Domestic Gas Meter Durability in Hydrogen and Natural Gas Mixtures

Blending hydrogen into the natural gas infrastructure is becoming a very promising practice to increase the exploitation of renewable energy sources which can be used to produce “green” hydrogen. Several research projects and field experiments are currently aimed at evaluating the risks associated with utilization of the gas blend in end-use devices such as the gas meters. In this paper, the authors present the results of experiments aimed at assessing the effect of hydrogen injection in terms of the durability of domestic gas meters. To this end, 105 gas meters of different measurement capabilities and manufacturers, both brand-new and withdrawn from service, were investigated in terms of accuracy drift after durability cycles of 5000 and 10,000 h with H2NG mixtures and H2 concentrations of 10% and 15%. The obtained results show that there is no metrologically significant or statistically significant influence of hydrogen content on changes in gas meter indication errors after subjecting the meters to durability testing with a maximum of 15% H2 content over 10,000 h. A metrologically significant influence of the long-term operation of the gas meters was confirmed, but it should not be made dependent on the hydrogen content in the gas. No safety problems related to the loss of external tightness were observed for either the new or 10-year-old gas meters.

Wettability and Treatability of Sengon (Paraserianthes falcataria (L.) I.C. Nielsen) wood from NTB

The supply of wood from natural forests is decreasing as a result of the imbalance between harvesting and planting. The lack of wood supply from natural forests has resulted in relatively expensive wood prices. This can be anticipated by using fast-growing wood species. One type of fast-growing wood which is very abundantly available in NTB is sengon wood (Paraserianthes falcataria (L.) I.C. Nielsen). However, sengon wood has low durability so it is easily attacked by wood-destroying organisms. This condition can be overcome by making efforts to prevent wood damage in the form of preservation. This study aims to determine the wettability and treatability properties of sengon wood. The results of this study are expected to be basic information to improve the quality of sengon wood. The wettability test was carried out by measuring the contact angle between the liquid and the sample surface using the sessile drop method and the wood durability testing was carried out by measuring the retention and penetration of preservatives. The treatability test was carried out by measuring the absorption, retention, and penetration of preservatives. The results showed that the wettability of sengon is high with an equilibrium contact angle (θe) of 16.88 in the radial section and 12.51 in the tangential section. This shows that sengon wood has a good adhesion system for preservation. Treatability of sengon wood showed that the average retention and penetration are 10,21 kg/m3 and 7,33 mm. Based on the results of these measurements, sengon wood has met SNI 03-5010.1-1999 (wood preservation for housing and buildings).

TAVI-Mimic for testing of heart valve leaflet materials in physiological loading situations

The loading situation of the aortic valve is complex, complicating the identification of innovative approaches for heart valve leaflet materials, e.g. for transcatheter aortic valve implantation (TAVI). Materials engineering experiments allow for screening of materials but especially for durability testing, the consideration of physiological loads is vital/critical for the suitability-assessment of innovative leaflet materials. For this reason, a framework structure for the testing of leaflet materials in physiological loading (TAVI-Mimic) was developed. The exemplary use case for the TAVI-Mimic was a test for calcification propensity of pericardium during durability testing. The TAVI-Mimic was designed as a fourparted frame, based on previous work of our group. The leaflet material can be attached between inner and outer shells without sewing. In a second step, the TAVI-Mimic was optimized regarding radial load-deformation in comparison to a commercial TAVI by means of finite element analysis (FEA) and hydrodynamic characterization in a pulse duplicator system. Mechanical properties dependent on water uptake of different materials for 3D-printing of the TAVI-Mimic were investigated. After optimization, TAVI-Mimics were equipped with glutaraldehyde-fixated pericardial tissue and prototypes were calcified by using a heart valve durability tester and a metastable calcification-liquid, developed in earlier studies. The development of the TAVI-Mimic using FEA and experiments was successful, leading to a radial load dependent deformation of 0.6 mm which correlates with commercial TAVI. Two methacrylic photopolymers were identified for 3D-printing of the TAVI-Mimic and prototypes attached with pericardial tissue were manufactured. Pericardium TAVI-Mimics were calcified in vitro for one week and an average calciumphosphate precipitate of 0.34- 0.54 mg/cm² was measured. The optimization of the TAVR-Mimic led to an improved load-dependent behaviour compared to a commercial prosthesis while testing. The calcification method, combining the TAVI-Mimic, the metastable calcification solution and the durability tester enabled a successfully calcification of pericardial tissue, approaching the in vivo situation.

