Search

• Integrated optimization model for biomass-based renewable hydrogen production systems is proposed. • We calculate and evaluate the biomass utilization potential of a certain area. • We made predictions through chemical reaction kinetics and thermodynamic models. • Inventory model is embedded in it to decide the optimal production and operation management. • The effectiveness of the model was tested through a mixed biomass project in Sichuan Province, China. In this study, we propose a novel optimization method for designing and operating various types of biomass-based renewable hydrogen production systems. To this end, we considered the coupling of multiple biomass hybrid utilization processes for hydrogen production. First, we calculated and evaluated the biomass utilization potential of a given area. Second, we predicted the biomass gasification products using chemical reaction kinetics and thermodynamic models. Finally, we determined the optimal annual total cost of the hydrogen production supply chain by optimizing the microscopic operation of the biomass gasification plant. Through the proposed method, it is possible to effectively conduct a comprehensive assessment of regional biomass material hydrogen production; moreover, the optimal design of the biomass hydrogen production supply chain can also be determined based on the availability of biomass and hydrogen demand. More precisely, the logistics operations under fluctuating demand conditions were realized, enabling strategic decision-making for planning a biomass hydrogen production system. To validate the model, a case study analysis of biomass hydrogen production, to be launched in Sichuan Province, China, is presented. [ABSTRACT FROM AUTHOR]

On August 14, 2020, it occurred a landslide-induced debris flow in Wangcang County, Sichuan Province, Southwest China, three people killed, and two houses destroyed. Behaved as a typical geohazard chain, it originated from a rockslide in marlstone, controlled initially by structural planes in rock mass, and evolved into a debris flow through successive geophysical process. This debris flow reached a run-out distance of 2050 m in the horizontal and 628 m in vertical direction. Remote sensing analysis, field survey, and laboratory tests were conducted to investigate its failure mechanism and dynamic characteristics. The results found that the source zone in the gully was 16.32 × 103 m2, with a volume of 317.52 × 103 m3. Interbedded marlstone with dense structural planes was one of controlling factors for the landslide failure. The continuous rainfall up to 315 mm during the previous 24 days and 32 mm at the date before the incident directly motivated rock slope failure. The contributions of topography, rock fragmentation, entrainment, and flow discharge for this process were discussed. It is found that changes in slope from 11° to 40° provided tremendous potential energy for the rock mass sliding with high speed and then disintegrating in traveling. Entrainment in the channel increased the fine content of the moving rocky mixture. In addition, the flow discharge changed the rheological properties of the mixture by adding seepage. These factors significantly affected the transformation process. Notably, the turning relief or confluence site may be accelerating this process. This research may provide references for further research on geohazard chains. [ABSTRACT FROM AUTHOR]

No shale-rock physical model has been established in the observation coordinate system. To this end, this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen, Daley, and Berryman solutions to characterize anisotropic acoustic wave velocity. Finally, the Daley solution was selected. Based on basic rock physical models, such as SCA and DEM methods, and combined with the Daley solution, an anisotropic shalerock physical model was established in the observation coordinate system and applied in Well B1 in the Luzhou area, Sichuan Basin. Our research conclusions were as follows: 1. for the samples from the same core, the P-wave velocities in three directions were in the order VP11 >VP45 >VP33, shear-wave velocity VS11 was the largest, but VS33 and VS45 did not follow the law of Vs33 >Vs45 for some samples; 2. the Daley solution, which not only considers the accuracy requirements but also has a complete expression of P-, SV-, and SH-waves, is most suitable for characterization of anisotropic wave velocity in this study area; 3. the rock physical model constructed in the observation coordinate system has high accuracy, in which the absolute value of the relative error of the P-wave slowness was between 0% and 5.05% (0.55% on average), and that of shear-wave slowness was between 0% and 6.05% (0.59% on average); 4. the acoustic waves recorded in Well B1 in the observation coordinate system were very different from those in the constitutive coordinate system. The relative difference of the P-wave was between 6.76% and 30.84% (14.68% on average), and that of the S-wave was between 7.00% and 23.44% (13.99% on average). The acoustic slowness measured in the observation coordinate system, such as in a deviated well or a horizontal well section, must be converted to the constitutive coordinate system before it can be used in subsequent engineering applications; 5. the anisotropic shale-rock physical model built in the observation coordinate system proposed in this paper can provide basic data and guidance for subsequent pore pressure prediction, geomechanical modeling, and fracturing stimulation design for deviated and horizontal wells. [ABSTRACT FROM AUTHOR]

