A pseudo transient nonequilibrium method for rigorous simulation of multicomponent separation columns

Nonequilibrium stage model is a significant improvement in multicomponent separation process simulation,but more equations are involved and the solution of the model equations,which relies on an adequate initial guess for convergence of the Newton method,is difficult.In this work,based on the concept of pseudo-transient continuation approach,we proposed a new pseudo-transient(PT)nonequilibrium method.The proposed method decouples the strongly coupled model equations by introducing dynamic equations for material and energy conservation,as well as transition equations.Thus,the steady-state solution of the nonequilibrium stage model can be obtained through a robust and fast integration process,and the initial guess issue in Newton method can be effectively avoided.Two simulation cases were used to demonstrate the advantages and applicability of the proposed PT nonequilibrium method.

Prognostic and diagnostic scoring models in acute alcoholassociated hepatitis:A review comparing the performance of different scoring systems

Alcohol-associated hepatitis(AAH)is a severe form of liver disease caused by alcohol consumption.In the absence of confounding factors,clinical features and laboratory markers are sufficient to diagnose AAH,rule out alternative causes of liver injury and assess disease severity.Due to the elevated mortality of AAH,assessing the prognosis is a radical step in management.The Maddrey discriminant function(MDF)is the first established clinical prognostic score for AAH and was commonly used in the earliest AAH clinical trials.A MDF>32 indicates a poor prognosis and a potential benefit of initiating corticosteroids.The model for end stage liver disease(MELD)score has been studied for AAH prognostication and new evidence suggests MELD may predict mortality more accurately than MDF.The Lille score is usually combined to MDF or MELD score after corticosteroid initiation and offers the advantage of assessing response to treatment a 4-7 d into the course.Other commonly used scores include the Glasgow Alcoholic Hepatitis Score and the Age Bilirubin international normalized ratio Creatinine model.Clinical AAH correlate adequately with histologic severity scores and leave little indication for liver biopsy in assessing AAH prognosis.AAH presenting as acute on chronic liver failure(ACLF)is so far prognosticated with ACLF-specific scoring systems.New artificial intelligence-generated prognostic models have emerged and are being studied for use in AAH.Acute kidney injury(AKI)is one possible complication of AAH and is significantly associated with increased AAH mortality.Predicting AKI and alcohol relapse are important steps in the management of AAH.The aim of this review is to discuss the performance and limitations of different scoring models for AAH mortality,emphasize the most useful tools in prognostication and review predictors of recurrence.

Study on Hydrolysis of Methyl Acetate in a Catalytic Distillation Column

A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calculations. A good operating mode was then obtained, which is helpful to the development of a new process.

A Theoretical Model for the Size Prediction of Single Bubbles Formed under Liquid Cross-flow

The size of initial bubbles is an important factor to the developed bubble size distribution in a gas-liquid contactor. A liquid cross-flow over a sparger can produce smaller bubbles, and hereby enhance the performance of contactor. A one stage model by balancing the forces acting on a growing bubble was developed to describe the formation of the bubble from an orifice exposed to liquid cross-flow. The prediction with this model agrees with the experimental data available in the literatures, and show that orifice size strongly affects the bubble size. It is showed that the shear-lift force, inertia force, surface tension force and buoyancy force are major forces, and a simplified mathematical model was developed, and the detachment bubble diameter can be predicted with accuracy of <±21%.

Simulation of Suspension Catalytic Distillation for Synthesis of Linear Alkylbenzene

Suspension catalytic distillation (SCD) has been developed recently as an innovative technology in catalytic distillation. In this paper, a brief introduction to SCD is given and an equilibrium stage (EQ) modei is developed to simulate this new process for synthesis of linear alkylbenzene (LAB) from benzene and 1-dodecene. Since non-ideality of this reaction systern is not strong, EQ modei developed could be applied to it successfully. Simulation results agree well with experimental data, and indicate some characteristics of SCD process as an advanced technology for the production of LAB: 100% conversion of olefins, low temperature (90-100℃) and low benzene/olefin mole ratio.

