Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent: equilibrium and dynamic studies

This paper summarizes the results of a study of adsorption of sulfur compounds from a high-sulfur feed on improved spherical-shaped nano-AgX zeolite. For this purpose, the nano-AgX zeolite was initially synthesized and improved with silver compounds such as silver nitrate, and then it was utilized in the adsorption process. In order to investigate the equilibrium and dynamics of the adsorption process, adsorptive desulfurization of real feed(i.e., sour gas condensate from the South Pars gas field) was carried out in batch and continuous processes under several operating conditions; a temperature-dependent Langmuir isotherm model was used to fit the equilibrium data. The value of monolayer adsorption capacity(q_m) and adsorption enthalpy(ΔH) were calculated to be 1.044 mmol/g and 16.8 kJ/mol, respectively. Furthermore, a detailed theoretical model was employed in order to model the breakthrough experiments. The results revealed that an increase in the feed flow rate and 1/T values will cause linear and exponential increase in the total mass transfer coefficient(ks). Isotherm and dynamic breakthrough models were found to be in agreement with the experimental data.

Deviation of Carbon Dioxide-Water Gas-Liquid Balance from Thermodynamic Equilibrium in Turbulence h Experiment and Correlation

The carbon dioxide-water system was used to investigate the flowing gas-liquid metastable state. The experiment was carded out in a constant volume vessel with a horizontal circulation pipe and a peristaltic pump forced CO2 saturated water to flow. The temperature and pressure were recorded. The results showed that some CO2 escaped from the water in the flow process and the pressure increased, indicating that the gas-liquid equilibrium was broken. The amount of escaped CO2 varied with flow speed and reached a limit in a few minutes, entitled dy- namic equilibrium. Temperature and liquid movement played the same important role in breaking the phase equilib- rium. Under the experimental conditions, the ratio of the excessive carbon dioxide in the gas phase to its thermody- namic equilibrium amount in the liquid could achieve 15%.

Dynamic limit equilibrium analysis of sliding block for rock slope based on nonlinear FEM

Traditional rigid body limit equilibrium method （RBLEM） was adopted for the stability evaluation and analysis of rock slope under earthquake scenario. It is not able to provide the real stress distribution of the structure, while the strength reduction method relies on the arbitrary decision on the failure criteria. The dynamic limit equilibrium solution was proposed for the stability analysis of sliding block based on 3-D multi-grid method, by incorporating implicit stepping integration FEM. There are two independent meshes created in the analysis： One original 3-D FEM mesh is for the simulation of target structure and provides the stress time-history, while the other surface grid is for the simulation of sliding surface and could be selected and designed freely. As long as the stress time-history of the geotechnical structure under earthquake scenario is obtained based on 3-D nonlinear dynamic FEM analysis, the time-history of the force on sliding surface could be derived by projecting the stress time-history from 3-D FEM mesh to surface grid. After that, the safety factor time-history of the sliding block will be determined through applying limit equilibrium method. With those information in place, the structure＇s aseismatic stability ean be further studied. The above theory and method were also applied to the aseismatic stability analysis of Dagangshan arch dam＇s right bank high slope and compared with the the result generated by Quasi-static method. The comparative analysis reveals that the method not only raises the FEM＇s capability in accurate simulation of complicated geologic structure, but also increases the flexibility and comprehensiveness of limit equilibrium method. This method is reliable and recommended for further application in other real geotechnical engineering.

A preliminary study of 3D difference scheme with energy dynamic equilibrium

In this paper, a difference scheme with energy dynamic equilibrium (DS-EDE) is presented, which can be used for the simulation of long-term atmosphere and sea motion. Based on three dimensional nonlinear evolution equations for atmosphere and sea motion, a three dimensional compact upwind scheme (CUWS) is constructed, as the basis of the DS-EDE. The DS-EDE satisfies the following condition of energy dynamic equilibrium (EDE): the total work of external forces on the region boundary is equal to the sum of the total effective variation of the kinetic energy and the energy dissipation in the average flow motion and the effective variation of the potential energy per unit time within the region of interest. It really reflects the basic mechanism of the action of external forces and dissipation in atmosphere and sea movement. Therefore, the DS-EDE developed in this paper is a suitable model for simulating long-term atmosphere and sea movement with forcing and dissipation.

