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AbstractClimate change effects along with anthropogenic activities present the main factors that threaten the existence of heritage sites across the north Nile Delta of Egypt close to the coastline of the Mediterranean Sea. Observing the changes in the landscape close to the archaeological sites is an important issue for decision‐makers in terms of reducing the negative impact of natural events and human activities. The coastal heritage sites are becoming strongly threatened by the rising sea level phenomena that will happen due to global warming. Focusing on the distribution of the archaeological sites, this study aims to detect the areas at risk of shoreline erosion or accretion in the northern shoreline of the Nile Delta. In this study, the changes in the northern shoreline of the Nile Delta were observed and calculated during the last hundred years based on the integration between the old topographic maps from surveys in 1900, 1925 and 1945, optical satellite images captured by Landsat in 1972, 1986 and 2000; Sentinel2 2021; and the Radar SRTM data. The results of this study showed that the changes were enormous with a great shoreline erosion process over the last 121 years recorded along the shoreline in the periods between 1900–1925, 1925–1945, 1945–1972, 1972–1986, 1986–2000 and 2000–2021. The areas eroded were about 5.3, 4.7, 5.6, 8.9, 2.5 and 5.4 km2, respectively. Such negative movements caused the loss of two heritage sites, and the expected changes will lead to the loss of additional heritage sites in the next 500 years. Furthermore, a model was suggested for protecting the coastal heritage sites threatened by the risk of submergence. This study can help the decision‐makers to detect the coastal archaeological sites at risk and create innovative solutions for protecting these irreplaceable heritage sites.

In this study we evaluate the skill of a new, merged soil moisture product (ECV_SM) that has been developed in the framework of the European Space Agency's Water Cycle Multi-mission Observation Strategy and Climate Change Initiative projects. The product combines in a synergistic way the soil moisture retrievals from four passive (SMMR, SSM/I, TMI, and AMSR-E) and two active (ERS AMI and ASCAT) coarse resolution microwave sensors into a global data set spanning the period 1979-2010. The evaluation uses ground-based soil moisture observations of 596 sites from 28 historical and active monitoring networks worldwide. Besides providing conventional measures of agreement, we use the triple collocation technique to assess random errors in the data set. The average Spearman correlation coefficient between ECV_SM and all in-situ observations is 0.46 for the absolute values and 0.36 for the soil moisture anomalies, but differences between networks and time periods are very large. Unbiased root-mean-square differences and triple collocation errors show less variation between networks, with average values around 0.05 and 0.04m3m-3, respectively. The ECV_SM quality shows an upward trend over time, but a consistent decrease of all performance metrics is observed for the period 2007-2010. Comparing the skill of the merged product with the skill of the individual input products shows that the merged product has a similar or better performance than the individual input products, except with regard to the ASCAT product, compared to which the performance of ECV_SM is inferior. The cause of the latter is most likely a combination of the mismatch in sampling time between the satellite observations and in-situ measurements, and the resampling and scaling strategy used to integrate the ASCAT product into ECV_SM on the other. The results of this study will be used to further improve the scaling and merging algorithms for future product updates.

Shipping is one of the most efficient transportation modes for moving freight globally. International regulations concerning decarbonization and emission reduction goals drive rapid innovations to meet the 2030 and 2050 greenhouse gas reduction targets. The internal combustion engines used for marine vessels are among the most efficient energy conversion systems. Internal combustion engines dominate the propulsion system architectures for marine shipping, and current marine engines will continue to serve for several decades. However, to meet the aggressive goals of low-carbon-intensity shipping, there is an impetus for further efficiency improvement and achieving net zero greenhouse gas emissions. These factors drive the advancements in engine technologies, low-carbon fuels and fueling infrastructure, and emissions control systems. This editorial presents a perspective on the future of ship engines and the role of low-life cycle-carbon-fuels in decarbonizing the marine shipping sector. A selection of zero-carbon, net-zero carbon, and low-lifecycle-carbon-fuels are reviewed. This work focuses on the opportunities and challenges of displacing distillate fossil fuels for decarbonizing marine shipping. Enabling technologies such as next-generation air handling, fuel injection systems, and advanced combustion modes are discussed in the context of their role in the future of low-CO2 intensity shipping.

