A new implementation of OntoSTEP: Toward flexible generation of ontology and knowledge graphs of EXPRESS-driven data

Barbau et al. (2012) proposed OntoSTEP that translates the STandard for the Exchange of Product Model Data (STEP) schema and its instances to an ontology and knowledge graphs represented in the Web Ontology Language (OWL). OntoSTEP models can be integrated with any OWL models to enrich their semantics. However, the current implementation has several limitations, mainly in (1) supporting the latest ISO 10303 schemas and (2) generating various representation types depending on the purpose of use. We present an improved implementation of OntoSTEP to overcome these limitations. In this paper, we demonstrate that the new implementation can successfully translate STEP schemas and instances in a faster and more flexible way, thus furthering the adoption of the full capabilities of ISO 10303. By encoding STEP entities in OWL, we facilitate integration with other standards through knowledge graphs.

Drawing structured plasmonic field with on-chip metalens

The ability to draw a structured surface plasmon polariton (SPP) field is an important step toward many new opportunities for a broad range of nanophotonic applications. Previous methods usually require complex experimental systems or holographic optimization algorithms that limit their practical applications. Here, we propose a simple method for flexible generation of structured SPP field with on-chip plasmonic metalenses. The metalens is composed of multiple plasmonic focusing nanostructures whose focal shape and position can be independently manipulated, and through their superposition, SPP fields with specially designed patterns are obtained. Based on this method, we demonstrate several structured SPP fields including S- and W-shaped SPP focal fields and tunable SPP bottle beams. This work could provide new ideas for on-chip manipulation of optical surface waves, and contribute to applications such as on-chip photonic information processing and integrated photonic circuits.

Application of ORC in a Distributed Integrated Energy System Driven by Deep and Shallow Geothermal Energy

This study presents a distributed integrated energy system driven by deep and shallow geothermal energy based on forward and reverse cycle for flexible generation of cold, heat and electricity in different scenarios. By adjusting the strategy, the system can meet the demand of heat-electricity in winter, cool-electricity in summer and electricity in transition seasons. The thermodynamic analysis shows that the thermal efficiency of the integrated energy system in the heating and power generation mode is 16% higher than that in the cooling and power generation mode or the single power generation mode. Meanwhile, the annual heat-obtaining quantity of the system is reduced by 11% compared with that of the independent power generation system, which effectively alleviates the imbalance of the temperature field of the shallow geothermal reservoir. In terms of net power generation, the integrated energy system can generate approximately 31% more electricity than the conventional independent cooling and heating system under the same cooling and heating capacity. An integrated system not only realizes the comprehensive supply of cold and thermal ower by using clean geothermal efficiency, but also solves the temperature imbalance caused by the attenuation of a shallow geothermal temperature field. It provides a feasible way for carbon emission reduction to realize sustainable and efficient utilization of geothermal energy.

Cost Increments of Electricity Supply to Achieve Carbon Neutrality in China

The Chinese government has set long-term carbon neutrality and renewable energy (RE) development goals for the power sector. Despite a precipitous decline in the costs of RE technologies, the external costs of renewable intermittency and the massive investments in new RE capacities needed to achieve carbon neutrality would drive electricity costs up. Here, we develop a power system expansion model to comprehensively evaluate changes in the costs of electricity supply over a 30-year transition to carbon neutrality, including the effects on the costs of various factors. RE supply curves across China, operating security constraints, and characteristics of various generation units are modelled in detail to assess the cost variations as accurately as possible. According to our results, approximately 5.5 TW of wind and solar photovoltaic capacities would be required to achieve carbon neutrality in the power system by 2050. The electricity supply costs would increase 21.5%, or 10.4 CNY¢/kWh (1.51 USD¢/kWh), which equates to a rise in the effective marginal price of carbon to 1082.6 CNY/t (157.0 USD/t) in 2050. The major cost increments would result from substantial investments in the new RE capacities, flexible generation resources, and network expansion that would be required to achieve carbon neutrality.

