Dry Wall Research Articles

Geological Insights on the Calcareous Tufas (Pietra Spugna) Used as Building and Ornamental Stones in the UNESCO Historical Centre of Urbino (Marche Region, Italy)

This study is addressed at the cultural heritage of the UNESCO historical centre of Urbino (Italy) through the focus on a very peculiar building and ornamental carbonate porous (spongy) stone also found in the opus quadratum Roman dry walls. For these rocks, the mathematician and historian Bernardino Baldi (16th century AD) and the mineralogist Francesco Rodolico (middle of the 20th century AD) introduced, respectively, the popular terms of Tufo spugnoso or Pietra Spugna. Physical observations and stable isotope data (δ13C and δ18O) of these rocks allowed, for the first time, their classification as calcareous tufas, thus contributing to the valorization of the stone heritage of the city. This carbonate lithotype was formed by the chemical precipitation of CaCO3, driven by the CO2 degassing of supersaturated calcium-bicarbonate-rich waters, coupled with the passive encrustations of organic material in continental environments. Radiocarbon analyses dated these stones mostly between 9100 and 4700 yr. BP when a maximum growth of these carbonate continental deposits occurred in Mediterranean regions and northern Europe, i.e., during the Holocene Atlantic climatic optimum. Work is still in progress on a perched springline of calcareous tufas found along the Metauro Valley (a few km from Urbino), being good candidates for provenance, at least for those blocks exploited by the Romans and successively reused in the architectural framework of Urbino.

Effect of a Novel Dowel and Cramp on the In-Plane Behavior of Multi-Leaf Stone Masonry Walls Proposed for Modern Masonry Buildings

This study discusses the experimental assessment of the in-plane mechanical behavior of a multi-leaf stone masonry wall built from cut stone and reinforced with metal connectors (cramps and dowels). Inspired by conventional multi-leaf stone walls, the wall is meant for use in modern stone masonry buildings. The wall is constructed from two parallel load-bearing walls with a cavity between them, which aims to conceal the installation and insulation needed in modern buildings. The load-bearing walls are connected with cramps and dowels at certain intervals, so the wall works as a single section against horizontal and vertical loads. To characterize the in-plane behavior of the proposed wall, compressive, triplet, and diagonal compression tests were conducted to investigate the compressive strength, shear strength, modulus of elasticity, stiffness, ductility, and energy absorption of the wall. Compared with dry and mortar joint walls, dowels increased the wall’s initial shear capacity by 11 and 19 times, respectively. Applying cramps without curving channels inside the individual stone elements decreased the compressive strength by 18%. The energy absorption of the designed walls with metal connectors was substantially increased to that of the specimens representing conventional stone walls. The results show the wall’s applicability due to its higher shear strength and minimal drop in compressive strength, which is within acceptable limits.

Easter in Milan.