Alcoholic hepatitis: A comprehensive review of pathogenesis and treatment

Alcoholic hepatitis(AH)is an acute hepatic inflammation associated with significant morbidity and mortality.Current evidence suggests that the pathogenesis is the end result of the complex interplay between ethanol metabolism,inflammation and innate immunity.Several clinical scoring systems have been derived to predict the clinical outcomes of patients with AH;such as Child-Turcotte-Pugh score,the Maddrey discriminant function,the Lille Model,the model for end stage liver disease scores,and the Glasgow alcoholic hepatitis score.At present,Corticosteroids or pentoxifylline are the current pharmacologic treatment options;though the outcomes from the therapies are poor.Liver trans-plantation as the treatment of alcoholic hepatitis remains controversial,and in an era of organ shortage current guidelines do not recommend transplantation as the treatment option.Because of the limitations in the therapeutic options,it is no doubt that there is a critical need for the newer and more effective pharmacological agents to treat AH.

Role of platelet-albumin-bilirubin score in predicting re-bleeding after band ligation for acute variceal hemorrhage

Platelet-albumin-bilirubin(PALBI)score was proposed by Roayaie et al with modification of previously studied albumin-bilirubin score to include platelet as an indicator of portal hypertension in 2015.Predictive value of this score was recently tested by Elshaarawy et al for re-bleeding in patients presenting with acute variceal hemorrhage.We did a similar study at our center(n=170)to look at incidence of re-bleeding after band ligation defined as drop in 2 units of hemoglobin and witnessed melena or hematemesis within 2 wk of the procedure.We calculated PALBI scores for all patients based on lab values prior to the procedure.Of 25.3%had re-bleeding episodes,area under receiver operating characteristic curve for PALBI as predictor of re-bleeding was 0.601(95%confidence interval:0.502-0.699).PALBI score showed moderate accuracy at predicting re-bleeding in our population.

Tongue thickness in health vs cirrhosis of the liver:Prospective observational study

BACKGROUNDMalnutrition affects 40%-90% of patients with cirrhosis of the liver. L3 skeletalmuscle index (L3SMI) is presently accepted as the most objective and quantitativemeasure available for sarcopenia, a surrogate marker of malnutrition. L3SMIapplication is, however, limited by non-availability of computed tomographyscanning in remote areas, cost, need for extensive training, and the risk ofexposure to radiation. Therefore, an alternative dependable measure with wideravailability is needed. Malnutrition causes sarcopenia not only in skeletal musclesbut also in other muscular structures such as the psoas muscle, diaphragm andtongue. We therefore hypothesised that the tongue, being easily accessible forinspection and for measurement of thickness using ultrasonography, may be usedto document sarcopenia.AIMTo measure and compare tongue thickness in healthy individuals and in patientswith cirrhosis of the liver and to study its correlation with conventionalprognostic scores for patients with cirrhosis of the liver.METHODSTongue thickness was measured using ultrasonography. One hundred twentysubjects of either gender aged 18 to 65 years were studied, with 30 subjects in eachgroup. The tongue thickness was compared between groups based on “ChildTurcotte Pugh” (CTP) scores. The correlations between measured tonguethickness and “Model for end stage liver disease” (MELD) score and between age and measured tongue thickness were also assessed.RESULTSMean tongue thickness (mean ± SD) in patients with CTP class A, B and C was4.39 ± 0.39 cm, 4.19 ± 0.53 cm, and 3.87 ± 0.42, respectively, and was 4.33 ± 0.49 cmin normal healthy individuals. Significant differences were seen in tonguethickness between patients with CTP class C and those with CTP class A and B (P< 0.05). Patients with CTP class C also had a significantly reduced tonguethickness than normal individuals (P < 0.05). However, no significant differencewas seen in tongue thickness between patients with CTP class A and B andnormal individuals. A statistically significant, negative correlation was foundbetween MELD score and tongue thickness (r = -0.331) (P < 0.001). No correlationwas observed between L3SMI and MELD score (r = 0.074, P = 0.424). L3SMI(mean ± SD) in healthy subjects was 39.66 ± 6.8 and was 38.26 ± 8.88 in patientswith CTP class C, and the difference was not significant. No significant correlationwas found between age of the patients and tongue thickness. Intra-classcorrelation coefficient was used to determine the reliability of the tonguethickness measurements. The intra-class correlation coefficient was 0.984 (95%CI:0.979-0.989) and was indicative of good reliability.CONCLUSIONTongue thickness measured by ultrasonography, correlates significantly with theseverity of liver disease, as assessed by CTP and MELD scores. The patients with aCTP score ≥ 10 have significantly reduced tongue thickness as compared tonormal individuals and those with less severe liver disease and CTP scores of 5-9.No significant difference in tongue thickness was found between healthyindividuals and CTP class A and B patients.

