A multiscale material model for metallic powder compaction during hot isostatic pressing

The prediction of the distortions during Near-Net-Shape Hot Isostatic Pressing (NNS-HIP) is an intrinsic multiscale problem where the local interactions among particles determine the macroscopic distortions taking place during the sintering and densification of a component. In this work, a multiscale approach is proposed to solve this problem. In particular, a viscoplastic constitutive model capable of predicting macroscopic contractions during a HIP process with high accuracy has been developed, implemented and validated. The macroscopic model incorporates the mechanical behaviour predicted at the meso-scale by means of multiple-particle finite element models (MP-FEM) of an agglomerate of powder particles. The model is validated through the prediction of distortions during HIP of a full scale industrial case. It is concluded that adding the microscopic information of the HIP process to simulate the contractions at the macroscopic level results in a considerable improvement of the accuracy of the predictions

Quantitative assessment of energy and resource recovery in wastewater treatment plants based on plant-wide simulations.

The growing development of technologies and processes for resource treatment and recovery is offering endless possibilities for creating new plant-wide configurations or modifying existing ones. However, the configurations’ complexity, the interrelation between technologies and the influent characteristics turn decision-making into a complex or unobvious process. In this frame, the Plant-Wide Modelling (PWM) library presented in this paper allows a thorough, comprehensive and refined analysis of different plant configurations that are basic aspects in decision-making from an energy and resource recovery perspective. In order to demonstrate the potential of the library and the need to run simulation analyses, this paper carries out a comparative analysis of WWTPs, from a techno-economic point of view. The selected layouts were (1) a conventional WWTP based on a modified version of the Benchmark Simulation Model No. 2, (2) an upgraded or retrofitted WWTP, and (3) a new Wastewater Resource Recovery Facilities (WRRF) concept denominated as C/N/P decoupling WWTP. The study was based on a preliminary analysis of the organic matter and nutrient energy use and recovery options, a comprehensive mass and energy flux distribution analysis in each configuration in order to compare and identify areas for improvement, and a cost analysis of each plant for different influent COD/TN/TP ratios. Analysing the plants from a standpoint of resources and energy utilization, a low utilization of the energy content of the components could be observed in all configurations. In the conventional plant, the COD used to produce biogas was around 29%, the upgraded plant was around 36%, and 34% in the C/N/P decoupling WWTP. With regard to the self-sufficiency of plants, achieving self-sufficiency was not possible in the conventional plant, in the upgraded plant it depended on the influent C/N ratio, and in the C/N/P decoupling WWTP layout self-sufficiency was feasible for almost all influents, especially at high COD concentrations. The plant layouts proposed in this paper are just a sample of the possibilities offered by current technologies. Even so, the library presented here is generic and can be used to construct any other plant layout, provided that a model is available

Optimal predictive control of water transport systems: Arrêt-Darré/Arros case study

This paper proposes the use of predictive optimal control as a suitable methodology to manage efficiently transport water networks. The predictive optimal controller is implemented using MPC control techniques. The Arrêt-Darré/Arros dam-river system located in the Southwest region of France is proposed as case study. A high-fidelity dynamic simulator based on the full Saint-Venant equations and able to reproduce this system is developed in MATLAB/SIMULINK to validate the performance of the developed predictive optimal control system. The control objective in the Arrêt-Darré/Arros dam-river system is to guarantee an ecological flow rate at a control point downstream of the Arrêt-Darré dam by controlling the outflow of this dam in spite of the unmeasured disturbances introduced by rainfalls incomings and farmer withdrawals

Application of Neural-Like P Systems With State Values for Power Coordination of Photovoltaic/Battery Microgrids

The power coordination control of a photovoltaic/battery microgrid is performed with a novel bio-computing model within the framework of membrane computing. First, a neural-like P system with state values (SVNPS) is proposed for describing complex logical relationships between different modes of Photovoltaic (PV) units and energy storage units. After comparing the objects in the neurons with the thresholds, state values will be obtained to determine the con guration of the SVNPS. Considering the characteristics of PV/battery microgrids, an operation control strategy based on bus voltages of the point of common coupling and charging/discharging statuses of batteries is proposed. At rst, the SVNPS is used to construct the complicated unit working modes; each unit of the microgrid can adjust the operation modes automatically. After that, the output power of each unit is reasonably coordinated to ensure the operation stability of the microgrid. Finally, a PV/battery microgrid, including two PV units, one storage unit, and some loads are taken into consideration, and experimental results show the feasibility and effectiveness of the proposed control strategy and the SVNPS-based power coordination control models

