Prediction of Europium Retention in Perovskite: Potential Candidates for an Engineering Barrier in the Disposal of Radioactive Waste

Perovskites, such as tausonite, are crystalline metal oxides with excellent optical and photocatalytic properties and have also been used successfully in the retention of metals, simulating the isotopes of uranium and plutonium. In this work, different pseudo-order and thermodynamic models were studied to achieve the prediction of the sorption of Eu3+ (chemical analogous for actinides) in tausonite. The effects of gamma irradiation and temperature on the structural characteristics of the material were determined, as an additional step in the evaluation of material as an engineering barrier in the disposal of radioactive waste. The results obtained show that the tausonite is resistant to the gamma irradiation and thermal energy. Likewise, it was possible to determine that europium sorption occurs through an exothermic and spontaneous reaction, as well as through the formation of surface complexes, where Eu3+ ions bind to sites on the tausonite by dipole-dipole interaction. Furthermore, it was shown that the sorption mechanism is influenced by diffusive phenomena, which participate in the formation of surface complexes. Additionally, a new sorption model with respect to pH was proposed, which allowed determining the physical parameter π. The evidence obtained suggests that π is a physical parameter that relates pH to an optimal value and could explain the equilibrium between the surface complexes that tausonite forms with europium. Likewise, the evidence suggests that 50 kg of tausonite would have the capacity to retain at least 26.59 g of alpha-emitting radionuclides, equivalent to a waste package (900 kg) with a maximum activity of 4000 Bq/g.

Analytical, Experimental, and Numerical Investigation of Energy in Hydraulic Cylinder Dynamics of Agriculture Scale Excavators

This paper discusses energy behaviors in hydraulic cylinder dynamics, which are important for model-based control of agriculture scale excavators. First, we review hydraulic cylinder dynamics and update our physical parameter identification method to agriculture scale experimental excavators in order to construct a nominal numerical simulator. Second, we analyze the energy behaviors from the port-Hamiltonian point of view which provides many links to model-based control at laboratory scale at least. At agriculture scale, even though the nominal numerical simulator is much simpler than an experimental excavator, the analytical, experimental, and numerical energy behaviors are very close to each other. This implies that the port-Hamiltonian point of view will be applicable in agriculture scale against modeling errors.

Constraints on the spatial variation of Planck constant

Inspired by recently published researches, we present two protocols for setting an upper limit to the claimed variation of $$\hbar $$ ħ upon the position. The protocols, both within today state of art, involve the use of two delayed laser pulses driving an atom. The distinct positions of the laboratory, due to the Earth motion, affects $$\hbar $$ ħ and hence the atomic dynamics. The first protocol measures the difference in population of the atomic ground state while the second one the red-shift of the harmonics emitted by the atom in the two moments of the experiment. The protocols improve the reported upper limit of $$\varDelta \hbar /\hbar $$ Δ ħ / ħ . The theory shows that $$\hbar (\varvec{r})$$ ħ ( r ) induces a chaotic evolution to the atom. This form of Chaos is generated by a variation of a physical parameter and is one example of Parametric Chaos.

The investigation of the scale effect on porosity in Bashkirian limestones

The article presents the methodology of the representative elementary volume definition for two 1 m long whole core segments. Scientific articles focused on practical methods of representative volume calculations using various physical parameter fluctuations have been studied. Porosity values of every whole core fragment evaluated in two ways using the 7.3 cm diameter core samples in the first approach and the 3 cm diameter core samples in the second one have been compared. Particularities of the scale effect occurring in core samples and depending on core size and porosity type have been analyzed. The cause of porosity increase in big core samples has been determined. The reason due to which porosity changes are explained by fracture porosity occurring in core samples having big volumes has been found. The comparison between neutron log porosity and core porosity has been made. Reasons of similarities or differences of core and log data have been established.

Optimization of Coagulation and Flocculation in Concrete Wastewater of Precast Industry

<p><strong>Abstract.</strong> The population increase until the end of 2019 reached 267 million. This is in line with developments that support activities. This is inseparable from the actions of one of the precast concrete companies PT.WB Precast Plant Karawang in supporting development that produces waste in the form of wastewater. The parameter measured as a reference in carrying out processing is the Minister of Health Regulation Number 32 of 2017. This study's method refers to turbidity as a physical parameter, namely 25NTU and hardness total as a chemical parameter, which is 500 mg / l. CaCO3. <strong>Objectives:</strong><strong> </strong>The purpose of this study was to determine the optimization of the use of PAC as a coagulant and flocculant to reduce the turbidity and total hardness and determine the optimum detention time of flocculation.<strong> </strong><strong>Method and results:</strong><strong> </strong>The sampling method in this study is observation. The population in this study is concrete wastewater with parameter values that are not in accordance with the standard.<strong> Conclusion:</strong> By using PAC 10% the optimum doses is 140 ppm, and the optimum detention time of flocculation is 5 minute that can reduce the turbidity from 275 NTU to be 11.615 NTU or 95.7% and can reduce total hardness from 948.75 mg/l CaCO3 to be 491.25 mg/l CaCO3 or 48.2%.</p>

Hydraulic Fracturing Simulations with Real-Time Evolution of Physical Parameters

During hydraulic fracturing, expansion of internal micro-fractures deforms the rock to different extents. Numerical studies typically assume fixed parameters; however, in the field site, parameters are likely to vary. Error accumulation underlies deviation of simulation results from actual data. In this study, it was found that the mean velocity of an in-lab active source obtained from the hydraulic fracturing experiment decreased. To explain the effect of physical parameter (velocity) on numerical simulation results, we performed numerical simulations based on the extended finite element method (XFEM) of indoor hydraulic fracturing considering the velocity variation. The simulation results considering the change of the physical parameter (velocity) of the rock sample reflect the rock damage evolution more exactly. Consequently, the real-time evolution of physical parameters during hydraulic fracturing should be considered in numerical simulations. Rock damage evolution can be better captured using the offered modification of physical parameters. The present work provides theoretical guidance for hydraulic fracturing simulations to some extent.