Fluid–structure interactions of elastic membrane aerofoils are investigated at Reynolds number $Re=10\,000$ and low angle of attack. The dynamics of the fluid and membrane coupled system are solved using direct numerical simulation (DNS), where the geometry and boundary conditions were applied using a boundary data immersion method. Although membrane aerofoils improve the aerodynamic performance close to stall conditions compared to rigid aerofoils, it has previously been found that membrane aerofoils show lower aerodynamic efficiency at low angles of attack. This study focuses on the coupling mechanism at an angle of attack of 8 degrees, which is below the stall angle. The dynamic behaviour of the coupled system was characterised via spectral analysis in the wavenumber and frequency domain, which allowed the propagating wave nature of the membrane vibrations and their effect on the surrounding pressure field to be clarified. The membrane vibrations are found to introduce upstream-propagating pressure waves that appear to be responsible for a loss in aerodynamic efficiency compared to a rigid aerofoil. Comparison of two- and three-dimensional results reveals that the three-dimensional flow development causes a decrease in the amplitude of the system fluctuations, but the same coupling mechanism is present.

Next space missions will investigate the possibility of extinct or extant life on Mars. Studying the infrared spectral modifications, induced by thermal processing on different carbonate samples (recent shells and fossils of different ages), we developed a method able to discriminate biogenic carbonates from their abiogenic counterparts. The method has been successfully applied to microbialites, i.e. bio-induced carbonates deposits, and particularly to stromatolites, the laminated fabric of microbialites, some of which can be ascribed to among the oldest traces of biological activity known on Earth. These results are of valuable importance since such carbonates are linked to primitive living organisms that can be considered as good analogues for putative Martian life forms. Considering that the microstructures of biogenic carbonate are different from those of abiogenic origin, we investigated the micromorphology of shells, skeletal grains and microbialites at different scale with a scanning electron microscope. The results show that this line of research may provide an alternative and complementary approach to other techniques developed in the past by our group to distinguish biotic from abiotic carbonates. In this paper, we present some results that can be of valuable interest since they demonstrate the utility for a database of images concerning the structures and textures of relevant carbonate minerals. Such data may be useful for the analysis of Martian samples, coming from sample return missions or investigated by future in situ explorations, aimed to characterize the near-subsurface of Mars in search for past or present life.

Logic Forms (LF) are simple, first-order logic knowledge representations of natural language sentences. Each noun, verb, adjective, adverb, pronoun, preposition and conjunction generates a predicate. LF systems usually identify the syntactic function by means of syntactic rules but this approach is difficult to apply to languages with a high syntax flexibility and ambiguity, for example, Spanish. In this study, we present a mixed method for the derivation of the LF of sentences in Spanish that allows the combination of hard-coded rules and a classifier inspired on semantic role labeling. Thus, the main novelty of our proposal is the way the classifier is applied to generate the predicates of the verbs, while rules are used to translate the rest of the predicates, which are more straightforward and unambiguous than the verbal ones. The proposed mixed system uses a supervised classifier to integrate syntactic and semantic information in order to help overcome the inherent ambiguity of Spanish syntax. This task is accomplished in a similar way to the semantic role labeling task. We use properties extracted from the AnCora-ES corpus in order to train a classifier. A rule-based system is used in order to obtain the LF from the rest of the phrase. The rules are obtained by exploring the syntactic tree of the phrase and encoding the syntactic production rules. The LF algorithm has been evaluated by using shallow parsing with some straightforward Spanish phrases. The verb argument labeling task achieves 84% precision and the proposed mixed LFi method surpasses 11% a system based only on rules.

A new in-situ rapid thermal annealing (RTA) apparatus which can be used to anneal entire wafers in an ultra high vacuum environment has been designed to be used in conjunction with the epitaxial growth of heterostructures. Drastic improvement in the crystallinity of CaF2/Si(100) can be achieved with RTA, and our results suggest that RTA can be used as an on-line processing technique for novel epitaxial structures.

