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In order to comply with the latest Emission Control Areas (ECAs) regulations, ships must use expensive low-sulphur fuel oil or relatively cheap high-sulphur fuel oil (HFO) with desulphurization equipment. This study investigates the choice of green fuel and green technology for a coastal container ship with endogenous decision of sailing pattern. The sufficient and necessary conditions for a ship to adopt scrubber installation (SI) strategy are derived, which is dependent on factors including the equivalent sailing distance, the fuel price ratio, and scrubber parameters. The case study based on the China's coastal area is conducted. Numerical examples show that the introduction of scrubber technology on coastal vessels will reduce their evasion behavior. However, the increased sulphur reduction efficiency of scrubbers increases the evasion strategies of ships, which will increase the total emissions in coastal areas. The numerical example shows that introduction the scrubber technology to the coastal ships will reduce their evasion behavior. However, the scrubber investment will increase ships' sailing speed, increasing emissions within ECA. Therefore, governments can subsidize high abatement efficiencies of the scrubber to reduce actual ship emissions. • Investigate the choice of technology for a coastal ship with endogenous decision of sailing pattern. • Study the properties of the optimal sailing speed under fuel switching and scrubber installation strategies. • Derive the sufficient and necessary condition for a coastal ship of adopting scrubber installation strategy. • Discuss the incentive of evasion behavior and effect on emissions within ECA.. [ABSTRACT FROM AUTHOR]

Scrubbers are the commonly used green technologies for a ship to reduce sulfur emissions. Various speed adjustment behaviors would distort the cost and desulfurization efficiency of scrubbers for ships, which causes a discrepancy between the government and the carrier to install scrubbers. This paper addresses the issue by considering three speed adjustment behaviors: rigidity, partial flexibility, and full flexibility. Under rigid behavior, the carrier maintains a constant sailing speed when adopting low-sulfur fuel oil (LSFO) and installing a scrubber. Partially flexible behavior only involves speed adjustments when adopting LSFO, while fully flexible behavior includes speed adjustments when adopting LSFO and installing a scrubber. Our analysis indicates that scrubber installation consistently precedes adopting LSFO in speed. Full flexibility behavior is the least costly speed adjustment behavior, while partial flexibility behavior results in the lowest emissions. The investment discrepancy on scrubbers between the carrier and the government would occur on whether or not to install a scrubber and which level of the scrubber's quality since the two parties are concerned about the sulfur emissions and cost, respectively. Government subsidies address these discrepancies, leading to improved emission reduction. • Study discrepancies between the government and the carrier on the installation of scrubbers for inland container ships. • Explore the influence of rigidity, partial flexibility, and full flexibility speed adjustment behaviors. • Provide effective subsidy solutions to the government to address discrepancies and achieve emission reduction. • Conduct a case study based on container shipping over the Yangtze River. [ABSTRACT FROM AUTHOR]

Symplectic ERKN methods have been shown to be a very powerful tool that can solve oscillatory Hamiltonian problems with high accuracy and efficiency. However, in order to obtain a symplectic ERKN method, it is necessary to solve a large system of equations which are derived from order conditions and symplectic conditions. In this paper, it is found that for symplectic ERKN methods, order conditions can be greatly simplified. A compact set of order conditions are then expressed in algebraic format, instead of the original functional format, specially for symplectic ERKN methods.The corresponding tri-coloured free-tree theory is developed. Furthermore, we present several approaches for constructing symplectic ERKN methods, by solving relatively small systems of algebraic equations. This is crucial, in particular, in the construction of high-order ERKN methods. [ABSTRACT FROM AUTHOR]

In last few years, many ERKN methods have been investigated for solving multi-frequency multidimensional second-order ordinary differential equations, and the numerical efficiency has been checked strongly in scientific computation. But in the constructions of (especially high-order) new ERKN methods, lots of time and effort are costed in presenting the practical order conditions firstly and then in adding some reasonable assumptions to get the coefficient functions finally. In this paper, a feasible and effective technique is given which makes the construction of ERKN methods finished in a few seconds or a few minutes, even for high-order integrators. Moreover, this technique does not need any more information and knowledge except the classical RKN method. And this paper also gives the theoretical explanation to guarantee that the ERKN method obtained from this technique has the same order and the same properties as the underlying RKN method. [ABSTRACT FROM AUTHOR]