Serum 25-hydroxyvitamin D deficiency and hepatic encephalopathy in chronic liver disease

To investigate the relationship between 25-hydroxyvitamin D (25-OHD) deficiency and hepatic encephalopathy (HE) in patients with chronic liver disease (CLD). METHODSA retrospective analysis of the results of 392 adult patients with chronic liver disease who were assessed for liver transplantation between 2006 and 2010 was undertaken. HE, severity of CLD, nutritional status and 25-OHD were analysed in patients assessed for liver transplantation between 2006 and 2010. Patients who presented with acute, fulminant or subacute disease, with a primary diagnosis of liver cancer, were assessed for re-transplantation or who did not have a 25-OHD measurement were excluded from the analysis. RESULTSOne hundred and sixty-five patients were included in this analysis. The mean age of all patients was 53 ± 8 years. Moderate to severe 25-OHD deficiency was identified in 49 patients of whom 36 had grade 2-3 HE compared with 13 patients who were not encephalopathic (P ≤ 0.0001). Mild 25-OHD deficiency was not associated with HE. There was a significant correlation between the severity of 25-OHD deficiency and the severity of liver disease (r = 0.39, P ≤ 0.0001) and disease severity and the presence of HE (P ≤ 0.0001). Importantly, individuals with 25-OHD deficiency were more likely to have a diagnosis of overt HE (OHE) at a significantly lower model for end stage liver disease (MELD) score than individuals without OHE (P ≤ 0.0001). This significant difference was observed with MELD scores from 10 to 38. CONCLUSION25-OHD deficiency was observed in the majority of patients with CLD and for the first time was found to be significantly worse in patients with OHE.

Relationships among Psychosocial Correlates and Stages of Change in a German-Chinese Sample

Promoting Health Enhancing Physical Activity (HEPA) behavior is an important undertaking in Germany as well as in China. In order to create successful interventions in different nations, knowledge about the relevant psychosocial correlates that may encourage successful progression through the behavior change process is necessary. Therefore, the relationships of selected psychosocial correlates of physical activity with stages of change were examined in a German-Chinese sample. In total, 2071 adults (865 Germans, 1206 Chinese) completed a questionnaire. The theoretical framework used was the FIT-model, which consists of the following stages of change: not considering, considering, preparing, exploring, fluctuating and maintaining. All data were analyzed with a two-way ANOVA. Significant main effects for the stages of change on all psychosocial correlates were found. Significant interactions between stages and nations emerged for all correlates except for social support, although these results revealed small effect sizes. To progress within the stages of inactivity, interventions should focus on outcome expectations, barriers, social support and affective attitudes. The successful initiation of physical activity depends on considerations of barriers, maintenance self-efficacy, intrinsic motivation and affective attitudes. These same correlates plus social support are relevant for long-term adherence to physical activity. In Germany, perceived barriers and emotional aspects of physical activity appear to be important for initiating and maintaining regular physical activity. Furthermore, for long-term adherence to physical activity, Germans—in contrast to Chinese adults—may not necessarily benefit from social support;however they could benefit from learning how to strengthen their physical activity outcome expectations.

