Harnack and pointwise estimates for degenerate or singular parabolic equations

In this paper we give both an historical and technical overview of the theory of Harnack inequalities for nonlinear parabolic equations in divergence form. We start reviewing the elliptic case with some of its variants and geometrical consequences. The linear parabolic Harnack inequality of Moser is discussed extensively, together with its link to two-sided kernel estimates and to the Li-Yau differential Harnack inequality. Then we overview the more recent developements of the theory for nonlinear degenerate/singular equations, highlighting the differences with the quadratic case and introducing the so-called intrinsic Harnack inequalities. Finally, we provide complete proofs of the Harnack inequalities in some paramount case to introduce the reader to the expansion of positivity method.Comment: Survey paper, 50 pages, 5 figures. Comments welcom

Circular economy and corporate social responsibility in the agricultural system: Cases study of the Italian agri-food industry

The persistent exploitation of natural resources and the consequent use of consumption are driving global food demand with the result that agricultural activity is becoming less and less environmentally friendly. The circular economy (CE) can become a valid alternative, inserting the economic-agricultural system into the harmonic process of material circulation. The corporate social responsibility (CSR) model is particularly interesting not only because of the ethical dimension of the company but also as a factor of strategic business improvement that combines the concepts of CSR and CE as possible solutions for developing sustainable business processes. The objective of the work is to highlight a detailed framework of how the small and medium-sized enterprises (SMEs) of the Italian agri-food industry can provide an ade-quate level of communication, circular strategies and social responsibility practices. The research methodology is based on a qualitative multiple study conducted on a sample of nine companies in the Italian territory. The study highlights the attention of companies on the issues of the CE for the achievement of the set sustainable objectives and the attention to CSR and CE practices. The work has several implications. It provides a further understanding of CSR and CE policies as enabling factors for the development of sustainable organizational performance in agriculture. Moreover, it better investigates the relationship between CSR and the CE. Finally, it analyses the SMEs state of the art in the CE field and strengthens the concept of CE by analysing corporate practices consistent with sustainability reports

Integrated Analysis and Tools for Land Subsidence Surveying and Monitoring: a Semi-Quantitative Approach

This paper presents an integrated approach for land subsidence monitoring using measures coming from different sensors. Eni S.p.A., the main Italian oil and gas company, constantly surveys the land with all the state of the art and innovative techniques, and a method able to integrate the results is an important and actual topic. Nowadays the world is a multi-sensor platform, and measure integration is strictly necessary. Combining the different data sources should be done in a clever way, taking advantages from the best performances of each technique. An integrated analysis allows the interpretation of simultaneous temporal series of data, coming from different sources, and try to separate subsidence contributions. With this purpose Exelis VIS in collaboration with Eni S.p.A. customize PISAV (Permanent Interferometric Scatterometer Analysis and Visualization), an ENVI extension able to capitalize on and combine all the different data collected in the surveys. In this article are presented some significant examples to show the potential of this tool in oil and gas activity: a hydrocarbon storage field where the comparison between SAR and production volumes emphasise a correlation between the two measures in few steps; and a hydrocarbon production field with the Satellite Survey Unit (S.S.U.), where SAR, CGPS, piezometers and assestimeters measure in the same area at the same time, giving the opportunity to analyse data contextually. In the integrated analysis performed with PISAV not always a mathematical rigorous study is possible, and a semi-quantitative approach is the only method for results interpretation. As a result, in the first test case strong correlation between injected hydrocarbon volume and vertical displacement were highlighted; in the second one the integrated analysis has different advantages in monitoring the land subsidence: permits a first qualitative "differentiation" of the natural and anthropic component of subsidence, and also gives more reliability and coverage to each measurement, taking advantages from the strong points of each technique

Participative ergonomics for the improvement of occupational health and safety in industry: a focus group-based approach

This paper introduces a participative approach to the investigation and promotion of health and safety in industry. The proposed methodology promotes the active participation of the workers in the analysis of consequences and causes of unsafe behaviours that may result in work-related musculoskeletal disorders, accidents, injuries or near-misses. The developed participative technique is the Focus Group with Workers, based on the Fault Tree Analysis method (FGW-FTA). Focus groups are conventionally used by social and behavioural researchers to understand opinions, motivations, attitudes, and mental processes that underlie people behaviours. The innovative procedure in this paper addresses researchers and safety professionals during the focus groups with the workers for the identification of critical risk factors in the workplace. The result is a structured analysis, operated by and with the workers, for the identification of consequences and causes of unsafe behaviours. Finally, the developed methodology addresses the definition of a set of preventive and protective measures, and corrective actions for the improvement of health and safety in the workplace. An experimental study in an Italian boiler manufacturer describes the proposed methodology and the results of the focus groups with the workers. An evaluation questionnaire was elaborated to investigate the workers’ knowledge on occupational health and safety. A second questionnaire was developed to understand the workers’ perception on occupational risks. Each participant was invited to fill in both the questionnaires before and after the focus groups with the workers. The results of the study proved the effectiveness of the developed methodology in improving workers knowledge and perceptions on occupational health and safety

Multiple Solutions to (p,q)-Laplacian Problems with Resonant Concave Nonlinearity

Abstract The existence of multiple solutions to a Dirichlet problem involving the ( p , q ) ${(p,q)}$ -Laplacian is investigated via variational methods, truncation-comparison techniques, and Morse theory. The involved reaction term is resonant at infinity with respect to the first eigenvalue of - Δ p ${-\Delta_{p}}$ in W 0 1 , p ⁢ ( Ω ) ${W^{1,p}_{0}(\Omega)}$ and exhibits a concave behavior near zero