Method of formation of loading cycles for performing forced bench tests of suspension elements at the stage of technical design

Ensuring the required vehicle service life is one of the most important and topical global engineering challenges. Automobile manufacturers and research engineers around the world are actively working to improve safety and durability testing methods of vehicles, their components and systems. This article touches upon the main issues of comparing the modes of vehicle road operation and the method of forming an adequate program for extreme testing of suspension elements. The developed method has been actively applied in FSUE “NAMI” in the field of research on durability of vehicle components and systems, in particular, of hub units, with the use of mathematical modeling tools and the test base capacities and capabilities.

Development and validation of vehicle wheel load scaling method for formation of durability testing loading cycle

For a vehicle durability study, performed with simulation or laboratory testing, impact on the object should be described as set of time-domain load signals, which reflects accelerated service modes of a vehicle operation. For a newly developed vehicle these load signals can be based on previously prepared loading cycle of a similar vehicle with use of the load scaling theory. Importance and certainty of the load scaling theory is approved by active use among foreign car makers and engineering centers. However, mathematical description of the theory and scaling procedure are strictly classified, despite of being based on fundamentals of vehicle dynamics. In this paper the method of scaling of time-domain wheel and driveline loads is suggested; the method is based on proportions of size and mass properties of the original and the new vehicles. Assumed that previously recorded loading cycle corresponds to the service life of a vehicle. It is worth noting that level of loading and damage accumulation, shown with scaled loading cycle and after first prototypes testing on a proving ground, will be different because of impact of chassis stiffness and damping properties. Suggested scaling theory is being studied in FSUE “NAMI” and is on the validation and verification stage. First completed experiments showed that a multiaxial test rig could perform the vehicle suspension loading cycle, obtained with the theory, with a satisfactory accuracy. This makes utilization of the theory limited to early stages of vehicle development.

Thermal Profiling of Automotive Turbochargers in Durability Tests

A major portion of the development of an automotive powertrain system is devoted to robustness and durability testing to ascertain the viability of the design. For turbochargers, thermo-mechanical fatigue is often considered as life limiting failure mechanism for the turbine section, therefore, these tests involve repeated and continuous cycling of the turbocharger for hundreds of hours. The Thermal History Coatings (THC) can offer a new and unique solution. THCs are applied to the surface of a component and, when heated, the coating permanently changes according to the maximum temperature of exposure. The technique has been used in several turbomachinery, and other applications to capture the spatial temperature distribution of critical components. However, the turbocharger durability test presents new challenges for the technique. It has not been tested in this type of application and repeated cycling operation can test the response of the coating on the temperature measurements. In this paper, the capability of the THC for this application was investigated. For the first time, the effect of cyclic operation on the THC is reported. The measurement capability was demonstrated on two turbine housings tested on a gas stand, one for a single cycle, another for 10 cycles. The results show that the surface temperature profile of the two turbine housings can be accurately recorded and the results are validated against the installed thermocouples. The demonstration indicates that the THC can be used to acquire accurate and detailed spatial temperature distributions. This information improves the interpretation of a durability test.

Antimicrobial properties of viscose yarns ring-spun with integrated amino-functionalized nanocellulose

Bio-based, renewable and biodegradable products with multifunctional properties are also becoming basic trends in the textile sector. In this frame, cellulose nanofibrils (CNFs) have been surface modified with hexamethylenediamine/HMDA and used as an antimicrobial additive to a ring-spun viscose yarn. The CNF-HMDA suspension was first characterized in relation to its skin irritation potential, antimicrobial properties, and technical performance (dispersability and suspensability in different media) to optimize its sprayability on a viscose fiber sliver with the lowest sticking, thus to enable its spinning without flowing and tearing problems. The impact of CNF-HMDA content has been examined on the yarn`s fineness, tensile strength, surface chemistry, wettability and antimicrobial properties. The yarn`s antimicrobial properties were increasing with the content of CNF-HMDA, given a 99% reduction for S. aureus and C. albicans (log 1.6–2.1) in up to 3 h of exposure at minimum 33 mg/g, and for E. coli (log 0.69–2.95) at 100 mg/g of its addition, yielding 45–21% of bactericidal efficacy. Such an effect is related to homogeneously distributed CNF-HMDA when sprayed from a fast-evaporated bi-polar medium and using small (0.4 mm) nozzle opennings, thus giving a high positive charge (0.663 mmol/g) without affecting the yarn`s tenacity and fineness, but improving its wettability. However, a non-ionic surfactant being used in the durability testing of functionalized yarn to 10-washing cycles, adheres onto it hydrophobically via the methylene chain of the HMDA, thus blocking its amino groups, and, as such, decreasing its antibacterial efficiency, which was slightly affected in the case when the washing was carried out without using it.