Experiments on integrated solidification and cementation of the cement-formation interface using the Mud Cake to Agglomerated Cake (MTA) method

Based on the scientific concept of Mud Cake to Agglomerated Cake (MTA), the integrated solidification and cementation of materials at the cement-formation interface was studied by mechanical evaluation, microstructure analysis (XRD, TG and ESEM), and fluid dissolution tests. The results of the mechanical evaluation show that compared with the existing method of MTC, the bond strength of the cement-formation interface increased by 37.81% (increasing up to 1 606.31% with longer curing time) with the MTA method. The results of microstructural analysis show that the synchronous hydration and hardening reaction between the mud cake and cement slurry occurred locally, and a little CSH(I) (calcium silicate hydrate) gel and heulandite gel formed. The results of fluid dissolution tests show that the mud cake in a finished sample made by the old method was dissolved and became a turbid drilling fluidr after it was immersed in water for 28 days. However, based on the MTA method, the agglomerated cake and hardened cement paste bonded together. The agglomerated cake was not dissolved and the water remained clear. All the above results corroborate two facts, one is that the mud cake has converted to agglomerated cake, the other is that the cement-formation interface has solidified and cemented integrally. 摘要: 基于泥饼仿地成凝饼的科学构想，采用力学性能评价（如胶结强度）、微观结构分析（如X射线粉末衍射分析、热失重分析、环境扫描电子显微镜分析）和流体溶蚀实验等方法对MTA方法固井二界面整体固化胶结进行了实验研究。研究结果表明：随着养护时间的延长，用MTA方法得到的固井二界面胶结强度较目前提高了37.81%～1 606.31%；泥饼与水泥浆发生了局部的同步水化硬化反应，且生成了少量的团状水化硅酸钙（CSH(Ⅰ)）凝胶和片沸石类凝胶，显示固井二界面整体固化胶结；流体溶蚀实验表明，采用目前方法，养护成型的样品浸泡28 d后，泥饼还原成了浑浊的稀钻井液，而用MTA方法得到的凝饼与水泥硬化体已胶结为一体，且凝饼未被溶蚀，表现为杯内流体仍清澈。这印证了两个事实：一是泥饼仿地成了凝饼，二是固井二界面已整体固化胶结。 Key words: cement-formation interface, Mud Cake to Agglomerated Cake (MTA), MTA method, integrated solidification and cementation, experimental evidenc

Effects of microwave time on quality of grass carp fillets processed through microwave combined with hot-air drying

In this study, the quality changes of grass carp fillets dried by microwave-hot-air combined drying under different microwave time were investigated. The salted fillets were dried at 385 W microwave with different time (0, 2, 4, 6, 8, and 10 min), followed by 65℃ hot air to the end. The quality of fillets was evaluated by drying time, color, hardness, rehydration ratio, and taste characteristics (ATP-related compounds, free amino acids, E-tongue taste profile, EUC, and TAV). Results showed that grass carp fillets dried by microwave-hot-air combined drying had better qualities compared with single hot-air drying. Besides, microwave time had obvious effects on the quality changes of grass carp fillets, and 6 min was considered as the optimal drying time

Mechanical Alloying of Fe 25 Al 75Àx Ti x Mixed Powders

Elemental aluminum, titanium and iron powders with compositions of Fe 25 Al 75Àx Ti x (x ¼ 0, 3.75, 7.5, 11.25 and 15) were mechanical alloyed in a planetary ball mill. The transformations and thermal stabilities of milled powders were characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Supersaturated solid solutions were found in low Ti concentration (x = 0-7.5). The addition of Ti shortened the milling time for the formation of solid solution. The amorphous phases were obtained with high Ti concentration (x ¼ 11:25 and 15). The activation enthalpies of crystallization for amorphous phases increased with Ti. The crystallization temperatures of amorphous alloys were calculated, which are in good agreement with the experimental values

Research on quality changes of grass carp (Ctenopharyngodon idellus) during short-term starvation

