Heteropolymers in a Solvent at an Interface

Exact bounds are obtained for the quenched free energy of a polymer with random hydrophobicities in the presence of an interface separating a polar from a non polar solvent. The polymer may be ideal or have steric self-interactions. The bounds allow to prove that a ``neutral'' random polymer is localized near the interface at any temperature, whereas a ``non-neutral'' chain is shown to undergo a delocalization transition at a finite temperature. These results are valid for a quite general a priori probability distribution for both independent and correlated hydrophobic charges. As a particular case we consider random AB-copolymers and confirm recent numerical studies.Comment: 4 pages, no figure

The ability of the turnaround index to assess going concern assumptions: evidence from its application to Italian listed companies.

In times of crisis, entrepreneur often must decide whether to liquidate the company and the whole business or to renew it by activating a turnaround process. A tool increasingly used in international practice is the turnaround index, which can determine whether a company can continue its activities in the future according to the going concern assumption, which is the index measured as a function of the economic and financial performance of the company. This measure can take values between 0.1, for satisfactory performance and therefore unlikely to turn around, and 0.9, for unsatisfactory performance and therefore a high propensity to turnaround. The index determines whether there is a higher or lower risk for a company to enter into crisis. The aim of this paper is to test the effectiveness of the turnaround index in assessing the turnaround urgency by choosing a sample of the Italian companies

EVIDENCE OF THE ITALIAN SPECIAL PURPOSE ACQUISITION COMPANY

In 1992 David Nussbaum with the support of the law firm Graubard Miller devised the formula of the specified purpose acquisition companies (SPAC): a financial vehicle that has the flexibility and functionality typical of the blank-check companies, which could provide investors with the right protections and guarantees in order to be a reliable instrument. The first SPAC officially debuted in 2003 through the Initial Public Offering (IPO) of Millstream Acquisition Corporation which then completed the merger with Nations Health in September 2004. In 2005 the first SPAC got listed in European Market and in 2011 the first SPAC joined in the Italian market. The aim of this research is to investigate the features of the Italian SPACs System because it\u201fs becoming a large phenomenon in Italy. This new type of investment is able to fit the needs of small-medium Italian companies, to solve crisis difficulties, to find new finance to grow, to be a good instrument for opening up venture capital and institutional investors respecting the past business history and the safeguard of corporate control. The study, then, performs an analysis on the Italian SPACs by examining their target firms, stock performance before and after the business combination and the impact of the SPACs on SME corporate governance models. These results will be compared with those of other research developed by academic literature

THE IMPACT OF THE NEW ITALIAN EARLY WARNING SYSTEM PROVIDED BY THE IC-CODE ON FAMILY SMES GOVERNANCE

The Early Warning System is intended as an instrument aimed at driving the companies in the identification of the very first signs of crisis. Monitoring the occurring of the crisis is no longer a responsibility of the sole entrepreneur or of the board of directors but other legitimized subjects are identified. The IC-Code sets up new corporate governance rules for a huge number of Italian Family SMEs pretending the introduction of independent control bodies, Board of Statutory Auditors, and/or External Auditor. Some of the suggestions coming from the family business framework seems then to be enforced by law in the Italian context

Evidence for using the cash conversion cycle to test the relationship with the corporate profitability an empirical analysis on a sample of textile Italian SMEs

The cash conversion cycle (CCC) is a financial index with increasing importance in recent years since analysts and investors consider it effective for financial analyses. The index provides a correct and truthful situation of the company's ability to cope with its liabilities and allows the company to monitor the cash cycle with reference to purchase operations, production, and sales of products. The CCC is an index expressed by days, so it is necessary to know the days inventory outstanding, the days sales outstanding, and the days payable outstanding to calculate it. The purpose of this research is to analyse characteristics of the CCC and differences with respect to the other liquidity ratios and its relationship with the most relevant financial ratios through empirical applications to verify if it is a reliable index for making decisions regarding a company's cash flow strategy