Background and purpose: The aim was to investigate the neurological complications associated with coronavirus disease 19 (COVID‐19) during the 2022 Omicron wave. Methods and analysis: The medical records of a cohort of people admitted to neurological wards of three participating tertiary centres in Sichuan from 12 December 2022 to 12 January 2023 were reviewed. Demographics and clinical data were obtained and analysed with an interest in COVID‐19‐related new‐onset or worse neurological symptoms. The current data were also compared in two centres with similar data from the same period 12 months earlier. Results: In all, 790 people were enrolled, of whom 436 were positive for COVID‐19. Ninety‐nine had new onset COVID‐related neurological problems, or their known neurological condition deteriorated during the wave. There was a significant difference in demographics from the findings amongst admissions 12 months earlier as there was an increase in the average age, the incidence of encephalitis and encephalopathy, and mortality rates. One hundred and one received COVID‐specific antivirals, intravenous glucocorticoids and intravenous immunoglobulin therapy. No differences were seen between these and those who did not use them. Conclusion: New‐onset neurological conditions, particularly encephalitis and encephalopathy, increased significantly during this period. Deterioration of existing neurological conditions, such as seizure exacerbation, was also observed. A large‐scale treatment trial of people with COVID‐19 infection presenting with neurological disorders is still needed. [ABSTRACT FROM AUTHOR]

Our aim was to clarify the incidence and risk of acute symptomatic seizures in people with coronavirus disease 2019 (COVID‐19). This multicenter retrospective study enrolled people with COVID‐19 from January 18 to February 18, 2020 at 42 government‐designated hospitals in Hubei province, the epicenter of the epidemic in China; Sichuan province; and Chongqing municipality. Data were collected from medical records by 11 neurologists using a standard case report form. A total of 304 people were enrolled, of whom 108 had a severe condition. None in this cohort had a known history of epilepsy. Neither acute symptomatic seizures nor status epilepticus was observed. Two people had seizurelike symptoms during hospitalization due to acute stress reaction and hypocalcemia, and 84 (27%) had brain insults or metabolic imbalances during the disease course known to increase the risk of seizures. There was no evidence suggesting an additional risk of acute symptomatic seizures in people with COVID‐19. Neither the virus nor potential risk factors for seizures seem to be significant risks for the occurrence of acute symptomatic seizures in COVID‐19. [ABSTRACT FROM AUTHOR]

Landslide modeling based on seismic signal characteristics is an effective method to study landslide evolution. The scientific challenge lies in how to systematically characterize and reconstruct the entire landslide evolution process using the recorded seismic data. We selected the 2017 "6.24" Xinmo landslide as a case study. Empirical mode decomposition (EMD) is used to analyze the seismic signals from 14 seismic stations near the landslide area. Numerical simulations using two-dimensional discrete element methods (DEM) are performed to simulate landslide dynamics using the calculated kinetic energy profile. After analyzing the short-time Fourier transform (STFT) and fast Fourier transform (FFT) characteristics of the signal, the landslide process is reconstructed and compared with the DEM simulation. The landslide process is observed to consist of a stationary stage, slipping stage, transition stage, entrainment-transportation stage, and a deposition stage. This is the first study that uses seismic signals to identify a transition stage, which is a feature that is difficult to constrain from field survey and analysis alone. Landslide development and movement in the transition stage are discussed considering the sedimentology of the study area. This study provides improved theoretical guidance for the reconstruction and characterization of landslide processes by seismic signals. • Seismic signals generated by the Xinmo landslide (Sichuan - China) were analyzed. • 5 stages of landslide were recognized from spectral variations of seismic recording. • One transition stage was identified between first slipping and entrainment stage. • Discrete element simulations supported the landslide process reconstruction. [ABSTRACT FROM AUTHOR]