Search results

The purpose of this paper is to closely study young French small and medium enterprises (SMEs). The authors highlight the structure of these target firms and build a typology of corresponding business models.

The authors used a dataset of 38,000 young French SMEs. It is constituted of all individual and consolidated year‐end financial statements submitted by French firms to the commercial court. Data analysis techniques (principal component analysis then hierarchical and ascending classification) were used on the data.

The business models stemming from this typology are typical (to the greatest extent possible) and actionable. The authors are particularly interested in identifying groups of SMEs where government assistance would be particularly effective and strategically valuable for the national economy.

One of the authors' conclusions is that the typology is not based on a classical growth model that reflects progressive phases of development in the life of a young firm. Furthermore, it is ineffective and wasteful to focus government assistance efforts on firms based on their age. The authors identify groups of business models where assistance would be more efficient and strategically more effective.

It is notable that this paper relies not upon a sample, but upon the exhaustive collection of all available data on the subject. This research questions the allocation efficiency of governmental assistance on the basis of growth models. It intends to provide a better understanding of the criteria that should be taken into account to enhance targeting of assistance toward businesses with the greatest potential for the nation.

This paper aims to investigate melting heat transfer of a non-Newtonian phase change material (PCM) in a cylindrical enclosure-space between two tubes using a deformed mesh method.

Metal foam porous layers support the inner and outer walls of the enclosure. The porous layers and clear space of the enclosure are filled with PCM. The natural convection effects during the phase change are taken into account, and the governing equations for the molten region and solid region of the enclosure are introduced. The governing equations are transformed into non-dimensional form and then solved using finite element method. The results are compared with the literary works and found in good agreement. The non-Newtonian effects on the phase change heat transfer and melting front are studied.

The results show that the increase of non-Newtonian effects (the decrease of the power-law index) enhances the heat melting process in the cavity at the moderate times of phase change heat transfer. The temperature gradients in porous metal foam over the hot wall are small, and hence, the porous layer notably increases the melting rate. When the melting front reaches the cold porous layer, strong non-linear behaviors of the melting front can be observed.

The phase change heat transfer of non-Newtonian fluid in a cylindrical enclosure partially filled with metal foams is addressed for the first time.

This study examines the survival probability of the firms during the COVID-19 pandemic and identifies the effects of pandemic-era business strategies on firm survival across sectors and sizes.

This study combines World Bank Enterprise Survey data with three consecutive follow-up COVID-19 survey data. The COVID-19 surveys are the follow-up surveys of WBES, and they are done at different points of time during the pandemic. Both WBES and COVID-19 surveys follow the same sampling methods, and the data are merged based on the unique id number of the firms. The data covers 12,551 firms from 21 countries in different regions such as Africa, Latin America, Central Asia and the Middle East. The study applies Kaplan–Meier estimate to analyze the survival probability of the firms across sectors and sizes. The study then uses Cox non-parametric regression model to identify the effect of business strategies on the survival of the firms during the pandemic. The robustness of the Cox model is checked using the multilevel parametric regression model.

The study's findings suggest that a firm's survival probability decreases during the pandemic era. Manufacturing firms have a higher survival probability than service firms, whereas SMEs have a higher survival probability than large firms. During the pandemic period, business strategies significantly boost the probability of firm survival, and their impacts differ among firm sectors and sizes. Several firm-specific factors affect firm survival in different magnitudes and signs. Except in a few cases, the findings also indicate that one strategy positively moderates the influence of another strategy on firm survival during a pandemic.

COVID-19 pandemic has drastically affected the business across the globe. Firms adopted new business processes and strategies to face the challenges created by the pandemic. The critical research question is whether these pandemic-era business strategies ensure firms' survival. This study attempts to identify the effects of these business strategies on firms' survival, focusing on a comprehensive firm-level data set that includes firms from different sectors and sizes of countries from various regions.

The aim of this study is to apply an enthalpy-based lattice Boltzmann method with multi distribution function model, to investigate melting process with natural convection inside a cavity with an obstacle. The cavity is filled with water (ice)-based nanofluid containing copper nanoparticles.

This methodology eliminates the requirement of satisfying conditions at the phase change front. The combination of lattice D2Q9 and D2Q5 models is implemented to determine the density, velocity and temperature fields. The simulations are carried out for Rayleigh number of 105, various volume fractions of the nanoparticles and various positions of the cubic obstacle.

The predicated results demonstrate that the use of nanoparticles leads to enhancement of thermal conductivity of nano-enhanced phase change materials in comparison with conventional PCMs. When the position of the obstacle changes from the top to the bottom of the cavity the melting rate increases 75 percent. The numerical study indicates that by increasing the solid concentration from 0 to 0.04, the heat release enhances 52.7, 41.2 and 30 percent when the obstacle is located on the top, middle and bottom sections of the cavity, respectively. It is also observed that, the employment of nanoparticles is more effective when the heat conduction dominates.

The main unacceptable property of most PCMs is their low thermal conductivity, and hence, heat transfer enhancement using nanofluid will be useful for thermal energy storage applications.

The purpose of this paper is to simulate a macrosegregation solidification benchmark by a meshless diffuse approximate method. The benchmark represents solidification of Al 4.5 wt per cent Cu alloy in a 2D rectangular cavity, cooled at vertical boundaries.

A coupled set of mass, momentum, energy and species equations for columnar solidification is considered. The phase fractions are determined from the lever solidification rule. The meshless diffuse approximate method is structured by weighted least squares method with the second-order monomials for trial functions and Gaussian weight functions. The spatial localization is made by overlapping 13-point subdomains. The time-stepping is performed in an explicit way. The pressure-velocity coupling is performed by the fractional step method. The convection stability is achieved by upstream displacement of the weight function and the evaluation point of the convective operators.

The results show a very good agreement with the classical finite volume method and the meshless local radial basis function collocation method. The simulations are performed on uniform and non-uniform node arrangements and it is shown that the effect of non-uniformity of the node distribution on the final segregation pattern is almost negligible.

The application of the meshless diffuse approximate method to simulation of macrosegregation is performed for the first time. An adaptive upwind scheme is successfully applied to the diffuse approximate method for the first time.

In a simple reciprocal dumping model of trade, this study scrutinizes the strategic role of trade and commodity taxes as environmental instruments when consumption of an imported product generates pollution. The results suggest that for sufficiently small values of the marginal disutility from pollution, commodity taxes can be preferred over import tariffs, and compared to the case of trade policies, free trade can be welfare dominating even for higher values of the marginal disutility from pollution when commodity taxes are used strategically as environmental instruments.

The authors employ a reciprocal dumping model of trade.

A sufficiently high marginal disutility from pollution (or sufficient asymmetries between the countries in terms of their marginal disutility from pollution) may jeopardize bilateral trade, especially if countries are given the option to set tariffs freely for imported goods (consumption of which generate environmental pollution). For sufficiently weak transboundary pollution and sufficiently low marginal disutility from pollution, (1) both Nash trade and domestic policies may prove to be helpful in addressing consumption-based pollution, and (2) it is possible to show in such a case that Nash domestic policies may be preferred over Nash trade policies, especially when both transboundary pollution and the trading partner's marginal disutility from pollution are sufficiently low.

The novel contribution of this paper is (1) to capture asymmetries among trading partners in terms of how much they account for environmental pollution when deciding on their (domestic/trade) policy measures and (2) to focus on environmental degradation that is caused by final consumption of a product imported from a trading partner.