Proximity search heuristics for wind farm optimal layout

A heuristic framework for turbine layout optimization in a wind farm is proposed that combines ad-hoc heuristics and mixed-integer linear programming. In our framework, large-scale mixed-integer programming models are used to iteratively refine the current best solution according to the recently-proposed proximity search paradigm. Computational results on very large scale instances involving up to 20,000 potential turbine sites prove the practical viability of the overall approach

Lower bounds and heuristic algorithms for the ki-partitioning problem

We consider the problem of partitioning a set of positive integers values into a given number of subsets, each having an associated cardinality limit, so that the maximum sum of values in a subset is minimized, and the number of values in each subset does not exceed the corresponding limit. The problem is related to scheduling and bin packing problems. We give combinatorial lower bounds, reduction criteria, constructive heuristics, a scatter search approach, and a lower bound based on column generation. The outcome of extensive computational experiments is presente

Leaf trapping and retention of particles by holm oak and other common tree species in Mediterranean urban environments

Holm oak (Quercus ilex), a widespread urban street tree in the Mediterranean region, is widely used as biomonitor of persistent atmospheric pollutants, especially particulate-bound metals. By using lab- and field-based experimental approaches, we compared the leaf-level capacity for particles’ capture and retention between Q. ilex and other common Mediterranean urban trees: Quercus cerris, Platanus × hispanica, Tilia cordata and Olea europaea. All applied methods were effective in quantifying particulate capture and retention, although not univocal in ranking species performances. Distinctive morphological features of leaves led to differences in species’ ability to trap and retain particles of different size classes and to accumulate metals after exposure to traffic in an urban street. Overall, P. × hispanica and T. cordata showed the largest capture potential per unit leaf area for most model particles (Na+ and powder particles), and street-level Cu and Pb, while Q. ilex acted intermediately. After wash-off experiments, P. × hispanica leaves had the greatest retention capacity among the tested species and O. europaea the lowest. We concluded that the Platanus planting could be considered in Mediterranean urban environments due to its efficiency in accumulating and retaining airborne particulates; however, with atmospheric pollution being typically higher in winter, the evergreen Q. ilex represents a better year-round choice to mitigate the impact of airborne particulate pollutants

Peanut digestome: Identification of digestion resistant IgE binding peptides

Stability to proteolytic degradation in the digestive tract is considered a general feature shared by most food allergens. Current digestibility models exclusively utilize purified allergen proteins, neglecting the relevant effects of matrix that occur for foodstuff systems. In the present study, we investigated digestion stability of the major peanut allergens directly in the natural matrix using an in vitro static model that simulates the gastrointestinal digestion including the oral, gastric, duodenal and intestinal (brush border membrane enzymes) phases. Immunogenicity was evaluated by Western Blot using N=8 pooled sera of peanut allergic pediatric subjects. Immunoreactive, large-sized and fragments of Ara h 2, Ara h 6 and Ara h 3 survived hydrolysis as assessed by SDS-PAGE. Smaller resistant peptides mainly arising from Ara h 3 and also Ara h 1 were detected and further identified by LC-high resolution-MS/MS. RP-HPLC purification followed by dot-blot analysis and MS/MS-based identification demonstrated that stable IgE-binding peptides derived from Ara h 3. These results provide a more realistic picture of the potentially allergenic determinants of peanuts that survived the human digestion, taking into account the role of the food matrix, which may significantly affect gastrointestinal breakdown of peanut allergens

Influence of lipoproteins at dry-off on metabolism of dairy cows during transition period and on postpartum reproductive outcomes

High-yielding dairy cows are metabolically challenged during transition, when intense mobilization and hepatic oxidation of lipids is achieved, thus leading to fatty infiltration, ketosis and generalized inflammation. The condition is associated to periparturient diseases and poor fertility. The aim of this study was to assess whether serum lipoprotein concentrations in the dry period could influence the occurrence of postpartum diseases and reproductive performance in dairy cows. The study was carried out on 30 multiparous Holstein Friesian cows. Blood samples were collected at dry-off ( 1260 days), 30 days after dry-off and within 12 h after parturition for biochemical and serum lipoprotein assays. From 10 to 60 days after parturition milk was collected twice weekly after feeding, for milk whey progesterone assay. The Optimal Cutpoint package identified a threshold of 89% for serum High Density Lipoprotein (HDL) concentration at the beginning of the dry period with 95% of confidence interval. Cows with serum HDL greater than 89% (High group, n = 10) showed better reproductive performance when compared to those with low values (Low group, n = 18). The odds ratio for reproductive disorders in High group was 0.6875, however, differences were not significant probably due to both the reduced number of animals per group and overall low incidence of postpartum reproductive disease. First postpartum luteal activity occurred around day 23, while the second one between days 40 and 48. The average calving to first AI interval was 64.00 \ub1 3.95 days and 94.50 \ub1 12.32 days in High and Low group, respectively (P 89% at dry-off could be suggestive of improved liver adaptation to the transition, and probably of enhanced fertility in High group