Developing architecture of a traveler information system for dynamic equilibrium in traffic networks

Having criticized the current architecture of Advanced Traveler Information Systems （ATISs）, this work discusses a new base of requirements to develop a new paradigm for traffic information systems. It mainly integrates three dimensions within a traffic system： drivers＇ pattern of behavior and preferences, urban traffic desires, and capabilities of traffic information service providers. Based on the above, functional segments from several related backgrounds are brought together to structure a new architecture, called Interactive Traveler Information System （ITIS）. The main interactive feature of this new architecture is a two-way communication track between drivers and the traffic information system provider-in fact, a decision on choosing a road at a particular time for an individual will be made based on the utility of both sides. This new configuration consists of driver-side smartphone application, centric traffic prediction, and decision-maker units, which will shape a new approach of decision-making processes. These all work together to satisfy the designated goal of ITIS, which is preserving the Wardrop equilibrium condition in the traffic network level. Finally, we concentrate on a comparison study, which shows a differentiation between performance of the proposed ITIS and the current ATIS model in a real situation. This has been done with simulations of analogical scenarios. The most noticeable advantage of the proposed architecture is not being limited to a saturation limit, and the positive effect of increasing system penetration in the performance of the newly introduced information system. In conclusion, new research subjects are suggested to be carried out.

Mathematical Modeling Applied to Understand the Dynamical Behavior of HIV Infection

The study of viral dynamics of HIV/AIDS has resulted in a deep understanding of host-pathogenesis of HIV infection from which numerous mathematical modeling have been derived. Most of these models are based on nonlinear ordinary differential equations. In Bangladesh, the rate of increase of HIV infection comparing with the other countries of the world is not so high. Bangladesh is still considered to be a low prevalent country in the region with prevalence and shown the local and global stability at disease free and chronic infected equilibrium points. Also we have shown that if the basic reproduction number , then HIV infection is cleared from T cell population and it converges to disease free equilibrium point. Whereas if , then HIV infection persists.

Critical anomaly and finite size scaling of the self-diffusion coefficient for Lennard Jones fluids by non-equilibrium molecular dynamic simulation

We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with temperature decreases by increasing density. For density ρ＊ = ρσ3 = 0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T＊ = kT/ε = 1.25. The value of the self-diffusion coefficient strongly depends on system size. The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments. This correction scales as N-α, where α is an adjustable parameter and N is the number of particles. It is observed that the values of a 〈 1 provide quite a good correction to the simulation data. The system size dependence is very strong for lower densities, but it is not as strong for higher densities. The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations fronl the literature.

The Analysis of the Dynamic Equilibrium State in Linear Control System

This paper discusses not a point of equilibrium to free system,but a certain family of equilibrium state of dynami- cal system with inputs.This equilibrium state depends on the input,so it is called the dynamic equilibrium state.The expression of the dynamic equilibrium state can be given under some certain condition.With deductions and proofs in linear control system,es- tablish the expression of the dynamic equilibrium state in two cases,where the linear systems are nonsingular or singular.Also pre- sent the concept and the condition of the controllability of the dynamic equilibrium state.The controllability of the dynamic equilib- rium state is different from the controllability of the state to system,but these two are closely related.

Dynamical evolution processes of traffic flow and travel cost in urban transportation networks

Considering such a fact that travellers dynamically adjust their routes and the resultant link traffic flows in a network evolve over time, this paper proposes a dynamical evolutionary model of the traffic assignment problem with endogenous origin-destination （OD） demands. The model＇s stability is analysed and the resultant user equilibrium （UE） state is shown to be stable under certain conditions. Numerical results in a grid network indicate that the model can generate convergent flow patterns and finally terminates at the UE state. Impacts by the parameters associated with OD demand function and link cost function are also investigated.

Adsorption equilibrium, kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid–nitric acid aqueous solution by strong acid cation resin

The separation of Ca2+and Mg2+ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer.This paper studied the adsorption equilibrium,kinetics,and dynamic separation of Ca2+and Mg2+ions by strong acid cation resin,and the effects of phosphoric acid and nitric acid on the adsorption process were investigated.The results reveal that the adsorption process of Ca2+and Mg2+ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g-1 and 1.83 mmol·g-1,respectively.The adsorption kinetics of Ca2+and Mg2+ions on resin fits better with the pseudo-first-order model,and the adsorption equilibrium in pure water is reached within 10 min contact time,while at the present of phosphoric acid,the adsorption rate of Ca2+and Mg2+ions on resin will go down.The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution,but the dynamic operation should control the flow rate of mix acid solution.Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

RESEARCH ON A DYNAMICAL MACRO ECONOMIC MODEL BASED ON SIDRAUSKI MODEL

This paper formulates a kind of dynamical macro economic model based on Sidrauski's work,then presents the sufficient and necessary conditions of the stability of model at equilibrium states,and shows some results for special production functions.

Theory of an Optimal Dynamical Water Resource Management Policy

Water markets even though not perfect and require a lot of effort to establish are considered as a robust tool to address water management issues around the world. However, the existing literature does not provide an optimal water resource management policy. To create a perfect water market, the government needs to identify the potential number of suppliers/producers and consumers of water against various extraction/supply/production rates of water, i.e., to identify a supply and a demand curve for number of suppliers/producers of water against each production rate in economy. This article presents a theory which is practically applicable for an optimal dynamical water resource management policy (JEL H20, H23, H27).

