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The Fertile Crescent, its hilly flanks and surrounding drylands has been a critical region for studying how climate has influenced societal change, and this review focuses on the region over the last 20,000 years. The complex social, economic, and environmental landscapes in the region today are not new phenomena and understanding their interactions requires a nuanced, multidisciplinary understanding of the past. This review builds on a history of collaboration between the social and natural palaeoscience disciplines. We provide a multidisciplinary, multiscalar perspective on the relevance of past climate, environmental, and archaeological research in assessing present day vulnerabilities and risks for the populations of southwest Asia. We discuss the complexity of palaeoclimatic data interpretation, particularly in relation to hydrology, and provide an overview of key time periods of palaeoclimatic interest. We discuss the critical role that vegetation plays in the human-climate-environment nexus and discuss the implications of the available palaeoclimate and archaeological data, and their interpretation, for palaeonarratives of the region, both climatically and socially. We also provide an overview of how modelling can improve our understanding of past climate impacts and associated change in risk to societies. We conclude by looking to future work, and identify themes of "scale" and "seasonality" as still requiring further focus. We suggest that by appreciating a given locale's place in the regional hydroscape, be it an archaeological site or palaeoenvironmental archive, more robust links to climate can be made where appropriate and interpretations drawn will demand the resolution of factors acting across multiple scales. This article is categorized under:Human Water > Water as Imagined and RepresentedScience of Water > Water and Environmental ChangeWater and Life > Nature of Freshwater Ecosystems.

Hydrogen rotary engines are promising power sources for the future hydrogen society, and improving their thermal efficiency helps propel tomorrow's car farther. This research looked into the combustion process to reduce fuel consumption. Primary studies of combustion duration and location showed that increasing the local mass burning rate in the L-side of the combustion chamber by generating turbulence was beneficial. Experiments with optical and real rotary engines proved that turbulence effectively increased mass burning rate in L-side and consequently engine's thermal efficiency and its lean limit.

Terracing and the construction of a flood control system in Petra has allowed a unique opportunity to examine landscape conditions and changes beginning with the Late Iron Age. The study area is the Hremiyyeh catchment that flows into the core of the archaeological city of Petra and therefore constitutes an important key to understanding the human settlement of the area. The location was chosen as a focal point for intensive investigation and the study of human response to environmental change. This study involved careful documentation of the topography, geology, and archaeology of the site. In addition, samples were taken for the dating of terrace construction and changes in the landscape. The study indicates that the hydrological interventions began in the Late Iron Age, and intensified during the Nabataean and Early Roman periods. At the time, some of the drainage areas were already deeply gullied, while other parts had recently accumulated sediments. The lower terraces became filled with water-logged sediments, leading to the deposition of carbonates. The upper terraces changed the drainage pattern and deposition of the sediments. The sediments trapped there seem to have been less waterlogged. The abandonment of the system at the end of the Byzantine to Early Islamic periods led to partial collapses, gullying, and bedrock downcutting. Due to soil accumulation, the upper terraces were restored and enhanced with new ones around the 11th. Century CE, probably due to partial reclamation of the area by nomadic settlers, with charred botanical evidence found indicating the burning of wild vegetation in favor of domesticated cereal and legumes, with relatively humid conditions. [ABSTRACT FROM AUTHOR]