Long-distance renewable hydrogen transmission via cables and pipelines

Intermittency is one of the main obstacles that inhibit the wide adoption of the renewable energy in the power sector. Small-scale fluctuations can be tackled by short-term energy storage system, whereas long-term or seasonal intermittencies rely on large-scale energy management solutions. Besides the supply and demand mismatch in temporal domain, renewable energy sources are usually far away from consumption points. To connect the energy sources to the demand cost-effectively, cable transmission is usually the default option, and considering the long distance, other emerging energy carriers such as hydrogen could be a feasible option. However, there is handful studies on the quantitative evaluation of the long-distance energy transmission cost. This paper investigated the economic feasibility of renewable energy transmission via routes of power cable and gas pipeline. In the direct power transmission case, renewable energy is transmitted via HVDC cable and then converted to hydrogen for convenient storage. The alternative case converts renewable energy into hydrogen at the source and transports the hydrogen in the gas pipeline to consumers. Existing data available from public domain are used for cost estimation. Results show that the improvements of capacity factor and transmission scale are the most cost-effective approach to make the renewable hydrogen economically viable. At 4000 km of transmission distance, renewable hydrogen LCOE of 7 US$/kg and 9 US$/kg are achievable for the corresponding optimum cases, respectively.     

Buying Power

The global push toward finalizing and implementing the next generation of connected smart machinery—the Industry 4.0 protocols—begs the question: how will these new standards influence equipment purchasing decisions for plastics manufacturers?     

Selective High‐Frequency Mechanical Actuation Driven by the VO2 Electronic Instability

Relaxation oscillators consist of periodic variations of a physical quantity triggered by a static excitation. They are a typical consequence of nonlinear dynamics and can be observed in a variety of systems. VO₂ is a correlated oxide with a solid‐state phase transition above room temperature, where both electrical resistance and lattice parameters undergo a drastic change in a narrow temperature range. This strong nonlinear response allows to realize spontaneous electrical oscillations in the megahertz range under a DC voltage bias. These electrical oscillations are employed to set into mechanical resonance a microstructure without the need of any active electronics, with small power consumption and with the possibility to selectively excite specific flexural modes by tuning the value of the DC electrical bias in a range of few hundreds of millivolts. This actuation method is robust and flexible and can be implemented in a variety of autonomous DC‐powered devices.     

Microstructured fibre Bragg gratings: analysis and fabrication

A microstructured fibre Bragg grating that relies on a partial and localised etching of the cladding layer along the grating region is proposed. The main effect is the formation of defect states inside the bandgap depending on surrounding refractive index. This leads to the possibility of realising novel optoelectronic devices for sensing and telecommunication applications.     

Characterization of solid embeddable reference electrodes for corrosion monitoring in reinforced concrete structures

Metal-metal oxide (MMO), graphite and laboratory-made Ag/AgCl electrodes were electrochemically characterized to be used as reference electrodes embedded in concrete structures. Electrodes were studied in both, aqueous solutions of pH ranging from 7 to 13.5 and embedded into cement mortars; and the electrochemical studies were carried out in the absence and presence of chloride ions. Potential evolution, polarization behaviour, galvanostatic pulse response and impedance characteristics of the electrodes were carried out in aqueous solutions. Besides, the electrochemical stability of the electrodes embedded in mortar was studied for an exposure period of 2 years. It was found that the MMO pseudo-reference electrode is pH-sensitive, the graphite pseudo-reference electrode is oxygen sensitive and the Ag/AgCl pseudo-reference electrode is chloride sensitive. In spite of the fact that any of them can be used to determine the corrosion rates of rebars because they do not depend on the absolute potential and/or the long-term stability of the reference electrode when using traditional electrochemical techniques, long-term drifts in the electrode potentials may lead to misinterpretations of the rebar state. In this context graphite electrodes are recommended because they provide conservative results regarding the active/passive state of the rebars.     

The influence of Pt on the electrooxidation behaviour of carbon in phosphoric acid

The electrooxidation behaviour of Pt/C catalysts for phosphoric acid fuel cells (PAFC) has been investigated by potentiostatic tests in the potential range 0.6 ÷ 1.0 V (rhe). Results indicate that the corrosion rate increases with an increase in Pt content, and is most noticeable at 0.6 V. At higher potentials anodic dissolution of Pt takes place, thus no metal is available to catalyze the corrosion of carbon. It is concluded that a definite influence of the presence of the supported metal on the extent of carbon corrosion under practical conditions does exist, but the understanding of mechanisms involved in the Pt-promoted carbon corrosion requires further studies.     

Evaluation of the cochlear aqueduct patency: comparison of 2 noninvasive techniques

Variations in cephalo-rachidian fluid pressure can be transmitted to the middle ear through the cochlear aqueduct (CA). This gives us a non-invasive manner to evaluate any changes in fluid pressure by measuring middle ear impedance (impedancemetry). The present study compared two indirect methods for measuring intracranial pressure: a) impedancemetry during evoked jugulo-tympanic reflex (JTR) and b) study of the tympanic membrane (TM) fine motility using a MMS-10 analyzer. The latter is a new procedure involving the indirect evaluation of the fluid pressure. In fact, when the CA is open the labyrinthine fluid pressure is transmitted to the oval window, the stapes platina and, finally, to the tympanic membrane where it can be measured with an MMS-10 unit. This equipment can measure nanoliter shifts in the TM. In particular, comparison between the clinostatic and orthostatic tympanic motility measurements enable one to establish whether the CA is patent or not. In the present study 15 subjects were examined using both a) impedancemetry during jugular compression and b) analysis of the TM shift using an MMS-10 unit. In 14 of the 15 cases there was good correlation between the data obtained using both methods: in all but one case it proved possible to record a JTR-induced variation in impedance whenever the MMS-10 indicated that the CA was open. The results suggest that, in clinical practice, the two methods can be used in parallel for non-invasive monitoring of variations in intracranial pressure in patients with neurological involvement. On the other hand, in the E.N.T. field these techniques could be used to study inner ear pathologies causing dynamic alterations of the endolabyrinth fluids (endolymphatic hydrops, labyrinthine fistula).