazilian Oil Company "Petrobras" S.A. Emergy accounting [START_REF] Odum | Environmental accounting -emergy and environmental decision making[END_REF] is suggested as an alternative scientific methodology in providing a biophysical perspective to quantify environmental liabilities.

Methodology

Case Study Description: Brazilian Oil Company "Petrobras"S.A.

The case study is considered mandatory to solidify the ideas under discussion and to point out how and where the liabilities could be estimated and included. Negative externalities caused by oil spill incidents are considered due to their high impact on environment and society. It is worth to say that Petrobras S.A. is signatory of the International Integrated Reporting Council. The oil spill incidents that occurred in Brazil 2000 yr were accounted and described in detail by [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF]. In short, about 78,740 oil barrels spilled under three different incidents, each one resulting in different damages.

Studied Alternatives for Presenting Environmental Liabilities into the Balance Sheet

Two alternatives of presenting environmental liabilities into the CBS are assessed and compared to the traditional CBS labeled as Baseline; considering the current Brazilian law for financial accounting techniques (no. 6,404/1976), as well as recent alterations by laws no. 11,638/2007 and 11,941/2009. It is worth to say that these alterations aimed to get closer and be compared with definitions and structures of international rules. The Baseline and the two alternatives discussed in this paper are the following: (a) Baseline: Traditional accounting approach considered in Brazil according to law no. 6,404/1976. This approach does not foresee any inclusion and/or disclosure of environmental liabilities into the CBS. (b) Alternative #1: Accounting approach suggested by [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF] aiming to improve the regulations of law no. 6,404/1976. These authors intended to establish an alternative way to include the environmental liabilities into the CBS by expressing clearly the related economic amount and its influence on the company's "equity" indicator. (c) Alternative #2: The suggested accounting approach in this work according to law no. 6,404/1976 and its alterations by laws no. 11,638/2007 and 11,941/2009. The intention is to establish a clearer structure for CBS compared to that proposed by [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF]. Initially, it is emphasized that alterations of law no. 6,404/1976 have created a category "intangible" within the subgroup "noncurrent assets", which represents the value of immaterial assets (e.g. exploration rights, copyrights, franchise rights, trademarks, licenses, and softwares).

Studied Alternatives for Environmental Damages Valuation

The role of using contingent valuation in the assessment of natural resources damage and public-decision making has become a major topic of debate for the economic community [START_REF] Carson | Contingent valuation: controversies and evidences[END_REF], although it is the most used method to valuate environmental damages [START_REF] Carson | Contingent valuation and lost passive use: damages from the Exxon Valdez oil spill[END_REF][START_REF] Martin-Ortega | Application of a value-based equivalency method to assess environmental damage compensation under the European Environmental Liability Directive[END_REF]. Additionally, as emphasized by [START_REF] León | Heterogeneity and emotions in the valuation of non-use damages caused by oil spills[END_REF], the use of stated preference valuation methods is necessarily sensitive to individual emotional concerns, resulting in high heterogeneity among individual's samples.

Alternatively to traditional economic approaches, the use of biophysical approaches to quantify environmental damages is increasing in scientific literature, in which eMergy accounting is receiving special emphasis. Emergy (spelled with an "m") is "the available energy of one kind previously used up directly and indirectly to make a service or product" [5; p.7]. A full description of emergy methodology, meanings and rules is beyond the scope of this paper, but deeper information are available at several published scientific works including, among others, the classical book of H.T. Odum [START_REF] Odum | Environmental accounting -emergy and environmental decision making[END_REF].

Emergy is used in this work to estimate the environmental damages caused by the oil spill incidents of Petrobras S.A. Brazilian Oil Company in 2000 yr. For this, the previous emergy evaluation of Exxon Valdez oil spill in 1991 done by [START_REF] Whoite | Emergy analysis of the T/V Exxon Valdez oil spill and alternatives for oil spill prevention[END_REF] is used as reference for the emergy of damage estimation caused Petrobras S.A.; from this work, we have estimated an average value of 8.15E22 seJ representing the impacts on natural biome caused by 258,000 oil barrels spilled in 1991 during Exxon Valdez incident. The emergy per money ratio of Brazil in 2000 yr of 7.80E12 seJ/$ [START_REF] Sweeney | Creation of a global emergy database for standardize national emergy synthesis[END_REF] is used to convert the emergy of damage from solar emjoules (seJ) into emdolars (Em$) units, which can be later compared to the values of environmental liabilities quantified under economical approach as published by [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF].

Results and discussion

Assessing Alternatives for Presenting the Environmental Liabilities into the Balance Sheet

Table 1 shows the balance sheet as divulgated by Petrobras S.A. related to its performance in 2000 yr. It can be noted the lack of detailed information regarding the economic investment on prevention of environmental incidents in the "assets" group, as well as the absence of a detailed description of economical obligations in the "liabilities" group related to the environmental damages caused. It is worth to say the existence of laws (no. 9,605/1998) regarding the inclusion of these items into the CBS at that time, which foresaw criminal responsibility for environmental impacts. The lacunae in Table 1 represented by symbol "?" indicates items that were not foreseen by the accounting regulation existing in 2000 yr, thus they were not considered in the Baseline structure for the CBS evaluated. The existence of these lacunae highlights the inability of this CBS structure in showing clearly the company's liabilitieswhen considered! -, which disallow deeper evaluations about the company's economic performance by society and investors. LG = long-term Table 2 shows the structure for CBS as suggested by [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF]. This structure highlights several information regarding actions for environmental damages prevention, including investments of 300,546 million $ in environmental protection and damages prevention projects. It is also clear the amount of liabilities occurred by Petrobras S.A. due to the caused environmental damages, reaching a value of 1,602,681 million $. This CBS structure shows higher values for "total long-term obligations" than Table 1 (from 9,122,181 to 10,724,863 million $), besides lower values for "equity" (from 13,802,668 to 12,199,987 million $), which could lead to a negative image of company for investors, at least for short-time period. Under a general view, this modified CBS structure can be considered more objective and detailed than the Baseline CBS structure, allowing better understanding by society and investors about where and how money is circulating within company's boundaries, mainly on the environmental-related aspects. LG = long-term; PEE = Program for environmental excellence; EPP = Environmental performance projects Table 3 shows the improved structure suggested for CBS. It includes all essential information for a deeper understand about company's economic performance. Besides highlighting the environmental liabilities as also suggested in Table 2, this new structure goes a step forward by detailing other items in the "equity" group to make available and transparent for investors the numbers regarding the reduction of company's goods and servicessince this aspect is already regulated by law 11,638/2007. The item "environmental result" shows the value of -1,602,681 million $, which allows an easy-to-understand interpretation about the real impact resulted from the caused environmental liabilities. Moreover, the direct relation between the investments in environmental programs presented in "assets" group (e.g. program for environmental excellence and environmental projects) and the "environmental results" shows a ratio of 1:5, suggesting that low investments in programs for environmental damages reduction could result in higher liabilities. LG = long-term; PEE = Program for environmental excellence; EPP = Environmental performance projects

Table 2 shows that "equity" [START_REF] León | Heterogeneity and emotions in the valuation of non-use damages caused by oil spills[END_REF]199,987 million $), which represents the company's economic power, is not detailed in that kind of CBS structure. On the other hand, Table 3 shows the existence of three items for "equity" group: (i) "shareholders", which indicates all money invested by shareholders; (ii) "earnings reserve", indicating the company's activity results; (iii) "environmental result". This last presents clearly the amount of money lost by company due to environmental damages. Inserting the item "environmental result" into the CBS represents, in an easy-to-understand way, the company's expense with environmental damage issues and its commitment in making this information as clear as possible.

Although recognizing that suggested CBS could be considered as a better way to present the company's financial annual dynamics, there still are two lacunae containing the symbol "?": "EPP" and "intangibles". The first one was not considered because Petrobras S.A. had no investment value declared in 2000 yr. The second one ("intangibles") was not considered because this item was created by law no. 11,638 in 2007. "Intangibles" can be considered as a key aspect in this new structure for CBS, because it could provide higher capacity for company's indebtedness or even to overestimate its results according to market functioning. The company's indebtedness capacity can be increased as much as higher its "assets" value, thus the item "intangibles" plays important role because it is composed by the value of immaterial goods (i.e. the immaterial goods tends to be higher as much as higher the company's value in the market).