I never imagined I'd be famous. People come from all over the world to see me. Yet my beginnings were humble. My mother, a buxom Milanese, was low in the pecking order. I was expected to follow the family tradition and cater for my embryonic relative. But I didn't get the chance to pursue that calling, for I was torn from my home at an early age and assigned to decorating duty.I was to help paint a dining room wall. The traditional method involved combining pigments with water and quickly applying the mix to fresh plaster before it dried. But my supervisor had no experience with this high-throughput fresco technique. His expertise was in painting dry surfaces like wood panels. He'd mix pigments with me or oil to produce bright paints that allowed for much greater freedom to adjust and correct, suiting his meticulous ways. But these tempera- or oil-based methods hadn't been tried out on murals. He decided to risk it and do the experiment. For good measure, he threw both me and oil into the mix.That's how I found myself clinging to a dry wall, 15 ft from the ground, my supervisor perched next to me on scaffolding. Friars came and went below, for the monastery dining room was still in use despite the renovations underway. Being so close to my supervisor, I could read his thoughts. He was planning to depict thirteen males (I only became aware that his species had females much later), taking supper at a long table. I was to contribute to blue mountains in a central window that backlit the scene.My supervisor was obsessed. Not only did he ceaselessly ponder the poses and composition of his mural; his mind overflowed with inventions of war machines, flying machines, architectural designs, theories of how mountains, rivers and living beings develop and function. He didn't trust accepted ideas but always made careful observations for himself, sketching what he saw and scribbling down notes in mirror script. His mission: look at the world with fresh eyes and find better ways of understanding, representing and improving it.I was three when they removed the scaffolding. Visitors came from far and wide to witness the revolutionary composition that lit the central figure, the dazzling combinations of red, green, yellow and ultramarine robes, the extraordinary interplay of contrasts, the lifelike expressive faces, plates of food and pleated tablecloth. My supervisor had achieved lasting fame, putting to rest accusations that he never completed his works.Fortunately, he didn't witness my decay, for he died in France 22 years later. It was around then that parts of me began to flake off. By my fifties I was in such a sorry state that the friars felt justified in cutting a door into the wall beneath me, amputating the central figure's feet and further loosening paint with blows from their pickaxes. When I reached 300, Napoleon's soldiers pelted me with bricks and used the room as a stable. Four years later there was a fifteen-day flood and I became covered in green mould. At 450, an RAF bomb blew the roof off and only tarpaulin protected me from the skies. A major restoration began 34 years later. They removed the grime, overpainting, waxes, varnishes, glues, shellacs and resins that had been used to preserve me. After 22 years of painstaking work, what little colour remained was said to be 20% supervisor, 80% restorer.I'm now 529. Visitors raise hand-held devices to capture my decayed state. What if my supervisor hadn't been so experimental? What if the spirit of his age had been to stick to the tried-and-tested rather than risk failure? Maybe they'd still be able to see his creation in its full glory. But then again, I wouldn't be here, and neither would those hand-held devices.

Precise control of water stress in the field reveals different response thresholds for forage yield and digestibility of maize hybrids.

With dwindling global freshwater supplies and increasing water stress, agriculture is coming under increasing pressure to reduce water use. Plant breeding requires high analytical capabilities. For this reason, near-infrared spectroscopy (NIRS) has been used to develop prediction equations for whole-plant samples, particularly for predicting dry matter digestibility, which has a major impact on the energy value of forage maize hybrids and is required for inclusion in the official French catalogue. Although the historical NIRS equations have long been used routinely in seed company breeding programmes, they do not predict all variables with the same accuracy. In addition, little is known about how accurate their predictions are under different water stress-environments. Here, we examined the effects of water stress and stress intensity on agronomic, biochemical, and NIRS predictive values in a set of 13 modern S0-S1 forage maize hybrids under four different environmental conditions resulting from the combination of a northern and southern location and two monitored water stress levels in the south. First, we compared the reliability of NIRS predictions for basic forage quality traits obtained using the historical NIRS predictive equations and the new equations we recently developed. We found that NIRS predicted values were affected to varying degrees by environmental conditions. We also showed that forage yield gradually decreased as a function of water stress, whereas both dry matter and cell wall digestibilities increased regardless of the intensity of water stress, with variability among the tested varieties decreasing under the most stressed conditions. By combining forage yield and dry matter digestibility, we were able to quantify digestible yield and identify varieties with different strategies for coping with water stress, raising the exciting possibility that important potential selection targets still exist. Finally, from a farmer's perspective, we were able to show that late silage harvest has no effect on dry matter digestibility and that moderate water stress does not necessarily result in a loss of digestible yield.

Numerical Simulation of Heat and Moisture Transfer in Corrugated Walls Dryer

The primary goal of the current work is to model heat and mass transfer during mango drying in a wavy airflow dryer. By modifying the dryer walls, we were able to produce the undulating airflow (with V-shaped obstacles). With convective boundary conditions applied to all product surfaces, the explicit finite difference approach was used to study heat and mass exchanges in two dimensions during the drying of mango slices. During drying, the transfer coefficients are thought to fluctuate. Using EasyCFD software, the external flow, temperature, velocity, and pressure fields were then analyzed. This provided the profile of the heat transfer coefficient. These profiles were then utilized to calculate the mass transfer coefficient using the Shilton-Colburn analogy. Moreover, the code created to determine the heat and mass transfer coefficients in the product was used to derive the evolution of temperature and moisture content over time. The results allowed for the discovery of a new air flow in dryers called an undular flow and demonstrated how modifying the drying air stream enhanced heat transfer efficiency. By changing the air flow in the dryer, it was possible to achieve heat transfer coefficients ranging from 47.55 W/m²K to 357.38 W/m²K and mass transfer coefficients of 3.21 x 10-5 to 3.21 x 10-4 m²/s. When the outcomes of this investigation were compared to experimental results from the literature (under identical drying circumstances), a reasonable level of adequacy was discovered.

