Spatially non‐local model of inelastic deformations: applications for rock failure problem

A spatially non‐local model for inelastic deformation of solids is proposed and studied. The non‐locality of deformation is taken into account by the additional parameter of state beyond the classical parameters such as stress and strain tensors. This additional parameter is the curvature tensor expressed in terms of the metric strain tensor, and it is called the failure parameter. In the case of small deformation, it is equivalent to the Saint‐Venant incompatibility tensor. Thermodynamic properties of the model are studied, and governing differential equations for spatially non‐local model are formulated, which are composed by the elasticity equations and parabolic equation for the failure parameter. The model can be applied to the study of the rock failure problem, and as an example, the one‐dimensional problem for the deformation of half‐plane loaded by the normal surface stress is studied. Stationary and non‐stationary formulations of the problem are considered, and qualitative agreement with available experimental data is observed.     

Adsorption of Zinc using Tea Factory Waste: Kinetics,Equilibrium and Thermodynamics

In India, the annual production of tea is ca. 857,000 tonnes, which is 27.4% of the total world production. The amount of tea factory waste (TFW) produced per annum after processing is ca. 190,400 tonnes. TFW can be used as a low cost adsorbent for the removal of toxic metals from the aqueous phase. An investigation was carried out to study the feasibility of the use of TFW as an adsorbent for the removal of the heavy metal, zinc. Equilibrium, kinetic and thermodynamic studies were reported. The straight line plot of log (q_e–q) versus time t for the adsorption of zinc shows the validity of the Lagergren equation. The various steps involved in adsorbate transport from the solution to the surface of the adsorbent particles were dealt with by using a Weber‐Morris plot, q_e versus t^0.5 for the TFW. The rate controlling parameters, k_id,1 and k_id,2, were determined and it was found that the macro‐pore diffusion rate was much larger than micro‐pore diffusion rate. A batch sorption model, which assumes the pseudo‐second‐order mechanism, was used to predict the rate constant of sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of initial zinc (II) ion concentration. Equilibrium data obtained from the experiments were analyzed with various isotherms, i. e., Freundlich, Langmuir, Redlich‐Peterson and Tempkin. The adsorption equilibrium was reached in 30 min and the adsorption data fitted well to all models. The maximum adsorption capacity of TFW for zinc (II) ions was determined to be 14.2 mg/g. The capacity of adsorption on Zn(II) increased with increasing temperatures and pH. The maximum uptake level of zinc was observed at pH of 4.2. The various thermodynamic parameters, i. e., ΔG°, ΔH° and ΔS°, were estimated. The thermodynamics of the zinc ion/TFW system indicated a spontaneous, endothermic and random nature of the process. The results showed that the TFW, which has low economical value, is a suitable adsorbent for the removal of zinc (II) ions from aqueous solutions.     

Li,K／Cl,SO4—H2O体系相平衡的热力学

介绍了根据自己研究测定的Li,K/Cl,SO4-H2O体系25℃的渗透系数等热力学性质获得的Pitzer混合参数，并用自己能量小化方法计算25℃Li,K/Cl,SO4-H2O体系的相图，结合测定得到的该体系50℃75℃的相图和复盐LiSO4转变温度的研究，整个体系相平衡和热力学的研究结果可用于盐湖卤水锂盐的分离提取。     

镇江地区高温气候特征分析及一次连续性高温天气的诊断

本文利用镇江1961—2013年的观测资料以及2.5°×2.5°的逐日NCEP再分析资料,在分析镇江地区高温气候特征的基础上,着重对2013年的连续性高温天气进行诊断。结果表明:镇江夏季高温日数有明显的上升趋势,突变点为2000年,突变后2001—2013年比1961—2000年的年平均高温日数增幅近9 d;镇江地区的高温日数存在3~4 a,6 a,9~13 a,19~27 a的周期,2000年后的准3 a周期稳定存在;强盛且稳定的副热带高压及南亚高压与副热带高压形成的垂直环流的下沉增温,是2013年8月4—18日连续高温产生的重要原因;温度平流和垂直加热对持续性高温天气起积极作用,非绝热加热为负值;连续高温期间海上台风路径偏西偏南,中高纬无明显冷空气活动且2013年梅雨结束时间较早,都为镇江地区出现连续性高温天气提供了有利条件。     

