Heterogeneity analysis of gas-solid flow hydrodynamics in a pilot-scale fluidized bed reactor

Mesoscale drag model is of crucial significance for the reliability and accuracy in coarse-grid EulerianEulerian two-fluid model(TFM)simulations of gas-solid flow hydrodynamics in fluidized bed reactors.Although numerous mesoscale drag models have been reported in the literature,a systematic comparison of their prediction capability from the perspective of heterogeneity analysis is still lacking.In this study,in order to investigate the effect of several typical drag models on the hydrodynamic behaviors,the nonuniformity analysis and the sensitivity to material properties,extensive coarse-grid TFM simulations of a bubbling pilot-scale fluidized bed reactor are carried out.The results demonstrate that the mesoscale drag models outperform the empirical drag model in terms of nonuniformity due to the consideration of the influence of the mesoscale structures on the drag force in the bubbling region.Furthermore,the results reveal that our previously developed three-marker gradient-based drag model considering the solid concentration gradient exhibits satisfactory performance in predicting the bubbling flow hydrodynamics.Besides,the material-property-dependent drag model considering the explicit effect of material properties on drag corrections is most sensitive to the particle diameter.This work provides guideline for possible future improvements of mesoscale models to simulate gas-solid flow more accurately and universally.

Spatial and temporal heterogeneity of the impact of per capita income on household indirect carbon emissions in western China

With China entering the stage of high-quality development,the issue of carbon emission has become a hot research topic.This paper analyzes the different temporal and spatial effects of per capita income on household indirect carbon emissions in western China.Based on the data of Chinese Family Panel Studies(CFPS)in 2016 and 2018 in the western China,this paper uses Regression analysis and Bayesian correlation analysis to study the relationship between per capita income and household indirect carbon emissions.The results showed that the indirect carbon emissions generated by the expenditure on food,housing and household equipment in the household consumption structure in the western China were relatively high.In 2016-2018,the per capita income and per capita household consumption indirect carbon emissions in the western China showed an increasing trend.There was a positive correlation between per capita income and indirect carbon emissions of per capita household consumption,and its correlation was gradually enhanced in time dimension.In the spatial dimension,the household indirect carbon emissions in Yunnan,Qinghai,Guangxi Zhuang and Ningxia in the western China were greatly affected by per capita income,while the household indirect carbon emissions in Guizhou was least affected by per capita income.Finally,the paper puts forward some problems that we should consider in the process of facing the per capita income growth and climate change:the collection of carbon tax,the optimization of household consumption structure,the research and development of low-carbon products,and the differentiated carbon reduction.

Application of the time-frequency polarization analysis to study the complexity of surface wave propagation

new technique called the timefrequency polarization analysis was introduced in this paper. The technique combined the traditional surface wave analysis techniques (moving window and multifilter) with the singular value decomposition method to measure the incidence azimuth of surface waves with different wavelengths. It was applied to study the propagation paths of surface waves across the different blocks of Chinese continent and different zones of QinghaiXizang (Tibet) plateau. The results show that the method can make full use of the differences in frequency compositions and arrival times of different surface wave modes, and give better polarization analysis results. The analysis by actual data shows that the lateral heterogeneity of the lithospheric structure influences the propagation paths of surface waves severely. Deviations of the paths across the QinghaiXizang plateau from great circle paths are great. Deviations of the surface waves across the different zones in QinghaiXizang plateau are different.

Correlation between radiologic features on contrastenhanced CT and pathological tumor grades in pancreatic neuroendocrine neoplasms

Contrast-enhanced computed tomography(CT)contributes to the increasing detection of pancreatic neuroendocrine neoplasms(PNENs).Nevertheless,its value for differentiating pathological tumor grades is not well recognized.In this report,we have conducted a retrospective study on the relationship between the 2017 World Health Organization(WHO)classification and CT imaging features in 94 patients.Most of the investigated features eventually provided statistically significant indicators for discerning PNENs G3 from PNENs G1/G2,including tumor size,shape,margin,heterogeneity,intratumoral blood vessels,vascular invasion,enhancement pattern in both contrast phases,enhancement degree in both phases,tumor-to-pancreas contrast ratio in both phases,common bile duct dilatation,lymph node metastases,and liver metastases.Ill-defined tumor margin was an independent predictor for PNENs G3 with the highest area under the curve(AUC)of 0.906 in the multivariable logistic regression and receiver operating characteristic curve analysis.The portal enhancement ratio(PER)was shown the highest AUC of 0.855 in terms of quantitative features.Our data suggest that the traditional contrastenhanced CT still plays a vital role in differentiation of tumor grades and heterogeneity analysis prior to treatment.

Intertumoral heterogeneity of molecular phenotype and analysis of prognosis in multifocal and multicentric breast cancer

Objective This study was designed to investigate the prognostic implications of the intertumoral heterogeneity of molecular phenotype in multifocal and multicentric breast cancer(MMBC).Methods The clinical and follow-up data of 146 patients with MMBC from Jan.2009to Dec.2009 treated in Tumor Hospital Affiliated to Zhengzhou University were retrospectively analyzed.

Jitter analysis of real-time services in IEEE 802.15.4 WSNs and wired IP concatenated networks

It is challenging and significant to explore the impacts of non-real-time services on real-time services from the perspective of jitter. Most of current researches on jitter made too many mathematical hypotheses on networks and traffic. This paper puts forward a tandem queuing model to characterize the real communication scenario where heterogeneous services are served by IEEE 802.15.4 wireless sensor networks（WSNs）, and then the packets served successfully are fed to Internet protocol（IP） networks. By analyzing the contention access processes in IEEE 802.15.4 WSNs, the authors derive the departure processes of the two types of services, i.e., the arrival processes of IP networks. The IP network is modeled as a queuing system, in which the real-time service is forwarded accompanied by the non-real-time service. Investigating the jitter of real-time services is intractable. Therefore, this paper abstracts this problem as a dynamic queuing system evolving on a dynamic time interval. Referring the transient analysis method（TAM）, this paper obtains the queue length in a random time interval which is scaled by the arrival of real-time services. Queue length evolution is closely connected with the jitter. Benefiting from the derivation in probability generation domain, the jitter of real-time services is obtained.

Media Inclination and Outward Foreign Direct Investment:Evidence from Chinese Firms

Media inclinations,whether favorable or biased,play a pivotal role in shaping public opinion.Sometimes,media coverage may unintentionally foster skepticism towards foreign firms,which could create challenges for those companies when they enter new markets.Based on a panel dataset from 2005 to 2020,this is one of the first studies to investigate empirically the impact of media opinion on outward foreign direct investment(OFDI)behaviors at the firm level.The media inclination index was constructed according to the varying inclinations of media from different countries in their reporting on each event.We examined the impact of media inclination on the investment value,frequency,and number of industries.This study has revealed the following insights:(i)Positive media coverage can stimulate the investment behavior of Chinese firms.(ii)The heterogeneity analysis indicates that the promotional effect of media reporting inclination on OFDI is more significant for state-owned firms from the investor's perspective and especially pronounced for firms in developing countries from the investee's perspective.(iii)Diplomatic visits and scientific research cooperation can amplify the positive impact of media opinions on the OFDI behaviors of Chinese firms.