“L’arte dei muri a secco”, confronti tra esperienze per la conservazione del patrimonio culturale dei paesaggi rurali

The European rural landscape has been designed for centuries by the art of the construction of dry stone walls and by the arrangement of terraced bands, becoming a cultural expression of identity common also to rural contexts geographically distant from each other. In 2018, eight European countries obtained the transnational recognition of the “Art of dry stone walls” in the UNESCO Intangible Cultural Heritage List. The contribution questions, on the basis of some case studies, how UNESCO recognition can concretely favor the start of that necessary support for studies and conservation of the knowledge preserved in the experience of the workers, who often lack professional recognition and regulatory support. It also proposes an analysis on the processes of protection, management, enhancement and conservation of this cultural heritage. If some case studies express guidelines and identifiable as repeatable good practices, others appear to be the lack of adequate policies for the protection of value landscapes.

Mitigation of nutrient leaching from bioretention systems using amendments

Bioretention systems have been showcased to be effective in reducing stormwater quantity and improving stormwater quality. However, the systems can also leach nutrients especially during their initial operation, which needs to be mitigated to optimize their benefits. To examine the efficiency of six amendments selected primarily for reducing phosphorus (P) leaching, six amended and two control cells were constructed and monitored soon after their construction in the field of the 2020 growing season. The effects of the amendments on both the hydrological performance (in terms of water retention rate (WRR)) and water quality performance (in terms of the event mean concentration and pollutant removal rate) were investigated. The results showed that all amendments had the capability of preventing or mitigating P leaching from bioretention systems to varying degrees, with the water treatment residual (WTR) outperforming all other amendments, followed by the activated aluminum (AA) and sorptiveMEDIA (SM) amendments. In addition, some of the amendments (i.e., drywall (DRY), WTR, and SM) were also found to be beneficial in reducing the nitrogen (N) leaching to a slight degree, whereas eggshell (EGG) introduced an extra source of N leached. Furthermore, the temporal evolution of the P leaching of the amendment cells was found to be different from that of the control cells. The same result was not observed for the temporal evolution of the N leaching, implying that the amendments (except EGG) did not largely affect the N leaching. Among the amendments’ effect on WRR, there was no obvious difference. Whereas the observed differences between the control cells and some amendment cells in vegetation growth and antecedent media moisture condition might imply their potential impacts on the hydrologic performance. Overall, other than P leaching, the use of amendments affected other functions of bioretention systems, which should be taken into consideration when selecting an amendment for practice.

The forced sound transmission of finite periodic plates using a variational approach

Many engineering structures consist of plates being periodically stiffened or loaded. Examples can be wooden joist floors, dry walls with wooden or metal beams, or metamaterials for increased sound insulation. Even though some of these structures are well known and thoroughly studied in the past, there lack prediction models that can handle both the finiteness and periodicity in a simple and accurate manner. In two previous attempts, the periodicity of the structure have been tried to be incorporated in a variational technique based on integral-differential equations of the fluid loaded plate, based on [J. Brunskog, JASA 132, 1482-1493, 2012]. These attempts have not worked well: they show a poor fit with measured data. In this paper, this issue is investigated again, and a different tactics is used to incorporate the periodicity, using space harmonics. In this way, the paper try to explain the previous misfit and improve the model.

