Low Temperature Conditions Research Articles

Optimization and Application of Bio-Enzyme-Enhanced Gel-Breaking Technology in Fracturing Fluids for Tight Sandstone Gas in the Linxing Block, Ordos Basin

The main tight sandstone gas reservoirs in the Linxing block of the Ordos Basin exhibit a temperature range of 35–60 °C. Under these low-temperature conditions, conventional oxidative gum breakers used in fracturing operations react sluggishly, fail to break the gum completely, and can cause significant reservoir damage. In order to achieve complete breakage of the fracturing fluid and reduce the damage to the fracture and reservoir, active bio-enzyme-enhanced breakers have been incorporated into fracturing fluid formulations, so as to achieve rapid breakage, re-discharge at low temperature, and reduce the contact time between the fracturing fluid and the formation, which is critical for enhancing production efficiency. Based on the preliminary success of bio-enzyme-enhanced fracturing technology, this paper carries out an optimization study of bio-enzyme-enhanced fracturing technology for the low-temperature reservoir in the Ordos Linxing block. The study simulates the temperature recovery of the injected fluids under different reservoir temperatures during the fracturing process, aiming to further optimize the concentration of the bio-enzyme-enhanced fracture breakers in the fracturing phases, and to achieve optimized fracturing technology which is more in line with the temperature environment of the fluids. This can further optimize the concentration of the bio-enzyme breaker added at each fracturing stage, and achieve enhanced breaking in a stepwise manner that is more in line with the fluid temperature environment, thus improving the efficiency and production capacity for subsequent production. The optimized fracturing fluid system, incorporating the tailored concentration of the bio-enzyme breaker, was applied to 54 wells in this block, resulting in about a two-times improvement in production compared to conventional non-optimized methods, with many wells achieving high output. These results demonstrate the strong applicability of the optimized breaker procedure in this geological context. Additionally, this study investigated an optimization model for the well shut-in time during winter operations involving low-temperature fracturing fluids in low-temperature reservoirs, providing a valuable design basis for future production planning.

ВЫЗРЕВАНИЕ РАСТЕНИЙ ДЛЯ СОЗДАНИЯ КОЛЛЕКЦИИ ВИНОГРАДА IN VITRO

The purpose of the study is to develop a method for creating a collection of the grape gene pool in vitro using the combined use of biotechnological methods: modification of the nutrient medium and cultivation of plants under conditions of low positive temperature. During the cultivation process with an increased content of sucrose in the nutrient medium (50−70 g/l), autumn color of the leaves appears and shoots ripen in various grape varieties: Sypun Cherniy, Vierul, Tsimlyansky Cherniy (clone 2–3), Cabernet Sauvignon, Kumshatsky, Rupestris du Lo, Tsimladar, less in varieties Krasnostop zolotovsky, Baklanovsky, Sibirkovy. This helped to extend the period of non-transplant storage of plants. The fairly high viability of plants at a sucrose concentration of 70.0 g/l during the first 5 months of cultivation gradually decreased when they were cultivated for 8–9 months. The possibility of in vitro regeneration of plants from mature microcuttings when cultivated for one year has been established. To increase the safety and viability of plants, matured test tube plants were stored in a pharmaceutical cabinet at a low positive temperature of 1−8 °C. Plants were stored in tightly closed tubes on solid culture medium. When stored under these conditions for 3–4 years, the plants had a length of the mature part of the shoots of 49.8−70.3 %. Better ripening compared to native ones occurs in interspecific grape varieties and rootstocks. After a month of cultivating lignified microcuttings with living tissues on the solid nutrient medium of Murashige and Skuga, single shoot regeneration and plant restoration were revealed. Cultivation of the restored plants under standard conditions on solid nutrient medium Murashige and Skuga with the addition of the growth regulator Melafen for 3 months contributed to further regeneration and improvement of growth processes of both roots and shoots. The plants were completely restored. The possibility of continuous storage of test tube grape plants for 3−4 years has been proven with a combination of two factors: an increased concentration of sucrose in the nutrient medium and a low positive temperature of 1−8 °C.