A new in-situ rapid thermal annealing (RTA) apparatus which can be used to anneal entire wafers in an ultra high vacuum environment has been designed to be used in conjunction with the epitaxial growth of heterostructures. Drastic improvement in the crystallinity of CaF2/Si(100) can be achieved with RTA, and our results suggest that RTA can be used as an on-line processing technique for novel epitaxial structures.

Chemical vapor deposition (CVD) has been used to deposit films such as silicon, silicon oxide, silicon nitride, tungsten, silicide, copper and titanium nitride in the semiconductor industry. The reaction driving forces for CVD are typically temperature for thermal CVD, plasma ionization for plasma enhanced CVD, or atomic oxygen for ozone CVD. In the recent years, plasma enhanced CVD (PECVD) and ozone CVD have found extensive applications in the semiconductor industry, due to the higher deposition rate and lower deposition temperature. For example, PECVD and ozone CVD are used to deposit almost all dielectric films such as silicon oxide and silicon nitride on a wafer. The dielectric films on wafers serve as insulating layers between conducting metal layers and as passivation layer on top of semiconductor devices.

A systematic evaluation of the stress-temperature behavior of O3-TEOS Sub-Atmospheric CVD (SACVD) oxide films used in IMD applications was performed in order to elucidate the surface dependence and mechanical stability of these films when deposited on different oxide underlayers such as PECVD TEOS-based, Silane-based, and thermally grown oxides. SACVD films were deposited at 360°C using different O3:TEOS molar flow ratios. The results obtained in this study indicate that the stress-temperature behavior of SACVD films deposited on PECVD Silane-based and TEOS-based oxides using N2O as the oxidizing agent is similar to that of the SACVD films deposited on silicon. However, a large stress hysteresis is obtained when SACVD films are deposited on PECVD TEOS-O2 and thermally grown oxide underlayers. This large stress hysteresis results from the surface dependence effects of the SACVD oxides on thermally grown and PECVD TEOS-O2 oxide underlayers. Also, this stress hysteresis can be reduced or eliminated by treating the oxide underlayer surface with an in-situ Ar, He, or N2 plasma. Furthermore, it was also found that the SACVD oxides deposited using higher O3:TEOS molar flow ratios are chemically and mechanically more stable.

The tropical flora remains chronically understudied and the lack of floristic understanding hampers ecological research and its application for large-scale conservation planning. Given scarce resources and the scale of the challenge there is a need to maximize the efficiency of both sampling strategies and sampling units, yet there is little information on the relative efficiency of different approaches to floristic assessment in tropical forests. This paper is the first attempt to address this gap. We repeatedly sampled forests in two regions of Amazonia using the two most widely used plot-based protocols of floristic sampling, and compared their performance in terms of the quantity of floristic knowledge and ecological insight gained scaled to the field effort required. Specifically, the methods are assessed first in terms of the number of person-days required to complete each sample (‘effort’), secondly by the total gain in the quantity of floristic information that each unit of effort provides (‘crude inventory efficiency’), and thirdly in terms of the floristic information gained as a proportion of the target species pool (‘proportional inventory efficiency’). Finally, we compare the methods in terms of their efficiency in identifying different ecological patterns within the data (‘ecological efficiency’) while controlling for effort. There are large and consistent differences in the performance of the two methods. The disparity is maintained even after accounting for regional and site-level variation in forest species richness, tree density and the number of field assistants. We interpret our results in the context of selecting the appropriate method for particular research purposes.

Recent discoveries of pebble mosaics in various settlements in southern Spain from the seventh to the fourth centuries B.C. reveal an early tradition in floor-making. These discoveries have thrown new light on the origins of the most commonly used floors in Roman times, opus signinum and opus tessellatum. The first technique, thought to be Italian in origin, was probably developed in Italy from previous experiments in other Mediterranean sites which were of Punic origin. The origin of tessellated floors has been widely discussed and, although they were being produced on a large scale in Italy towards the first century A.D., we can assume that there existed a long experimental stage prior to the Roman period in which two general types of mosaic floors were developed—those with a uniform surface and those formed with small elements.