This paper develops an improved tri-coloured rooted-tree theory for the order conditions for ERKN methods solving general multi-frequency and multidimensional second-order oscillatory systems. The bottleneck of the original tricoloured rooted-tree theory is the existence of numerous redundant trees. In light of the fact that the sum of the products of the symmetries and the elementary differentials is meaningful, this paper naturally introduces the so-called extended elementary differential mappings. Then, the new improved tri-coloured rooted tree theory is established based on a subset of the original tri-coloured rooted-tree set. This new theory makes all redundant trees disappear, and thus, the order conditions of ERKN methods for general multi-frequency and multidimensional second-order oscillatory systems are reduced greatly. Furthermore, with this new theory, we present some new ERKN methods of order up to four. Numerical experiments are implemented and the results show that ERKN methods can be competitive with other existing methods in the scientific literature, especially when comparatively large stepsizes are used. [ABSTRACT FROM AUTHOR]

Recently, the International Maritime Organization (IMO) and government sectors have enacted several stringent regulations to curb the emissions of ships. Green fuel and scrubber installation are two prevailing adaptation strategies used by ships to reduce emissions. Green fuel leads to a high shipping cost with the consumption of low-sulphur but highly-priced oil, while scrubber installation is a long-term decision, which incurs a high capital cost from the setting up of desulphurization facilities but ensures ships can continue consuming low-priced oil. This paper makes a theoretical and holistic investigation of the strategy choice of a container ship in an inland river by taking into account the impact of streamflow velocity. For the inland shipping service, the sailing speed of a ship is the sum of its engine speed and streamflow velocity. The engine speed determines the fuel consumption, and the sailing speed determines the round-trip time of a ship. We found that the engine speed of a ship increases with respect to the streamflow velocity under both strategies in the sense of cost minimization. Also, the streamflow velocity increases the incentive of a ship to install a scrubber. Finally, numerical experiments based on the Yangtze River are conducted to demonstrate our proposed models. • Study strategy choice between scrubber installation (SI) and fuel switching (FS) for an inland container ship. • Explore the effects of the streamflow velocity of the river on strategy choice. • Investigate sulphur emissions under SI and FS for ship owner and government sector. • Conduct a case study based on the container shipping over Yangtze River. [ABSTRACT FROM AUTHOR]

Abstract: China is a big agricultural country and one of the most abundant straw resources in the world, producing more than 620million tons of straw in 2002, and representing about 33–45% of energy consumption for livelihood in rural areas. Utilization of straw as energy with high efficiency and rationality not only meets the demands for energy as the economy grows, but also provide a basis for environmental protection and sustainable development of society in China. This paper reviews the present utilized technologies of straw in biomass energy, including improved stove, biogas, straw gasification and straw briquette, which are already commercialized and popularized in China. Other technologies, such as liquefaction, straw carbonization and bio-coal, are also presented. Based on the technology status and potential, the future research and development of straw in the biomass energy portfolio in China are proposed. [Copyright &y& Elsevier]

Geometric complexities play an important role in the nucleation, propagation, and termination of strike-slip earthquake ruptures. The 2021 Mw7.4 Maduo earthquake rupture initiated at a large releasing stepover with a complex fault intersection. In the epicentral region, we conducted detailed mapping and classification of the surface ruptures and slip measurements associated with the earthquake, combining high-resolution uncrewed aerial vehicle (UAV) images and optical image correlation with field investigations. Our findings indicate that the coseismic ruptures present discontinuous patterns mixed with numerous lateral spreadings due to strong ground shaking. The discontinuous surface ruptures are uncharacteristic in slip to account for the large and clear displacements of offset landforms in the epicentral region. Within the releasing stepovers, the deformation zone revealed from the optical image correlation map indicates that a fault may cut diagonally across the pull-apart basin at depth. The left-lateral horizontal coseismic displacements from field measurements are typically ≤0.6 m, significantly lower than the 1–2.7 m measured from the optical image correlation map. Such a discrepancy indicates a significant proportion of off-fault deformation or the possibility that the rupture stopped at a shallow depth during its initiation phase instead of extending to the surface. The fault network and multi-fault junctions west and south of the epicenter suggest a possible complex path, which retarded the westward propagation at the initial phase of rupture growth. A hampered initiation might enhance the seismic ground motion and the complex ground deformation features at the surface, including widespread shaking-related fissures. [ABSTRACT FROM AUTHOR]