Gate leakage mechanisms in Al2O3/SiN/AlN/GaN MIS-HEMTs on Si substrates

Abstract This study investigates the gate leakage mechanisms of AlN/GaN metal-insulator-semiconductor highelectron-mobility transistors (MIS-HEMTs) fabricated on silicon substrate with Al2O3/SiN as stacked gate dielectrics, analyzing behaviors across high and low temperature conditions. In the high-temperature reverse bias region (T > 275 K, V G < 0 V), Poole-Frenkel emission (PFE) dominates at low electric fields, while trap-assisted tunneling (TAT) is the primary mechanism at medium to high electric fields. The shift from PFE to TAT as the dominant conduction mechanism is due to the increased tunneling effect of electrons as the electric field strength rises. Additionally, TAT is found to be the main gate leakage mechanism under low-temperature reverse bias (T < 275 K, V G < 0 V). At lower temperatures, the reduction in electron energy causes the emission process to rely more on electric field forces. Furthermore, under forward bias conditions at both high and low temperatures(225 K < T < 375 K, V G > 0 V), conduction is primarily dominated by defect-assisted tunneling (DAT).

Study of Aedes albopictus Hatching Rate by Low‐Temperature Stress

ABSTRACTAedes albopictus overwinters as eggs and lays diapause eggs under conditions of low temperatures, low humidity, and short photoperiods. We compared the hatchability of diapause and nondiapause eggs in response to cold stress. Nondiapause eggs were acquired at 27°C ± 1°C, 70% ± 5% humidity, and 16:8 (L:D) photoperiod, and diapause eggs were acquired at 21°C ± 1°C, 40% ± 5% humidity, and 8:16 (L:D) photoperiod. The obtained eggs were dried under the same conditions and then exposed to low‐temperature stress for each temperature and time. After that, eggs were transferred to a thermostat to induce hatching at room temperature, and the hatching rate and the time required for hatching were measured and analyzed by two‐way ANOVA and multiple regression analyses. When exposed to low temperatures for 1–24 h at a temperature of 0°C to −10°C, the diapause eggs had a hatching rate higher than that of nondiapause eggs in all sections. The difference in hatching rate according to temperature, exposure time, and diapause status was all considered significant at −6°C or less (two‐way ANOVA). A significant regression equation was calculated to estimate the hatching rate, a dependent variable (R2 = 0.439, p < 0.000). We found a significant difference in hatching rates for low‐temperature stress between diapause eggs and nondiapause eggs of Ae. albopictus, which may explain why Ae. albopictus spreads in high‐latitude regions. The morphological differences between diapause and nondiapause and variables such as dryness and light intensity should be studied to understand the overwintering of Ae. albopictus.

Two antagonistic gene regulatory networks drive Arabidopsis root hair growth at low temperature linked to a low-nutrient environment.

Root hair (RH) cells can elongate to several hundred times their initial size, and are an ideal model system for investigating cell size control. Their development is influenced by both endogenous and external signals, which are combined to form an integrative response. Surprisingly, a low-temperature condition of 10°C causes increased RH growth in Arabidopsis and in several monocots, even when the development of the rest of the plant is halted. Previously, we demonstrated a strong correlation between RH growth response and a significant decrease in nutrient availability in the growth medium under low-temperature conditions. However, the molecular basis responsible for receiving and transmitting signals related to the availability of nutrients in the soil, and their relation to plant development, remain largely unknown. We have discovered two antagonic gene regulatory networks (GRNs) controlling RH early transcriptome responses to low temperature. One GNR enhances RH growth and it is commanded by the transcription factors (TFs) ROOT HAIR DEFECTIVE 6 (RHD6), HAIR DEFECTIVE 6-LIKE 2 and 4 (RSL2-RSL4) and a member of the homeodomain leucine zipper (HD-Zip I) group I 16 (AtHB16). On the other hand, a second GRN was identified as a negative regulator of RH growth at low temperature and it is composed by the trihelix TF GT2-LIKE1 (GTL1) and the associated DF1, a previously unidentified MYB-like TF (AT2G01060) and several members of HD-Zip I group (AtHB3, AtHB13, AtHB20, AtHB23). Functional analysis of both GRNs highlights a complex regulation of RH growth response to low temperature, and more importantly, these discoveries enhance our comprehension of how plants synchronize RH growth in response to variations in temperature at the cellular level.