The CBS structure as suggested in this work by Table 3 aims to make available, in a clear way, all the information regarding the company's financial issues, as envisaged by the general principle of accounting. On the other hand, it must be highlighted that the effect of this kind of CBS structure on the investors' perception is not evaluated, for instance, the issues regarding the investor's confidence by investing in the company (low risk) and the consequent cash injection. However, the study of [START_REF] Cormier | Investors' assessment of implicit environmental liabilities: An empirical investigation[END_REF] has indicated a strong relation between a clear divulgation of company's liabilities and the investments reduction by shareholders. All these aspects are being considered more and more by the IR [1] in the search for a more holistic CBS, in which using a systemic strategy could lead to the attraction of "faithful investors" for long time periods. In this scenario, the shares volatilization in the stock market would be strongly reduced as well as the risk in the investment.

Evaluating Alternatives to Quantify Environmental Damages in Economic Terms

Table 4 shows the in-dollar values of environmental liabilities estimated by economic and emergy perspectives for the oil spill incidents of Petrobras SA in 2000. Two important aspects should be highlighted in this table: (i) the difference between the economic cost of 1,602 million $ (established by court and other national committees for the environment under a willing-to-pay and other subjective approaches) and emergy-based cost of 55 million Em$; (ii) the difference between the emergy-based cost associated exclusively to biota damage of 55 million Em$ and its equivalent when accounting for all information associated after public pressure (3,170 million Em$). a from [START_REF] Whoite | Emergy analysis of the T/V Exxon Valdez oil spill and alternatives for oil spill prevention[END_REF]; it include birds, marine mammals, intertidal producers and invertebrates, phytoplankton, and zooplankton; average value obtained from a Monte Carlo simulation considering a uniform probabilistic distribution function under 10,000 interactions. b assumed as 3.28 times lesser than Exxon Valdez oil spill due to ratio of barrels spilled c from [START_REF] Bertoli | Passivo ambiental: estudo de caso da Petróleo Brasileiro S.A. Petrobrás. A repercussão ambiental nas demonstrações contábeis em consequência dos acidentes ocorridos (in Portuguese)[END_REF]; values set out by court action several years after the Petrobras' oil spill incidents d obtained by dividing the natural resource loss of 2.49E22 seJ by the Brazilian emergy per money ratio in 2000 year of 7.80E12 seJ/$ [13] e according to [5; p.130], the information role related to oil spilled by Exxon Valdez incident resulted in an emergy amplification of 57-fold; this amplification ratio was assumed as the same for Petrobras S.A. case study for calculation purposes

The three different estimated values for the environmental damages caused by Petrobras S.A. in 2000 yr are important as quantitative reference to be included in the CBS, within the item "environmental provision". Table 3 shows the Petrobras' balance sheet by including the liabilities as estimated under an economical view (1,602,681 million $), resulting in a company's "equity" of 12,199,987 million $. Now, considering the liabilities value as estimated under an emergy view (55,619,435 million $), the "equity" is increased by 12.7% reaching 13,747,049 million $, resulting in higher credibility of company by investors and economic development. On the other hand, by considering the liability as estimated under emergy perspective after public pressure (3,170,307,796 million $), the "equity" is reduced by 12.8% reaching (10,632,360 million $), resulting in disrepute of company by investors and low economic development.

According to [START_REF] Odum | Environmental accounting -emergy and environmental decision making[END_REF], since half of the world´s empower (emergy flow per unit time) comes from the renewable environment, the amplification value obtained for environmental liabilities after public pressure of 3,170,307,796 Em$ might have been appropriated as a good opportunity to compensate the environmental damage, but mainly to educate companies avoiding future oil spill incidents. This goes in parallel with [START_REF] Martin-Ortega | Application of a value-based equivalency method to assess environmental damage compensation under the European Environmental Liability Directive[END_REF] statement in which, more than educational purposes, there is a need for complementary remediation to compensate for the loss of services during the restoration period. We recognize that there are still some conceptual barriers that must be overcome to reach consensus among the scientific community about the most suitable economic value that should be charged due to environmental liabilities, but emergy methodology suggest to be a powerful alternative which reflects the biophysical donor side perspective.

Conclusions

(a) The suggested structure for CBS could be considered as more appropriated compared to other two assessed ones to show in detail the economical performance of companies, mainly regarding environmental aspects. Through this improved structure, society and investors can have better-based information about how company is operating or being managed and its concerns related to environmental damages, which could result in a beneficial image to investors at long time periods. (b) Quantifying environmental liabilities in economic terms claims for additional efforts among the scientific community. Defining the real objectives in estimating the economical compensation values should be the first criteria, i.e. establishing purposes for repairing the environmental damage or also including educational purposes. Anyway, emergy accounting suggests to be a powerful approach in quantifying environmental damages.

Table 1 .

 1 Traditional (Baseline) annual balance sheet of Petrobras S.A. for 2000 yr (values in 1,000 $)

	Asset (A)		Liabilities (B)
	Total current assets	11,670,386	Total current liabilities	12,604,377
	Total LG receivables	9,245,301	Total LG obligations	9,122,181
	Permanent assets		?	?
	Investments	5,300,076	?	?
	Properties	9,020,700	?	?
	?	?	Equity (C)	13,802,668
	?	?	?	?
	?	?	?	?
	Deferred	292,762	?	?
	Total (A)	35,529,227	Total (B) + (C)	35,529,227

Table 2 .

 2

	Modified (Alternative #1) annual balance sheet of Petrobras S.A. for 2000 yr (values
	in 1,000 $)
	Asset (A)		Liabilities (B)
	Total current assets	11,670,386	Total current liabilities	12,604,377
	Total LG receivables	9,245,301	Total LG obligations	10,724,863

Table 3 .

 3 Improved (Alternative #2) annual balance sheet of Petrobras SA for 2000 yr (values in 1,000 $)

	Asset (A)		Liabilities (B)
	Current assets	11,670,386	Current liabilities	12,604,377
	Noncurrent assets	23,858,840	Noncurrent liabilities	10,724,863
	LG receivable assets	9,245,301	Environmental provision	1,602,681
	Investments	5,300,076	Penalties	122,950
	Properties	9,020,700	Indemnities	1,479,730
	PEE	300,546	Equity (C)	12,199,987
	EPP	?	Shareholders	8,251,100
	Intangibles	?	Earnings reserve	5,551,568
	Deferred	292,762	Environmental result	-1,602,681
	Total (A)	35,529,227	Total (B) + (C)	35,529,227

Table 4 .

 4 Estimative of economic and emergy costs related to oil spill incidents of Petrobras SA.

	Description

Acknowledgements. We are grateful to Dr. Carlos Alberto Di Agustini for his valuable comments. This work received financial support from the Vice-Reitoria de Pós-Graduação e Pesquisa of Universidade Paulista (UNIP).


Geraldo Cardoso De Oliveira Neto
email: geraldocardosodeoliveiraneto@ig.com.br

Washington Carvalho De Sousa

Economic and environmental advantage evaluation of the reverse logistic implementation in the supermarket retail

Keywords: Reverse Logistic, Supermarket Retail, Economic and Environmental Advantage

In this article it is presented a market study case that allowed a recycling specialized organization with physical space to implement the reverse logistic of the following packing residues: cardboard, Styrofoam, plastic and aluminum into correct residue destination. This study's objective consists in developing a methodology to evaluate economic and environmental advantage of the reverse logistic implementation in the supermarket. The utilized method consists in observing and semi-structure interviewing, allowing it to develop a case study. To analyze the environmental improvement, the Mass Intensity Total was measured, to determine the environmental impact reduction. The research results indicate economic and environmental advantage very representative, which may improve the decision making and access to the reverse logistic, favoring the sustainability in the supermarket retail.

Introduction

The Solid Residue National Plan of Brazil is driving many segments to implement the reverse logistic, to promote the solid residue management by developing procedures to improve the gathering and restitution of solid residues to their producers, so that they are treated and repurposed in new products, by input means, in its cycle or in other productive cycles, seeking the non-producing of tailings [START_REF] Brasil | PNRS -Política Nacional de Resíduos Sólidos[END_REF].

With that, the reverse logistic can reduce costs related to the raw material, storage, finished products and information from the selling point to the origin point with the objective of adding value or the correct use of resources [START_REF] Rogers | Going backwards: reverse logistics trends and practices[END_REF] to give the correct direction to material goods [START_REF]RLEC -Reverse Logistics Executive Council[END_REF], ensuring the environmental and economic advantage in the operation by recuperating, reusing and remanufacturing of goods [START_REF] Sheriff | Logistics network design: a review on strategic perspective[END_REF].

The reverse logistic use is extending to the retail sector, including supermarkets [START_REF]RLEC -Reverse Logistics Executive Council[END_REF]. The supermarket retail is characterized by the auto-service system with a variety of products, being the edible and non-edible products with, a minimum of, 2 check-outs and valid selling space between 300m 2 and 5000m 2 and, still, offers the consumer, shopping carts and baskets to be used while shopping, without a selling-man presence [START_REF] Alexander | Emerging markets and the internationalization of retailing: the Brazilian experience[END_REF].