Investigation of the Quaternion Dynamical System

The quaternion Mandelbrot set is one of the most important sets in mathematics. In this paper we first give some properties of the quaternion algebra. Then, we introduce the quternion dynamical system. We are concerned with analytical and numerical investigation of the quaternion dynamical system.

The Impact of Climate Change on Agriculture Production in Ethiopia: Application of a Dynamic Computable General Equilibrium Model

The challenge of meeting the ever-increasing food demand for the growing population will be further exacerbated by climate change in Ethiopia. This paper presents the simulated economy-wide impacts of climate change on the agriculture sector of Ethiopia using a dynamic computable general equilibrium (CGE) model. The study simulated the scenarios of agricultural productivity change induced by climate change up to the year 2050. At national level, the simulation results suggest that crop production will be adversely affected during the coming four decades and the severity will increase over the time period. Production of teff, maize and sorghum will decline by 25.4, 21.8 and 25.2 percent, respectively by 2050 compared to the base period. Climate change will also cause losses of 31.1 percent agricultural GDP at factor cost by 2050. Climate change affects more the income and consumption of poor rural households than urban rural non-farming households. The reduction in agricultural production will not be evenly distributed across agro ecological zones, and will not all be negative. Among rural residents, climate change impacts tend to hurt the income of the poor more in drought prone regions. Income from labor, land and livestock in moisture sufficient highland cereal-based will decline by 5.1, 8.8 and 15.2 percent in 2050. This study indicated that since climate change is an inevitable phenomenon, the country should start mainstreaming adaptation measures to sustain the overall performance of the economy.

A non-equilibrium molecular dynamics study of the thermal conductivity of uranium dioxide

The thermal conductivity of uranium dioxide in the temperature range of 300–2400 K was estimated by non-equilibrium molecular dynamics calculation using Fourier law.The Kawamura function was adopted as the interatomic potential function.The calculated thermal conductivities are found to be strongly dependent on the temperature of the simulation cube.The thermal conductivity simulation results are compared with the experiment results and agreed well with the experimental results when the temperature is above 600 K.The thermal conductivities scale effects are found to be existed in uranium dioxide nanometer thin film.The approximate mean free paths of phonons in different temperatures can be examined.

Non-equilibrium Thermodynamic Analysis of The Transport Properties of Formed-in-Place Zirconium (Ⅳ) Hydrous Oxide-Polyacylate Membranes in aqueous NaNO_3 solution

Nanofiltration of aqueous NaNO3 solution with a dynamically formed Zr(IV) hydrousoxide-PAA membrane is presented. The practical transpoft coefficients Lp, σ, ω were obtainedusing relationships of the non-equilibrium thermodynamics and were used to calculate thefrictional coefficients of a friction model.

Dynamic process of trace boron non-equilibrium grain boundary segregation and the effect of cooling rate

The dynamic process of non-equilibrium grain boundary segregation of traceboron in Fe-40 percent Ni alloy during cooling and the effect of cooling rate were investigated byboron tracking autoradiography technique. The results indicate that during cooling process, theamount of segregated boron on grain boundary firstly increases fast, then enters a comparativelyeven increasing stage and increases rapidly again at the third stage. The details of each stagevaried with cooling rate are explained. When the segregation develops to a certain degree, thesegregated boron atoms transform from solute status to precipitate status.

Dynamical localization effect in a coupled quantum dot array driven by an AC magnetic field

We have studied the transport properties of a ring-coupled quantum dot array driven by an AC magnetic field, which is connected to two leads, and we give the response of the transport current to the dynamical localization. We found that when the ratio of the magnetic flux to the total quantum dots number is a root of the zeroth order Bessel function, dynamical localization and collapse of quasi-energy occurs and importantly~ the transport current displays a dip which is the signal of dynamical localization. The dynamical localization effect is strengthened as a result of the increase of the quantum dot number, and it is weakened on account of the increase of the dots-lead hopping rate.

Industrial Linkage: Dynamic Equilibrium Supply Chain of Foundry Landmark Industrial Chain -- An Analysis Based on Zhejiang

In the face of the impact of the epidemic on the industrial chain and supply chain,it is an inevitable requirement for industrial development to ensure the dynamic balance of the supply chain.Supply chain is the basis for the generation of industrial chain.Industrial linkage can promote the rational layout of industries.The operation mode of supply chain is the main driving force of industrial linkage.To build a dynamic and balanced supply chain,we must focus on symbolic industries and adopt measures of chain protection,chain supplement,chain creation and chain financing.