This study was aimed at to investigate the quality changes of grass carp during short-term starvation. The pH, lactic acid, free amino acid, and adenosine triphosphate-related compounds of dorsal meat, belly meat and red meat in grass carp were measured during starvation for 6 days, and the quality of grass carp was evaluated by K value, equivalent umami concentration (EUC), taste activity value (TAV), and electronic tongue. The pH of three parts meat reached the maximum value on the fourth day, which was closely related to the lactic acid content. Concurrently, the contents of fresh sweet amino acids were higher on the fourth day in all parts. The K values in dorsal meat and belly meat were below 10% during starvation. Considering the overall results of electronic tongue, EUC, and TAV analysis, it is suggested that grass carp should be marketed and eaten with a starvation period of 2–4 days for best taste and quality

Micro fractures and pores in lacustrine shales of the Upper Triassic Yanchang Chang7 Member, Ordos Basin, China

Following the successful exploration of shale oil in North America, China recently started to explore unconventional oil resources. Industrial shale oil flows were obtained from some strata in lacustrine basins, especially in the Chang7 Member of the Ordos Basin that may reach 150 barrels a day (e.g., in well Geng 295, 2655 m). So one of the most significant questions now being asked focuses on the shale oil storage within the reservoir interval. In the present study, five organic rich shale samples were collected from the Chang 7 Member of the Yanchang Formation in the Ordos Basin and were analyzed by field emission scanning electron microscopy to characterize pores and fractures in the shales. The results show that microfractures are predominant storage space for shale oil produced from the Chang 7 Member. Three types of fractures and pores were recognized, including (i) fractures and pores associated with interstitial organic matter and organic lamina, (ii) fractures and pores occurring in minerals such as pyrite framboid, mica, and feldspar, and (iii) fractures and pores that are present along the contact interface of organic matter and minerals. These fractures and pores were mainly formed by oil generation, tectonic stress, or dissolution. The total organic carbon and brittle minerals are main factors controlling the abundance of pores and fractures. High total organic carbon and brittle minerals are favorable for the formation and preservation of pores and fractures in shale. These results may provide an insight that helps to locate sweet spots for shale oil exploration in Ordos Basin and affect oil exploration in shales in other lacustrine basins of China

Density and viscosity of tight oil from Yanchang Formation, Ordos Basin, China and the geochemical controls

For assessing the density and viscosity of tight oil and their geochemical controls, 47 tight oil samples across the Ordos Basin were analyzed. The oil density and viscosity lay in the ranges of 0.81-0.88g/ml and 1.9-13.36mPa<bold>s</bold>, which are low in overall. The average saturated hydrocarbon content is higher than 80%. The molecular compositions suggest a source dominated organic matter by lacustrine type I/II with minor input of terrestrial type III kerogen. The oils were mainly generated at relatively high maturities. Fractionation during the oil expulsion may also result in the depletion of heavy-ends compounds. These are the main controlling factors for the overall good quality of the Ordos tight oil

Aptamer–Molecularly Imprinted Polymer Multiple-Recognition System: Construction and Application

Molecularly imprinted polymers (MIPs) and aptamers (Apts) are widely used in substance detection due to their specific recognition abilities. However, both of them have limitations in terms of stability or sensitivity. Therefore, an increasingly employed strategy is to combine MIPs and aptamers to form mixed components for detecting various substances, such as viruses, bacteria, proteins, heavy-metal ions, and hormones. The aim of this review is to provide a comprehensive summary of the scientific research conducted on the construction and application of aptamer–MIP multiple-recognition components in the past five years. It also aims to analyze their research and development strategies, construction mechanisms, advantages, and potential applications, as well as limitations and current challenges that need to be addressed

Changes in Protein Degradation and Non-Volatile Flavor Substances of Swimming Crab (Portunus trituberculatus) during Steaming

To investigate the effect of steaming time (0, 5, 10, 15, 20, and 25 min) on the protein degradation and non-volatile flavor substances of swimming crab (Portunus trituberculatus), the moisture content, total nitrogen (TN), non-protein nitrogen (NPN), free amino acids (FAAs), flavor nucleotides, electronic tongue analysis, and sensory evaluation were determined. The results showed that the contents of NPN and total FAAs were the highest after crabs steamed for 10 min. Meanwhile, the AMP (adenosine monophosphate) content reached the maximum value (332.83 mg/100 g) and the taste active value (TAV) reached 6.67, which indicated that AMP contributes the most to the taste of steamed crab at 10 min. The electronic tongue distinguished the taste difference well, and the sensory score was the highest at 15 min. Combined with equivalent umami concentration (EUC) and TAV value, swimming crab (weight = 200 ± 20 g) steamed for 10–15 min tasted best