Taking into account the international policies in the field of environmental protection in the world in general, and in the European Union in particular, the reduction of greenhouse gas (GHG) emissions, and primarily of carbon dioxide, has become one of the most important objectives. This can be obtained through various renewable energy sources and non-polluting technologies, such as the mixing of hydrogen and natural gas. Combining hydrogen with natural gas is an emerging trend in the energy industry and represents one of the most important changes in the efforts to achieve extensive decarbonisation. The importance of this article consists of carrying out a techno-economic study based on the simulation of annual consumptions regarding the construction and use of production capacities for hydrogen to be used in mixtures with natural gas in various percentages in the distribution network of an important operator in Romania. In order to obtain relevant results, natural gas was treated as a mixture of real gases with a known composition as defined in the chromatographic bulletin. The survey presents a case study for the injection of 5%, 10%, and 20% hydrogen in the natural gas distribution system of Bucharest, the largest city in Romania. In addition to conducting this techno-economic study, the implications for final consumers of this technical solution in reducing greenhouse gas emissions—mainly those of carbon dioxide from combustion—are also presented.

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The natural gas consumption of the operators connected to the gas transport system depends on the gas needs. As gas needs vary in time, the whole process of gas transportation is, therefore, nonstationary. The paper presents nonstationary simulations for a gas transportation network and highlights the parameters values (flows, pressures) that are necessary to assure the safety of the system.

This work focuses on a very important and current problem in the gas field: gas losses in natural gas distribution networks and their impact on the environment, as well as on the company operating the network. The paper starts with a bibliographic study and aims to identify the sources leading to losses, estimate loss volumes, reduce these losses by replacing high-risk pipeline sections, as well as trace the economic, environmental, and social impact. The calculation methodologies used in various countries in estimating these consumptions are very diverse. Romania uses a very dense methodology that can prompt very broad variations in the values obtained for technological consumption calculations using Order 18/2014, due to the multitude of parameters that must be estimated. To reduce some of the uncertainties in estimating these parameters, a study was proposed and carried out on the ill-fittings in the natural gas distribution systems. The article presents the experimental stand, the analysis of the experimental data, the methodology for calculating gas losses in the natural gas distribution system through leaking equipment, as well as the results obtained and the conclusions. Moreover, an application was made for a dynamic area check of the gas balance. Based on the correlations between the annual values in M&R stations, AMR, the volume for small consumers, technological consumption, linepack, and the equipment and materials used in the network, useful data were obtained in the diagnosis of problem areas. The end of the paper shows an economic calculation regarding the replacement of problematic pipeline sections in natural gas distribution networks. The difference between the volume of investments and the income from loss reduction is very large, but the aspect of protecting the environment and eliminating technological risks intervenes, thus increasing social security and health.

In time, osteoarthritis (OA) generates the misalignment of the affected joint structures. However, due to the nature of bipedal gait, OA in the lower limb can also cause pathological gait patterns, which can generate instability and falls, with great consequence, especially in the aged population. With goniometry used to evaluate the range of motion (ROM) of joints, we wanted to evaluate how gender impacts gait dynamics in OA patients. For this study, we have compared 106 OA patients (74 females and 32 males) to age matched controls. All participants had their right leg as dominant. Video recording of normal gait was analyzed with a digital goniometry tool phone application, and the knee's ROM was measured in midstance and midswing moment of the gait. During midstance, significant extension and flexion of the knee excursion have been observed in both males and females. During midswing, knee OA presents more differences, whereas subjects with hip and knee OA present changes on the dominant knee. Midstance changes suggest that the knee's joint degenerative changes, such as synovitis, can be linked to hip OA secondary changes. Midswing changes in lower limb OA suggest a connection to the activities of daily life. Gender differences generated by OA must furthermore be studied in both lower limbs so that the best therapeutic approach can be chosen.