Potential of Lactiplantibacillus Plantarum 20174 for Vitamin B12 Production in Pineapple: An Enhanced Nutritional Quality and Storage Stability of Processed Jelly

Background: Vitamin B12 is the micronutrient, present naturally in animal products. The present study was conducted with the aim of developing a naturally fortified vitamin B12 rich fruit product, which can easily be consumed by vegan population. Methods: Pineapple (Ananas comosus) fruit pulp was fermented with Lactiplantibacillus plantarum 20174 to produce vitamin B12 rich jelly. The selected microbial strain grew well in pineapple (Ananas comosus) fruit pulp matrix. The physiochemical properties and nutritional content were analysed and compared for the jellies prepared from fermented (fermented pineapple jelly or FPJ) and spontaneous fermented (control pineapple jelly or CPJ) pineapple pulp. Both CPJ and FPJ were packed and stored for 30 days at low (4 ºC) and ambient (30 °C) temperature conditions, and were subjected to analysis at 10 days intervals. Results: The Total soluble solids (TSS), pH, and reducing sugars were higher in CPJ than FPJ. The FPJ contained 8.17 µg vitamin B12/100 g, while it was not detected in CPJ. There was no microbial growth detected in FPJ throughout the storage period when stored at 4 ºC, rendering it safe for consumption up to 30 days at both the storage temperatures. The decrease in scores of various sensory attributes during storage was little and the developed FPJ was still in the “liked very much” category throughout the storage period. The vitamin B12 content of FPJ was stable during storage and sufficient enough to fulfil an individual’s daily requirement. Conclusion: The developed fermented pineapple jelly can be recommended as an excellent vegan source of vitamin B12.

Effect of low-temperature conditioning using 1-methylcyclopropene versus preservative paper treatment on the aroma volatiles derived from fatty acid metabolism in flat peaches

Effect of low-temperature conditioning using 1-methylcyclopropene versus preservative paper treatment on the aroma volatiles derived from fatty acid metabolism in flat peaches

Taming the Ion-Dipole Interaction via Rational Diluent Selection for Low-Temperature Li-Metal Batteries.

Developing advanced electrolytes with high Li affinity is crucial for achieving long-cycling lithium metal batteries (LMBs). However, the strong Li+-solvent interactions in conventional electrolytes often induce difficult Li+ desolvation especially under low-temperature conditions, resulting in the formation of fragile electrode interfaces involving solvents, and thus dissatisfactory cycling stability of LMBs. Herein, by introducing various diluents into the lithium hexafluorophosphate in 1, 2-dimethoxyethane electrolyte, we reveal that Li+ desolvation is influenced by not only the diluent-solvent interaction but also the diluent-anion interaction. Based on these findings, a diluent selection parameter (DSP), which is calculated based on the product of interaction energies of diluent-solvent/diluent-Li+ and diluent-anion/diluent-Li+, is proposed for diluent selection. A diluent with a larger DSP is more favorable for promoting Li+ desolvation and improving the low-temperature performance of LMBs. With the rationally selected 1, 2-dichloroethane diluent (DSP=3.95), Li||Cu cell enables high Li reversibility (98.5% after 300 cycles). Li||LiFePO4 cell barely loses capacity at -20 °C for 300 cycles. The Li||LiNi0.8Co0.1Mn0.1O2 cell with the anode-to-cathode capacity ratio of 2.7 retains 87% capacity retention after 100 cycles. This work not only provides new insights into taming strong Li-solvent interactions but also offers a new paradigm for advanced electrolyte design.

