Laboratoire Génie Industriel

International audience

HyMeX-SOP1 collected unprecedented observations of atmosphere, ocean, land, and rivers

Purpose The purpose of this paper is to better identify, define and model complexity within the field of project management in order to manage better under conditions of complexity (and manage better complexity‐induced risks). Design/methodology/approach An extensive literature review enlightens the lack of consensus on project complexity and thus provides a broad view and a critical analysis of the underlying concepts. A project complexity framework and definition are then proposed. After underlining the stakes of project complexity in accordance with these proposals, a project complexity model is then built notably due to systems analysis. Findings Proposal of standard project complexity framework and definition. Proposal of a synthesis of the relationships between the concepts of project uncertainty and project complexity. Proposal of a project complexity model (and validation due to industrial application). Research limitations/implications The literature review and project complexity framework tries to be exhaustive even though it is likely to be completed. The final version of the model is still to be computed and tested. Practical implications Avoiding confusion when defining and managing a complex project, particularly between project team members (and as a consequence improving communication and information sharing), improves the assessment of the propagation of a change within the project. Originality/value The paper proposes an original framework and a definition of project complexity. The complexity model permits the navigation from any element of the project to any other (when detail is needed) and is, as a consequence, original and complementary with traditional project management models and tools.

Abstract Cyphos IL 101 (tetradecyl(trihexyl)phosphonium chloride) was immobilized on Amberlite XAD-7. The extractant impregnated resin (EIR) was very efficient at removing Zn(II) from HCl solutions (optimum found between 2 and 4 M HCl). Metal ions were removed as anionic chlorocomplexes (ZnCl4 2−) by ion exchange mechanism. The sorption strongly depended on the Cyphos IL 101 concentration in the EIR. The maximum sorption capacity was close to 20 mg Zn(II) g−1 EIR (i.e. 0.40 mol Zn(II) mol−1 Cyphos IL 101). The uptake kinetics were controlled by intraparticle diffusion (De: 1.2 10−11 − 6 10−11 m2 min−1). Zn(II) can be easily desorbed using a number of eluents (including water and 0.1 M solution of HNO3, H2SO4, and Na2SO4), which maintained performance levels over 5 cycles.

International audience

Assessing product circularity performance is not straightforward. Meanwhile, it gains increasingly importance for businesses and industrial practitioners who are willing to effectively take benefits from circular economy promises. Thus, providing methods and tools to evaluate then enhance product performance—in the light of circular economy—becomes a significant but still barely addressed topic. Following a joint agreement on the need to measure product circularity performance, this paper provides an overview of mechanisms aiming to help industrial practitioners in this task. In fact, three existing approaches to measure product circularity performance have been tested on an industrial case study and criticized regarding both their applicability in industry and their accordance with circular economy principles. Although these methods and tools deliver a first and rapid trend of product circularity performance, the whole complexity of circular economy paradigm is far from being considered. In addition, operational guidance for engineers, designers or managers to improve their products in a circular economy context are missing. As a result, both recommendations for industrial practitioners and guidelines for the design and development of new frameworks, tools and indicators aiming at measuring product circularity performance are provided. This includes cornerstones, key requirements and practical implications to support enhanced circularity measurement that will be developed in further work, accordingly to circular economy paradigm and industrial reality.

The durability of a control method for plant protection is defined as the persistence of its efficacy in space and time. It depends on (i) the selection pressure exerted by it on populations of plant pathogens and (ii) on the capacity of these pathogens to adapt to the control method. Erosion of effectiveness of conventional plant protection methods has been widely studied in the past. For example, apparition of resistance to chemical pesticides in plant pathogens or pests has been extensively documented. The durability of biological control has often been assumed to be higher than that of chemical control. Results concerning pest management in agricultural systems have shown that this assumption may not always be justified. Resistance of various pests to one or several toxins of Bacillus thuringiensis and apparition of resistance of the codling moth Cydia pomonella to the C. pomonella granulovirus have, for example, been described. In contrast with the situation for pests, the durability of biological control of plant diseases has hardly been studied and no scientific reports proving the loss of efficiency of biological control agents against plant pathogens in practice has been published so far. Knowledge concerning the possible erosion of effectiveness of biological control is essential to ensure a durable efficacy of biological control agents on target plant pathogens. This knowledge will result in identifying risk factors that can foster the selection of strains of plant pathogens resistant to biological control agents. It will also result in identifying types of biological control agents with lower risk of efficacy loss, i.e., modes of action of biological control agents that does not favor the selection of resistant isolates in natural populations of plant pathogens. An analysis of the scientific literature was then conducted to assess the potential for plant pathogens to become resistant to biological control agents.

We consider a capacitated supply system that produces a single item that is demanded by several classes of customers. Each customer class may have a different backorder cost, so stock allocation arises as a key decision problem. We model the supply system as a multi customer make-to-stock queue. Using dynamic programming, we show that the optimal allocation policy has a simple and intuitive structure. In addition, we present an efficient algorithm to compute the parameters of this optimal allocation policy. Finally, for a typical supply chain design problem, we illustrate that ignoring the stock allocation dimension—a frequently encountered simplifying assumption—can lead to incorrect managerial decisions.

