An agent-based genetic algorithm for hybrid flowshops with sequence dependent setup times to minimise makespan

This paper deals with a variant of flowshop scheduling, namely, the hybrid or flexible flowshop with sequence dependent setup times. This type of flowshop is frequently used in the batch production industry and helps reduce the gap between research and operational use. This scheduling problem is NP-hard and solutions for large problems are based on non-exact methods. An improved genetic algorithm (GA) based on software agent design to minimise the makespan is presented. The paper proposes using an inherent characteristic of software agents to create a new perspective in GA design. To verify the developed metaheuristic, computational experiments are conducted on a well-known benchmark problem dataset. The experimental results show that the proposed metaheuristic outperforms some of the well-known methods and the state-of-art algorithms on the same benchmark problem dataset.     

Liquid-liquid extraction of protease from cold-adapted yeast Rhodotorula mucilaginosa L7 using biocompatible and biodegradable aqueous two-phase systems

This work aimed to optimize the extraction of an extracellular protease produced by the cold-adapted yeast Rhodotorula mucilaginosa L7 using aqueous two-phase systems (ATPS) comprising polyethylene glycol (PEG) and sodium citrate or sodium tartrate. First, the biocompatibility of the phase forming agents was assessed. The results obtained with PEG-2000, PEG-4000, and PEG-6000 demonstrated that even at large PEG concentrations (32 wt%) the protease maintains its activity after 3 h of reaction, whereas an increase in salt concentration provokes a gradual decrease in protease stability. Subsequently, the partitioning of the protease in both types of ATPS was assessed, evaluating the effect of temperature, molecular weight, and concentration of PEG on protease purification, using two 2³-full factorial designs. The best partitioning conditions were obtained in PEG-6000/sodium tartrate-based ATPS, at 30ºC (with a yield of 81.09 ± 0.66% and a purification factor of 2.51 ± 0.03). Thus, considering the biodegradable characteristics of the system, the PEG/sodium tartrate ATPS is a viable and economic low-resolution step in protease purification, with a strong potential for future industrial application.     

Incorporation of citrus fibers in fermented milk containing probiotic bacteria

The incorporation of Lactobacillus acidophilus CECT 903, Lactobacillus casei CECT 475 and Bifidobacterium bifidum CECT 870 together with lemon (LF) and orange (OF) fibers obtained from juice by-products were tested in (i) a model system: fiber enriched with de Man Rogosa Sharp (MRS) broth cultured with each probiotic bacteria and (ii) evaluation of populations of probiotic bacteria in fermented milks formulated with citrus fibers. Citrus fibers enhanced L. acidophilus CECT 903, and L. casei CECT 475 survival in MRS during refrigerated storage, whereas erratic results were obtained for B. bifidum CECT 870, OF enhanced its growth and LF had inhibitory effect. Populations of probiotic bacteria decreased with storage time in MRS broth. The presence of yogurt starter bacteria in probiotic fermented milks favored the growth and survival of L. acidophilus and B. bifidum. Citrus fiber presence in fermented milks also enhanced bacterial growth and survival of the tested probiotic bacteria. This study indicates that citrus fiber enriched fermented milk have good acceptability and are good vehicles for a variety of commercial probiotics but survival of B. bifidum will need to be improved.     

Effect of orange fiber addition on yogurt color during fermentation and cold storage

Orange fiber obtained from orange juice by‐products was added to yogurt. Fiber (0%, 0.6%, 0.8%, and 1% doses and different fiber size: 0.417–0.701 and 0.701–0.991 mm) effects on color during yogurt fermentation and cold storage were studied. Overall composition, pH, acidity, syneresis, L*, a*, and b* values were determined. Sensory evaluation of yogurts was carried out. Fiber addition did not cause changes in yogurt acidification and color during fermentation process, though decreased L* value and increased b* value of the milk. Color evaluation along fermentation is pH dependent (R > 0.870). pH decreased and syneresis increased along cold storage. Because of the acidification process, L* value decreased and a* and b* values increased in all yogurts. Yogurts with 1% fiber were significantly different from the others along cold storage, presenting lower L*, higher a* and b* values, and lower syneresis. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 457–463, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20158     

Methylarsonic and dimethylarsinic acids toxicity and total arsenic accumulation in edible bush beans, Phaseolus vulgaris