Supermarkets could implement the reverse logistic because the commercialized products are the main producers of solid residues of packing, considering edible products and appliances [START_REF] Breen | Give me back my empties or else! A preliminary analysis of customer compliance in reverse logistics practices (UK)[END_REF][START_REF] Kumar | A Study of the supermarket industry and its growing logistics capabilities[END_REF].

The reverse logistic implementation could be a differentiation strategy [START_REF] Fernie | Retail Logistics in the UK: Past, present and future[END_REF], which promotes sustainable marketing [START_REF] Sharma | Sustainability and Business-tobusiness: A framework and implications[END_REF], as by an example, in the Wal-Mart, that demands the feeders, devolution of damaged products and packing [START_REF] Kumar | A Study of the supermarket industry and its growing logistics capabilities[END_REF], utilizing the same truck that delivers the order to take the residue from the clients, cutting costs with transport [START_REF] Mckinnon | The potential for reducing empty running by trucks: a retrospective analysis[END_REF], generating financial gain [START_REF] Junior | Um estudo comparative das práticas de logística reversa no varejo de médio porte[END_REF].

Other researches support the development of a return plan in the solid residue supermarkets and product devolution guaranteed. Especially Wal-Mart, that implemented the reverse logistic to repairing, replacing parts and consumer return, inspection and reuse [START_REF] Krumwiede | A model for reverse logistics entry by third-party providers[END_REF][START_REF] Reinartz | Retailing Innovations in a Globalizing Retail Market Environment[END_REF], resulting in a cost reduction and improvement of product recuperation [START_REF] Jack | Reverse Logistics capabilities: antecedents and cost savings[END_REF][START_REF] Stock | Product Returns Processing: An examination of practices of manufacturers, wholesalers/distributors, and retailers[END_REF], and in Spanish Carrefour that has a specialized recycling infrastructure to manage solid residues [START_REF] Chaves | Estudo das variáveis utilizadas na decisão de compras no comércio varejista de alimentos de autosserviço -Supermercados[END_REF][START_REF] Combra-Fierro | Notions for the successful management of the supply chain: Learning with Carrefour in Spain and Carrefour in China[END_REF].

It was noted the need to improve the governmental support to implement the reverse logistic. In Brazil, it is still considered embryonic, due to lack of governmental support, actions by the producing organizations, lack of gathering spaces and environmental conscience from the society [START_REF] Oliveira | Collection and recycling of electronic scrap: A worldwide overview and comparison with the Brazilian situation[END_REF]. In China, the situation is not different, despite establishing legislation, which pressures the producers [START_REF] Ye | The impact of institutional pressures, top manager's posture and reverse logistics on performance -Evidence in China[END_REF]. This discovery drives the supermarkets and the recycling organization in the propagation of gathering points and motivating their clients [START_REF] Chaves | Estudo das variáveis utilizadas na decisão de compras no comércio varejista de alimentos de autosserviço -Supermercados[END_REF], mainly because the majority of the clients don't deposit their solid residues, due to lack of economic support [START_REF] Breen | Give me back my empties or else! A preliminary analysis of customer compliance in reverse logistics practices (UK)[END_REF].

In the existing researches analysis about the reverse logistic implementation in the supermarket sector it was noted that despite some articles mention in a positive way about the economic and environmental gain they did not evaluate theses gains. With that, the article's objective consists in developing a methodology to evaluate if it has occurred economic and environmental advantage from the reverse logistic implementation in the supermarkets.

Methodology

In the research's first phase, it was realized a bibliometric analysis to quantify and select the scientific production [START_REF] Cooper | Research synthesis and meta-analysis[END_REF].

The Databases Proquest, Ebsco, Science Direct, Emerald, Capes and academic Google by using the following keywords: (i) "reverse logistics" AND "supermarket"; (ii) "reverse logistics" AND "grocery"; (iii) "reverse logistics" AND "retail" AND "market"; (iv) "reverse logistics" AND "retail"; (v) "reverse logistics" AND "retailing" (vi) "reverse logistics" AND "retailing" AND "market" in summaries, keywords and scientific publication titles with the objective of analyzing the existence of researches that helps understanding the environmental and/or economic results in reverse logistic implementation process in the supermarkets retail.

In the analysis it was noted 15 articles about the reverse logistic in the supermarket retail, allowing the categorizing of research results about environmental and economic gain [START_REF] Bardin | El análisis de contenido[END_REF]. In the analysis it was identified a lack of researches that produced quantity evaluations in economic and environmental terms.

To attend this lack of research, it was realized an exploratory research of qualitative and quantitative nature through the unique-case method, which allowed developing a methodology to evaluate if it has occurred economic and environmental advantage from the reverse logistic implementation in the supermarket.

The case study is a research strategy focused in comprehending the researched scene dynamic, which combine data gathering methods, as data, interviews, questionnaires and observations, resulting in qualitative and/or quantitative evidence [START_REF] Eisenhardt | Building Theories from Case Study Research[END_REF]. With that, it is possible to create the adequate conditions to comprehend the researched study object [START_REF] Yin | Case Study Research. Design and Methods[END_REF].

In the case study, it was adopted the observation and interviews as the logistic base, which allowed to gather quantitative data about the recycled goods and the economic results of implementing the reverse logistic. The observation was realized in files and efficiency indicators with recycling data provided by the supermarket, being an adequate technique for case study [START_REF] Bogdan | Qualitative Research for education: an introduction to Theory and Methods[END_REF][START_REF] Westbrook | Action Research: a new paradigm for research in production and operations management[END_REF], with support of the semi-structured interview to ask questions and align the comprehension of the observation [START_REF] Seidman | Interviewing as qualitative research. A guide for researchers in Education and the Social Sciences[END_REF].

With the environmental and economic results obtained it was developed a methodology to evaluate if it has occurred environmental and economic advantage from the reverse logistic implementation in the supermarket.

With the economic results obtained, it was possible to evaluate the economic advantage of reverse logistic implementation by calculating the return of investment (ROI) based on equations 1 and 2 presented [START_REF] Gitmann | Principio de Administração Financeira[END_REF]: %ROI = semiannual liquid profit/ reverse logistic investment Eq. 1 ROI Period= reverse logistic investment / semiannual liquid profit Eq. 2

After that, with the recycled goods results it was possible to evaluate the environmental gain through the Mass Intensity Factors method (MIF) identified in the file provided by the Wuppertal Institute supported on the abiotic, biotic, water and air compartments.

The ecosystem is composed of biotic and abiotic compartments with interaction between them, the biotic compartment consists of the set of all live organisms as plants and decomposers, while the abiotic compartment is the set of all non-alive factors of an ecosystem, but influences the biotic compartment, consists of temperature, pressure, rain falling in the landscape, among others [START_REF] Odum | Ecologia. Rio de Janeiro[END_REF].

With that, the total goods quantity of each compartment that was processed to supply a material data is called Mass Intensity. To determine the Mass Intensity Factors (MIF) in equation 3, the Mass entry flux (M) -express in the corresponding units is multiplied by the Intensity Factors (IF), that corresponds to the quantity of necessary goods to produce an entry flux unity [START_REF]Calculating MIPs, resources productivity of products and services[END_REF]. The IF values used in this research are presented on Table 1.

MIF = (M x IF)

Eq. 3 After calculating the IF by recycled residue in relation to compartments, it becomes possible to calculate the Mass Intensity per Compartment (MIC), that measures the environmental impact reduction by abiotic compartment (w), biotic (x), water (y), and air (z), following the Equation 4. And at last, it is realized the calculation of the Mass Intensity Total (MIT) summarizing the total environmental reduction, when applied to MIC's, following the Equation 5.

*MIC = (IF residue A of compartment w + IF residue B of compartment w + IF residue C of compartment w + IF residue n of compartment w)

Eq. 4 *MIC example to the w compartment, equal to the others.

MIT = (MICw + MICx + MICy + MICz)

Eq. 5

To finish it is compared the economic gain with the environmental gain and vice versa to verify the economic gain index (IGE) and environmental gain index (IGA). To evaluate the IGE, it is considered the Total Saved Goods (MTE) in relation to the GE and to calculate the IGA, is it divided the Mass Intensity Total (MIT) by the GE. The equations are presented: IGE = (MTE/GE) Eq. 6 IGA = (MIT/GE) Eq. 7

Results and Discussion

Economic Advantage

The economic advantage results of the Reverse Logistic implementation were summarized in Table 3. The gathered residues resulted in a semiannual gain of $9.236.77.