The impact of air pollution on influenza incidence in high-altitude regions: a time-stratified case-crossover study based on Qinghai Province.

The unique characteristics of air pollution in high-altitude regions may significantly influence the transmission and incidence of influenza. However, current research on this phenomenon is limited, and further investigation is urgently needed. This study collected influenza outpatient data from Qinghai Province between January 1, 2016, and December 31, 2021. We employed a time-stratified case-crossover design combined with conditional Poisson regression models to quantitatively analyze the relationship between air pollutants (PM2.5, SO2, NO2) and influenza incidence and explored the moderating role of temperature in this relationship. Additionally, stratified analyses were conducted to identify potential vulnerable populations. The study results indicated that exposure to PM2.5, SO2, and NO2 was positively associated with the risk of influenza incidence. For every 10µg/m³ increase in the concentration of PM2.5, SO2, and NO2, the percentage change in relative risk (RR) of influenza incidence was 0.35% (95% CI: 0.02%, 0.68%), 2.24% (95% CI: 1.42%, 3.06%), and 1.91% (95% CI: 1.16%, 2.67%), respectively. Under low-temperature conditions, the impact of pollutants other than O3 on influenza incidence was particularly pronounced. Children, the elderly, and individuals living at altitudes of 3000-3500m were more sensitive to these pollutants. This study revealed a close link between air pollution and influenza in high-altitude regions, with greater health risks under low-temperature conditions. The findings underscore the necessity of strengthening air quality monitoring and raising public awareness of environmental health.

Evaluation of CRDi engine fueled with binary and ternary blends of biodiesel, butanol and diesel

Abstract An automotive-type four-cylinder turbocharged CRDi engine has been considered to utilize a higher proportion of biodiesel beyond 20% while effectively addressing the NOx-soot-engine performance trade-off with biodiesel, butanol and petro-diesel fuel blends. Mixed feedstock obtained from Sterculia Foetida Oil and Used Palm Oil in equal proportions, to prepare biodiesel, and three binary and three ternary blends, prepared in different proportions, have been considered. Investigations were carried out at various speed and load conditions similar to idling, urban and highway drive conditions by varying the main injection timing and boost pressure, keeping other parameters at optimized values. The speed test conditions are chosen from a modified Indian Driving Cycle to simulate real driving conditions. The results obtained with different blends are compared against engine operation with neat petro-diesel operation. The engine is incorporated with a variable geometry turbine for increasing intake air and an open ECU for setting the operating parameters. For facilitating split injections, a dwell period (time between start of pilot and start of main injection) of 27° CA (i.e. with PIT at 28°bTDC and MIT at 1°bTDC), PIQ of 11%, and FIP of 61.4 MPa are recommended for the speed and load conditions under consideration and the given engine configuration. Among the tested ternary blends, B20Bu10D70 and B30Bu10D60 showed improvement in NOx and smoke emissions, with low-temperature combustion-like conditions observed. The use of renewable fuels will effectively address UNO's sustainable development goals.

Temperature-Robust Solvation Enabled by Solvent Interactions for Low-Temperature Sodium Metal Batteries.

