Lacunary generating functions of Hermite polynomials and symbolic methods

We employ an umbral formalism to reformulate the theory of Hermite polynomials and the derivation of the associated lacunary generating functions

TIPOLOGIE EDILIZIE: Edificio a corpi trasversali.Ostello del Parco Naturale delle Alpi Marittime a Trinità di Entraque (Cuneo)

Manuale di buone pratich

Understanding how porosity gradients can make a better filter using homogenization theory

Filters whose porosity decreases with depth are often more efficient at removing solute from a fluid than filters with a uniform porosity. We investigate this phenomenon via an extension of homogenization theory that accounts for a macroscale variation in microstructure. In the first stage of the paper, we homogenize the problems of flow through a filter with a near-periodic microstructure and of solute transport owing to advection, diffusion and filter adsorption. In the second stage, we use the computationally efficient homogenized equations to investigate and quantify why porosity gradients can improve filter efficiency. We find that a porosity gradient has a much larger effect on the uniformity of adsorption than it does on the total adsorption. This allows us to understand how a decreasing porosity can lead to a greater filter efficiency, by lowering the risk of localized blocking while maintaining the rate of total contaminant removal

Electromagnetic and thermal homogenisation of an electrical machine slot

In this paper we propose an original technique based on the finite element method to couple electromagnetic and thermal homogenisation of multiturn windings. The model accurately accounts for skin and proximity effects considering the temperature dependence of electrical resistivity. We validate the approach by modelling a reference electrical machine open slot with representative boundary conditions. The case study refers to a particular wire shape and winding periodic configuration but the method can be applied to any symmetrical wire shape. The homogenisation allows us to efficiently evaluate the hot- spot temperature within the slot. The solution provided by the homogenised model proves to be very accurate over a large range of frequencies, when compared to the results using a fine model where all the conductors are physically reproduced

Internal Logistics Process Improvement using PDCA: A Case Study in the Automotive Sector

Background: The Plan-do-check-act (PDCA) cycle methodology for a continuous improvement project implementation aims for the internal logistics upgrade, which is especially important in the industrial context of a component manufacturing company for the automotive sector. Objectives: The goal is to quantify the gains from waste reduction based on the usage of the PDCA cycle as a tool in the implementation and optimisation of a milk run in an assembly line of a company in the automotive sector by determining the optimal cycle time of supply and the standardisation of the logistic supply process and the materials’ flow. Methods/Approach: The research was conducted through observation and data collection in loco, involving two main phases: planning and implementation. According to the phases of the PDCA cycle, the process was analysed, and tools such as the SIPOC matrix, process stratification, 5S, and visual management were implemented. Results: Using Lean tools, it was possible to reduce waste by establishing concise flows and defining a supply pattern, which resulted in a reduction of movements. The transportation waste was reduced by fixing the position of more than half of the materials in the logistic trailers. The developed Excel simulator provided the logistic train\u27s optimal cycle time. Conclusions: The assembly line supplied by milk-run was fundamental to highlight a range of improvements in the process of internal supply, such as better integration of stock management systems, greater application of quality, or the adoption of better communication systems between the different areas and employees

Strategies to control Staphylococcus epidermidis biofilms

Staphylococcus epidermidis is the staphylococci species most commonly associated with bacteremia and hospital-acquired infections and has recently arisen as the leading cause of infections related to indwelling medical devices such as vascular catheters, prosthetic joints and artificial heart valves. The prevalence of S. epidermidis in hospital-acquired infections is due to its ability to adhere and form biofilms on biomaterial surfaces. This feature is one of the most important virulence factors found in S. epidermidis. In biofilm form, bacteria are protected from antimicrobial agents and the host immune system contributing to the persistence of biofilm infections. In addition, the emergence of S. epidermidis resistance to conventional therapies, based in the use of traditional antibiotics, leads to the failure of the current treatments used in the combat of S. epidermidis infections and is becoming a major concern. These facts are stimulating the continuous search for novel agents able to eradicate S. epidermidis biofilm infections or that can work in synergy with the currently available antimicrobial agents. New strategies have been showing encouraging in vitro results in controlling S. epidermidis biofilms and seem to be promising alternatives to standard antibiotics usually used in the treatment of S. epidermidis related infections