Polybius’ ‘previous landslide’: Proof that Hannibal’s invasion route crossed the col de la traversette

Both Polybius and Livy described a landslide/landslip that blocked the Punic Army’s exfiltration from a high col on the water divide in the Western Alps. The landslide, more aptly termed rockfall, has been a source of contention amongst classicists for centuries despite the fact that only two cols—Clapier and Traversette—exhibit rockfall debris on the lee side of the Alps. While the Clapier rockfall is too small and too young to have provided blockage, the Traversette debris is nearly as Polybius described it when he retraced the invasion route some 60 years after the event. His ‘two-tier’ description of the deposit, a doublet of younger and older rock rubble, including measurements of width and volume are close to modern measurements and prove that he knew, in advance, the route Hannibal had followed. It would take a practiced eye to correctly identify the stratigraphic complexity inherent in the Traversette Rockfall. Here we present weathering ratios, soil stratigraphic, mineral, chemical and microbiological evidence in support of Polybius’ observations as a considerable background database for future geoarchaeological exploration.

The effects of the specific adsorption of anion on the reactivity of the Ru(0001) surface towards CO adsorption and oxidation: in situ FTIRS studies

The dynamics of adsorption and oxidation of CO on Ru(0001) electrode in sulfuric acid solution have been studied using in situ FTIR spectroscopy under potential control and at open circuit, the latter at 20 and 55 degrees C. The in situ IR data show clearly that the bisulfate anion adsorbs on the Ru(0001) surface over the potential range from -200 mV to 350 mV (vs. Ag/AgCl) at 20 degrees C in the absence and presence of adsorbed CO; however, increasing the temperature to 55 degrees C and/ or increasing the concentration of dissolved O-2 reduces the bisulfate adsorption. The formation of surface (hydro-) oxide at higher potentials replaces the bisulfate adsorbates. Both linear (COL) and three-fold hollow bonded CO (COH) adsorbates were produced following CO adsorption at Ru(0001) in H2SO4, as was observed in our previous studies in HClO4. However, the amount of adsorbed CO observed in H2SO4 was ca. 10% less than that in HClO4; in addition, the COL and COH frequencies were higher in H2SO4, and the onset potential for COads oxidation 25 mV lower. These new results are interpreted in terms of a model in which the adsorbed bisulfate weakens the CO adlayer, allowing the active Ru oxide layer to form at lower potentials. Significantly different results were observed at open circuit in H2SO4 compared both to the data under potential control and to our earlier data in HClO4, and these observations were rationalized in terms of the adsorbed HSO4- anions (pre-adsorbed at -200 mV) inhibiting the oxidation of the surface at open circuit (after stepping from the initial potential of -200 mV), as the latter was no longer driven by the imposed electrochemical potential but via chemical oxidation by trace dissolved O-2. Results from experiments at open circuit at 55 degrees C and using oxygen-saturated H2SO4 supported this model. The difference in Ru surface chemistry between imposed electrochemical control and chemical control has potential implications with respect to fuel cell electrocatalysis.

Reaction Mechanisms of Crotonaldehyde Hydrogenation on Pt(111): Density Functional Theory and Microkinetic Modeling

The microkinetics based on density function theory (DFT) calculations is utilized to investigate the reaction mechanism of crotonaldehyde hydrogenation on Pt(111) in the free energy landscape. The dominant reaction channel of each hydrogenation product is identified. Each of them begins with the first surface hydrogenation of the carbonyl oxygen of crotonaldehyde on the surface. A new mechanism, 1,4-addition mechanism generating enols (butenol), which readily tautomerize to saturated aldehydes (butanal), is identified as a primary mechanism to yield saturated aldehydes instead of the 3,4-addition via direct hydrogenation of the ethylenic bond. The calculation results also show that the full hydrogenation product, butylalcohol, mainly stems from the deep hydrogenation of surface open-shell dihydrogenation intermediates. It is found that the apparent barriers of the dominant pathways to yield three final products are similar on P(111), which makes it difficult to achieve a high selectivity to the desired crotyl alcohol (COL).

Opening the Frontier: The Gubbio-Perugia Frontier in the Course of History.

The frontier between Gubbio (ancient Umbria) and Perugia (ancient Etruria), in the northeast part of the modern region of Umbria, was founded in the late sixth century BC. The frontier endured in different forms, most notably in the late antique and medieval periods, as well as fleetingly in 1944, and is fossilized today in the local government boundaries. Archaeological, documentary and
philological evidence are brought together to investigate different scales of time that vary from millennia to single days in the representation of a frontier that captured a watershed of geological origins. The foundation of the frontier appears to have been a product of the active agency of the Etruscans, who projected new settlements across the Tiber in the course of the sixth century BC,
protected at the outer limit of their territory by the naturally defended farmstead of Col di Marzo. The immediate environs of the ancient abbey of Montelabate have been studied intensively by targeted, systematic and geophysical survey in conjunction with excavation, work that is still in progress. An overview of the development of the frontier is presented here, employing the data currently available.

A novel TRNSYS type for short-term borehole heat exchanger simulation: B2G model

Models of ground source heat pump (GSHP) systems are used as an aid for the correct design and optimization of the system. For this purpose, it is necessary to develop models which correctly reproduce the dynamic thermal behavior of each component in a short-term basis. Since the borehole heat exchanger (BHE) is one of the main components, special attention should be paid to ensuring a good accuracy on the prediction of the short-term response of the boreholes. The BHE models found in literature which are suitable for short-term simulations usually present high computational costs. In this work, a novel TRNSYS type implementing a borehole-to-ground (B2G) model, developed for modeling the short-term dynamic performance of a BHE with low computational cost, is presented. The model has been validated against experimental data from a GSHP system located at Universitat Politècnica de València, Spain. Validation results show the ability of the model to reproduce the short-term behavior of the borehole, both for a step-test and under normal operating conditions.