Determination of the single droplet post-impingement pattern on a dry wall: A data-driven approach

Basic droplet-wall interaction such as post-impingement patterns is of great importance since it can quantitatively provide an estimation of energy transformation in spray-wall interaction dynamics. Most existing studies have developed physical-based empirical criteria to determine the droplet-wall post-impingement patterns. However, these approaches are subject to common issues such as scalability and low accuracy. In this study, a data-driven approach utilizing machine learning (ML) classification models is proposed for the identification of droplet-wall post-impingement patterns. An experimental data pool with 1093 observations of a single droplet impinging on a dry wall is established. 16 input features describing liquid properties and wall characteristics are first determined based on domain knowledge. Feature engineering methods are adopted to investigate the most informative and influential features of the splash phenomenon. The selected feature subsets/spaces are then fed into six well-known classification models (i.e., classifiers) individually for the model tuning. The performance of the classifiers is evaluated by metrics such as accuracy, precision, recall, and F1 score. The results show that ML classifiers achieve a good performance in identifying splash cases, providing a higher prediction performance than existing criterion-based approaches. More importantly, this study demonstrates the applicability of ML method on droplet/spray-wall interaction research and proposes a feasible workflow schematic for future studies.

Cartographic determination of the dry stone walls of the Mallorcan Tramuntana mountain range (Balearic Islands): Exploratory analysis

The construction technique of dry stone, declared Intangible Cultural Heritage of Humanity by UNESCO, has historically materialized in Mallorca in the form of a varied range of constructions with different functions. The massive construction of dry stone walls in the Mallorcan countryside has left an outstanding landscape and territorial imprint, which constitutes a rich source of geographical analysis. An unpublished cartography of the walls located in the Serra de Tramuntana mountain range in Mallorca is presented as an essay, a cartography that has served as a basis for their classification and provisional quantification. With the support of basic cartographic, photo-interpretation and GIS techniques, the detailed examination of two official cartographic bases has allowed us to determine their usefulness as reliable sources for locating and understanding the dry stone walls in our study area, with a view to a more far-reaching geographical study of them.

Cultural Heritage and Sustainable Rural Development: The Case of Tàrbena, Spain

The population decline of small villages is a very serious problem for our society. This situation is not easy to reverse. The challenge is to generate consensus among the inhabitants of small villages to develop projects that have both a link with social and cultural heritage and the aid of the regional and local authorities. This framework can be successful when it also has the capability to provide new lines of development growing from this initial seed that can attract new inhabitants. In this paper, we present research that follows these requirements. Our proposal is based on a traditional agriculture resource, which is the art of building dry stone walls. We study the case of Tàrbena (642 inhabitants in the province of Alicante, Spain). Stone artifacts are recovered: some of them are still useful for agriculture, and others are cataloged and transformed into a product for cultural tourism. This project is expected to develop local, manual, and specialized work through the development of workshops, crafts, and small businesses. This will provide more income for the municipality and the private sector and more opportunities to attract new inhabitants.

Confronting Complexity: Interpretation of a Dry Stone Walled Landscape on the Island of Cres, Croatia

Dry stone walls are a worldwide phenomenon that may shape entire regions. As a specific form of vernacular agro-pastoral practice, they are expressions of the culture and history of a region. Dry stone walls have recently received increased attention in Croatia, primarily due to research in landscape architecture and (historical) geography, though archaeological research on such remains is rare in part due to the challenges of undertaking such work in areas covered by dense evergreen maquis vegetation. In this paper, this type of landscape has been studied in detail for the first time using Airborne Laser Scanning (ALS) based digital feature models as a basis to articulate dynamic dry stone wall landscapes in a diachronic archaeological interpretation. Using a case study from the Mediterranean region of Punta Križa, Croatia, we show that what superficially appears to be a simple system of dry stone walls contains a wealth of information on a complex sequence of human activity. The systematic, detailed, and diachronic interpretation applies a transparent workflow that provides a tool for all those undertaking interpretative mappings of archaeological prospection datasets and has proved highly effective when working with ALS-derived visualizations. The capacity to develop spatio-temporal interpretation within the framework of GIS and a Harris Matrix is especially powerful and has the potential to change our image of any region. While the case study presented here deals with a small area in Croatia, the methods described have a broad application in any areas of complex landscape remains.

