D. De Wrachien

Quantum mechanics applied to the dynamic assessment of a cluster of water particles in sprinkler irrigation

The problem of liquid droplets crossing a gas is common to many scientific and technical issues and, in particular, also to sprinkler irrigation; thus, when designing a sprinkler irrigation system, it is essential to fully understand how droplets mechanically behave during their flight and how a mathematical modeling can cope with all the variables affecting one another during such a complicate thermal fluid dynamic process. In the thematic scientific literature, the classic approach has been recently challenged by an alternative quantum one, provided in two different formulations referring to a single droplet dynamics: one focusing on a full description of the process (time-dependent Schrödinger equation); the other focusing on the discovery of an easier-to-use method (scale relativity theory); both allowing for a broader microscopical insight of the actual mechanics of single water droplets in sprinkler irrigation. The present contribution is aimed at developing the quantum procedure extending it to a cluster of water particles, as one droplet during its aerial flight conditions the others, which are in its vicinity and vice versa.

Mathematical models for flood hazard assessment

One-third of the annual natural disasters and economic losses, and more than half of the respective victims are flood-related. Knowledge and advanced scientific tools play a role of paramount importance in the strain of coping with flooding problems. The paper, after a brief discussion of the terms hazard, vulnerability, and risk, presents the governing equations for 1D, 2D, and 3D models, together with examples of their applications and discussion of the carried out results. It is shown that 1D models can be used only in very particular cases, but actually they are still the most reliable and robust of all the models; wide spread use of 2D models is justified by the relatively easiness in their use, and because the time consumption is still quite reduced. As for 3D models, their use in environmental hydraulic is still limited to very peculiar cases, because of the difficulties encountered in their use and the impressive time consumption they require, which in the largest cases necessitates the dramatic simplification of the topography or of the turbulence models that implies poor quality results. Keywords case studies, flood hazard, mathematical models Language: en

Risk Analysis and Vulnerability Assessment in Flood Protection and River Basin Management

The water-related disasters are considerably increasing worldwide in the last years. While certain trends are global (like climate change), some actions to contrast these problems have to be taken locally. In any case, the land characteristics should be known and analyzed in order to contrast the hazards and avoid their transformations into damages or disasters when exceptional events occur. This paper firstly presents preliminary definitions about the concepts of hazard, vulnerability, risk and damage/disaster, because there is a certain lack of uniformity in the use of terms, which sometime drives towards a confusion; thus definitions are offered, with a special attention paid to the flood problems. Then, risk analysis procedures are described, which consist of systematic actions in a cycle of preparedness, response and recovery, and should form part of the integrated water resources management. Moreover, the flooding problem characteristics and the policy and related measures adopted by different European countries, to protect themselves against floods, are considered and the lessons learnt from flood defence analyzed, with the aim of featuring a new integrated flood and management approach that allocates more space for rivers and keeps a balance between present and foreseeable future spatial requirements of both water and people.

Land Use Planning: A Key to Sustainable Agriculture

Sustainable use of the soil is a form of land management which retains the natural fertility of the soil and allows for the production of food and fiber supplies and renewable natural resources on a long-term basis. It implies that the natural environment should be treated and managed in such a way that the cycles and energy fluxes among the soil, bodies of water and atmosphere are considered, preserved or restored. To this respect, the term «sustainable land use» is more comprehensive than the term «sustainable soil use». Land, commonly, stands for a section of the earth’s surface with all the physical, chemical and biological features that influence the use of the resource. It refers to soil, spatial variability of landscape, climate, hydrology, vegetation and fauna, and also includes improvements in land management, such as drainage schemes, terraces and other agrobiological and mechanical measures. The term «land use» encompasses not only land use for agricultural and forestry purposes, but also use of the land for settlements, industrial sites, roads and other human activities. Land use, in this meaning, can be termed sustainable only if is achieved such a spatial distribution or configuration of the different uses, as to guarantee biodiversity and preserve the eco-balance of the whole system. Rational land use planning is fundamental to this process. With reference to the aforestated issues, the paper describes the main physical, social and economic features of land use planning projects, along with their environmental impacts and constraints to sustainable development. The importance and role of institutional strengthening, sound financial and managerial frameworks, availability of human resources involved, research thrust, technology transfer and networking improvement are also analyzed.

Water Droplets Behavior in Sprinkler Irrigation: Thermal-Fluid Dynamical Assessment and Quantum Considerations

The present paper is aimed at analyzing the behavior of water droplets traveling in air from the nozzle to the ground according to a traditional numerical and a quantum point of views. Considering a single-droplet system, an analytical model based on the Newtonian kinematics is here described, considering the most relevant parameters involved: droplet initial diameter, droplet initial velocity, water and air temperatures, diffusion coefficient of water in air, air relative humidity, environmental radiation, and presence of wind. The effect of those parameters on water evaporation is, hence, discussed. Differently, when a multi-droplet system in considered, the problem becomes even more complicated due to the difficulty of assessment of interdroplet reciprocal affections and both a Newtonian description and a numeric implementation are definitely hard to obtain. An alternative to traditional approaches to treat the water droplet dynamics is the quantum approach, which is here introduced and pointed out in order to give an as full as possible description of the whole phenomenon. Such an approach offers a more tight description of the microscopic phenomena that influence the evolution of the whole multi-droplet system.

Assessment Of Debris Flow Deposition Areas: Empirical Methods, Laboratory Tests And Application To A Case Study

Debris and hyper-concentrated flows are among the most destructive of all water-related disasters and in the recent years have attracted more and more attention from the scientific and professional communities and concern from public awareness, due to the increasing frequency with which they occur and the death toll they claim. The study of debris flows can be subdivided into three main topics: the assessment of the magnitude of the phenomenon, the study of debris flow motion and the determination of the extension of the deposits. This last issue is of paramount importance from an engineering point of view, due to the fact that it determinates the areas that must be considered at risk, with all the consequences linked to the protection of population, and the predisposition of safety plans concerning different activities such as building construction. In this paper, a review of the most important empirical procedures of prediction of depositional areas is presented, with the aim to verify the applicability of the formulas to events different from those for which the methods were calibrated and then to try to unify them in order to originate a more reliable methodology. Laboratory tests were carried out to integrate the data available in the literature. The experimental data have been recorded with photogrammetry methods and 3D models of the deposits have been designed and validated. Then, the carried out procedure is applied to a small catchment in the North of Italy. The proposed empirical method will allow one to improve both mitigation measures and hazard mapping procedures. Keywords Debris flow, deposits on alluvial fan, empirical method, laboratory tests Language: en

DEFENCE MEASURES IN FLOOD RISK ASSESSMENT: A CASE STUDY

Flood defense is a problem of vital importance, for which knowledge and advanced scientific tools play a paramount important role in the strain of coping with flooding problems. In this context, flood modeling represents the basis for effective flood mitigation measures. By using models, an attempt is made to replace trial-and-error-based strategies, as practiced in the past, with more physically based measures of flood management and control. Mathematical models are the best tools, nowadays available, for the design of efficient flood protection strategies and excellent supporters of decision-makers. With reference to these issues, the paper provides a complete application of the procedures, nowadays available, for risk assessment, from catchment to a very local scale, on the Lambro River in Milano, Italy. It is shown that social and political constraints may force risk managers to find different solutions to solve the problems they have to face, which may be related to non-hydraulic issues. Keywords case studies, early warning, flood hazard, mathematical models Language: en