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Abstract In this paper, a general mathematical model for the dynamic simulation of a single-effect LiBr/water absorption chiller is presented. The model is based on mass and energy balances applied to the internal components of the machine, and it accounts for the non-steady behaviour due to thermal and mass storage in the components. The validation of the mathematical model is performed through experimental data collected on a commercial small-capacity water-cooled unit. Due to the peculiar technology adopted in the real chiller, a special effort was made to identify the appropriate values of the main physical parameters. The validation of the model is based on the values of the water temperature at the outlet of the machine, as no measurement inside the machine was possible; anyway, a consistency analysis applied to the internal parameters is also presented. The agreement between experimental and simulated results is very good, both on a daily and on a seasonal basis.

The ‘4 per mille Soils for Food Security and Climate’ was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New Zealand, Chile, South Africa, Australia, Tanzania, Indonesia, Kenya, Nigeria, India, China Taiwan, South Korea, China Mainland, United States of America, France, Canada, Belgium, England & Wales, Ireland, Scotland, and Russia). We asked whether the 4 per mille initiative is feasible for the region. The outcomes highlight region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates globally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha− 1), and at the first twenty years after implementation of best management practices. In addition, areas which have reached equilibrium will not be able to further increase their sequestration. We found that most studies on SOC sequestration only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille number was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille in the top 1m of global agricultural soils, SOC sequestration is between 2-3 Gt C year− 1, which effectively offset 20–35% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.

This paper addresses the study of vibrations induced by turbulent boundary layers (TBLs) flowing over plate-like structures. The aim is here to propose a predictive method in order to evaluate the vibroacoustical behaviour of a plate excited by TBL pressure fluctuations. The ultimate goal is to develop tools for predicting internal cabin noise in an aircraft during flight. Hence TBL is considered. Different TBL models are discussed and compared. A prediction method well suited for mid-high frequencies is also presented. The method called simplified energy method (SEM) is based on local energetic considerations and extends the well-known statistical energy analysis (SEA). Two different SEM formulations are presented. The first one is of heat conduction type, whilst the second is radiative. The TBL source model was integrated in the local energy proposed formulations. When applied to a simple Kirchhoff-Love simply supported plate, SEM allows prediction of averaged energy quantities. Comparisons are drawn between heat and radiative formulations. Good concordance was observed between energy results and pure analytical calculations of the structural response under TBL excitation over a wide frequency range.

Cu(In,Ga)Se-2-based solar cells buffered with indium sulfide grown by numerous techniques have reached efficiencies comparable to those achieved by standard devices buffered with (CBD)CdS. The present paper firstly recalls some of the properties of the indium sulfide single crystal and Points Out the disagreements concerning the thin films properties inventoried in the literature. Secondly, the influence of the presence of some "foreign elements" within file indium sulfide on its properties is presented. It is shown that these "foreign elements", even at low concentration levels, are possibly at the origin or the thin films properties deviations compared to the single crystal. The impact of these contaminants on the solar cells performance is finally discussed.

The lignocellulosic C4 perennial crop miscanthus and, more particularly, one of its species, Miscanthus × giganteus, are especially interesting for bioenergy production because they combine high biomass production with a low environmental impact. However, few varieties are available, which is risky due to disease susceptibility. Gathering worldwide references, this review shows a high genotypic and environmental variability for traits of interest related to miscanthus biomass production and composition, which may be useful in breeding programs for enhancing the availability of suitable clones for bioenergy production. The M. × giganteus species and certain clones in the Miscanthus sinensis species seem particularly interesting due to high biomass production per hectare. Although the industrial requirements for biomass composition have not been fully defined for the different bioenergy conversion processes, the M. × giganteus and Miscanthus sacchariflorus species, which show high lignin contents, appear more suitable for thermochemical conversion processes. In contrast, the M. sinensis species and certain M. × giganteus clones with low lignin contents were interesting for biochemical conversion processes. The M. sacchariflorus species is also interesting as a progenitor for breeding programs, due to its low ash content, which is suitable for the different bioenergy conversion processes. Moreover, mature miscanthus crops harvested in winter seem preferred by industry to enhance efficiency and reduce the expense of the processes. This investigation on miscanthus can be extrapolated to other monocotyledons and perennial crops, which may be proposed as feedstocks in addition to miscanthus.