Colour morph predicts social behaviour and contest outcomes in a polymorphic lizard (Podarciserhardii)

Space is a limited resource in which many animals need to perform basic functions such as feeding and reproducing. Competition over access to space can induce a variety of behaviours that may result in differential access to crucial resources related to survival and fitness. The Aegean wall lizard, Podarcis erhardii , is a colour-polymorphic lizard that inhabits dry stone walls where they access food, safely thermoregulate, shelter from predators and interact with other lizards. Many colour-polymorphic species have morphs with distinct behavioural strategies, which may play a role in morph evolution and maintenance. Here, we conducted the first behavioural experiments on P. erhardii colour morphs. Our goal was to compare morph competitive ability and characterize morph differences in social behaviours using laboratory contest experiments over limited heated space on a stone wall in a neutral arena. Contest experiments revealed that colour morph, not size, predicted intermorph contest outcomes. White and yellow morphs were associated with winning and the orange morph was associated with losing contests. Male colour morphs exhibited different levels of aggressive, boldness, chemical signalling and visual signalling behaviours depending on which morph they were in contest with. White morphs always performed aggressive and scent-marking behaviours more frequently during contests with other morphs. Yellow morphs performed aggressive, bold, chemical signalling and visual signalling behaviours at intermediate frequencies relative to other morphs. Orange morphs performed aggressive behaviours equally often when in contest with yellow morphs but performed all other behaviours less frequently against yellow and white morphs. Considering these results, behavioural variation among P. erhardii colour morphs may promote morph maintenance. • Male lizard colour morphs differed in their ability to win staged contests for space. • White and yellow morphs were associated with winning contests over space. • Larger orange morphs were associated with losing and were the least aggressive. • White morphs were the most aggressive and scent-marked territories often. • Different social strategies among morphs may help maintain polymorphism.

Effect of daily or intermittent addition of fenugreek (Trigonella foenum graecum L.) seeds to concentrate on intake, digestion, and growth performance of Barbarine lamb

An 82-day experiment was carried out to determine the response of growing lambs to the intermittent administration of fenugreek (FG) seeds (Trigonella foenum graecum L.) into concentrate. Twenty-Four 3-month-old Barbarine lambs (initial body weight 16.6 ± 0.42 kg) were divided into four equal groups (n = 6). All lambs received 600 g alfalfa pellets and 250 g concentrate containing or not 12% ground FG seeds. Control concentrate (CC) was composed (as fed) of barley (200 g), faba bean (40 g) and mineral and vitamin supplement (MVS, 14 g). The experimental concentrate (CE) contained barley (200 g), FG seeds (30 g) and MVS (14 g). The two concentrates have the same crude protein content. The control group (FG-0) received CC while groups FG-D, FG-2D and FG-4D received CE daily, or in alternation with concentrate CC at 2 or 4-day intervals (FG-2D or FG-4D, respectively). The feeding trial was followed by a 5-day in vivo digestibility trial. The frequency of distribution of FG-containing concentrate (CE) had no effect (P > 0.05) on diet intake and diet apparent digestibility of dry matter, organic matter, crude protein and cell wall (NDFom), nitrogen balance and the concentrations of urea, total protein and glucose in sheep plasma. The intermittent supply of FG seeds in concentrate tended to increase (P = 0.087)the average daily gain in FG-2D and FG-4D lambs and the microbial nitrogen synthesis (P = 0.052)with the FG administration. However, it decreased (P < 0.001) ruminal protozoa count by 33%, 44% and 66% in the FG-D, FG-2D and FG-4D lambs, respectively compared to FG-0 group. Similarly, the intermittent administration of FG seeds decreased ruminal ammonia nitrogen (NH3-N) concentrations (P < 0.001) by 28%, 31% and 35% in the FG-D, FG-2D and FG-4D, respectively. The antiprotozoal activity of FG seeds could have been induced by secondary compounds like saponins. This activity was more efficient when the frequency of incorporation of FG seeds into the concentrate is wider. It is concluded that the intermittent administration of 120 g/kg to concentrate (DM basis), had an antiprotozoal effect but failed to improve diet digestibility and growth performance of Barbarine lambs. Therefore, there is a need to emphasize further investigation to identify the active components responsible for the antiprotozoal activity of FG seeds.