In the main project the initial investment was of $20.000.00 for employees training about solid residue management and implementing residue gatherers in the supermarkets so that the clients could deposit its residues and, implemented in the receiving sector the solid residue retention resulting of the delivery process and store assortment. This result shows an practical example of the reverse logistic implementation in the supermarket retail [START_REF] Bernoon | Retail Reverse Logistics: a call and grounding framework for research[END_REF], in relation to the adequate destination of the residue to reuse and remanufacture [START_REF] Breen | Give me back my empties or else! A preliminary analysis of customer compliance in reverse logistics practices (UK)[END_REF][START_REF] Reinartz | Retailing Innovations in a Globalizing Retail Market Environment[END_REF][START_REF] Brasil | PNRS -Política Nacional de Resíduos Sólidos[END_REF] by an specialized organization [START_REF] Chaves | Estudo das variáveis utilizadas na decisão de compras no comércio varejista de alimentos de autosserviço -Supermercados[END_REF][START_REF] Combra-Fierro | Notions for the successful management of the supply chain: Learning with Carrefour in Spain and Carrefour in China[END_REF].

To the recycling operation implementation the organization decided outsourcing to a specialized organization. With that, the recycling organization provided infra-structure, as which: press, involved people, load accommodation and transport to the residues destination in a correct way and began to pay the supermarket by Kg of collected residue (Cardboard -$0.17; Plastic -$0.37; Styrofoam -$0.10; Aluminum -$2.30). The financial return invested in reverse logistic was of 46, 18% per semester in one year and two months, since this period the monthly liquid gain, considering the reverse logistic increased to $9.236.77, resulting in economic advantage to the market. This result exemplifies the proposition about the possibility of obtaining financial resources with reverse logistic [START_REF] Fernie | Retail Logistics in the UK: Past, present and future[END_REF].

Environmental Advantage

In the total sum of goods, it is considered all the products that were not disposed in the environment. The organization provided the Mass in goods (M) by Kg of residue that were submitted to the recycling process in the semester, which are: 40.196 kg of Cardboard, 6.327 kg of Plastic, 198 kg of Styrofoam e 63.55 kg of aluminum, con-substantiating 46785 Kg of Total Saved Mass (MTE).

Applying equation 3 it is determined the Mass Intensity Total (MIT) to evaluate the environmental gain, as for an example, 6,327 x 6.45abiotic goods, represents MIT of 40.809.15, as it is presented on table 3. The recycling total in mass was of 46785 Kg of residue per semester with Mass Intensity Total (MIT) of 6100331.5, representing the environmental impact reduction in compartment (w) abiotic of 119053.5 Kg, contributing with sustainability in global warming matters, the ozone layer waste, the atmospheric pressure, among others; (x) biotic -30147 Kg, which reduced the vegetation pollution, the soil and the decomposers, (y) water -5719238.3 Kg and the (z) air with 350946 Kg. The results show that it is possible to measure the environmental gain with the reverse logistic implementation, subject still considered incipient in literature.

Comparison between economic and environmental advantage

To finish it is compared the economic with the environmental gain and vice versa to verify the representation in percentage of the economic gain (GE) and environmental gain (GA). GE = (46785 Kg of Residue/$9236.77) = 5.07

Eq. 6 GA = (6100331.5//$9236.77) = 660.44 Eq. 7

The results show that in relation to the IGE, that each Brazilian Real saved corresponds to 5.0 Kg of goods. When it is considered the Mass Intensity Total (MIT), by each Brazilian Real, there is a benefit of IGA -675.42 Kg of goods that are not modified nor taken from the ecosystems. This discovery contributes with the possibility of conquering economic and environmental gain through reverse logistic actions [START_REF] Bernoon | Retail Reverse Logistics: a call and grounding framework for research[END_REF][START_REF] Rogers | Going backwards: reverse logistics trends and practices[END_REF], subject that was not explored in quantitative methodology terms to analyze, mainly because it presents just qualitative results.

Conclusions

The present research shows that the reverse logistic implementation in the supermarket retail resulted in an economic and environmental gain, which was the research's objective. The action taken to achieve the result was of implementing residue gatherers in the supermarket so that clients could deposit their residues. Also, implemented in the receiving sector the retention of solid residues resulted from the deliver process and the store assortment.

The result in the semester showed the retention and correct destination of 46785Kg, considering just the gathered and weighted residue resulting in an economic gain of $9.236.77 each semester. When the Mass Intensity Factor was calculated, it was noted that it avoided the pollution of: (i) 119053.7 Kg in the abiotic level, considering as indispensable factors to survival, as temperature, pressure, rain falling in the landscape, among others; (ii) 30147 Kg in the biotic level, represented by the set of all live organisms such as plants and decomposers and (iii) 5719238.3 Kg in the water and 350946 Kg in the air. The results show that despite occurring economic advantage $9.236.77 to the businessmen the environmental advantage was the most representative when considered the Mass Intensity Total (6100331.5 Kg).

It is important to highlight that the presented and tested methodology may be used in cleaner production processes, environmental projects (DfE), among others. A limitation of the case study consists in the impossibility of generalizing the results, suggesting the realization of new researches to generate comparisons.

Table 1 .

 1 Goods Intensity Factors used in the Research

			Mass Intensity Factor
		Abiotic	Biotic	Water	Air
		Goods	Goods
	Plastic (g/g) a	6.45		294.2	3.723
	Cardboard (g/g) b	1.86	0.75	93.6	0.325
	Styrofoam (g/g) c	5.70		146	1650
	Aluminum (g/g) d	37		1047.7	108.870
	Source a e c Germany Data
	b e d Europe Data

Table 2 .

 2 Economic Gain with the Reverse Logistic Implementation

	Period	Cardboard	Plastic	Styrofoam	Aluminum
	June	$1.509.00	$552.30	$4.30	$18.98
	July	$590.00	$221.00	$4.00	$14.49
	August	$1.297.00	$410.40	$0.00	$24.15
	September	$1.698.00	$228.40	$1.50	$34.50
	October	$598.40	$202.30	$5.00	$26.45
	November	$1.068.00	$696.00	$5.00	$27.60
	Total	$6.760.40	$2.310.40	$19.80	$146.17
	Applying equations 1 and 2 proposed [27], summarized:
	%ROI = $9.236.77/ $20.000.00 = 46.18% per semester.
	Period ROI = $20.000.00 / $9.236.77 = 1 year and 2 months.

Table 3 .

 3 Environmental gain with the reverse logistic implementation

		Abiotic Goods	Biotic Goods	Water	Air
	Plastic (g/g) a	40809.15		1861403.4	23.555
	Cardboard (g/g) b	74764.56	30147	3762345.6	13063.7
	Styrofoam (g/g) c	1128.6		28908	326700
	Aluminum (g/g) d	2351.35		66.581.335	691
	Mass Intensity per Compartment
	(MIC)	119053.7	30147	5719238,3	350946
	Mass Intensity Total (MIT)				6100331.5


Apostolos Fysikopoulos

Georgios Pastras

Aikaterini Vlachou

George Chryssolouris

An Approach to Increase Energy Efficiency Using Shutdown and Standby Machine Modes

Keywords: Energy Efficiency, Sustainable Manufacturing, Machine Tools, Production Planning, Scheduling

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

The manufacturing industry is one of the greatest energy consumers and carbon emitters in the world [START_REF]Worldwide Trends in Energy Use and Efficiency[END_REF]. The manufacturing sector is responsible for about 28% of the primary energy use [3] and for 38% of the CO2 emissions globally [2]. Thus, energy and eco-efficiency has emerged as one of the most significant manufacturing decision attributes [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF], especially in countries that are not energy independent [START_REF] Seow | A framework for modelling energy consumption within manufacturing systems[END_REF]. Additionally, energy is an increasingly important cost factor due to its increasing price [START_REF] Moreno | The electricity prices in the European Union.: The role of renewable energies and regulatory electric market reforms[END_REF]. Manufacturing enterprises have to reduce energy consumption for both cost saving and environmental friendliness, trying to find new ways to produce "more with less" [START_REF] Chryssolouris | A perspective on manufacturing strategy: Produce more with less[END_REF] and furthermore, evolve from the strategy "maximum gain from minimum capital" to "maximum gain from minimum resources" [START_REF]Tracking Industrial Energy Efficiency and CO2 Emissions[END_REF].

Several initiatives on energy efficiency are on-going [9][START_REF]Cooperative Effort on Process Emissions in Manufacturing CO2PE![END_REF][START_REF]Energy and Resource Efficiency &Effectiveness[END_REF]. Energy saving management, technologies and policies/regulations [START_REF] Bruzzone | Energy-aware scheduling for improving manufacturing process sustainability: A mathematical model for flexible flow shops[END_REF] are used to deal with the energy efficiency issues [START_REF] Schlosser | Sustainabilty in Manufacturing: Energy Consumption of Cutting Processes[END_REF].

