Schiff Base-Modified Nanomaterials for Ion Detection: A Review

The continuity and homogeneity of sandstone uranium deposits are inherent characteristics that affect in situ leaching performance indexes and have important guiding effects on the optimization of mining design. In this work, we propose a spatial information entropy calculation method based on a convex hull search strategy to quantitatively evaluate the geological characteristics of uranium deposits. We use the 3-D block model of sandstone-hosted uranium deposits as hard data. First, we use the Alpha-Shapes algorithm to calculate the convex hull of the space area where various types of unit blocks are located. Second, we formulate a suitable multi-point configuration based on the convex hull size. Then, we use the multi-point density function. Scanning the convex hull point cloud establishes a probability density function to calculate the local information entropy of various sub-regions. Finally, the local spatial information entropy is aggregated using addition and multiplication to obtain the joint spatial information entropy of the entire evaluation area. A series of parameter sensitivity and performance analysis experiments prove the stability of the method and the accuracy of the quantitative and homogeneous evaluations of the complex geological conditions. In order to solve the problem of the difference between the designed production capacity and actual production capacity of a uranium deposit, we use a new method to evaluate the homogeneity and continuity of the lithology and grade of the deposit. The new method and evaluation conclusions can be used for the automation and understanding of future engineering optimization processes.

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Entropy Evaluation Method for Sandstone Uranium Reservoir Characteristics Based on Convex Hull Search

Injection/falloff testing (IFT) is an important method for obtaining coalbed methane (CBM) reservoir permeability It is necessary to evaluate IFT interpretation reliability for more accurate perme

A new reliability evaluation method of injection/falloff testing interpretation in coal reservoir based on FAHP and cloud model

The micropore throat of the Gao 3 section tight sandstone reservoir was studied using sampling and experimental (high-pressure mercury injection and scanning electron microscopy) methods. Based on the relative permeability, the reservoir can be divided into three categories: conventional, unconventional and low permeability. To determine the displacement pressure, porosity and other relevant parameters of various reservoirs, the mercury injection curve of all samples was projected to the same coordinate system. According to the position of the inflection point on the mercury injection curve of all levels of reservoirs, the pore throat was divided into three types: micropores, transition pores and macropores. Based on the theory that the throat is characterised by the mercury withdrawal curve, the throat in the present study is divided into three categories: the large throat, the medium throat and the small throat. Combined with the ordinate position at the inflection point, the critical point of micropore-throat classification of all kinds of reservoirs was determined. By analysing the histogram of pore-throat distribution of all kinds of reservoirs, the peak value of reservoir pore-throat distribution was determined. From the definition of expectation and variance in mathematics, the concept of grading parameters was introduced to determine the size and concentration degree of micropore-throat distribution at all levels of reservoirs, and a correlation analysis with permeability was performed to determine the control law of permeability.

Grading evaluation of pore throats in a tight sandstone reservoir: a case study of the Gao 3 section reservoir in the Qijia area of the Songliao Basin

Quaternized salicylaldehyde Schiff base side-chain polymer-grafted magnetic Fe3O4 nanoparticles for the removal and detection of Cu2+ ions in water

Accurate and quantitative evaluation of low-permeability reservoirs and other more complex reservoirs not only depends on various control factors related to the reservoir but is also affected by our incomplete understanding of reservoirs and the imperfections inherent in evaluation methods. The evaluation of reservoirs may be improved by determining the integrity and uncertainty of the reservoir evaluation process and effectively examining the differences between evaluation results. Taking membership as the linking factor, utilizing the idea of information superposition, and combining the fuzzy comprehensive and gray relational evaluation methodologies in the uncertainty evaluation, this study presents a differentiated and improved internal algorithm and establishes a more effective fuzzy-gray comprehensive evaluation method. The example of E32 interval evaluation in the southern Nanbaxian gas field of the Qaidam Basin shows that this method not only considers the fuzziness and grayness related to reservoir evaluation but also provides improved discrimination of low-permeability reservoirs and increased accuracy in the reservoir description. According to the improved reservoir classification results, the E32 intervals are divided into four types of reservoirs, of which types I and II are favorable reservoirs. The lateral distribution of the reservoir is described in more detail than previously, with near-continuous knowledge, and there is a good distinction between the reservoir type. The obtained results are in line with the development rules of geological deposition and the geological knowledge base, approximately matching existing practical results and geological knowledge. This method can be used to quickly and effectively guide exploration and development strategies related to gas fields, and provides a new approach for low permeability and tight reservoir evaluation.

Quantitative evaluation of low-permeability gas reservoirs based on an improved fuzzy-gray method

An inorganic-organic chemosensing material (MS-NSP) was developed by anchoring the bis-Schiff base fluorophore onto the channel surface of a SBA-15 mesoporous silica surface with a quaternary ammonium linker. The mesostructure, morphology, and spectral features of MS-NSP were systematically described. The nanohybrid could be implemented as a multifunctional fluorescent nanosensor for Cu2+ ions. A good linearity was observed over the concentration range from 0 to 4 mM, and the lower Cu2+ detection limit by MS-NSP was found to be 0.19 μM. Additionally, the fluorescence response of MS-NSP was remarkably specific for Cu2+ ions compared to other competitive ionic species. Moreover, the MS-NSP can also be utilized as an adsorbent for the effective elimination of Cu2+ from an aqueous solution. The kinetic features of adsorption were well described by the pseudo-second-order model and the sorption isotherm was in agreement with the Langmuir model. The theoretical maximum adsorption amount of Cu2+ ions was determined at 58.5 mg g-1. Finally, the interaction of MS-NSP and Cu2+ was investigated using theoretical calculations. Overall, the material in the present study is useful for both the sensitive detection and effective extraction of Cu2+ ions.

Yuanyuan Zhang

Papers

Quantitative evaluation of low-permeability gas reservoirs based on an improved fuzzy-gray method

Preparation of a bis-Schiff base immobilized mesoporous SBA-15 nanosensor for the fluorogenic sensing and adsorption of Cu2.

Bis-Schiff Base Functionalized Fe3O4 Nanoparticles for the Sensitive Fluorescence Sensation of Copper Ions in Aqueous Medium

Quaternized salicylaldehyde Schiff base side-chain polymer-grafted magnetic Fe3O4 nanoparticles for the removal and detection of Cu2+ ions in water

Preparation of pyridine Schiff base grafted ion-imprinted mesoporous sorbent for selective separation of Pb(II) from aqueous medium