Nonlinear numerical assessments for the in-plane response of historic masonry walls

This study examines the in-plane cyclic response of historic masonry elements using a micro modelling approach that incorporates damage-plasticity and surface-based cohesive-contact interface approaches. The nonlinear procedures adopted are validated against tests on dry and wet panels in diagonal compression and large walls under reverse shear-compression loading. Considering the inherent material variability, the numerical results are shown to correlate well with the test results in terms of stiffness, strength, ductility, overall hysteretic response, and cyclic degradation. Based on the validated models, followed by exploratory sensitivity studies, detailed parametric assessments are carried out. The parameter ranges are selected to cover historical masonry materials, consisting of bricks and mortar, and address both dry and wet conditions. Four typical failure modes, namely, flexural strut crushing, diagonal cracking, flexural toe crushing, and mixed sliding, in an order of increasing ductility, are quantified and discussed. It is shown that wet masonry walls have an average reduction of 16% in terms of stiffness and capacity compared with the dry counterparts. Although the failure modes in dry and wet wall pairs are similar, some cases are identified in which the weaker moisture-affected joint strength results in a shift to a more brittle mode. It is also shown that the ductility of the flexural strut crushing mode, which often governs the failure of historical masonry due to its low strength, is considerably overestimated in existing guidelines. Based on the results of the parametric investigations, analytical models for predicting the inelastic response are evaluated, and suggestions for modifications are proposed.

Effects of particle size and liquid film viscosity on characteristics of particles colliding with dry and wet walls

Particle-wall collisions frequently occur in fluidized beds, granulation processes, and the transportation of gas–solid two-phase flows in pipelines. Exploring the rebound characteristics of particles after colliding with the wall will enable more accurate calculation models of collision rebound, enhanced control of the collision–rebound process, and improved efficiency of industrial production. This paper studies the relationship between the energy consumed by the liquid film and the energy consumed in the collision and investigates the effects of different particle sizes and liquid film viscosities on the liquid bridge morphology, coefficient of restitution (COR), and critical capture angle (CCA). The results show that the normal COR is affected by particle size, incident velocity, and viscosity, while the tangential COR is only related to the existence of the liquid film. Additionally, the maximum size of the liquid bridge and the growth rate of COR change suddenly in a transition region. The particle size and liquid film viscosity have significant effects on the CCA of the particle. The numerical results enable us to propose a general form of the normal wet collision model.

IMETHODS OF INTENSIFICATION OF HEAT EXCHANGE IN BIOGAS REACTORS

Proposed research method intensification of heat exchange in biogas reactions using alternative energy sources. The distribution of active and passive methods of heat exchange intensification is determined. The three most effective methods of heat exchange intensification are identified: the method of flow turbulence in the adjacent areas, based on purposeful artificial creation of small dry wall zones, which is the source of additional flow turbulence; the method of flow winding inside the twisted oval tubes and at longitudinal and transverse winding of tightly packed beams and tubes; the method of controlled break-out of the boundary layer at transverse tubulars by creating turboblicators on them. It is determined that in practice the most effective is the use of combined methods of intensification. The important conditions for choosing the method of heat exchange intensification are: the amount of permissible energy costs for heat exchange intensification and the type of energy available for this energy; the task of heat exchange intensification in a particular class of equipment; the technological capacity of equipment with heat exchange intensification, availability at purchase and durability in operation of equipment; the nature of distribution, structure of thermal flows and temperature fields, in which there is a need for intensification of heat exchange. The main indicator of intensification of the heat exchange process in the equipment is found – the efficiency of the process, that is, the process should be economically profitable. From the above it appears that the intensification of heat exchange can’t be considered isolated from the necessary energy costs. The determining criterion of optimization is the efficiency of the heat exchange process at a given level of energy consumption at transfer of the working environment through the equipment. Heat exchange intensification during use of gaseous working environments is of particular importance, for which characteristic reduction of intensity of heat exchange processes and high energy consumption for removal of supports at pumping of gases is characteristic. Tasks of heat exchange intensification are usually set: to reduce the size and weight of heat exchange devices; to decrease the temperature pressure, i.e. to decrease the temperature of the walls at the given temperature of heat carrier or to increase the temperature of heat carrier at the given temperature of walls. Reduction of thickness of heat transfer wall and increase of its thermal conductivity, as well as prevention waste contamination on the wall is an obvious method of intensification of heat exchange.

