Evolving localizations in reaction-diffusion cellular automata

We consider hexagonal cellular automata with immediate cell neighbourhood and three cell-states. Every cell calculates its next state depending on the integral representation of states in its neighbourhood, i.e. how many neighbours are in each one state. We employ evolutionary algorithms to breed local transition functions that support mobile localizations (gliders), and characterize sets of the functions selected in terms of quasi-chemical systems. Analysis of the set of functions evolved allows to speculate that mobile localizations are likely to emerge in the quasi-chemical systems with limited diffusion of one reagent, a small number of molecules is required for amplification of travelling localizations, and reactions leading to stationary localizations involve relatively equal amount of quasi-chemical species. Techniques developed can be applied in cascading signals in nature-inspired spatially extended computing devices, and phenomenological studies and classification of non-linear discrete systems.Comment: Accepted for publication in Int. J. Modern Physics

Data-driven approaches for techno-economic assessment of waste heat recovery and utilisation in the industrial sector

The industrial sector is a critical element in the sustainability transition as it is currently the largest consumer of fossil fuels, and the consumption is forecasted to continue to increase. Approximately one-fifth of the total industrial primary energy consumption is wasted due to the lack of proven attractive schemes for effective recovery. When addressing the opportunities of industrial waste heat recovery (WHR), it is found that the feasibility depends on multiple factors, including the forms and capacities of the heat sources, the potential heat sinks, and the effectiveness, technological maturity, and economic impact of available technologies. Developing systematic approaches to identify optimal WHR options for different applications is key to effectively reduce plant-scale energy consumption. In particular, power consumption accounts for more than half of the industrial energy use, and its share is expected to grow with the expansion of electrification aspirations. In this paper, industrial WHR technologies are investigated, and tools are developed to understand the sustainability and techno-economic impact of integrating these technologies within industrial processes. We specifically propose a data-driven technology-agnostic approach to evaluate the use of heat engines, which can in practice be organic Rankine cycle (ORC) systems, and of thermally- driven (i.e., absorption) heat pumps in the context of industrial WHR for plant-scale power demand reduction. The scope of this work explores three pathways to achieving efficiency improvements in bulk chemicals plants, represented by olefins production facilities, which are: (i) direct onsite power generation; (ii) enhancement of existing power generation processes; and (iii) reduction in power consumption by compressor efficiency improvements through waste-heat-driven cooling. The techno-economic performance of these technologies is assessed, with particular attention to industrial facilities that reside in hot climates, using fine-tuned technology-agnostic thermodynamic and market-based costing models. Finally, decision-aiding performance maps are derived by varying the quantity and the quality of waste-heat sources and heat sinks, offering application- specific guidelines for selecting appropriate waste-heat recovery schemes. These findings reveal valuable factors for selecting such integration schemes for various industries and scenarios

A modular software package for the analysis of power networks and electrical drives

This paper deals with a software package for the numerical analysis in transient and steady-state modes of power electrical networks or variable speed drives with arbitrary topologies. The package is composed of a series of units, each representing a specific cell in the network : voltage supply, electrical machine, mechanical system, transmission line, circuit-breaker, phase shifting transformer, static converter with control and command organ, regulator, etc. SIMSEN is highly flexible and efficient. It is implanted on microcomputer or on workstation. The network or the variable speed drive to be simulated is assembled using a graphic input interface by adequatly choosing and linking the building units, so as to fulfill a desired topology. An existing system may be easily extended or modified. A simple procedure can be used in order to define a new unit or to modify an existing one. The initial conditions of operation can be partly or entirely specified by the user. A transient mode of operation may include several successive perturbations. The simulation results are displayed through an efficient graphic interface. An original feature of SIMSEN is its ability to analyse electrical networks involving semi-conductors (diodes rectifiers, thyristor or GTO current converters, voltage inverters, etc.). Thus, systems having a complex structure can be simulated. Practical examples of applications to such systems constitute the main part of this paper : constant or variable speed groups involving induction and synchronous machines, HVDC networks, reactive power static converter SVC. These examples show how SIMSEN can be used for an optimized design of complex networks

FACTS, which advantages for the modern electrical networks?