System to control indoor air quality in energy efficient buildings

This work looks at monitoring air quality in indoor environments through the integration of several sensing technologies into a single robust, reliable and cheap detection platform, which shares air pre-conditioning and electronics. Target gases and detection limits have been set according to recommendations of different agencies in Europe and the US. The system has reached detection limits stated by the OSHA (Occupational Safety and Health Administration) for benzene. The pre-conditioning fluidic platform has also been designed, simulated, fabricated and tested with sensors so the gas flow has been optimized. Field tests in real buildings are being carried out to contrast current measurement procedures and results with the obtained using the device under development. The main aim of the system is to control HVAC (Heat Ventilation and Air Conditioning) in energy-efficient way while keeping a high air quality standard inside the building

Green value stream mapping approach to improving productivity and environmental performance

[EN] Purpose The purpose of this paper is to introduce a new methodology called overall greenness performance for value stream mapping (OGP-VSM). Using value-added concepts, this approach has the potential to integrate, measure, control and improve productive and environmental performance in accordance with a company¿s context. Design/methodology/approach The OGP-VSM approach was developed by reviewing and integrating the environmental aspects of existing lean thinking tools and approaches. Findings This research revealed the lack of practical integration between productive and environmental performance. Using OGP-VSM, managers can see that environmental practices have a direct impact on productivity. OGP-VSM allows a balance to be found between lean and green practices in order to achieve the simultaneous improvement of productivity and environmental performance. Practical implications The proposed approach is applied to a case study in an automotive company in Spain and lays the groundwork for moving toward functional environmental sustainability in manufacturers. Originality/value Companies are increasingly implementing environmentally focused practices. Pursuing environmentally friendly (green) performance poses several challenges, but it also affords opportunities to create new methodologies for generating a competitive advantage for manufacturing companies. There are a limited number of approaches to drawing together the elements and attributes that are essential for a holistic, practical and long-lasting improvement of environmental performance in the manufacturing sectorThe work presented in this paper was carried out within the framework of the LIFE MCUBO research project funded by the European Union (LIFE15 ENV/ES/000379), through the LIFE programme. In addition, the authors would like to acknowledge the support received from AdP, the Special Patrimonial Fund at Universidad de La Sabana and the doctoral grant from TECNUN Escuela de Ingenieros, Universidad de Navarra.Muñoz-Villamizar, A.; Santos, J.; García Sabater, JJ.; Lleo, A.; Grau, P. (2019). Green value stream mapping approach to improving productivity and environmental performance. International Journal of Productivity and Performance Management. 68(3):608-625. https://doi.org/10.1108/IJPPM-06-2018-0216S608625683Diaz-Elsayed, N., Jondral, A., Greinacher, S., Dornfeld, D., & Lanza, G. (2013). Assessment of lean and green strategies by simulation of manufacturing systems in discrete production environments. CIRP Annals, 62(1), 475-478. doi:10.1016/j.cirp.2013.03.066Maroto-Sánchez, A. (2012). Productivity in the services sector: conventional and current explanations. The Service Industries Journal, 32(5), 719-746. doi:10.1080/02642069.2010.531266Mason, R., Nieuwenhuis, P., & Simons, D. (2008). Lean and green supply chain mapping: adapting a lean management tool to the needs of industrial ecology. Progress in Industrial Ecology, An International Journal, 5(4), 302. doi:10.1504/pie.2008.021921Molina-Azorín, J. F., Tarí, J. J., Claver-Cortés, E., & López-Gamero, M. D. (2009). Quality management, environmental management and firm performance: A review of empirical studies and issues of integration. International Journal of Management Reviews, 11(2), 197-222. doi:10.1111/j.1468-2370.2008.00238.xMolina‐Azorín, J. F., Claver‐Cortés, E., López‐Gamero, M. D., & Tarí, J. J. (2009). Green management and financial performance: a literature review. Management Decision, 47(7), 1080-1100. doi:10.1108/00251740910978313Montabon, F., Sroufe, R., & Narasimhan, R. (2006). An examination of corporate reporting, environmental management practices and firm performance. Journal of Operations Management, 25(5), 998-1014. doi:10.1016/j.jom.2006.10.003Morioka, S. N., & de Carvalho, M. M. (2016). A systematic literature review towards a conceptual framework for integrating sustainability performance into business. Journal of Cleaner Production, 136, 134-146. doi:10.1016/j.jclepro.2016.01.104Muñoz-Villamizar, A., Santos, J., Viles, E., & Ormazábal, M. (2018). Manufacturing and environmental practices in the Spanish context. Journal of Cleaner Production, 178, 268-275. doi:10.1016/j.jclepro.2018.01.026Netland, T. H., Schloetzer, J. D., & Ferdows, K. (2015). Implementing corporate lean programs: The effect of management control practices. Journal of Operations Management, 36(1), 90-102. doi:10.1016/j.jom.2015.03.005Ng, R., Low, J. S. C., & Song, B. (2015). Integrating and implementing Lean and Green practices based on proposition of Carbon-Value Efficiency metric. Journal of Cleaner Production, 95, 242-255. doi:10.1016/j.jclepro.2015.02.043(2001). Measuring Productivity - OECD Manual. doi:10.1787/9789264194519-enOrmazabal, M., Viles, E., Santos, J., & Jaca, C. (2018). An overview of environmental management in the Spanish food sector: a survey study. Management of Environmental Quality: An International Journal, 29(1), 49-62. doi:10.1108/meq-10-2016-0072Sunder M., V., Ganesh, L. S., & Marathe, R. R. (2018). A morphological analysis of research literature on Lean Six Sigma for services. International Journal of Operations & Production Management, 38(1), 149-182. doi:10.1108/ijopm-05-2016-0273Thanki, S. J., & Thakkar, J. J. (2016). Value–value load diagram: a graphical tool for lean–green performance assessment. Production Planning & Control, 27(15), 1280-1297. doi:10.1080/09537287.2016.1220647Tilina, D. I., Zapciu, M., & Bendic, V. (2014). The Link between Lean and Green Manufacturing - A Way to Reach Sustainable Development. Applied Mechanics and Materials, 656, 534-541. doi:10.4028/www.scientific.net/amm.656.534US EPA (2007), “The lean and environment toolkit”, available at: www.epa.gov/lean/lean-environment-toolkit (accessed January 24, 2018).US EPA (2011), “The lean and water toolkit”, available at: www.epa.gov/lean/lean-water-toolkit (accessed January 24, 2018)