Hydrodynamics of Liquid Flow in the Model of Theoretical Stage with Perfect Displacement

For the cyclic process of mass transfer in tray columns there are considered the hydrodynamic models of liquid flow during steam supply and during overflow of liquid from tray to tray. During steam supply, the hydrodynamic model is determined as perfect displacement model, and during liquid overflow, it is described as cell model. There were received the characteristics of liquid flow as follows： average residence time of liquid, degree of dispersion around the mean on the tray, number of perfect mixing cells depending on multiplication factor of exchange of liquid delay. In Y-X coordinates there is depicted a work line and theoretical stage of perfect displacement model. There were considered the conditions of mutual transfer of theoretical stage and theoretical stage with perfect displacement. The advantages of the mass transfer cyclic process to the stationary one arc stated.

Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode

Electrochemical oxidation of polyethylene glycol(PEG) in an acidic(pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified(PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon(TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

STAGED PROGRESSION MODEL FOR EPIDEMIC SPREAD ON HOMOGENEOUS AND HETEROGENEOUS NETWORKS

In this paper, epidemic spread with the staged progression model on homogeneous and heterogeneous networks is studied. First, the epidemic threshold of the simple staged progression model is given. Then the staged progression model with birth and death is also considered. The case where infectivity is a nonlinear function of the nodes＇ degree is discussed, too. Finally, the analytical results are verified by numerical simulations.

Modeling of Fluidized Bed Gasification:Assessment of Zero-dimensional and CFD Approaches

In modeling fluidized bed gasification experiments,equilibrium and CFD models are valuable options.The existence of multi-dimensional effects inside the reactor vessel due to the kinetics of the process and the fluid dynamics phenomena could result in deviation from the zero-dimensional assumption.Complex models integrating kinetics and hydrodynamics are being developed by using a computer fluid dynamics(CFD)approach.The objective of this investigation is to assess and compare the adequacy of zero-dimensional and CFD approaches in modeling fluidized bed gasification regarding a semi-industrial scale(numerical results are validated under experimental runs).Results show that the zero-dimensional model based on the approach of dual stage equilibrium performs reasonably well in adequately predicting the product gas composition at different operating conditions and for different feedstocks,although with quantitative discrepancy.Furthermore,the discrepancy depends on the oxygen content of the oxidation agent and on the steam-to biomass ratio decreasing when these parameters increased.CFD models provide deeper information being able to estimate the syngas composition or other operating parameter at any point of space and time.Despite of some quantitative discrepancy,the zero-dimensional modeling approach is deemed satisfactory from the viewpoint of the determining design conditions simulation.

Protein-coding genes combined with long noncoding RNA as a novel transcriptome molecular staging model to predict the survival of patients with esophageal squamous cell carcinoma

Background:Esophageal squamous cell carcinoma(ESCC)is the predominant subtype of esophageal carcinoma in China.This study was to develop a staging model to predict outcomes of patients with ESCC.Methods:Using Cox regression analysis,principal component analysis(PCA),partitioning clustering,Kaplan-Meier analysis,receiver operating characteristic(ROC)curve analysis,and classification and regression tree(CART)analysis,we mined the Gene Expression Omnibus database to determine the expression profiles of genes in 179 patients with ESCC from GSE63624 and GSE63622 dataset.Results:Univariate cox regression analysis of the GSE63624 dataset revealed that 2404 protein-coding genes(PCGs)and 635 long non-coding RNAs(lncRNAs)were associated with the survival of patients with ESCC.PCA categorized these PCGs and lncRNAs into three principal components(PCs),which were used to cluster the patients into three groups.ROC analysis demonstrated that the predictive ability of PCG-lncRNA PCs when applied to new patients was better than that of the tumor-node-metastasis staging(area under ROC curve[AUC]:0.69 vs.0.65,P<0.05).Accord-ingly,we constructed a molecular disaggregated model comprising one lncRNA and two PCGs,which we desig-nated as the LSB staging model using CART analysis in the GSE63624 dataset.This LSB staging model classified the GSE63622 dataset of patients into three different groups,and its effectiveness was validated by analysis of another cohort of 105 patients.Conclusions:The LSB staging model has clinical significance for the prognosis prediction of patients with ESCC and may serve as a three-gene staging microarray.