The broad temperature adaptability associated with the desolvation process remains a formidable challenge for organic electrolytes in rechargeable metal batteries, especially under low-temperature (LT) conditions. Although a traditional approach involves utilizing electrolytes with a high degree of anion participation in the solvation structure, known as weakly solvation electrolytes (WSEs), the solvation structure of these electrolytes is highly susceptible to temperature fluctuations, potentially undermining their LT performance. To address this limitation, we have devised an innovative electrolyte that harnesses the interplay between solvent molecules, effectively blending strong and weak solvents while incorporating anion participation in a solvation structure that remains mostly unchanged by temperature variations. Remarkably, the competitive coordination between the two solvent molecules introduces local disorder, which not only boosts ionic conductivity but also prevents salt precipitation and solidification. Therefore, this electrolyte has a conductivity of 3.12 mS cm-1 at -40 °C. Na3V2(PO4)3||Na cells demonstrated a high reversible capacity of 95.9 mAh g-1 at -40 °C, which is 87.6% of that at room temperature, as well as stable cycling for 3400 cycles with capacity retention of 98.2% at -20 °C and 5 C and 600 cycles with capacity retention of 96.1% at -40 °C and 1 C. This study provides a new perspective on designing LT electrolytes by regulating temperature-robust solvation structures.

High-Conductivity, Self-Healing, and Adhesive Ionic Hydrogels for Health Monitoring and Human-Machine Interactions Under Extreme Cold Conditions.

Ionic conductive hydrogels (ICHs) are emerging as key materials for advanced human-machine interactions and health monitoring systems due to their unique combination of flexibility, biocompatibility, and electrical conductivity. However, a major challenge remains in developing ICHs that simultaneously exhibit high ionic conductivity, self-healing, and strong adhesion, particularly under extreme low-temperature conditions. In this study, a novel ICH composed of sulfobetaine methacrylate, methacrylic acid, TEMPO-oxidized cellulose nanofibers, sodium alginate, and lithium chloride is presented. The hydrogel is designed with a hydrogen-bonded and chemically crosslinked network, achieving excellent conductivity (0.49 ±0.05 S m-1), adhesion (36.73 ±2.28kPa), and self-healing capacity even at -80°C. Furthermore, the ICHs maintain functionality for over 45 days, showcasing outstanding anti-freezing properties. This material demonstrates significant potential for non-invasive, continuous health monitoring, adhering conformally to the skin without signal crosstalk, and enabling real-time, high-fidelity signal transmission in human-machine interactions under cryogenic conditions. These ICHs offer transformative potential for the next generation of multimodal sensors, broadening application possibilities in harsh environments, including extreme weather and outer space.

Foliar application of 24-epibrassinolide enhances leaf nicotine content under low temperature conditions during the mature stage of flue-cured tobacco by regulating cold stress tolerance

BackgroundLow temperatures disrupt nitrogen metabolism in tobacco, resulting in lower nicotine content in the leaves. 24-epibrassinolide (EBR) is a widely used plant growth regulator known for its roles in enhancing cold tolerance and nitrogen metabolism. Nevertheless, it remains unclear whether EBR enhances leaf nicotine content under low temperature conditions during the mature stage of flue-cured tobacco.ResultsTo investigate the effects of EBR on leaf nicotine content under low temperature conditions during the mature stage of ‘Yunyan 87’ flue-cured tobacco, four treatments (foliar spraying of 0, 0.1, 0.2 and 0.4 mg·L− 1 EBR solutions) were performed by using a single-factor randomized complete block design. The result showed that foliar spraying of different concentrations of EBR notably improve the agronomic and economic traits of flue-cured tobacco to varying degrees, as well as increase the total nitrogen and nicotine content in the tobacco leaves. 0.2 mg·L− 1 EBR treatment showed better results, with nicotine content in the middle and upper leaves after curing increasing by 11.11% and 19.90%, respectively, compared to CK. Compared to the single EBR, foliar spraying of EBR compound containing α-Cyclodextrin and Tween 80 prolongs the effect of EBR, promotes the growth and development of tobacco plants. Combining EBR with CaCl2 and ZnSO4·7H2O significantly enhances the cold resistance of tobacco plants. Furthermore, combining EBR with higher concentrations of KH2PO4 is more effective in promoting the maturation and yellowing of the upper leaves than those with lower concentrations.ConclusionsThis study provides new insights that foliar application of EBR enhances leaf nicotine content under low temperature conditions during the mature stage of flue-cured tobacco by regulating cold stress tolerance. The integration of EBR with α-Cyclodextrin, Tween 80, CaCl2, ZnSO4·7H2O and KH2PO4 showcases a novel approach to extending the effectiveness of plant growth regulators and improving agricultural sustainability. Furthermore, these findings may be applicable to other cold-sensitive crops, offering broader benefits for improving resilience and productivity under low temperatures. However, the research focuses on two growth cycles, without investigating the long-term impact of EBR on soil health, crop sustainability, and ecosystem. And further research is needed to elucidate the molecular mechanisms of EBR on enhancing leaf nicotine content.Clinical trial numberNot applicable.