After more than 70 years of chemical pesticide use, modern agriculture is increasingly using biological control products. Resistances to conventional insecticides are wide spread, while those to bio-insecticides have raised less attention, and resistance management is frequently neglected. However, a good knowledge of the limitations of a new technique often provides greater sustainability. In this review, we compile cases of resistance to widely used bio-insecticides and describe the associated resistance mechanisms. This overview shows that all widely used bio-insecticides ultimately select resistant individuals. For example, at least 27 species of insects have been described as resistant to Bacillus thuringiensis toxins. The resistance mechanisms are at least as diverse as those that are involved in resistance to chemical insecticides, some of them being common to bio-insecticides and chemical insecticides. This analysis highlights the specific properties of bio-insecticides that the scientific community should use to provide a better sustainability of these products.

There are wafer fabrication processes in cluster tools that require wafer revisiting. If a swap strategy is applied to dual-arm cluster tools handling wafer revisiting, a three-wafer periodical process is formed with three wafers completed in each period. Such a period contains three cycles in a revisiting process and three cycles in a nonrevisiting one. Hence, analysis and scheduling of such tools become very complicated. In this paper, a Petri net (PN) model is developed to describe their operations. Based on it, it is found that, if a swap strategy is applied, such tools are always in a transient state. A systematic method is then presented to analyze their performance. With the help of the proposed PN model, this work, for the first time, derives the optimality conditions of three-wafer period scheduling. Industrial application examples are given to show the results.

Although immune checkpoint inhibitors (ICIs) are established as effective cancer therapies, overcoming therapeutic resistance remains a critical challenge. Here we identify interleukin 6 (IL-6) as a correlate of poor response to atezolizumab (anti-PD-L1) in large clinical trials of advanced kidney, breast, and bladder cancers. In pre-clinical models, combined blockade of PD-L1 and the IL-6 receptor (IL6R) causes synergistic regression of large established tumors and substantially improves anti-tumor CD8+ cytotoxic T lymphocyte (CTL) responses compared with anti-PD-L1 alone. Circulating CTLs from cancer patients with high plasma IL-6 display a repressed functional profile based on single-cell RNA sequencing, and IL-6-STAT3 signaling inhibits classical cytotoxic differentiation of CTLs in vitro. In tumor-bearing mice, CTL-specific IL6R deficiency is sufficient to improve anti-PD-L1 activity. Thus, based on both clinical and experimental evidence, agents targeting IL-6 signaling are plausible partners for combination with ICIs in cancer patients.

ABSTRACT Following our investigations on food additive production through fermentation, we studied properties of red pigments secreted by Monascus ruber in submerged culture, using ethanol and glutamate as carbon and nitrogen sources. After extraction and purification, these colorants were suspended in water for evaluation. The stability of the extract was tested both in solution and when incorporated into meat products (sausage and pâté). The pigments added to sausage or pate remained stable when stored for 3 mo at 4°C; their stability was between 92 and 98%. Sensory tests revealed that Monascus pigments could replace some traditional food additives such as nitrite salts or cochineal.

Abstract Modelling and simulation have long been dominated by equation-based approaches, until the recent advent of agent-based approaches. To curb the resulting complexity of models, Axelrod promoted the KISS principle: ‘Keep It Simple, Stupid’. But the community is divided and a new principle appeared: KIDS, ‘Keep It Descriptive, Stupid’. Richer models were thus developed for a variety of phenomena, while agent cognition still tends to be modelled with simple reactive particle-like agents. This is not always appropriate, in particular in the social sciences trying to account for the complexity of human behaviour. One solution is to model humans as belief, desire and intention (BDI) agents, an expressive paradigm using concepts from folk psychology, making it easier for modellers and users to understand the simulation. This paper provides a methodological guide to the use of BDI agents in social simulations, and an overview of existing methodologies and tools for using them.

ABSTRACT: The inhibitory activity of chitosan‐based edible coatings and films was assessed against the Aspergillus niger food pathogen and deterioration microorganism. Spore‐counting assays showed an almost total inhibition of A. niger growth when either film‐forming solution or film were used at a low concentration of chitosan (0.1% w/v). Epifluorescence microscopic results showed the action of chitosan on the relative proportion of RNA compared with DNA. The water vapor permeability (WVP) of chitosan film was relatively low compared with the poor moisture barrier of some polysaccharide films. Moreover, a coating with chitosan film on an agar gel, used as a food model, induced a 30% reduction in water loss. These results showed potential applications of chitosan‐based films as bioactive packaging with properties to limit the food dehydration phenomenon.