The main objective was to evaluate whether arsenic accumulated in the edible pods and seeds of Phaseolus vulgaris, cv. F15 above the Spanish maximum recommended concentration for food crops, 1 mg kg^-1 on a fresh weight basis. Only organic arsenicals, methylarsonic and dimethylarsinic acids were used because they were: (1) the only arsenic species allowed for agricultural applications and (2) more mobile than inorganic species. Selection of French beans, a sensitive plant to arsenic, was based on the fact that arsenic-upward translocation is higher in sensitive than in tolerant plants. A 2 ×3 factorial experiment was conducted with two organic arsenic species (methylarsonic acid, dimethylarsinic acid) and three arsenic concentrations (0.2, 0.5, 1.0 mg l^-1). Experimental results showed that the low bean plant tolerance to arsenic was possibly due to the high arsenic-upward transport to shoots, which could result in profound negative metabolic consequences. Even under extreme adverse conditions, arsenic residues in edible beans were below the maximum statutory limit set by the Spanish legislation. It is concluded that the major drawback of organic arsenical herbicides is that of decreased productivity rather than high arsenic intake by consumers of edible products from sensitive plant species.     

Mathematical programming model for centralised master planning in ceramic tile supply chains

The object of this article is to develop a centralised replenishment, production, and distribution model for ceramic tile supply chains. These supply chains are assumed to be multi-item, multi-supplier, multi-facility, multi-type and multi-level distribution centres. The model deals with multi-period master planning where sourcing considerations for replenishments, production facilities, and distribution centres are important to maximise an objective function involving the total net profit. This model is deterministic and has been formulated as a mixed-integer linear programming (MILP) model. An example based on modifications of real-world industrial problems is presented.     

Development of a High Sensory Quality Garlic Paste

ABSTRACT: Different processes of preparing garlic paste were studied. All methods involved the addition of antioxidant agents (AA): sodium bisulfite and citric acid; a sanitation step (SS) was optional. Sodium hypochlorite and citric acid and 3 pH values (3.0, 3.5, or 4.0) were evaluated. The paste had a shelf life of approximately 60 d and high sensory quality. The combination of the 2 unit operational procedures, SS and AA, and a pH of 4.0 provided the paste with the best chemical and sensory properties during storage at room temperature (20 ± 2 °C): intense pungent character, intense garlic odor and flavor, and white-yellowish color.     

Quantitative models for supply chain planning under uncertainty: a review

Managing uncertainty is a main challenge within supply chain management. Therefore, it is expected that those supply chain planning methods which do not include uncertainty obtain inferior results if compared with models that formalise it implicitly. This article presents a review of the literature related to supply chain planning methods under uncertainty. The main objective is to provide the reader with a starting point for modelling supply chain under uncertainty applying quantitative approaches. We have defined a taxonomy to classify models from 103 bibliographic references dated 1988–2007. Finally, some conclusions about the works analysed have been drawn and future lines of research have been identified.     

Enterprise Integration—Business Processes Integrated Management: a proposal for a methodology to develop Enterprise Integration Programs

An approach to develop Enterprise Integration Programs to assist enterprises in their migration path towards integration is proposed. It is called IE—GIP (Enterprise Integration—Business Processes Integrated Management, acronyms in Spanish). The topic is very important in industrial engineering nowadays because of the growing need to improve existing industrial systems and to organise such complex systems faster, better, and in a more systematic way. The contribution to the field of Enterprise Integration is mostly a methodological one. More specifically, it is based on the integration of Purdue Enterprise Reference Architecture (PERA) and Open System Architecture for Computer Integrated Manufacturing (CIMOSA) principles to propose an integration approach for industrial enterprises. Starting from existing leading proposals (CIMOSA, PERA, GERAM), a methodology has been defined and some extension to an architecture and supporting computer tools are discussed. The proposal covers the life cycle of an Enterprise Integration Program in a top-down approach. The approach is centred on the business process concept, but is based on a vision/process/people/technology view of the enterprise. The methodology divides the work into two major phases before system construction: master planning and CIM programme development. The method adapts the system life cycle of PERA but uses, whenever possible, the CIMOSA architecture with its business process approach. New CIMOSA-like constructs are introduced to be used in activities along with the methodology when necessary. To support the modelling phases of the proposal and to provide guidance to users of the methodology, computer supported tools have been developed in the course of this work.