Solid air hydrogen liquefaction, the missing link of the hydrogen economy

The most challenging aspect of developing a green hydrogen economy is long-distance oceanic transportation. Hydrogen liquefaction is a transportation alternative. However, the cost and energy consumption for liquefaction is currently prohibitively high, creating a major barrier to hydrogen supply chains. This paper proposes using solid nitrogen or oxygen as a medium for recycling cold energy across the hydrogen liquefaction supply chain. When a liquid hydrogen (LH2) carrier reaches its destination, the regasification process of the hydrogen produces solid nitrogen or oxygen. The solid nitrogen or oxygen is then transported in the LH2 carrier back to the hydrogen liquefaction facility and used to reduce the energy consumption cooling gaseous hydrogen. As a result, the energy required to liquefy hydrogen can be reduced by 25.4% using N2 and 27.3% using O2. Solid air hydrogen liquefaction (SAHL) can be the missing link for implementing a global hydrogen economy

Perda de carga promovida por influxo radial em poços horizontais de produção de petróleo

he present work investigates the influence of radial inflows on pressure profiles and maximum axial flow velocity in the center line of horizontal oil production wells. It aims to help in understanding the dynamics of well-reservoir coupling in the context of the oil industry. The flow is characterized as monophasic, incompressible and turbulent, flowing internally to a horizontal pipe 3 m long and 10 cm in diameter. The fluid enters the duct radially through several holes of 1 cm diameter present in the pipe wall. Numerical modeling is performed using ANSYS FLUENT 15.0 software, with post-processing and data collection through CFD-Post. The results show that the presence of the radial influx results in an increase in the pressure differential along the pipe, due to the restriction to the axial flow through the appearance of a hydrodynamic barrier promoted by the radial influx. It is also noted that the higher the radial flow intensity, the greater the maximum axial flow velocity

Measuring Success in Family Businesses: The Concept of Configurational Fit

The problems associated with measuring success in small businesses are primarily caused by a lack of comparable data due to the ambiguity of success and by subjective biases. Success evaluation is dominated by the estimates of business owners, who tend to overestimate overall success and internal strengths. However, reliable success measurement instruments would be useful for small business owners/managers as well as small business policymakers. The main purposes of this article are to compare various measures of success, to explore the differences in their outcomes, and to analyze whether a model of success measurement using configurational fit can be used to overcome subjective biases. The study is based on a recent survey of 103 small family-owned businesses in the eastern Austrian border region. Our analysis of the data confirmed the existence of the measurement problems mentioned above. While some individual indicators show significant biases as well as effects due to company age, size and industry, the aggregated indicator based on the concept of configurational fit seems to be an appropriate means of overcoming most of these drawbacks.(author's abstract