The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists ...of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is used to compute the spatial and temporal water pressure response to rainfall. Preferential flow is simulated with a dual-permeability continuum model consisting of a matrix domain coupled to a preferential flow domain. The second part is a soil mechanics model and is used to compute the spatial and temporal distribution of the local factor of safety based on the water pressure distribution computed with the subsurface flow model. Two types of rainfall events were considered: long-duration, low-intensity rainfall, and short-duration, high-intensity rainfall. The effect of preferential flow on slope stability is assessed through comparison of the failure area when subsurface flow is simulated with the dual-permeability model as compared to a single-permeability model (no preferential flow). For the low-intensity rainfall case, preferential flow has a positive effect on drainage of the hillslope resulting in a smaller failure area. For the high-intensity rainfall case, preferential flow has a negative effect on the slope stability as the majority of rainfall infiltrates into the preferential flow domain when rainfall intensity exceeds the infiltration capacity of the matrix domain, resulting in larger water pressure and a larger failure area.
Systemic Lupus Erythematosus (SLE) is a progressive disease leading to immune-mediated tissue damage, associated with an alteration of lymphoid organs. Therapeutic strategies involving regulatory T ...(Treg) lymphocytes, which physiologically quench autoimmunity and support long-term immune tolerance, are considered, as conventional treatment often fails. We describe here a therapeutic strategy based on Tregs overexpressing FoxP3 and harboring anti-CD19 CAR (Fox19CAR-Tregs). Fox19CAR-Tregs efficiently suppress proliferation and activity of B cells in vitro, which are relevant for SLE pathogenesis. In an humanized mouse model of SLE, a single infusion of Fox19CAR-Tregs restricts autoantibody generation, delay lymphopenia (a key feature of SLE) and restore the human immune system composition in lymphoid organs, without detectable toxicity. Although a short survival, SLE target organs appear to be protected. In summary, Fox19CAR-Tregs can break the vicious cycle leading to autoimmunity and persistent tissue damage, representing an efficacious and safe strategy allowing restoration of homeostasis in SLE.
Most real-world networks, from the World-Wide-Web to biological systems, are known to have common structural properties. A remarkable point is fractality, which suggests the self-similarity across ...scales of the network structure of these complex systems. Managing the computational complexity for detecting the self-similarity of big-sized systems represents a crucial problem. In this paper, a novel algorithm for revealing the fractality, that exploits the community structure principle, is proposed and then applied to several water distribution systems (WDSs) of different size, unveiling a self-similar feature of their layouts. A scaling-law relationship, linking the number of clusters necessary for covering the network and their average size is defined, the exponent of which represents the fractal dimension. The self-similarity is then investigated as a proxy of recurrent and specific response to multiple random pipe failures – like during natural disasters – pointing out a specific global vulnerability for each WDS. A novel vulnerability index, called
Cut-Vulnerability
is introduced as the ratio between the fractal dimension and the average node degree, and its relationships with the number of randomly removed pipes necessary to disconnect the network and with some topological metrics are investigated. The analysis shows the effectiveness of the novel index in describing the global vulnerability of WDSs.
This paper aims to solve three issues frequently present in the optimal placement of water quality sensors for protecting water distribution systems (WDSs) from both accidental and intentional ...contamination, namely i) computational intractability of the optimization problem as the size of the WDS increases, ii) unrealistic assumption that sensors are positioned at nodes, rather than on system pipes, and iii) neglecting site-specific practical conditions impacting on sensor installation. The three drawbacks were tackled by i) restraining the optimization to the hydraulic/topological-wise most important pipes, ii) introducing dummy nodes in the middle of these pipes as potential sensor locations, iii) applying a multi-criteria decision-making tool incorporating urbanistic and economic factors for selecting the most effective sensor locations. The method is tested on the WDS of the town of Parete (Italy), showing the manyfold benefits of the solution obtained.
•Water quality sensors are located on pipes of water distribution system, as is in reality.•Weighted topology is used for reducing the computational burden of optimization phase.•Potential sensor locations are defined on the hydraulic/topological-wise most central pipes.•Detection performance, economic and logistic criteria are used to select the best solution.•A weighted multi-parametric Decision Support System for selecting the monitoring layout is proposed.
This paper proposes a new multi-step approach for sensitivity assessment of surface runoff parameters. The procedure has been tested on a peri-urban basin in southern Italy, interested by intense ...urbanization. The basin has limited data about land characteristics, and nearby precipitation measurements are not available. Accordingly, rainfall events are defined based on depth-duration-frequency curve valid for the area. The main novelties of the work are to provide a general framework for assessing the influence of runoff parameters (i.e. depression storage and surface roughness) for a basin model in SWMM in relation to rain events of various intensity/duration, and to provide a ranking of crucial parameters significantly affecting peak discharge and total volume of the hydrograph, for an ungauged basin, by means the Fourier Amplitude Sensitivity Test (FAST). Results indicate the dependence on rainfall characteristics of the relative importance of the parameters describing the pervious and impervious areas. Notably, the peak discharge of the shortest considered event is influenced only by the two parameters of the impervious area, while the opposite holds for the longest rain event. The total runoff volume is mostly influenced by the depression storage of impervious areas, with the parameters of pervious areas becoming more influential for longer rain events. Results allow a clear interpretation of the modelled physical processes variability within the basin and their relationship with rainfall/areas features, thus providing useful insights for key parameter definition in other contexts and for other models.