Applicability of Strategic Engineering in Floating Production Storage Offloading (FPSO) Project Execution

Floating Production Storage and Offloading (FPSO) units are pivotal assets in offshore oil and gas production, yet the execution of FPSO projects is inherently fraught by significant risks due to their complexity, large scale, and the substantial financial investment due to their high capital cost. These projects typically demand billions of dollars in investment upfront, making any delays in the delivery timeline potentially catastrophic to the financial model, resulting in considerable losses. The conventional project management methodology for FPSOs follows the Engineering, Procurement, and Construction (EPC) approach: the phases are executed sequentially with minimal overlap. Although this method involves risk identification, monitoring, and mitigation, it is largely reactive, focusing on managing risks after they arise, rather than proactively eliminating them at the beginning. This thesis investigates the potential of applying “Strategic Engineering” principles to FPSO project execution to eliminate or mitigate these risks more effectively and identify new opportunities for enhancing project performance. By integrating advanced risk management frameworks with innovative engineering methodologies, this research proposes a shift from reactive to proactive risk management. Through the analysis of case studies and empirical data, the study identifies key risk factors such as cost overruns, schedule delays, and execution inefficiencies. It introduces an alternative strategic procurement and construction model, grounded in statistical analytics, which leverages historical project data to predict and mitigate risks before they manifest. A significant portion of the research is dedicated to the collection and analysis of historical data from FPSO projects. This data was used to evaluate critical project paths, identify recurring bottlenecks, and pinpoint risks that could potentially delay the delivery of FPSO units. Once these risks were identified, strategies for mitigating them were developed. The study also explored the best practices for collecting and analyzing historical data to yield meaningful insights for future projects. Central to the study is the introduction of the "Meccano" approach, which identifies the fundamental elements affecting the critical path of FPSO projects, categorizes and clusters them to facilitate more effective management. By focusing on these "basic elements" (in the early stages of the project), this approach allows for more efficient risk management, even before engineering completion. To further reduce project duration, the study also engaged with suppliers of critical items, such as piping, to assess how improvements in their delivery schedules could be achieved. The "Meccano" approach advocates for a departure from the traditional sequential execution of EPC projects. Instead, it promotes a model of PCE (Procurement, Construction and Engineering), where supply and fabrication of critical items are prioritized and launched at the beginning of the project, thus eliminating the need to wait for the completion of engineering phases. This approach results in more efficient and streamlined project execution, with the potential to significantly reduce the FPSO delivery timelines risks. The "Meccano" approach was applied in three key areas of FPSO project execution: 1. Local Content Optimization: The study demonstrates how fine-tuning the local content requirements could minimize the local content penalties (applied to Brazilian project). 2. Early Construction Activities: By initiating construction activities earlier in the project timeline, this approach mitigates delays that typically arise from waiting for engineering or procurement completion and allows a steadier workload for the construction yard. 3. Early Procurement Activities: The research emphasizes the importance of engaging suppliers early in the process to ensure the timely delivery of critical components, reducing the risk of procurement-related delays. The findings of this research suggest that “Strategic Engineering” not only mitigates risks in FPSO projects but also creates new opportunities for innovation and value creation. By focusing on early risk identification and adopting a proactive project execution strategy, this research contributes significantly to the field of FPSO project management. It provides practical tools and insights for project managers, enabling them to improve the reliability, efficiency, and overall execution of FPSO EPCI (Engineering, Procurement, Construction, and Installation) projects. In conclusion, this thesis offers a comprehensive framework for applying Strategic Engineering to FPSO projects, demonstrating that it is possible to both reduce risks and enhance project outcomes. The proposed model allows for greater flexibility and responsiveness in project execution, ultimately leading to more resilient project execution which protects the FPSO delivery. This approach represents a paradigm shift in FPSO project management, moving away from traditional, reactive methods (EPC) and towards a more dynamic, proactive strategy: PCE (Procurement, Construction, Engineering)