The energy market liberalization requires using the actual transportation network in a more flexible and more efficient way. What is needed are strategies and facilities that will improve the energy flux sharing, as well as the maintaining of the node voltages. These goals can only be partially reached in the conventional networks. However, the FACTS are offering a very promising solution. The UPFL (Unified Power Flow Controller) will be briefly presented as an example of FACTS, and its behaviour will be illustrated with simulations

Once-Weekly Exenatide Versus Once- or Twice-Daily Insulin Detemir: Randomized, open-label, clinical trial of efficacy and safety in patients with type 2 diabetes treated with metformin alone or in combination with sulfonylureas

OBJECTIVEdThis multicenter, open-label, parallel-arm study compared the efficacy and safety of exenatide once weekly (EQW) with titrated insulin detemir in patients with type 2 diabetes inadequately controlled with metformin (with or without sulfonylureas). RESEARCH DESIGN AND METHODSdPatients were randomized to EQW (2 mg) or detemir (once or twice daily, titrated to achieve fasting plasma glucose #5.5 mmol/L) for 26 weeks. The primary outcome was proportion of patients achieving A1C #7.0% and weight loss $1.0 kg at end point, analyzed by means of logistic regression. Secondary outcomes included measures of glycemic control, cardiovascular risk factors, and safety and tolerability. RESULTSdOf 216 patients (intent-to-treat population), 111 received EQW and 105 received detemir. Overall, 44.1% (95% CI, 34.7–53.9) of EQW-treated patients compared with 11.4% (6.0–19.1) of detemir-treated patients achieved the primary outcome (P , 0.0001). Treatment with EQW resulted in significantly greater reductions than detemir in A1C (least-square mean 6 SE, 21.30 6 0.08% vs. 20.88 6 0.08%; P , 0.0001) and weight (22.7 6 0.3 kg vs. +0.8 6 0.4 kg; P , 0.0001). Gastrointestinal-related and injection site–related adverse events occurred more frequently with EQW than with detemir. There was no major hypoglycemia in either group. Five (6%) patients in the EQW group and six (7%) patients in the detemir group experienced minor hypoglycemia; only one event occurred without concomitant sulfonylureas (detemir group). CONCLUSIONSdTreatment with EQW resulted in a significantly greater proportion of patients achieving target A1C and weight loss than treatment with detemir, with a low risk of hypoglycemia. These results suggest that EQW is a viable alternative to insulin detemir treatment in patients with type 2 diabetes with inadequate glycemic control using oral antidiabetes drugs

Expected benefits of adjustable speed pumped storage in the European network.

In the context of a sustainable development the optimal use of the electrical energy will require advanced networks allowing interconnections on very long distances and addressing the storage challenge. These requirements are essentially due to the following reasons: - Electrical energy, contrary to most other kind of energies, must be simultaneously produced and consumed, because it is not possible to store directly large amounts of it. - Electrical energy is generated to a large extent by thermal power plants or by run-of-river stations operating as base load units at nearby constant power

Investigation of the 3-Level Unified Power Flow Controller (UPFC)

Flexible AC Transmission Systems (FACTS) are systems based on power electronics using GTO or IGCT semiconductors [1] that allow a better use of the transfer capacities of the transmission lines and permit to satisfy the requirements due to the liberalization of the electrical energy market. The Unified Power Flow Controller (UPFC) is one of the most versatile topologies of the FACTS family. The UPFC can be decomposed in two different power circuits: the parallel one maintaining the network bus voltage by consuming or producing reactive power, and the series one controlling the active and reactive power flow with the insertion of a series voltage in the transmission line. The aim of the present paper is to investigate in details the power quality and the dynamic performance of the 3-level UPFC

Modeling of Multi-winding Phase Shifting Transformers : Application to DC and Multi-level VSI Supplies.

This paper deals with the modeling of multi-winding transformers. Based on the real example of a railway DC - supply, a modeling methodology is presented as the original part of the paper. Afterwards two application examples of multi-winding phase shifting transformers (18 and 24 pulse) are described, these applications have been simulated using the SIMSEN simulation software package [1,2]. Harmonics analysis of simulation results (elimination of low order harmonics 5, 7, 11, 13) has validated the proposed methodology