The study of energy efficiency in manufacturing systems can be divided into four main levels (Fig. 1) [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF]. The study of each level and their inter-level interactions are important steps towards the effective study of energy and eco-efficiency hence, the need for a holistic approach is necessary [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF][START_REF] Herrmann | Energy Efficiency in Manufacturing: Perspectives from Australia and Europe 15[END_REF]. [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF] 2

Fig. 1. Energy efficiency analysis division

Energy Efficiency at Production Line Level

Decisions on planning and operating production systems are mainly based on traditional metrics such as time, cost, quality and flexibility [15]. In terms of energy cost, a limited number of studies regarding time-dependent industrial planning, under the point of view of electricity cost, have been reported [START_REF] Nilsson | Industrial Applications of Production Planning with Optimal Electricity Demand[END_REF][START_REF] Yusta | Optimal methodology for a machining process scheduling in spot electricity markets[END_REF][START_REF] Moon | Optimization of production scheduling with time-dependent and machine-dependent electricity cost for industrial energy efficiency[END_REF].

Several reviews on commercially available manufacturing simulation tools reveal that they do not support energy and eco-efficiency indicators yet [START_REF] Herrmann | Energy oriented simulation of manufacturing systems -Concept and application[END_REF][START_REF] Thiede | Environmental aspects in manufacturing system modelling and simulation: State of the art and research perspectives[END_REF][START_REF] Wohlgemuth | Combining discrete event simulation and material flow analysis in a component-based approach to industrial environmental protection[END_REF]. Fysikopoulos et al. [START_REF] Fysikopoulos | An Empirical Study of the Energy Consumption in Automotive Assembly[END_REF] have incorporated simple energy formulas into a "real life" automotive assembly line, with the use of discrete event simulation (DES). DES in combination with the life cycle assessment (LCA) method was presented by Johanson et al. [START_REF] Johansson | Discrete event simulation to generate requirements specification for sustainable manufacturing systems design[END_REF]. With the help of this model, the energy aspects of the line along with other performance measures, have been investigated. Wohlgemuth et al. [START_REF] Wohlgemuth | Combining discrete event simulation and material flow analysis in a component-based approach to industrial environmental protection[END_REF] suggested an approach for the integration of DES and the material flow analysis into a component-based framework, based on a single model towards a customized Environmental Management Information System (EMIS). In this framework, production processes and all kinds of energy and material flows can be analysed in terms of both economic measures and their environmental impacts. Herrmann et al. [START_REF] Herrmann | Energy oriented simulation of manufacturing systems -Concept and application[END_REF] presented an energy oriented simulation model for the planning of manufacturing systems. They reported up to 30% improvement in energy efficiency through simulation-assisted process planning.

Mouzon et al. [START_REF] Mouzon | Operational methods for minimization of energy consumption of manufacturing equipment[END_REF] developed mathematical multi-objective models to investigate the problem of scheduling jobs, on a single CNC machine, towards the reduction of time and energy consumption. An impressive outcome is the finding that when a nonbottlenecked machine is turned-off, the energy consumption savings may reach even 80%. Additionally, by forecasting the inter-arrival time of the orders, significant savings can be achieved with the use of proper dispatching rules. Other studies focus on social and environmental issues and not just on energy consumption [START_REF] Yin | A Process Planning Method for Reduced Carbon Emissions[END_REF][START_REF] Sheng | Multi-Objective Process Planning in Environmentally Conscious Manufacturing: A Feature-Based Approach[END_REF][START_REF] Tan | Research on the diagnosis and improvement method of a process route in an enterprise production process in terms of sustainable development III[END_REF][START_REF] Srinivasan | Feature-based process planning for environmentally conscious machining: Part 1 : micro planning[END_REF].

It is evident [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF][START_REF] Fysikopoulos | An Empirical Study of the Energy Consumption in Automotive Assembly[END_REF][START_REF] Duflou | Towards energy and resource efficient manufacturing : A processes and systems approach[END_REF][START_REF] Fysikopoulos | Energy Efficiency Assessment of Laser Drilling Process[END_REF][START_REF] Matta | Machine Control Policies for Energy Saving in Manufacturing[END_REF] that the reduction of the idle time can significantly assist towards energy and eco-efficiency. Drake et al. [START_REF] Drake | Data Collection Framework on Energy Consumption in Manufacturing[END_REF] have reported significant energy consumption during machine idle time. As presented in [START_REF] Fysikopoulos | Energy Efficiency Assessment of Laser Drilling Process[END_REF][START_REF] Gutowski | Environmentally benign manufacturing : Observations from Japan , Europe and the United States[END_REF], in a production machine tool and generally in a mass production environment, the percentage of energy used for functions that are not directly related to the actual production of parts, may be as high as 85% or even more. However, "correct" order distribution (better batch and orders organization) combined with early or periodical "machine shut down" can considerably reduce the idle time, which is the most inefficient state of a system [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF]. Additionally, the incorporation of energy consumption measuring, peak power management, monitoring, controlling and scheduling may lead to better prediction of the workflow and thus, to improved energy savings [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF][START_REF] Neugebauer | Structure principles of energy efficient machine tools[END_REF][START_REF] Kara | Global manufacturing and the embodied energy of products[END_REF]. Thanks to the Information and Communication Technologies (ICT), innovative production management systems can be built to support energy efficient manufacturing [START_REF]ENEPLAN: Energy Efficienct Process pLAnning system. The seventh framework program -FoF.NMP.2011-1: The Eco-Factory: cleaner and more resource-efficient production in manufacturing Program[END_REF].

Machine Tools and Energy Efficiency

The demand for greener machine tools creates new challenges for the machine tool builders. The state of the art in machine tools is the use of energy-efficient components that can reduce energy consumption during idle times up to 65% [START_REF] Duflou | Towards energy and resource efficient manufacturing : A processes and systems approach[END_REF]. Several studies on the energy efficiency of machine tools exist, regarding both conventional and nonconventional processes [START_REF] Fysikopoulos | Energy Efficiency Assessment of Laser Drilling Process[END_REF][START_REF] Li | Eco-efficiency of manufacturing processes : A grinding case[END_REF][START_REF] Mori | A study on energy efficiency improvement for machine tools[END_REF]. Besides the process variables optimisation, the development of energy and eco-efficient components is a basic task for machine tool builders [START_REF] Neugebauer | Structure principles of energy efficient machine tools[END_REF].

The first step towards improving the energy efficiency of machine tools is the identification of the power requirements for different machine tool activities and the categorization of the peripheral devices. Fysikopoulos et al. [START_REF] Fysikopoulos | Energy Efficiency of Manufacturing Processes: A Critical Review[END_REF] indicated that the actual consumed energy required for processing is exceeded to a great extent by the energy demand of the related peripheral equipment, especially for the laser based processes. The analysis can become complex, since several peripherals may be shared among different machines in the factory. Furthermore, they concluded that the consumption of machine peripherals per manufactured part depends on process variables through factors such as process time. Moreover, the overall energy consumption can be significantly reduced, if during idle times, the peripherals go to a complete off or stand-by phase (energy-saving mode) by integrating simple technological features. Nowadays, machine tool controls are equipped with the possibilities of switching the machine into energy-saving modes or even to shutting it down completely [START_REF] Siemens | Energieeffiziente Werkzeugmaschinen mit Sinumerik Ctrl-Energy von Siemens sind sparsam und produktiv[END_REF][START_REF] Gildemeister | DMG MORI[END_REF][START_REF] Eberspächer | Realizing energy reduction of machine tools through a controlintegrated consumption graph-based optimization method[END_REF]. These new machine tool capabilities can be used for the significant reduction of a production line's energy consumption.

A Strategy to Gain Energy Using Shut-down and Stand-by (energy-saving) Modes

In practice, it is not possible to perfectly match the output rates of all the resources in a flow line thus, at least some resources remain idle for some time. The issue is to implement shut-down and stand-by modes in a production line which has already being optimised in terms of idle time. It has to be noted that the incorporation of such modes is not always gainful and actually, it may not even be possible, depending on the idle time available. While a machine is in idle mode, it usually consumes a constant power (Pidle). Thus, the energy wasted in the idle mode is equal to Eidle=Pidlet, where t is the idle time available.

