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Solid-state synthesis and phase transitions of RE2(MoO4)3(RE ≡ Nd, Sm, Eu, and Gd) samples have been monitored by X-ray thermodiffraction with synchrotron radiation. The experiment was divided in two stages. In the first heating, different non-stoichiometric molybdates (Eu4Mo7O27, Eu2Mo4O15, and Pr2Mo4O15structure types) emerged from the RE2O3and MoO3oxides before the expected phases (with α-Eu2(WO4)3and La2(MoO4)3structure types and the β-Gd2(MoO4)3phase). The formation and coexistence of intermediate phases have been explained by common structural motifs with unit cell volumes per atom among those with the formula RE2(MoO4)3. Subsequent heating–cooling cycles showed the occurrence of the reversible and reconstructive α [La2(MoO4)3] ↔ β phase transition, including the less common transition β → α [La2(MoO4)3] obtained by heating the β′-Gd2(MoO4)3phase from room temperature and clarifying much of the controversy in the literature. The transition mechanisms were studied by proposing a common supercell and comparing the RE and vacancy ordering within similar layers of MoO42–tetrahedra. The possible formation of stacking faults in Nd2(MoO4)3was explained as a mixture of modulated scheelite phases. This research supports the importance of a directed and rational synthesis analyzing the intermediate products and their phase transitions for the enrichment of materials with new or improved properties.

Hydrogen is a bright energy vector that could be crucial to decarbonise and combat climate change. This energy evolution involves several sectors, including power backup systems, to supply priority facility loads during power outages. As buildings now integrate complex automation, domotics, and security systems, energy backup systems cause interest. A hydrogen-based backup system could supply loads in a multi-day blackout; however, the backup system should be sized appropriately to ensure the survival of essential loads and low cost. In this sense, this work proposes a sizing of fuel cell (FC) backup systems for low voltage (LV) buildings using the history of power outages. Historical data allows fitting a probability function to determine the appropriate survival of loads. The proposed sizing is applied to a university building with a photovoltaic generation system as a case study. Results show that the sizing of an FC–battery backup system for the installation is 7.6% cheaper than a battery-only system under a usual 330-minutes outage scenario. And 59.3% cheaper in the case of an unusual 48-hours outage scenario. It ensures a 99% probability of supplying essential load during power outages. It evidences the pertinence of an FC backup system to attend to outages of long-duration and the integration of batteries to support the abrupt load variations. This research is highlighted by using historical data from actual outages to define the survival of essential loads with total service probability. It also makes it possible to determine adequate survival for non-priority loads. The proposed sizing is generalisable and scalable for other buildings and allows quantifying the reliability of the backup system tending to the resilience of electrical systems.

Purpose: Banks are institutions that inject money in the economy and help to boost it when there are problems in some markets, especially in productive sectors. In this way, analysing the competition in this sector is an important tool for policymakers as non-competitive behaviour could affect the financial system and economy. The purpose of this paper is to measure the degree of competition in the Ecuadorian private banking sector divided by size, from 2000 to 2015, using panel data collected by the official regulator institution. Design/methodology/approach: The authors applied the model proposed by Panzar and Rosse (1987) and its H-statistic using a reduced price and revenue equation estimated by pooled ordinary least squares, fixed effects, random effects, feasible generalised fixed effects and panel correction standard errors (PCSE). Findings: The authors show that given the presence of some problems in data such as heteroskedasticity and autocorrelation, the most appropriate technique is PCSE. The authors also found robust evidence supporting that large banks compete in a monopolistic market, small and medium-sized banks operate in monopolistic competition, and Ecuadorian small, medium-sized and large banks stay in long-run equilibrium. Originality/value: This paper contributes to the actual literature of competition degree in two ways. First, different from traditional papers, we do not control by size; so, we divided the analysis by size, because in Ecuador and also in many developing countries, bank’s competition is different for each group of size because the levels of liquidity, risk and other indicators are different from one group to another. Second, we show the robustness of the results using a scaled and unscaled equation, using many controls and using five methods to contrast the competition degree.

This paper addresses the Energetic Macroscopic Representation EMR, the modelling and the control of photovoltaic panel PVP generation systems for simulation purposes. The model of the PVP considers the variations on irradiance and temperature. A maximum power point tracking MPPT algorithm is considered to control the power converter. A novel EMR is proposed to consider the dynamic model of the PVP with variations in the irradiance and the temperature. The EMR is evaluated through simulations of a PVP generation system.

A benchmark of different starting modes of a passive Fuel Cell (FC)/Ultracapacitors (UCs) hybrid source is presented. Passive hybridization consist to directly connect the FC and the UC without power electronics. Compared with active sources, passive hybridization presents some advantages: lower volume and weight, ease of implementation, and lower cost. However, the power distribution among the sources is no longer controllable. Additionally, the FC–UC passive hybrid source’s start-up could lead to high inrush currents and faster FC degradation. A FC–UC passive hybrid source start-up is evaluated by simulations and experimentally. Three starting modes for an automobile application are considered: progressive starting, short circuit, and using a resistive pre-charge device.