Several properties of chitosan films associated or not with hydroxypropylmethylcellulose polymer (HPMC) and HPMC films incorporating or not nisin and/or milk fat were studied. Nisin addition at a level of 250 microg mL-1 and likewise chitosan at 1% (w/v) concentration were efficient for total inhibiting Aspergillus niger and Kocuria rhizophila food deterioration microorganisms. HPMC and chitosan films were transparent, whereas nisin and/or fat incorporation induced a 2-fold lightness parameter increase and, consequently, involved more white films. Measurements of tensile strength, as well as ultimate elongation, showed that chitosan and HPMC initial films were elastic and flexible. High thermal treatments and additive incorporation induced less elastic and more plastic films. Water vapor transmission as far as total water desorption rates suggested that chitosan films were slightly sensitive to water. Water transfer was decreased by <60% as compared with other biopolymer films. Regarding its hydrophobic property, the capacity of fat to improve film water barrier was very limited.

Denaturation of beta-lactoglobulin during heating of milk in a plate heat exchanger has been investigated as an important factor in fouling the heat transfer surface. Using, on one hand, data on chemical composition of deposits obtained from biochemical analysis technics and, on the other hand, kinetic data of beta-Iactoglobulin denaturation, the distribution profile of deposits along the surface and the experimental fouling curves can be adequately predicted.

Eighteen healthy male volunteers, with a mean age of 24 yrs (range 18-40), underwent an open pharmacokinetics study, aimed at detecting rifaximin concentration in blood and urine after a single oral administration of 400 mg of the antibiotic. Administration took place after a 9 hours' fast and was followed by a breakfast after 2 hours and a lunch after 5 hours. Blood samples were collected before rifaximin administration and 1, 2, 4, 8, 12, 24 and 48 hours after dosing. Urine samples were collected immediately before dosing (reference sample) and then at the end of the following intervals of time: 0-6 h, 6-12 h, 12-24 h, 24-48 h. During the whole study period, the local and general tolerance to rifaximin administration was checked. Rifaximin concentration was assessed by reversed phase high performance liquid chromatography with electrochemical detection. In almost every plasma sample, rifaximin concentration was undetectable (lower than the detection limit of the analytical method, i.e. 2 ng/ml). In urine, very small amounts of the unchanged molecule (< 0.01% of the administered dose) were found in the period 0-48 hours. These results confirm the negligible absorption by the intestinal tract of a single oral dose of rifaximin (400 mg). Local and general tolerance of the administered drug was very good.

In this paper, we analyze a call center with impatient customers. We study how informing customers about their anticipated delays affects performance. Customers react by balking upon hearing the delay announcement and may subsequently renege, particularly if the realized waiting time exceeds the delay that has originally been announced to them. The balking and reneging from such a system are a function of the delay announcement. Modeling the call center as an M/M/s + M queue with endogenized customer reactions to announcements, we analytically characterize performance measures for this model. The analysis allows us to explore the role announcing different percentiles of the waiting time distribution, i.e., announcement coverage, plays on subsequent performance in terms of balking and reneging. Through a numerical study, we explore when informing customers about delays is beneficial and what the optimal coverage should be in these announcements. We show how managers of a call center with delay announcements can control the trade-off between balking and reneging through their choice of announcements to be made.

ABSTRACT: In the human diet, coffee is the major source of caffeoyl‐quinic acids known as powerful antioxidants. The aim of this study was to assess the effect of usual coffee consumption, such as the addition of milk, and of processing conditions, such as spray‐drying, on beverage antioxidant power and potential polyphenol bioavailability impairments. When 25% milk was added to coffee, up to 40% of coffee chlorogenic acid were found to be bound to dairy proteins, using an ultrafiltration technique. However, neither milk addition nor spray‐drying had a significant effect on beverage antioxidant power, evaluated using 2,2‐diphenyl‐1‐pycrylhydrazyl (DPPH), 2‐2′‐azobis (2‐amidinopropane) dihydrochloride (AAPH), and total antioxidant capacity (TAC) tests. Moreover, these interactions tended to decrease during in vitro gastric and intestinal digestion, thus suggesting that interactions between chlorogenic acid and milk proteins in coffee and milk beverage may not have any significant effect on coffee antioxidant power before and after consumption.

Abstract Increasingly, humanitarian organizations have opened regional warehouses and pre‐positioned resources locally. Choosing appropriate locations is not easy and frequently based on opportunities rather than rational decisions. Dedicated decision‐support systems could help humanitarian practitioners design their supply networks. Academic literature suggests the use of commercial sector models but rarely considers the constraints and specific context of humanitarian operations, such as obtaining accurate data, high uncertainties, limited budgets and increasing pressure on cost efficiency. We propose a tooled methodology to properly support humanitarian decision makers in the design of their supply chains. Our contribution is based on the definition of aggregate scenarios to reliably forecast demand using past disaster data and future trends. Demand for relief items based on these scenarios is then fed to a mixed‐integer linear programming model in order to improve current supply networks. The specifications of this model have been defined in close collaboration with humanitarian workers. The model allows analysis of the impact of alternative sourcing strategies and service level requirements on operational efficiency. It provides clear and actionable recommendations for a given context, bridging the gap between academics and humanitarian logisticians. The methodology was developed to be useful to a broad range of humanitarian organizations, and a specific application to the supply chain design of the International Federation of Red Cross and Red Crescent Societies is discussed in detail.