Provided that the machine was switched-off, this constant consumption would have been avoided; however, there would be a period of maximum power consumption, necessary to start up the machine for its next task. It is assumed that the duration of the shut-down and start-up procedures is equal to tstartup and that the corresponding energy consumption is equal to Estartup. Then, the energy consumed if the shut-down mode is used equals Eshutdown=Estartup and it is possible only if the time available is larger than tstartup. From the above arguments, it is evident that the incorporation of the shut-down mode is profitable only when Eshutdown<Eidle, which is equivalent to the available time being larger than a critical value equal to startup idle .

cr E t P  (1)
Similarly, an intermediate stand-by (energy-saving) mode can be incorporated. In such a mode, some of the machine's peripheral systems are turned off, while the more critical ones remain operative. Such a mode is characterized by some constant power consumption Pstandby, smaller than Pidle, while the machine remains in stand-by mode. However, some time and energy is also required in order for the machine to "sleep" and then become operative again, namely twake and Ewake. If both stand-by and shut-down modes are available, it is typically true that Ewake<Estartup and twake<tstartup. The energy consumed if the standby mode is used equals Estandby=Ewake+Pstandby(t-twake). The standby mode can be used only if the available time is larger than twake. Similarly to what is stated above for the shut-down mode, the stand-by mode is preferable to the idle mode provided that the available time is larger than wake standby wake 1 idle standby

cr E P t t PP    (2)
and preferable to the shut-down mode if the available time is smaller than startup wake 2 wake standby . cr EE tt P

 

(3) It has to be noted that a standby mode is never profitable if tcr1>tcr2.

All the above arguments are summarized in Fig. 2. According to what was analysed above, a strategy to gain energy using the shutdown and stand-by modes can be specified. For every machine, the idle time durations predicted by suitable simulation method have to be compared with the critical times tcr1 and tcr2 and then the resource has to:

1. be shut-down, if the idle time is larger than tcr2 2. be switched to stand-by mode, if the idle time lies between tcr1 and tcr2 3. remain idle, if the idle time is smaller than tcr1

The procedure has to be repeated for every resource. A logical diagram showing the above for a system consisting of N resources is depicted in Fig. 3. It has to be noted that in the proposed method, the shutting-down or switching to a stand-by mode is not performed manually, but on the contrary, these actions are scheduled during the production planning stage.

Conclusions

In this study, a strategy to increase the energy efficiency of an already balanced production line, using the machine's tool stand-by (energy saving) or shut-down (completely turned-off) modes, during idle time, was introduced. The main outcomes can be summarised as following:

 Energy efficiency metrics should be included in the commercially available multiobjective optimization decision support systems.  Application of the shut-down or stand-by modes is not always profitable. It depends on the available idle time, the energy consumption for starting up and waking up, as well as the power consumption during the idle and stand-by modes, as described in Section 4 and depicted in Fig. 2.  Application of the shut-down or stand-by modes can be gainful in terms of energy and consequently, in terms of the related energy costs.  Since the inclusion of energy saving modes in the production schedule can be gainful, the machine tool builders should incorporate the required simple technological features into their machines.  Machine tool builders should be careful when incorporating a stand-by function into their machines. Depending on the stand-by power consumption and the necessary wake-up energy, the use of this mode may never be preferable over the idle or shutdown mode (when tcr1>tcr2).

Future work will focus on methods to arrange the schedule of a production line so that the duration of the idle states is allowing the use of energy saving modes. Such methods will lead to maximum utilisation of these modes and thus, of the related energy and energy cost gains. Moreover, the method is going to be validated in a real industrial case study.

Fig. 2 .

 2 Fig. 2. An indicative diagram for the energy consumption of a machine during non-working time periods under different available modes

Fig. 3 .

 3 Fig. 3. A basic logic diagram describing the decision process for incorporation of shut-down and stand-by modes

Acknowledgements

The work reported in this paper was supported by the collaborative program entitled "Energy Efficient Process planning System -ENEPLAN", which is under the seventh framework program -FoF.NMP.2011-1: The Eco-Factory: cleaner and more resourceefficient production in manufacturing Program.


José Barrozo De Souza
email: josébarrozodesouza@gmail.com

José Benedito Sacomano

Sergio Luiz Kyrillos

Francisco José Santos Milreu

Fabio Paparlado

The maintenance function in the context of corporate sustainability: a theoretical-analytical reflexion

Keywords: Environmental 1, Operations 2, Production 3

The paper presents an analytical reflection, based on the context of knowledge management, risk management, quality management, intra-organizational relationships through attributes associated with corporate sustainability. For reasons of theoretical essay, research was supported in mapping the primary references and analysis of different interpretations of sustainability reports from companies associated with the Ethos Institute (Brazil). This paper presents a reflective approach to assess the importance of integration between the maintenance and production, considering some attributes of corporate sustainability.

Introduction

The background and purpose of this study

The term "sustainable development" was popularized by the publication of the report Our Common Future in 1987 [START_REF]WCED -World Commission on Environment and Development (WCED). Our Common Future[END_REF]. Although sustainable development is a social concept, is increasingly being applied as a corporate concept under the name of "Corporate Sustainability" [START_REF] Steurer | Corporations, stakeholders and sustainable development I: a theoretical exploration of business-society relations[END_REF]. Several authors have questioned whether sustainable development actually applies to the corporate level [START_REF] Gray | Is accounting for sustainability actually accounting for sustainability and how would we know? An exploration of narratives of organizations and the planet[END_REF].

In particular, firms as actors in society have been pressed to change the way they do business to integrate the principles of sustainability into their everyday business practices and promote their impacts and contributions to sustainable development [START_REF] Kolk | CSR in China: analysis of domestic and foreign retailers' sustainability dimensions[END_REF]. Thus arose alternative to the maximization of financial profit captured in phrases like "triple bottom line", where the criteria of economic, social and environmental performance must be integrated [START_REF] Hopwood | Accounting for Sustainability: Practical insights[END_REF].

The urgency and magnitude of the threats and risks to global sustainability, together with its opportunities, will transform the disclosure of sustainability and transparency in a key success factor for any company [START_REF] Gri | Sustainability reporting guidelines[END_REF]. In his lecture of the day 22/05/2013, titled "From Dilution is the Solution to Pollution to Regional Sustainable Development is the Solution for improved Quality of Life for All: The Long and Challenging Journey", 4rd International Workshop on Advances in Cleaner Production held in São Paulo, Brazil, in 2013, the chief editor of the Journal of Cleaner Production, Donald Huisingh urged "global sustainability as the Third Industrial Revolution".

With a growing social demand of corporate sustainability, companies embrace the strategic importance of environmental management practices for competitive advantage. Furthermore, firms tend to increase their market value when they announce that they are adopting environmental management systems such as ISO 14001 [START_REF] Yang | Mediated effect of environmental management on manufacturing competitiveness: an empirical study[END_REF].

The promotion of sustainable development mission has been shaping the practice of all sectors of activity, for example, including the development of housing for sustainable practice, working to balance the economic, social and environmental performance [START_REF] Zhang | Green strategy for gaining competitive advantage in housing development: a China study[END_REF]. Current studies indicate a need to integrate environmental management with the manufacturing strategy, including some themes, such as crossfunctional integration, environmental impact and waste reduction [9a].

Reliable information on the operational availability of production systems is of great importance for users of complex production facilities, especially when such facilities operate at capacity. Following the requirements of environmental regulations and the increasing complexity of production systems over the last decades, the maintenance function evolved with the growth of technology [START_REF] Ahmad | An overview of time-based and condition-based maintenance in industrial application[END_REF]. The maintenance function is defined as a set of activities or tasks used to restore an item to a state in which it can perform its designated functions with minimum negative impact on the environment.

Eco-efficiency is a matter of concern at present and is receiving increasing attention in political, academic and business media. In general, this concept refers to the ability to create more goods and services with less impact on the environment and less consumption of natural resources, involving both economic and ecological level issues. Although organizations have embraced the rhetoric of sustainability in their speeches and external reports, little is known about the processes by which systems of management control contributed to greater integration of sustainability into organizational strategy.

Even showing some promise, it was argued that the challenge of accreditation is forcing companies essentially to adopt certifications (hence internalize certifications in daily practice), not just the adoption of certifications symbolic form [START_REF] Castka | The effect of pressure from secondary stakeholders on the internalization of ISO 14001[END_REF]. For example, emphasize that the quality of maintenance and environmental impact are determined by the use of energy and resources, guided by environmental standards, as well as dependent on the policies adopted by the maintenance function and experience of workers. The adoption of environmental management systems is one of the most important elements of corporate sustainability in recent years. Although theoretically the importance of sustainable business models has become widely accepted in the literature, little is known about how managers deal with practical issues, such as differences in stakeholder interests.