Carbon dioxide emissions resulting from fossil fuels (brown energy) combustion are the main cause of global warming due to the greenhouse effect. Large IT companies have recently increased their efforts in reducing the carbon dioxide footprint originated from their data center electricity consumption. On one hand, better infrastructure and modern hardware allow for a more efficient usage of electric resources. On the other hand, data-centers can be powered by renewable sources (green energy) that are both environmental friendly and economically convenient. In this paper, we tackle the problem of targeting the usage of green energy to minimize the expenditure of running multi-center Web search engines, i.e., systems composed by multiple, geographically remote, computing facilities. We propose a mathematical model to minimize the operational costs of multi-center Web search engines by exploiting renewable energies whenever available at different locations. Using this model, we design an algorithm which decides what fraction of the incoming query load arriving into one processing facility must be forwarded to be processed at different sites to use green energy sources. We experiment using real traffic from a large search engine and we compare our model against state of the art baselines for query forwarding. Our experimental results show that the proposed solution maintains an high query throughput, while reducing by up to ~25% the energy operational costs of multi-center search engines. Additionally, our algorithm can reduce the brown energy consumption by almost 6% when energy-proportional servers are employed.

Thermal hydrolysis pretreatment coupled with Thermophilic Anaerobic Digestion (TAD) for Waste Activated Sludge (WAS) treatment is a promising combination to improve biodegradation kinetics during stabilization. However, to date there is a limited knowledge of the anaerobic biomass composition and its impact on TAD process performances. In this study, the structure and dynamics of the microbial communities selected in two semi-continuous anaerobic digesters, fed with untreated and thermal pretreated sludge, were investigated. The systems were operated for 250 days at different organic loading rate. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses allowed us to identify the majority of bacterial and archaeal populations. Proteolytic Coprothermobacter spp. and hydrogenotrophic Methanothermobacter spp. living in strict syntrophic association were found to dominate in TAD process. The establishment of a syntrophic proteolytic pathway was favoured by the high temperature of the process and enhanced by the thermal pretreatment of the feeding sludge. Proteolytic activity, alone or with thermal pretreatment, occurred during TAD as proven by increasing concentration of soluble ammonia and soluble COD (sCOD) during the process. However, the availability of a readily biodegradable substrate due to pretreatment allowed to significant sCOD removals (more than 55%) corresponding to higher biogas production in the reactor fed with thermal pretreated sludge. Microbial population dynamics analysed by FISH showed that Coprothermobacter and Methanothermobacter immediately established a stable syntrophic association in the reactor fed with pretreated sludge in line with the overall improved TAD performances observed under these conditions.

Policies to reduce carbon emissions from electricity generation will be crucial for negotiations at the UN climate conference (COP21) in Paris. In 2012, we presented data in Nature Materials on the contribution that photovoltaic (PV) power plants installed in Germany, Italy and the UK are making to reducing greenhouse emissions. Here we update our analysis with three more years worth of data, extending our study not only to other countries but also to wind power and bio-electricity generation. This analysis focuses mainly on the technical feasibility of an electricity supply based on all-renewable sources; more detailed cost considerations will be discussed in a forthcoming work.

Optical (refractive index) and structural properties of silicon oxynitride (SiON) and amorphous silicon (a-Si) multilayers grown by RF sputtering with thickness in the 10-30 nm range have been analysed by ellipsometry and TEM. Satisfactory agreement between the two techniques is obtained as regards the thickness determination of the SiON films. Disagreement with values obtained by the stylus method by extrapolation for the two types of layers is discussed. The interfaces of the SiON films are very good when n-type P doped Si is used as a target. They are wavy with average periodicity and amplitude on the order of 50 and 2 nm, respectively, when a semi-insulating Si target is used, despite the presence of a buffer layer. Hypothesis is made that P incorporation may improve the reconstruction of the SiON surface.