Assessing stone walls habitat quality – Which factors affect bryophytes and macrolichens on farmland stone walls in Ireland?

Stone walls are ubiquitous field boundaries used to restrict livestock movement or to separate property. Bryophytes and lichens are often the dominant vegetation in dry stone walls and are strongly affected by local microhabitat characteristics. Bryophytes and lichens related metrics can be used to define habitat quality of stone walls.The current study assessed how richness and cover of bryophytes and macrolichens in dry stone walls related to each other and how different environmental variables and farm management descriptors determined richness and cover of both groups in dry stone walls. Bryophytes and macrolichens were sampled in stone walls on sixteen farms across a management intensity gradient in Ireland.Bryophyte cover correlated positively and significantly with bryophyte richness and macrolichen cover and richness, and can thus be used to assess stone walls quality. Farm management intensity emerged as the variable most strongly related with species richness of bryophytes and cover of both groups. Altitude also emerged as a strong predictor of both groups’ richness and cover. This study provides a novel perspective on stone wall habitat quality and results indicate that by promoting extensive farming it is possible to increase stone walls quality.

Numerical Study of Consecutive Drop/Wall Impacts Using Smoothed Particle Hydrodynamics

A fundamental understanding of drop/wall interactions is of vital importance to many engineering applications, particularly in internal combustion engines; the outcomes of drop/wall interactions directly affect an engine's overall performance. Numerical models developed for drop-wall interactions are mostly based on the impact of a single drop on dry or wet walls. To accurately mimic and model real engine conditions, it is necessary to have a comprehensive study of drop/wall interactions with consecutive droplets. A theoretical splashing criterion based on the K parameter incorporating the impingement frequency is presented in this paper. In this study, a numerical method, based on Smoothed Particle Hydrodynamics (SPH), is used to simulate the impact of a droplet train on a heated wall at different impingement frequencies. The present SPH method is validated against the experimental results on the propagation of the crown rim's diameter as a function of the non-dimensional time. Impact regimes are identified for various impact conditions based on the study of the time evolution of the post-impingement process. In this work, simulations were conducted for n-heptane drops at different impingement frequencies and diameters. It is found that the K parameter provides a better prediction for the impingement outcomes and the effect of impingement frequency is seen as the kinematic discontinuity among the spreading lamellae, film formation, and rapidness of drop impact. Additionally, the inhibition by high ambient pressure on the crown rim propagation is also quantified. The results of this study can be used to further improve spray/wall interactions models at realistic engine conditions.

Biocultural diversity in the traditional landscape of Vallecorsa

In Italy, agricultural intensification and the abandonment of rural areas since the 1960s has led to a transformation of the traditional agricultural landscape, bringing with it a series of environmental and socio-economic issues and problems such as those linked to hydrogeological instability, a reduction in biocultural diversity and migration to urban centres, especially of the younger population. These phenomena have also led to a progressive loss of all the cultural and traditional practices related to these systems, thus contributing to a homogenization of the landscape structure due to abandonment. On the other hand, in the last years, we are witnessing a return to rural and traditional practices with the aim of recovering local cultures, especially those associated to agricultural practices, and to a more sustainable management of the territory. Vallecorsa, a municipality in central Italy, is one of the landscapes inscribed in the Italian National Register of Historical Rural Landscapes and it is still characterized by traditional agricultural practices that provide multiple benefits also in ecological terms, maintaining a specific level of biodiversity, interpreted as part of the biocultural diversity of the area. The aim of the present research is to analyse the structure of the traditional landscape of Vallecorsa and to determine its main characteristics, using landscape as the scale. Through the use of GIS software, by means of photo-interpretation and the use of DTM, the present study analyses the structure of land use, and in particular of terraced surfaces, and the associated data on area size, fragmentation, altitude and slope. The results take into account the diversity of land uses and mosaic patches, as well as terraced surfaces, and their distribution in the territory, relating them to the local biodiversity, in particular that of dry stone walls.