Presented as an introduction to the special volume of the 3rd International Workshop Advances in Cleaner Production, held in Sao Paulo, Brazil, in 2011, the theme of "Cleaner Production Initiatives and Challenges for a sustainable world", the content emphasizes recognition of the urgent and inevitable to make changes from unsustainable patterns of consumption for sustainable production need [START_REF] Almeida | Cleaner Production initiatives and challenges for a sustainable world: na introduction to this special volume[END_REF].

Sustainable development depends on more sustainable consumption and production patterns that respond to basic needs and bring a better quality of life while minimizing the use of natural resources so as not to jeopardize the needs of future generations [START_REF] Ivete Delai | Corporate sustainability in emerging markets: insights from the practices reported by the Brazilian retailers[END_REF].

Research suggests that the preconditions for the ISO 14001 certification motivations can be a good indicator of environmental strategy a company pursues. Moreover, the environmental strategy relates to the environmental performance results and operating company practices [START_REF] Gavronski | ISO 14001 certified plants in Brazil e taxonomy and practices[END_REF], i.e., the impact of proactive maintenance policy function in the productive system and hence into the environment are incorporating environmentally benign parameters in the three levels of the model input-processingoutput [15a], thus developing the Corporate Sustainability.

Corroborating, [16b] investigated that green teams are often considered in the literature as an essential for companies aiming to implement and improve the approaches and practices of environmental management factor.

The process Maintenance management can be divided into two parts: the definition of the strategy and strategy implementation. The first part, the definition of maintenance strategy, requires the definition of the tasks of maintenance function as an input, which derive directly from the business plan. This initial part of the process for the Management of Maintenance conditions for maintaining the success of an organization determines the effectiveness of subsequently implementing maintenance plans, schedules, controls and improvements.

The second part of the process, the implementation of the chosen strategy -has a different level of significance. Our ability to deal with the problem of deployment Maintenance Management (for example, our ability to secure adequate levels of qualification, preparation of suitable work, proper tools, and performance schedule) will allow us to minimize the cost of maintaining direct (work maintenance and other necessary resources). In that part of the process, we deal with the efficiency of our management, which should be less important. Efficiency is acting and producing with minimum waste, expense or unnecessary effort. Efficiency is then understood as the combination of the Operations and Maintenance Management with providing maintenance function equal to, or better for the same cost.

The third part is to create synergy in the association of operations and maintenance tasks, as it is important for the formulation of tasks, programming strategies and daily operations. However, maintenance should also be integrated throughout the manufacturing industry to better long-term benefits [START_REF] Yamashina | Japanese manufacturing strategy competing with tigers[END_REF], as shown in Figure 1.

Font: Authors based on mapping the studied literature (2012) Figure 1 -Relationship between operations and maintenance function Therefore, for many authors, as [START_REF] Pintelon | Maintenance Management[END_REF][START_REF] Yang | Maintenance priority assignment utilizing on-line production information[END_REF] the existing research on the prioritization of maintenance tasks have three major limitations: (1) long-term problem is considered as a short-term dynamics is ignored; [START_REF] Steurer | Corporations, stakeholders and sustainable development I: a theoretical exploration of business-society relations[END_REF] the relationship between production and maintenance functions, regarding the work order must be clear and (3) decisions are often made by heuristic rules.

Present a proposal for decision support in the short term for the prioritization of maintenance tasks function that can answer two important questions in relation to decision making: (1) On which machines the tasks of maintaining function without affecting the production system will be carried out? (2) Which task of the maintenance function should be performed first so improving obtains the highest throughput? [START_REF] Muchiri Peter; Pintelon | Development of maintenance function performance measurement framework and indicators[END_REF] The growing importance of the maintenance function of the industrial scenario and technological developments, especially the environmental advances of recent years have produced the development of modern maintenance strategies such as conditionbased maintenance and predictive maintenance [START_REF] Ni | Short-term decision support system for maintenance task prioritization[END_REF].

A major research question guided the construction of this article. "What are the environmental attributes that drive proactive maintenance policy function for a minimal negative impact on the production system to the environment"? In answering this question, this paper contributes by providing objective evidence on how policies influence function of maintaining the potential outcomes of the production system. Furthermore, it provides new evidence on the potential economic, social and environmental benefits of efforts for the development of corporate sustainability.

The other sections of the paper are structured as follows: in section 2, a reflection on the term corporate sustainability, in section 3, a discussion of the methodology used in the study is presented, in section 4, the results of a reflective analysis are reviewed, in

Operations and Processes

Maintenance function them partners in building a sustainable and just society, for example, Institute Ethos (Brazil).

Despite the ongoing debate on the relationship between environmental management and financial performance, the survey allows us to observe inconsistency, making clear between companies, organizations and companies utopia. By identifying possible utopia between the binomial economic developments versus sustainable development are observed needs to work with these underlying conflicts in order to find fair and meaningful solutions to the problems facing us.

The assessment results help not only to choose an alternative design more suitable for a specific set of requirements and maintenance policies with minimal environmental impact, but also to assess the degree to which aspects of proactive maintenance policy can be incorporated into strategic planning. Furthermore, the processes of maintenance and environmentally benign procedures also have a greater role to play in reducing the environmental impact, in particular production systems. Facilitate the interaction of operations with maintenance systems through intuitive interfaces is a competitive advantage in terms of time and costs to industry is shown in Table 1. All the attributes shown in shaded rectangles can be met in the design phase of the product. The other attributes are those that can be maintained during the maintenance operation.

Conclusions and recommendations

In conclusion, the paper presents a new definition for the Maintenance function: the continuing development of systematic, coordinated, economic and implements through more proactive implementation of intra-organizational relationships in order to develop the optimization tasks in the three levels of the model input-processingoutput. As proposed in Figure 3, which shows the connections of continuous improvement with regard to the Maintenance function in the context of corporate sustainability. Finally, it is considered that the points analyzed were able to subsidize the authors of this article with regard to the response of the research question: "What are the environmental attributes that drive proactive maintenance policy function for a minimal negative impact to the production system environment "? In this sense, we believe that the research problem was answered.

Ultimately, we suggest a study on small businesses, because they have not received enough attention and are not represented in our study. Furthermore, the integration of production and maintenance system in the context of organizational culture and corporate sustainability will require further exploration in the context of a small business.

Table 1 -

 1 Attributes necessary to the practice of consistent policies and environmentally proactive maintenance strategies

	Environmental compatibility	Energy Efficiency	Human health and safety
			risks
	Biodegradable Lubricants	Synthetic lubricants	Rules and regulations
	and Cleaning agents	derived from renewable
		resources
	Prevention of leaks	Facility maintenance	Adequate ventilation and
			lighting
	Adaptability during	Material and energy	Use of non-toxic
	maintenance	efficient lubricants	solvents and lubricants
	Waste treatment policies	Maintenance	Maintenance tasks
		management system	secure and easy
	Material with longevity	Reduction of	-
		unnecessary travel easy
		transport
	Minimal problems with	-	-
	landfill
		Font: Adapted from: [22b].

section 5, a discussion of the main conclusions is provided. The article ends with conclusions and recommendations for future research in section 5.

Methodology

The paper presents an analytical reflection, based on the context of knowledge management, risk management, quality management, intra-organizational relationships through attributes associated with corporate sustainability. For reasons of theoretical essay, research was supported in mapping the primary references and analysis of different interpretations of sustainability reports from companies associated with the Ethos Institute (Brazil). To sort the search and consequently reply the research problem has been taken as the basis for taxonomy, who qualifies on three aspects:

(1)

Regarding purposes -exploratory, because the main objective of the research is to clarify the influence of organizational factors and conceptual integration of the production system maintenance and function in the transfer of the Corporate Sustainability practices, with the understanding that there is little accumulated knowledge and systematized on that strategic integration; (2) As for the means -the research is classified as documents and literature, and (3) Answer the question: What are the environmental attributes that drive proactive maintenance policy function for a minimal negative impact on the production system to the environment? This research is justified by current and continuing need for theoretical and analytical reflection in the field of management of the production system integration and maintenance function.

Results and Discussion

This section presents a discussion of the results obtained in the research. Seeks to systematize and consolidate the literature review and theoretical and analytical reflection contextualized in order to expand the ongoing debate and deepen the nascent field of research. In light of these divergent views, while organizations recognize that environmental sustainability has implications for their competitive positions, companies are not clear about the details of implementation of environmental management practices. Although few environmental attributes that drive proactive maintenance policy function have been suggested in the literature mapping done, the article provides evidence needed for the use of these attributes in practice.

The possibility of benchmarking is particularly relevant for companies and organizations operating in the same sectors in the same country, especially if they are associated with some environmental institution with a mission to mobilize, sensitize and help companies manage their business in a socially responsible manner making


Alexande Chadeneau

Emilie Dol

Solène Martinez

Catherine Da Cunha

Evaluation of sustainable mass customized habitation: the case of CAP 44

Keywords: Satisfaction, Customization, Home, Evaluation 1

Measuring the value of a product before launching its production is a way to assure its good sale. The present study proposes a methodology to evaluate the intrinsic value of an habitation. The value is measured in terms of sustainability and customization.