A thermo-chemo-electro-mechanical framework of unsaturated expansive clays

Prediction of the coupled chemo-mechanical behaviours of porous media is an important problem in many areas, i.e., expansive clays in geotechnical and petroleum engineering, engineered barriers in the underground storage of nuclear wastes, and biological tissues in biological engineering. A further complex condition occurs when the voids are not fully saturated by liquid, such that capillary effects cannot be neglected a priori and might play an important role. Focusing on the modelling of expansive clays in the geotechnical field and based on the modified mixture theory, the work presented in this paper contributes to the construction of a theoretical framework used to model such complex coupling behaviours. The Clausius–Duhem inequality, which governs the dissipation associated with mechanical work, phase transformation, mass transport and thermal transport, is rigorously derived. Based on this theoretical framework, a chemo-poro-elastic unsaturated model is developed. The model is subsequently used to simulate the salt solution infiltration process through an unsaturated expansive clayey soil that induces changes in the mechanical and hydraulic field quantities. The logical tendencies are obtained and provide a preliminary demonstration of the capabilities of the newly developed theoretical framework.     

Solar oscillations and the equation of state

Summary Accurate measurements of observed frequencies of solar oscillations are providing a wealth of data on the properties of the solar interior. The frequencies depend on solar structure, and on the properties of the plasma in the Sun. Here we consider in particular the dependence on the thermodynamic state. From an analysis of the equations of stellar structure, and the relevant aspects of the properties of the oscillations, we argue that in the convection zone one can isolate information about the equation of state which is relatively unaffected by other uncertainties in the physics of the solar interior. We review the different treatments that have been used to describe the thermodynamics of stellar plasmas. Through application of several of these to the computation of models of the solar envelope we demonstrate that the sensitivity of the observed frequencies is in fact sufficient to distinguish even quite subtle features of the physics of solar matter. This opens up the possibility of using the Sun as a laboratory for statistical mechanics, under conditions that are out of reach in a terrestrial laboratory.     

Removal of Heavy Metals from Synthetic Mixture as well as Pharmaceutical Sample Via Cation Exchange Resin Modified with Rhodamine B: Its Thermodynamic and Kinetic Studies

A new sorbent was prepared by loading rhodamine B on Amberlite IR‐120. Various physico‐chemical parameters such as effects of adsorbate concentration, contact time, pH, and temperature on the sorption of the dye have been studied. Thermodynamic parameters (ΔH° and ΔS°) were also evaluated for the sorption of dye. Kinetic studies revealed that the sorption of the dye was best fit for pseudo‐second‐order kinetic. The metal ion uptake in different solvent systems has been explored through column studies. On the basis of distribution coefficient (K_d), some heavy metal ions of analytical interest from binary mixtures have been separated. The limit of detection (LOD) for the Ni²⁺ and Fe³⁺ metal ions was 0.81 and 0.60 µg L^?1, and the limit of quantification (LOQ) was found to be 2.72 and 2.0 µg L^?1. This sorbent has also been successfully applied in the analysis of multivitamin formulation. The applicability of the modified resin in the separation of heavy metals constituting real and synthetic samples has been explored.     

http://dx.doi.org/10.1016/j.gsf.2016.06.008

The mineral schreibersite, (Fe,Ni)₃P, provides a reactive source of phosphorus capable of forming phosphorylated molecules. These molecules may have been an important component of prebiotic chemistry, allowing their build-up and eventual commencement of autopoiesis. Discussed here are potential geochemical routes to providing schreibersite, as a potentially important prebiotic mineral, to the Hadean Earth. Two routes are identified: delivery of phosphides by meteoritic material and the reduction of phosphates to phosphides by high-temperature, low-redox conditions. About 1–10% of all crustal phosphorus is estimated to have been in schreibersite during the Hadean, making the long-term reaction of this mineral with organic-laden water plausible for many years. Ultimately, such conditions would have been conducive to the formation of life as we know it today.     

