Sorption of Fulvic Acids and Their Compounds with Heavy Metal Ions on Clay Minerals

In real soils the interaction of humic substances with clay minerals often occurs with the participation of metal cations. The adsorption of fulvic acids (FA) solution and their solutions in the presence of heavy metal ions (Pb or Zn) on two clay minerals (kaolinite and bentonite) was investigated by measurement of the optical density changes in the of equilibrium solutions. The FA adsorption by bentonite at the concentrations 0.05–1 g/L proceeds according to the polymolecular mechanism and has a stepwise character. The adsorption of FA on kaolinite can be described by the mechanism of monomolecular adsorption. In three-component systems, including FA, trace element ions and a clay mineral, complex processes occur, including the formation of complexes and salts and their adsorption. The sorption of colored complexes of FA with Pb on the surface of kaolinite and bentonite increases with increasing metal concentrations (0.5–2 mmol/L). The interaction of the FA-Zn2+ compounds with bentonite is a more complicated process—adsorption takes place at the lowest concentration used only. Thus, binding of FA by clay minerals in the presence of metal cations is a complex phenomenon due to the chemical heterogeneity of FA, different properties of metals, characteristics of mineral surfaces and the variability of environmental conditions.

Analysis of the chemical composition and technological process of processing ash and slag waste from chpp

This article studies sorption method of extraction of rare earth elements (REEs) from ash and slag waste of Novo- Angren TPP. In this regard, the possibility of extracting REE from acidic solutions on the Purolite C100-H cation exchanger was investigated in the example of one of the REEs, lanthanum. Furthermore, dependence of the sorption of lanthanum on Purolite C-100N cation exchanger on pH of solution and dependence of the sorption of lanthanum on the Purolite C-100H cation exchanger on the concentration of the equilibrium solution were studied. In addition, lanthanum sorption was calculated from the difference in concentrations in the initial and equilibrium solutions.

Resolving the conflict of nuclear wastewater discharging into the ocean based on the GMCR

PurposeJapan's decision to release nuclear wastewater into the Pacific Ocean in 2023 has sparked strong opposition at home and abroad. In this study, Graph Model for Conflict Resolution (GMCR) method is adopted to analyze the conflict problem, and reasonable equilibrium solutions are given to solve the conflict event.Design/methodology/approachIn this study, GMCR is adopted to solve the conflict problem. First, identify the key decision-makers (DMs) on the issue of nuclear effluent and the relevant options they might adopt. Second, the options of each DM are arranged and combined to form a set of feasible states. Thirdly, the graph model is constructed according to the change of DM's options, and the relative preference of each DM is determined. Finally, the conflict problem is solved according to the definition of GMCR equilibrium.FindingsDischarging nuclear wastewater into the ocean is not the right choice to solve the problem. Developing more space to store nuclear wastewater is more conducive to the protection of the ocean environment.Practical implicationsIt is undesirable for the Japanese government to unilaterally discharge nuclear wastewater into the ocean. Objectively assessing the radioactivity of nuclear wastewater and the cooperation of relevant stakeholders can better solve this conflict.Originality/valueThe problem arising from Japan's releasing plan is complicated because of a lack of information and the existence of multiple stakeholders, while GMCR can help us with a better view of the current circumstance in the conflict.

How to operate physical showrooms: Service decision and pricing based on product quality

This paper addresses operation strategies of the physical showroom under e-commerce, and studies joint decisions of the showroom service and pricing based on product quality. First, we propose an analytical model to capture the feature of consumer purchase behaviors and model three operation strategies of the physical showroom: the cooperation operation (CO), the manufacturer operation (MO), and the e-retailer operation (RO). Then, the equilibrium solutions in the above three strategies are obtained based on product quality, and the optimal operation strategy is analyzed. Besides, we extend the model to the scenario of endogenous product quality. The results are as follows. First, in contrast to the conventional wisdom, we find that the optimal showroom service may decrease with product quality when the production cost coefficient is high. Second, the results illustrate that enterprises should consider both product quality and production cost before opening physical showrooms. When the production cost coefficient is low, both the MO strategy and the RO strategy are better than the CO strategy, which means that the enterprise should open the physical showroom separately than jointly. However, when the production cost coefficient is high, the CO strategy provides the optimal showroom service. The enterprises in the supply chain should cooperate to balance costs and benefits. Besides, when product quality is endogenous, our analysis reveals that the RO strategy may offer better product quality than the CO strategy when the production cost coefficient is moderate.

The Neimark–Sacker Bifurcation and Global Stability of Perturbation of Sigmoid Beverton–Holt Difference Equation

We present the bifurcation results for the difference equation x n + 1 = x n 2 / a x n 2 + x n − 1 2 + f where a and f are positive numbers and the initial conditions x − 1 and x 0 are nonnegative numbers. This difference equation is one of the perturbations of the sigmoid Beverton–Holt difference equation, which is a major mathematical model in population dynamics. We will show that this difference equation exhibits transcritical and Neimark–Sacker bifurcations but not flip (period-doubling) bifurcation since this difference equation cannot have period-two solutions. Furthermore, we give the asymptotic approximation of the invariant manifolds, stable, unstable, and center manifolds of the equilibrium solutions. We give the necessary and sufficient conditions for global asymptotic stability of the zero equilibrium as well as sufficient conditions for global asymptotic stability of the positive equilibrium.