AbstractThe detection of contaminant intrusion into a water-distribution network (WDN) is a difficult issue due to uncertainty related to the type of injected contaminant, source location, and ...intrusion time. The placement of water quality sensors has received increasing interest in the last years, and it still represents an open problem and a great challenge for researchers and utilities. Efficient numerical techniques are needed to support any contamination warning system (CWS) design. These require a well-calibrated hydraulic model of the WDN and a great deal of information, both of which are often unavailable to water utilities. In addition, as the size of the WDN increases, the choice of effective sensor placement becomes a computationally intractable problem. This paper introduces a methodology to support water utilities in the design of an effective CWS without any use of hydraulic information, but just exploiting the knowledge of the topology of the WDN. To ensure a complete coverage of the network, the method relies on a priori clustering of the WDN and on the installation of quality sensors at the most central nodes of each cluster, selected according to different topological centrality metrics. The procedure is tested on a benchmark network and on a real WDN serving a town close to Naples, Italy. The solutions obtained with topological criteria are effective in terms of detection time, detection likelihood, redundancy, and population exposed through ingestion.
In recent years there has been a strong increase in interest in the world of barbecues and outdoor cooking in high-income countries. Referring to FAO data, an exponential growth in imports of ...charcoal was observed in Europe and North America. Italy is one of the major European consumers and importers. On the market it is possible to find material with different characteristics and origins. However, analysis aimed at ascertaining the quality of the material are poorly performed. This research aimed to analyze the energy properties of charcoal commonly available on the Italian market. Twenty-four bags of charcoal and charcoal briquettes were analyzed. Eighteen samples represent the products most easily found on the market, in stores and on websites. In addition, six samples were supplied directly by the producer/importing company. The samples were grouped according to the continent of origin of the material (Europe, North-Central America and South America). Charcoal briquette samples were included together in a group. Referring to the ISO 17225-1 standard, the moisture content, ash content, heating value, volatile matter and fixed carbon were determined. Except for the moisture content, the results of the tests performed on all parameters show a strong variability both between different groups and within the same group. In detail, the European charcoal samples show characteristics more suitable for their use in barbecues. These have the highest values of fixed carbon and heating value and, at the same time, low values of ash and volatile matter. On the contrary, charcoal briquettes have less suitable characteristics for barbecue. The work also highlighted some gaps in the reference standard relating to laboratory analyses. To ensure careful control of the qualitative characteristics of the products on the market, it is necessary to promote the creation of a quality brand.
•Absence of information on the characteristics of the charcoal on the market.•Properties influenced by origin, wood species and production process.•Presence of gaps in reference standards relating to laboratory analysis.•High variability of the energy properties of the charcoal and briquettes.•Poor representativeness of the HHV0 determined as indicated by the standard.
Charcoal; Charcoal briquettes; Charcoal properties; Proximate analysis; Barbecue; Heating value; Biofuel; Grilling.
A one-dimensional hydrological model of a slope covered with pyroclastic materials is proposed. The soil cover is constituted by layers of loose volcanic ashes and pumices, with a total thickness ...between 1.8 m and 2.5 m, lying upon a fractured limestone bedrock. The mean inclination of the slope is around 40°, slightly larger than the friction angle of the ashes. Thus, the equilibrium of the slope, significantly affected by the cohesive contribution exerted by soil suction in unsaturated conditions, may be altered by rainfall infiltration. The model assumes a single homogeneous soil layer occupying the entire depth of the cover, and takes into account seasonally variable canopy interception of precipitation and root water uptake by vegetation, mainly constituted by deciduous chestnut woods with a dense underbrush growing during late spring and summer. The bottom boundary condition links water potential at the soil-bedrock interface with the fluctuations of the water table of the aquifer located in the fractured limestone, which is conceptually modelled as a linear reservoir. Most of the model parameters have been assigned according to literature indications or from experimental data. Soil suction and water content data measured between 1 January 2011 and 20 July 2011 at a monitoring station installed along the slope allowed the remaining parameters to be identified. The calibrated model, which reproduced very closely the data of the calibration set, has been applied to the simulation of the hydrological response of the slope to the hourly precipitation record of 1999, when a large flow-like landslide was triggered close to the monitored location. The simulation results show that the lowest soil suction ever attained occurred just at the time the landslide was triggered, indicating that the model is capable of predicting slope failure conditions.
An inverse procedure for the estimation of soil water content profiles along TDR probes is presented. A TDR metallic probe is considered as a transmission line, for which relevant partial derivatives ...equations apply. The direct problem consists in the integration of transmission line equations, providing
V(
x,
t) along the line. To this aim, the unit length parameters of the transmission line must be known. In particular, unit length capacitance
C(
x) and transverse conductance
G(
x) depend on water content distribution along the probe
θ(
x) through relative permittivity
ε
r(
x) and bulk soil electrical conductivity
σ(
x), respectively. The inverse procedure consists in finding the water content distribution, and the relevant unit length parameters, giving rise to the best fit between the numerically simulated voltage
V
(
x
¯
,
t
)
at the beginning of the line and the experimental voltage trace
V
exp
(
x
¯
,
t
)
measured by a cable tester. In order to reduce the ill-posedness of the inverse problem, unknown water content profiles are expressed by means of a four parameters functional form. The search for the best fitting parameters vector is carried out with a genetic algorithm. The proposed inverse procedure is successfully applied to the determination of vertical water content profiles along a soil sample in the laboratory by means of a single three rods metallic TDR probe. Water content profiles estimated either in steady flow conditions, or during controlled infiltration-evaporation transients are compared with independent water content measurements carried out by means of horizontal TDR probes at various depths, showing in all cases good agreement.
PDF