Root microbiota shift in rice correlates with resident time in the field and developmental stage

Land plants in natural soil form intimate relationships with the diverse root bacterial microbiota. A growing body of evidence shows that these microbes are important for plant growth and health. Root microbiota composition has been widely studied in several model plants and crops; however, little is known about how root microbiota vary throughout the plant's life cycle under field conditions. We performed longitudinal dense sampling in field trials to track the time-series shift of the root microbiota from two representative rice cultivars in two separate locations in China. We found that the rice root microbiota varied dramatically during the vegetative stages and stabilized from the beginning of the reproductive stage, after which the root microbiota underwent relatively minor changes until rice ripening. Notably, both rice genotype and geographical location influenced the patterns of root microbiota shift that occurred during plant growth. The relative abundance of Deltaproteobacteria in roots significantly increased overtime throughout the entire life cycle of rice, while that of Betaproteobacteria, Firmicutes, and Gammaproteobacteria decreased. By a machine learning approach, we identified biomarker taxa and established a model to correlate root microbiota with rice resident time in the field(e.g., Nitrospira accumulated from 5 weeks/tillering in field-grown rice). Our work provides insights into the process of rice root microbiota establishment.

ANALYSES OF LOCATION-PRICE GAME ON NETWORKS WITH STOCHASTIC CUSTOMER BEHAVIOR AND ITS HEURISTIC ALGORITHM

In this paper,a two-stage model is developed to investigate the location strategy andthe commodity pricing strategy for a retail firm that wants to enter a spatial market with multiplecompetitive facilities,where a competitor firm is already operating as a monopoly with several outlets.Expected market shares are calculated based on the stochastic customer behavior on networks.Theauthors provide a sufficient condition for the existence of equilibrium prices in the price game for thefirst time.The existence and uniqueness of the pure strategy Nash equilibrium price with a specifiedutility function are proved in the subgame.A metaheuristic based on tabu search is proposed tosearch the optimal location-price solution of the model.In addition,the authors provide two numericalexamples to illustrate how to obtain the optimal solution and conduct sensitivity analysis.The analysisshows that the best location decision is robust for the follower firm,price game is more intense whenincomes of consumers are lower or there are more substitution products,and neither chain retail gainsfrom the price competition.

Non-equilibrium model for catalytic distillation process

A new improved tri-diagonal method was developed for the non-equilibrium stage model of the catalytic distillation by coupling consumptive reaction coefficient.The reactions in the distillation column were divided into generative reaction and consumptive reac-tion.The non-equilibrium stage model was introduced for the catalytic distillation process of the dimethyl car-bonate(DMC)synthesis by urea methanolysis over solid based catalyst,and the improved tri-diagonal method was used to solve the model equations.Comparison of pre-dicted results with experiment data shows that the mean relative error of the yield of DMC was 3.78%under dif-ferent conditions such as different operating pressures and reaction temperatures.The improved tri-diagonal matrix method could avoid the negative values of the liquid com-positions during the calculations and restrain the fluc-tuation of compositions by slowing down the variations of the values in the iteration.The modeling results show that the improved tri-diagonal method was appropriate for system containing a wide range of boiling point com-ponents and a different rate of reactions.

ApplicationofNon─equilibriumStageModeltoLiquid─liquidExtraction

The application of the non equilibrium stage model to the multicomponent, non ideal liquid liquid extraction process is described in this paper. Pilot plant experiments and a commercial process of aromatic separation by sulfolane in sieve tray extraction columns were chosen as examples to show the advantages and benefits of the non equilibrium stage model over the conventional model.

Frequency equation for the submicron CMOS ring oscillator using the first order characterization

By utilizing the first order behavior of the device,an equation for the frequency of operation of the submicron CMOS ring oscillator is presented.A 5-stage ring oscillator is utilized as the initial design,with different Beta ratios,for the computation of the operating frequency.Later on,the circuit simulation is performed from 5-stage till 23-stage,with the range of oscillating frequency being 3.0817 and 0.6705 GHz respectively.It is noted that the output frequency is inversely proportional to the square of the device length,and when the value of Beta ratio is used as 2.3,a difference of 3.64%is observed on an average,in between the computed and the simulated values of frequency.As an outcome,the derived equation can be utilized,with the inclusion of an empirical constant in general,for arriving at the ring oscillator circuit’s output frequency.