Determination of material properties of a linearly elastic peridynamic material

We investigate the properties of an isotropic linear elastic peridynamic material in the context of a three-dimensional state-based peridynamic theory, which considers both length and relative angle changes, and is based on a free energy function proposed in previous work that contains four material constants. To this end, we consider a class of equilibrium problems in mechanics to show that, in interior points of the body where deformations are smooth, the corresponding solutions in classical linear elasticity are also equilibrium solutions in peridynamics. More generally, we show that the equations of equilibrium are satisfied even when two of the four peridynamic constants are arbitrary. Pure torsion of a cylindrical shaft and pure bending of a cylindrical beam are particular cases of this class of problems and are used together with a correspondence argument proposed elsewhere to determine these two constants in terms of the elasticity constants of an isotropic material from the classical linear elasticity. One of the constants has a singularity in the Poisson ratio, which needs further investigation. Two additional experiments concerning bending of cylindrical beam by terminal load and anti-plane shear of a hollow cylinder, which do not belong to the previous class of problems, are used to validate these results.

Fuzzy Random Bimatrix Games Based on Possibility and Necessity Measures

In this study, we formulate bimatrix games with fuzzy random payoffs, and introduce equilibrium solution concepts based on possibility and necessity measures. It is assumed that each player has linear fuzzy goals for his/her payoff. To obtain equilibrium solutions based on the possibility and necessity measures, we propose two algorithms in which quadratic programming problems are solved repeatedly until equilibrium conditions are satisfied.

Green Supply Chain Game Model and Contract Design: Risk Neutrality vs. Risk Aversion

This paper incorporates the players’ risk attitudes into a green supply chain (GSC) consisting of a supplier and a retailer. The supplier conducts production and determines the green level and wholesale price as a game leader, the retailer sells green products to consumers and determines the retail price as a follower. Equilibrium solutions are derived, and the influence of risk aversion on the GSC is examined. Our results show that, for the centralized GSC, risk aversion lowers the green level and the retail price; while for the decentralized GSC, risk aversion lowers the wholesale price and the retail price, but it may induce the supplier to increase the green level given a large risk tolerance of the supplier. Meanwhile, the risk-averse decentralized GSC may obtain more expected profit than the risk-neutral decentralized GSC. Furthermore, this paper designs a revenue-and-cost-sharing joint contract to coordinate the risk-neutral GSC, and such a contract can improve the risk-averse GSC under specific conditions.

A Mathematical Modelling of The Dynamics of Voters Model of Two Political Fanaticism Figures with The Interaction Between Voters in Indonesian Presidential Elections

In this study, we present a dynamical analysis of the NS1S2A mathematical model that describe votes movement of voters in presidential elections. The NS1S2A deterministic voters model of two political fanaticism figures is described by ordinary differential equations. We considering the interaction between voters in the supportive voters compartment. We investigate the existence and the stability of four equilibrium solutions; free of supportive voters, supportive voters to first political figure, supportive voters to second political figure, and supportive voters to all political figures. Then we demonstrate this model by estimating the number of votes of two presidential candidates in Indonesian presidential elections. A numerical simulation is given to verify our analytical results. The result shows that the difference in the number of votes between the model with the interaction between voters and survey conducted by Litbang KOMPAS is smaller than the model without the interaction between voters.

Modeling of Photosynthesis Process and Assessing Of Phytoplankton Dynamics Based On Droop Model

Droop's well-known model simulates phytoplankton biomass dynamics based on nutrient limitation. The defining parameter is the nutrient concentration in phytoplankton cells (cell quota). This model is modified to description of the photosynthesis processes. The effects of photosynthetically active radiation must be taken into account. At the same time, the nutritional factor remains the main one. Water temperature is considered as a controlling factor. The influence of light during photosynthesis plays a decisive role. The decisive factor is the presence of photosynthetic substances. We conventionally combine them under the name "chlorophyll". Sufficient variability in the proportion of chlorophyll in phytoplankton (chlorophyll quota) directly affects biomass production. The equation for the dynamics of chlorophyll quota is added to the Droop model. The parameters of the model depend on the concentration of nutrients, illumination and water temperature. The properties of the solutions in the model are investigated, the conditions for the existence and stability of equilibrium solutions are clarified. Complex dynamic regimes are revealed in the case of unstable equilibria. It was found that the most sensitive parameter for biomass dynamics is the minimum value of the cell quota. The dynamics of indicators for the daily cycle and the annual cycle of seasonal changes are calculated. The influence of nutrition, illumination and temperature on biomass production has been clarified. During the day, the chlorophyll quota fluctuates insignificantly due to a short period of time. The changes are noticeable at longer times for example during the season.