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We report on the magnetic properties of NdFeB powders produced by gas atomization, which is a powder manufacturing technology scarcely used in the past to produce such alloys. Using this technique, we have produced several ternary NdFeB alloys with Nd contents between 26.9 wt.% and 28.5 wt.%. The as-atomized powders were split into different size fractions by sieving. Subsequently, we measured the magnetic properties as a function of temperature, between 10 and 400 K, and particle size. The magnetic behavior depends strongly on the microstructure of the material, which in turn is determined by the particle size. It is reported a slope anomaly in the curve of magnetization as a function of temperature at around 150 K due to a spin-reorientation transition. Since gas-atomized powders are isotropic, this magnetic transition produces an increment of the magnetization below this temperature.

Abstract In Italy, more than 1150 agricultural anaerobic digestion (AD) plants are currently running. Their concentration in specific areas resulted in an increase in the biomass price and transport distances. For the AD plants located on farms with small area, often the feedstock are purchased on the market. However, when transport distances increase, it can be less expensive to buy biomasses with high energy density. With this regard, maize experimental tests were carried out to evaluate the methane production by harvesting the whole plant, the plant cut at 0.75 m and only the ear. The aim of this paper is to evaluate the economic performances of biogas plants fed with different maize silages by considering increasing extra-farm transport distances. Two different scenarios were considered with regard to the subsidy framework and to the maize biomass yield. The results show that, for short distances (

Reduced graphene oxide (rGO) has been prepared from commercial graphene oxide by a thermal reduction method, and NiO/rGO photocathodes were obtained by a mixed NiCl2/rGO sol–gel process by using di...

Abstract The rapid development of distributed generation in different forms and capacities is transforming the conventional planning of distribution networks. Despite the benefits offered by renewable distributed generation technologies, several economic and technical challenges can result from the inappropriate integration of distributed generation in existing distribution networks. Therefore, the optimal planning of distributed generation is of paramount importance to ensure that the performance of distribution network can meet the expected power quality, voltage stability, power loss reduction, reliability and profitability. In this paper, we firstly discuss several conventional and metaheuristic methodologies to address the optimal distributed generation planning problem. Metaheuristic algorithms are often used as they offer more flexibility, particularly for multi-objective planning problems without the pursuit of globally optimized solution. Analytical techniques are considered suitable for modeling power system mechanisms and validating numerical methods. Then, this paper conducts a comprehensive review and critical discussion of state-of-the-art analytical techniques for optimal planning of renewable distributed generation. The analytical techniques are discussed in detail in six categories, i.e. exact loss formula, loss sensitivity factor, branch current loss formula, branch power flow loss formula, equivalent current injection and phasor feeder current injection. In addition, a comparative analysis of analytical techniques is presented to show their suitability for distributed generation planning in terms of various optimization criteria. Finally, we present conclusive remarks along with a set of recommendations and future challenges for optimal planning of distributed generation in modern power distribution networks.

Electrical power systems have been traditionally designed to be reliable during normal conditions and abnormal but foreseeable contingencies. However, withstanding unexpected and less frequent severe situations still remains a significant challenge. As a critical infrastructure and in the face of climate change, power systems are more and more expected to be resilient to highimpact low-probability events determined by extreme weather phenomena. However, resilience is an emerging concept, and, as such, it has not yet been adequately explored in spite of its growing interest. On these bases, this paper provides a conceptual framework for gaining insights into the resilience of power systems, with focus on the impact of severe weather events. As quantifying the effect of weather requires a stochastic approach for capturing its random nature and impact on the different system components, a novel sequential Monte-Carlo-based time-series simulation model is introduced to assess power system resilience. The concept of fragility curves is used for applying weather-and time-dependent failure probabilities to system's components. The resilience of the critical power infrastructure is modeled and assessed within a context of system-of-systems that also include human response as a key dimension. This is illustrated using the IEEE 6-bus test system.

The increasing demand for temporary housing in many developing countries necessitate the use of sustainable and affordable construction options. Earthbag units have the potential to be integrated into such housings as they are inexpensive, sustainable, and straightforward material options for building structures. Nevertheless, due to their thermal characteristics, earthbag units cannot provide a thermally comfortable environment. Thus, the present study focuses on developing an environmentally and sustainable earthbag unit integrated with phase change materials (PCM) to convert severely harsh indoor spaces to moderately harsh ones. For the design and development of earthbag blocks, several units are developed with varying amounts of PCM encapsulated in expanded perlite (EP) and expanded graphite (EG) within each unit, including block A (reference), Block B (PCM 2.2% of sample weight), C (4.3%), and D (6.5%). An experimental study is then conducted to understand the microstructural properties of the embedded PCM composite in soil. Following this initial study, practical differential techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), thermal conductivity, and Oozing circle test, have been employed over the developed units to measure their thermal characteristics. Test results from DSC and TGA show good thermal stability of PCM and PCM composites, while SEM results indicated that PCM is well distributed within the pores of EP at 50%EP of the PCM weight. The study found the average indoor surface temperatures by block B, block C, and block D to drop compared to the reference block about 1.2 °C, 3.3 °C, and 4.1 °C, respectively. This clearly shows the benefit of integrating phase change materials in an earthbag unit.

The future electricity network has to be able to manage energy coming from different grids as well as from renewable energy sources (RES) and other distributed generation (DG) systems. Advanced power electronic converters can provide the means to control power flow and ensure proper and secure operation of future networks. This paper presents analysis, design, and experimental validation of a back-to-back three-phase ac-dc-ac multilevel converter employed for universal and flexible power management (UNIFLEX-PM) of future electrical grids and its advanced control technique. The proposed system has been successfully tested for bidirectional power flow operation with different grid operating conditions such as voltage unbalance, frequency variation, harmonic distortion, and faults due to short circuits.

There is strong social and political pressure to reduce pesticide use in European agriculture. Evaluating the sustainability of cropping systems is a complex task due to the conflicting objectives underlying its economic, social and environmental dimensions. Multi-criteria assessment of different Integrated Pest Management (IPM) scenarios and evaluation of the most sustainable options at regional, national and European level is essential. Within the EU Network of Excellence ENDURE, two expert-based surveys were conducted (i.e. interviews), where experts from four European regions (northern region, Denmark and The Netherlands; central-eastern, Tolna and Békés counties in Hungary; south-western, Ebro Valley in Spain; southern, Po Valley in Italy) determined which are the main current maize-based cropping systems (MBCSs) in their region and proposed innovative IPM-based systems. The DEXiPM® (DEXi Pest Management) model for arable cropping systems was used to evaluate and compare the economic and environmental sustainability of these systems. The social sustainability was evaluated by adapting indicators of this model to the specificities of maize systems. The assessments showed that all innovative rotated MBCSs proposed in the four regions can have a higher environmental sustainability than and maintain the same economic sustainability as current rotated systems. These cropping systems are thus acceptable for testing under "real" field conditions. Only the innovative continuous maize system proposed in the central-eastern region was both economically and environmentally more sustainable than the current system. All innovative systems had a positive impact on work safety but according to local expert opinion producers and consumers are not ready to implement them or to accept their higherpriced products, with the exception of consumers in the northern region. These results suggest the need for European and regional policies to encourage the adoption of innovative rotated MBCSs that have positive agronomic and environmental impact through IPM implementation. The major constraints that inhibit this adoption were predominantly relating to (1) the lack of access that farmers have to the practical knowledge needed to effectively manage these systems and (2) the insufficient consumer awareness and acceptance of product improvements associated with IPM. To overcome these constraints supportive policy environments, well-functioning knowledge management systems (including good farmer support networks) and effective marketing is required.