The methodology is composed of a first step of determination of value drivers, an evaluation step, an aggregation step and finally recommendation. step

The methodology is applied on a real case: the CAP 44 housing project in Nantes, France.

Introduction

Mass customization is a policy than enables the satisfaction of personalized requirements with near mass production efficiency. Among other benefits, it enables to gain competitive advantage on a given market share.

Mass customization can be offered either via product variability or process variability [START_REF] Daaboul | Design for Mass Customization: Product variety vs. Process variety[END_REF]. Numerous researches identify the existence of Mass customization enablers but also of pitfalls (Gilmore and Pine, 1996[START_REF] Da Silveira | Mass customization: literature review and research directions[END_REF][START_REF] Fogliatto | The mass customization decade: An updated review of the literature[END_REF].

A raise in customization may lead to a raise in complexity, in the production as well as in management [START_REF] Blecker | Controlling variety-induced complexity in mass customisation: a key metrics-based approach[END_REF]. A company should then address several questions before implementing mass customization (Daaboul et al., 2010):

-Can the product be customized? -Does the customer want a customization? -Is the company ready for mass customization? [START_REF] Barlow | Choice and delivery in housebuilding: lessons from Japan for UK housebuilders[END_REF] reported that Mass customization, which is already functional for Japanese housing industry, could be a new business model for the European one. The challenge is the evaluation of the value of this new type of habitation. First theories on value go back to ancient Greece (with Plato and Epicurus). Modern research also has interest in this area, promoting transdisciplinary definition and evaluation for this concept [START_REF] Gallarza | Value dimensions, perceived value, satisfaction and loyalty: an investigation of university students' travel behaviour[END_REF] [START_REF] Ueda | Value creation and decision-making in sustainable society[END_REF]. Value is neither a constant in time nor an objective characteristic. Yet this characteristic has a huge influence on the customer behavior, particularly on product choice, repeated purchases and product recommendation.

For the particular product which is a "home" the value concept is declined into an elicited valuation named "Housing satisfaction". This indicator measures the proximity of an current and ideal housing of an individual subject to its needs, expectations and achievements [START_REF] Amérigo | A theoretical and methodological approach to the study of residential satisfaction[END_REF].

The article is structured as follows: section 2 presents the methodology. Section 3 depicts the use case. Conclusion and research directions close the article

Methodology

We followed a generic methodology to evaluate the value of a given product [START_REF] Daaboul | Design for Mass Customization: Product variety vs. Process variety[END_REF].

1. Identification of the Housing satisfaction drivers 2. Determination of a test population for the drivers' weighting 3. Weighting of the satisfaction drivers

We adapted this methodology to the housing product and add to this 3 first steps a final step of aggregation.

Housing satisfaction drivers identification

It is mandatory to define the limits of the product. In our case of housing, we limited the product to the private volume belonging to one or several people. The building as a whole, the neighborhood, transportation systems are then exterior elements that should not be considered.

Thanks to a study led by the French housing sector (Century 21, 2010) an exhaustive list of satisfaction drivers has been established. A reduction of this list to the most pertinent ones was done with the architectural staff of the CAP 44 project, see figure 1 for a hierarchical representation.

2.2

Evaluations and aggregation.

For multicriteria evaluation, Analytic Hierarchy Process (AHP) [START_REF] Saaty | Decision making with the analytic hierarchy process[END_REF]) is often used to weight the different criteria. One of the difficulties in implementing AHP is to limit the number of pairwise comparison the test population has to perform. Therefore a hierarchical partitioning of the criteria can be done, the pairwise comparison will then be limited to criteria belonging to the same subset. The tree representation of those drivers is given in figure 1.

A difficulty occurs when the decomposition levels are not equal for every driver. We choose to address this issue using sparse pairwise-comparison matrices [START_REF] Tan | A methodology for augmenting sparse pairwise comparison matrices in AHP: applications to energy systems[END_REF] The aggregation phase has a significant impact on the obtained results. The choice of aggregation type must answer to two questions:

-What is the most efficient mean type? -When do we have to use it? On the comparisons? On the weight?

We chose to use the geometric mean which is the most congruent with pairwise comparison [START_REF] Adamcsek | The Analytic Hierarchy Process and its Generalizations[END_REF]. The order of the operation also has an impact on weighting. The mean can be done either on the comparisons or on the weights (figure 2)

Fig. 2. -Aggregation solutions
The choice between the 2 aggregations

3

Usecase: the CAP 44 project

Project description

CAP 44 is a building that followed Nantes's evolution since its building in 1895. At first was a flourmill, ideally placed along the river Loire, and then it has been transformed into offices. The chosen redevelopment is modular. The architects wish to pre-build the housing and offices and then insert them into the structure, in a Plug & Play approach. This idea of a common plateform for different product is in line with mass customization policies [START_REF] Martin | Design for variety : a methodology for developing product plateform architectures[END_REF].

Satisfaction drivers and housing evaluation

To weight the satisfaction drivers, a small panel (30 people) of engineer-architect students, civil engineers, real estate agents, Nantes inhabitants was formed and questioned. The AHP method was applied, it gives the following results. The ten most important drivers are the same, see table 1. Yet for some drivers the relative difference can be up to 56% therefore the 2 aggregations will be conserved for the evaluation phases. For the evaluation, the housing project was described through: artist's interpretations, 2D-plans and synthesis tables related to satisfaction drivers (surface in m2, description of the heating characteristics,…). Based on this information (which was then unbiased by the interviewer) subjects had to evaluate the housing on a 5-scale basis for each of the 47 drivers. Figure 5 illustrates the variation of the evaluations for 7 of our subjects, the evaluation are given in the y-axis while the drivers are represented in the x-axis. Those drivers are of great interest for a mass customization point of view. They should constitute a set of "modules" that the customers could chose or not.

Figure 6 presents the average weighted evaluation for the different drivers per categories. The average grade of the housing is of 3.92. This evaluation is a reference for further evolution of the project. It should be improved, while the architects take the subjects into account. For instance the initial design proposed a plug-in loggia for each apartment. Thanks to this analysis, they identify that the global preference goes to either a balcony or an extra-room to the housing.

Discussion and conclusion

This study enriches a methodology of Housing satisfaction evaluation. The application to a housing project validates the relevance of the different steps.

The Cap 44 project's architects used the results of the satisfaction drivers' identification and evaluation to better understand the expectation of future users and then to modify the design of the building. Next steps of the projects include in an evaluation of the new design.

Further research should address the genericity of the obtained drivers and the robustness of their weight for the French housing sector. The stabilized Housing satisfaction evaluation grid could then be used for future building development project in Nantes.

Fig. 1 .

 1 Fig. 1. Satisfaction drivers

Fig. 3 .

 3 Fig. 3. -Localization of CAP 44 buildingToday the city wants to transform this building and use it as the center of a new neighborhood based on the "fertile city" concept. The future building should be a meeting point offering housing, offices place, restaurants, services, etc. figure4presents the proposed evolution of the building.

Fig. 4 .

 4 Fig. 4. -Evolution of CAP 44

Fig. 5 .

 5 Fig. 5. Evaluation of the drivers A special category of drivers can be identified: the ones having an evaluation of 0 resp. 5. These drivers are deal-breakers resp. mandatory for other subjects. These drivers are:  Fireplace/Wood burner  Garage/Parking  Furniture  Walls material  Numbers of toilets  Terrace/balcony

Fig. 6 .

 6 Fig. 6. Average grade of drivers, per categoryThe drivers having the highest weighted grades are: Total area, Walls isolation, Windows, Services charges.The average grade of the housing is of 3.92. This evaluation is a reference for further evolution of the project. It should be improved, while the architects take the subjects into account. For instance the initial design proposed a plug-in loggia for each apartment. Thanks to this analysis, they identify that the global preference goes to either a balcony or an extra-room to the housing.

Table 1 .

 1 Weight for the 10 most important Drivers

	Drivers	Geometric mean of the in-	Geometric mean of the
		dividual weights	individual comparison
	Rent	12,86%	35,38%
	# of rooms	5,63%	3,76%
	# of bedrooms	5,42%	3,62%
	Orientation	4,51%	2,73%
	# of widows	4,16%	2,52%
	Service charges	4,01%	11,03%
	Evolution possibility	3,92%	2,62%
	Levels	3,58%	2,39%
	Surface per room	3,34%	2,23%
	Fitted kitchen	2,81%	1,88%