Shape analyticity and singular perturbations for layer potential operators

We study the effect of regular and singular domain perturbations on layer potential operators for the Laplace equation. First, we consider layer potentials supported on a diffeomorphic image (Ω) of a reference set Ω and we present some real analyticity results for the dependence upon the map. Then we introduce a perforated domain Ω(ϵ) with a small hole of size ϵ and we compute power series expansions that describe the layer potentials on Ω(ϵ) when the parameter ϵ approximates the degenerate value ϵ = 0

Dependence of effective properties upon regular perturbations

In this survey, we present some results on the behavior of effective properties in presence of perturbations of the geometric and physical parameters. We first consider the case of a Newtonian fluid flowing at low Reynolds numbers around a periodic array of cylinders. We show the results of [43], where it is proven that the average longitudinal flow depends real analytically upon perturbations of the periodicity structure and the cross section of the cylinders. Next, we turn to the effective conductivity of a periodic two-phase composite with ideal contact at the interface. The composite is obtained by introducing a periodic set of inclusions into an infinite homogeneous matrix made of a different material. We show a result of [41] on the real analytic dependence of the effective conductivity upon perturbations of the shape of the inclusions, the periodicity structure, and the conductivity of each material. In the last part of the chapter, we extend the result of [41] to the case of a periodic two-phase composite with imperfect contact at the interface

Existence results for a nonlinear nonautonomous transmission problem via domain perturbation

In this paper we study the existence and the analytic dependence upon domain perturbation of the solutions of a nonlinear nonautonomous transmission problem for the Laplace equation. The problem is defined in a pair of sets consisting of a perforated domain and an inclusion whose shape is determined by a suitable diffeomorphism. First we analyse the case in which the inclusion is a fixed domain. Then we will perturb the inclusion and study the arising boundary value problem and the dependence of a specific family of solutions upon the perturbation parameter

A new CFD-Simulink based systems engineering approach applied to the modelling of a hydraulic safety relief valve

A safety relief valve is a simple hydro-mechanic device, needed to avoid overpressure transients inside hydraulic circuits. Such valves are a critical part of the hydraulic system of aircraft; hence their performances must be adapted to a specific nominal pressure level and design requirements. In the following paragraphs the authors will address the issue of designing and validating a safety valve through a hybrid CFD/MATLAB-Simulink® approach. The main constraints are the geometrical dimensions and the need to limit the weight of the device. A significant part of the work consists of gathering all the possible information available in the literature, dealing with the best design practices to achieve the performance objective. Thanks to a robust computational procedure, it should be possible to reduce the amount of “physical” prototypes required to validate the functionality of a safety relief valve. The process presented uses a numerical computational fluid dynamic (CFD) approach, to define the pressure field inside the valve and the forces acting on it; identifying the force distribution inside the valve is paramount to address the performance evaluation of the valve itself. The first step deals with the definition of a computer aided design (CAD) model of the valve. Then the CFD software uses the above-mentioned CAD model to define the domain of the problem. Once obtained the pressure field, it is possible to integrate it through the surface of the valve, thus obtaining the forces acting on the moving part (poppet). After the numerical scheme has been calibrated, some investigations are done to reduce the computational cost: the main aim is to run a complete simulation (meshing and solving) on a standard computer. Some of the positions (i.e. strokes) of the valve have been simulated as static, hence a steady-state calculation has been applied to solve the motion field. Another important result consists of creating a MATLAB-Simulink® model, capable to reach results comparable to the CFD simulation, but in shorter times. While the CFD model can provide high quality results, the MATLAB-Simulink® calculation should be used to create a “first guess” instrument, useful to address the very first valve geometry. The implementation of the Look-Up Tables (LUTs) links the MATLAB-Simulink® model to the CFD simulation, but increases the time required to obtain a solution: on the other hand, this reduces the amount of equation-modeled quantities, delivering a greater precision to the calculations