Organic and inorganic geochemistry of low temperature gas discharges at the Baia di Levante beach, Vulcano Island, Italy

Discharge from subaereal and submarine gas vents of the Baia di Levante beach gases from the Vulcano Island were sampled for major and trace gas components in May and November 1995.Chemical compositions and equilibrium calculations suggest three different groups of CO₂-rich gas emissions depending on their distance from the La Fossa crater: (1) gas vents close to the Faraglione area are characterised by high H₂S contents, high calculated equilibrium temperatures based on inorganic species and relatively high proportion of alkene compounds; (2) gas vents close to Vulcanello are characterised by low calculated equilibrium temperatures and low amounts of alkenes; and (3) Pontile sample has the highest equilibrium CO₂ pressure (up to 68 bars) which may account for the observed absence of benzene. The relative large variability of H₂S in the Baia di Levante beach gas discharge may be attributed to either different interactions between iron sulphides and weakly acid waters or catalytic effect of elemental sulphur on the de-hydrogenation of cyclo-hexane. Thermodynamic calculations suggest that the main inorganic species and CH₄ may have re-equilibrated at relatively shallow depth (10–200 m b.s.l. and 30–600 m b.s.l. for a lithostatic and hydrostatic pressure, respectively). The slow kinetics of reactions in the C_nH_2n/C_nH_2n+2 systems, with respect to that of CH₄–CO–CO₂, may explain the observed propene/propane ratios, which can only be reached at reaction temperatures of 300–350°C. This low speed of reactions can also explain the observed disequilibrium of C1–C4 alkanes.     

Petrological geodynamics of mantle melting III. AlphaMELTS + multiphase flow: The effect of water

The influence of water is evaluated in this last contribution of a series aiming to study the petrological and dynamic evolution of mantle melting. Water is considered to be either a chemical component in the melt or solid assemblage but it can also be present as a pure water phase in a oversaturated environment. A three-phase-flow model was developed for this purpose.Only a limited set of conditions has been applied to the 1-D upwelling mantle column. A range of fixed temperatures (1150–1450 °C) and water contents in the solid mantle (0, 0.02 wt.%, 0.2 ​wt.%) have been imposed at the entry point (120 ​km deep) for the two melting models introduced in the previous installments, dynamic equilibrium melting (DEM) and dynamic fractional melting (DFM) model.As expected, for a given temperature at the base of the mantle column, the depth of the first melt formation increases with higher water content in the mantle. After the first melt is created, very negligible amount of melt is formed over a certain depth interval which approximately ends at the depth where the first melting of the dry mantle would take place. However melt is present as a dynamic phase thorough the entire region regardless whether the DEM or DFM model has been applied.Under a quasi-steady state regime, the melt and residual mantle compositions vary significantly over depth, depending on the conditions imposed to the model (DEM, DFM, bottom temperature and water content). Several distinctions can be made at the extraction point (top of the mantle column ​= ​15 ​km deep). For DEM and DFM models at this lowest depth, the most influential factor affecting the melt composition after the quasi-steady state condition has been reached is the temperature at the base of the column. In general, for a high temperature model, the input water in the mantle does not seem to play a significant role on the bulk composition of the melt (except for the water content in melt). But at low temperature water does have some noticeable influence on the variation of some chemical components in melt ($Si{O}_2$, $F{e}_2{O}_3$, $CaO$, $N{a}_{2}O$ at T ​= ​1250 °C or lower). A similar conclusion can be made also for the residual mantle composition. The presence of a dynamic free water phase is detected only in absence of melt or in coexistence with a melt phase when the mantle is relatively cold (bottom temperature $\le$1250 °C) and the input water content at the base of the model is relatively high (0.2 ​wt.%).Complete output data for several numerical simulations and six animations illustrating various melting models are available following the instructions in the supplementary material.