BALANSING OF POWER AND ELECTRICITY IN THE ELECTRIC POWER SYSTEM WITH RENEWABLE ENERGY SOURCES BY CRITERIONAL METHOD

This article considers the features of the development of renewable energy sources in electrical networks. The main changes in the functional properties of power systems, which include a significant reduction in electricity consumption, change in the structure of electricity consumption, rapid increase in the installed capacity of solar and wind power plants. Electricity consumption in 2020 is almost halved compared to 1990 (from 227 to 119 billion kWh) and as a consequence the share of semi-peak thermal generation, which gave the power system basic flexibility, has significantly decreased (from 71 % in 1990 to 35 % in 2020) and at the same time the share of nuclear generation, which operates in base mode, has increased (from 25 % to 51 %). In particular, consumption by industry with a stable load schedule, decreased (from 146 billion kWh (64 %) to 49 billion kWh (42 %)). At the same time, the demand for electricity by the households, whose consumption profile of which is characterized by significant daily unevenness and sensitivity to meteorological factors, has significantly increased (from 21 billion kWh (9 %) to 37 billion kWh (31 %)). Therefore, the article analyses the preconditions for the problem of flexible generation and explores possible ways to solve them. The optimal composition of electricity generation for Ukraine in the period 2021–2025 is proposed, which provides for the preservation and even increase by optimizing the repair campaign of the share of electricity production by nuclear power plants, the introduction of additional 2–2.5 GW of highly flexible generation and up to 2 GW storage systems (taking into account the pumped-storage power plant), as well as a gradual evolutionary decline in both installed capacity and electricity production by semi-peak coal-fired power plants and maintaining a policy of decarbonisation to ensure its own energy security. A comprehensive approach to compensating for the instability of renewable energy sources generation has been developed, which consists in minimizing the cost of power redundancy in various available ways. The problem of cost optimization for ways to compensate for the instability of renewable energy sources generation is solved by the method of criterion programming. The impact of each backup method on total costs is determined using sensitivity theory.

Experimental demonstration of multiple dimensional coding decoding for image transfer with controllable vortex arrays

Vortex beams carrying orbital angular momentum (OAM), which featuring helical phase front, have been regarded as an alternative spatial degree of freedom for optical mode coding and multiplexing. For most reported OAM-based mode coding schemes, data information is only encoded by different OAM mode states. In this paper, we introduce a novel design technique to construct vortex array phase grating (VAPGs) for the flexible generation of vortex arrays, and employ the proposed VAPGs to realize multi-dimensional space/mode/amplitude coding/decoding. By designing VAPGs with different parameters and loading them on to a single spatial light modulator (SLM), we successfully generate vortex array with different mode states and relative power in the experiments. Moreover, a 10-bit multi-dimensional space/mode/amplitude data coding/decoding scheme for image transfer in free-space link with a zero bit-error-rate is experimentally demonstrated, which confirm the feasibility of our proposed VAPG-based coding/decoding scheme.

Demand-Driven Biogas Production from Anaerobic Digestion of Sewage Sludge: Application in Demonstration Scale

The power system needs flexible electricity generators. Whilst electricity generation from anaerobic digestion (AD) of sewage sludge has traditionally been baseload, transforming the generation capacity into a modern flexible operator is an opportunity to further valorise the resource. This work aims to demonstrate that AD of sewage sludge can support flexible generation and be operated dynamically in a relevant operational environment, to promote full scale implementation. A demonstration scale plant (20 m3 conventional AD reactors) was used to test several feeding regimes designed to return a biogas production rate that matches the demand. Two demand profiles are defined, either by common corporate power purchase agreements or by the main balancing mechanism used by the grid operator in UK. Demand-driven biogas production is demonstrated in this relevant operational environment, and the flexibilisation performance is positive in all scenarios. The value of the biogas increases by up to 2%, which outperforms the results obtained at pilot scale. Additionally, an increase in biogas yield is observed. Whilst transitional imbalances are recorded, they last for few hours and the overall stability is not affected. In conclusion, these trials demonstrate demand-driven biogas production is a feasible operational solution and full-scale implementation is possible. Graphical Abstract