Reliable and High QoS Wireless Communications over Harsh Environments, Journal of Telecommunications and Information Technology, 2013, nr 1

One of the most challenging research fields in which research community has taken a very active role is focused on trying to bring the features of wireless networks into line with the traditional wired solutions. Given the noisy and lossy nature of the wireless medium, it is more difficult to provide a comparable Quality of Service (QoS) and Reliability over wireless networks. This lack of reliability avoids the use of wireless solution in scenarios under harsh environment and mission-critical applications. In this paper we propose an inter-node collaborative schema with the aim of improving the achievable QoS level for multicast streaming, through the use of Network Coding and the algebra it is based on. We also present an implementation of the described algorithm on the OPNET discrete event simulation tool. Experimental results highlighting the performance achieved by the proposed algorithm and its improved efficiency as compared to other solutions are described

ETCS On-board Unit Safety Testing: Saboteurs, Testing Strategy and Results

It is necessary to verify the faults tolerance of the European Train Control System (ETCS) on-board unit even if these faults are uncommon. Traditional test methods defined and used in ETCS do not allow to check this, so it is necessary to develop a new mechanism of tests. This paper presents the design and implementation of a saboteur applied to the railway sector. The main purpose of the saboteur is the fault injection in the communication interfaces. By means of a virtual laboratory it is possible to simulate actual train journeys to test the ETCS on-board unit. Making use of the saboteurs and the virtual laboratory it is possible to analyse the behaviour of the train in the presence of unexpected faults, and to verify that the decisions taken are correct to ensure the required safety level. Therefore, this work shows a testing strategy based on different kinds of train journeys when faults are injected, and the analysis of the results.</p

Simulation and validation of the gas flow in close-coupled gas atomisation process: Influence of the inlet gas pressure and the throat width of the supersonic gas nozzle.

The effectiveness of a close-coupled gas atomisation process largely depends on the operational and the geometric variables. In this study, Computational Fluid Dynamics (CFD) techniques are used to model and simulate the gas flow in the melt nozzle area for a convergent-divergent, close-coupled gas atomiser in the absence of the melt stream. Firstly, a reference case, in which the atomisation gas is nitrogen at 50 bar and a supersonic gas nozzle with a throat width of L0 has been modelled, is presented. Then, the influence of both the inlet gas pressure and this design parameter are investigated, comparing the numerical results provided by simulations varying the inlet pressure from 5 to 80 bar and modelling different convergent-divergent gas nozzles with throat widths of 0.29 center dot Lo, 0.5 center dot Lo, 0.77 center dot Lo and 2 center dot Lo respectively. The simulation results show how similarly these two parameters modify gas mass flow rates, gas velocity fields, aspiration pressures in the melt delivery tube or the size of the recirculation zones below the melt nozzle. Therefore, it can be stated that this geometric variable of the gas nozzle may be as relevant as the inlet pressure in the atomisation process. The most important novelty of this study is related to experimental validation of the numerical results using the Particle Image Velocimetry (PIV) technique and through direct measurements of gas mass flow rates, with a clear correlation between simulated and measured data. Moreover, some results obtained with experimental atomisations using copper and nitrogen are also presented. The experimental results show that finer powders are produced by increasing th