The 2021 Mw 7.4 Maduo (Madoi) earthquake that struck the northern Tibetan Plateau resulted in widespread coseismic deformation features, such as surface ruptures and soil liquefaction. By utilizing the unmanned aerial vehicle (UAV) photogrammetry technology, we accurately recognize and map 39,286 liquefaction sites within a 1.5 km wide zone along the coseismic surface rupture. We then systematically analyze the coseismic liquefaction distribution characteristics and the possible influencing factors. The coseismic liquefaction density remains on a higher level within 250 m from the surface rupture and decreases in a power law with the increasing distance. The amplification of the seismic waves in the vicinity of the rupture zone enhances the liquefaction effects near it. More than 90% of coseismic liquefaction occurs in the peak ground acceleration (PGA) > 0.50 g, and the liquefaction density is significantly higher in the region with seismic intensity > VIII. Combined with the sedimentary distribution along-strike of the surface rupture, the mapped liquefaction sites indicate that the differences in the sedimentary environments could cause more intense liquefaction on the western side of the epicenter, where loose Quaternary deposits are widely spread. The stronger coseismic liquefaction sites correspond to the Eling Lake section, the Yellow River floodplain, and the Heihe River floodplain, where the soil is mostly saturated with loose fine-grained sand and the groundwater level is high. Our results show that the massive liquefaction caused by the strong ground shaking during the Maduo (Madoi) earthquake was distributed as the specific local sedimentary environment and the groundwater level changed. [ABSTRACT FROM AUTHOR]

Direct emissions of volatile organic compounds (VOCs) not only pollute the environment, but also waste a lot of resources. To overcome above problem, this paper creatively proposed the solution by porous media combustion technology. In this study, ethylene with different N 2 content levels of 10%, 30%, and 50% (used to simulate VOCs) was experimentally burned in a self-designed porous medium burner stacked with 9 mm alumina balls. The effects of equivalence ratio, premixed gas flow velocity and dilution ratio on flammable region, maximum combustion temperature, combustion wave velocity, pollutant emissions and combustion treatment efficiency were investigated. The maximum combustion temperature increased with the equivalence ratio and the premixed gas flow velocity. Consequently, the corresponding combustion treatment efficiency increased and CO emissions decreased. With increasing the dilution ratio, the flammable region, maximum combustion temperature, and combustion treatment efficiency became smaller but CO emissions and the combustion wave velocity became larger, except the case with 10% N 2 content in which combustion was better than that with pure ethylene. In general, with relatively higher φ (φ ≥ 0.50), medium V fv (V fv ≥ 0.50), and appropriate α (α = 10%), the premixed gas could burn well with high combustion treatment efficiency. • ►Burning fuel-lean C 2 H 4 in a porous burner stacked with alumina balls. • ►Exploring the flammable region and flame propagation characteristics of transient combustion. • ►Uncovering the relationship between combustion wave and premixed flow velocities. • ►Comprehensively considering pollutant emissions and C 2 H 4 treatment efficiency. [ABSTRACT FROM AUTHOR]

Summary: A porous burner stacked in turn with 3‐ and 9‐mm alumina pellets was established to perform C2H4 combustion experiments by acquiring the flammable limits, temperature variation characteristics, combustion wave velocity, pollutant emissions, and treatment efficiency. The burner operated well at equivalence ratios within 0.3 to 0.7. Larger alumina pellets widened the burner's lower flammable limit. As the flame propagated downstream, the higher premixed gas flow velocity and larger alumina pellets, the higher combustion wave velocity, whereas the circumstances were opposite as the flame spread upstream. The combustion temperature increased with the equivalence ratio and premixed gas flow velocity. In response to the effect of the alumina pellet dimension, 3‐mm alumina pellets corresponded to higher combustion temperatures, lower CO emissions, and higher treatment efficiency than those less than 9‐mm conditions. Schematic representation of flame behaviors in the porous burner with different alumina pellets. [ABSTRACT FROM AUTHOR]

Highlights: [•] Down-fired boilers suffer from poor burnout and asymmetric combustion. [•] Shortening secondary-air port area was proposed to improve these problems. [•] Cold-modeling and in situ experiments were conducted to demonstrate the validity of this scheme. [•] The port shortening retrofit achieved symmetric combustion and apparently improved burnout. [ABSTRACT FROM AUTHOR]