Self-Reactive Carbon Dioxide Absorbent with Sodium Carbonate-Based Hydrogel.

Sodium carbonate is an abundant, low-cost, and low-hazard raw material widely used as a food additive and CO2 absorbent in the food industry. However, its application in food packaging is limited because it is used in solid form, either in sachets or as a compounding ingredient in plastics. Solid sodium carbonate requires an external moisture supply for CO2 absorption, with its performance dependent on moisture availability. This limitation hinders its commercialization in food packaging applications. We developed a sodium carbonate-based, self-reactive CO2 absorbent hydrogel incorporating polyacrylic acid sodium salt (PAAS). This sodium carbonate hydrogel (SCH-PAAS) exhibits self-reactivity, eliminating the need for external moisture, and demonstrates a high CO2 absorption capacity. PAAS incorporation facilitates the formation of a porous structure during gel solidification through reactions with CO2. Increased PAAS content accelerates CO2 absorption rates, particularly under low-temperature conditions (10 °C and 25 °C). Notably, absorption was faster at 10 °C than at 25 °C. The proposed SCH-PAAS exhibits a significantly enhanced absorption performance at low temperatures compared to conventional sodium carbonate-based materials, which exhibit reduced efficiency under such conditions. The increased gas-liquid contact area in SCH-PAAS makes it highly suitable for fresh food packaging applications, particularly under low temperatures.

Liquid-vapor phase separation under shear by a pseudopotential lattice Boltzmann method

Abstract In this paper, the liquid-vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method. Physically, the multiphase shear flow is governed by two competing mechanisms: surface tension and shear force. It is interesting to find that the liquid tends to form a droplet when the surface tension dominates under conditions of low temperature, shear velocity, and viscosity, and in larger domain size. Otherwise, the liquid tends to form a band if shear force dominates. Moreover, the average density gradient is used as a physical criterion to distinguish the spinodal decomposition and domain growth. Both spatial and temporal changes of density are studied during the phase separation under shear.

Ultrafast deconstruction and reconstruction of corn starch via synergistic effect of high-frequency electric field and water motion.

The intricate multi-level microstructure of starch, formed through extensive inter- and intra-molecular hydrogen bonds, significantly influences the processability and performance of starch-based products. Consequently, the ability to effectively manipulate the multi-level microstructure holds substantial implications for the development of biomass products. This study introduces a novel approach utilizing high-frequency electric field (HFE) to produce a transparent and robust starch product. HFE facilitates the deconstruction of hydrogen bonds under low-temperature conditions through the synergistic effect of the electric field and water motion, resulting in a decrease of Va crystalline content by up to 20.3 %. This method offers advantages in enhancing starch plasticization efficiency and minimizing degradation caused by thermomechanical action in conventional processing techniques. The synergistic effect also promotes the reconstruction of hydrogen bonds within the materials, leading to improved mechanical properties and transparency of the starch products. The resulting products exhibited a tensile strength of 16.36 MPa and a toughness of 2.21 J/m3, comparable to those of commercial plastics. This research presents a promising approach for the fabrication of high-performance bio-based polymer materials.

Tracking thermal histories through the detrital record using rutile U-Pb-He double-dating

Investigation of source-to-sink relationships using the detrital record is frequently reliant on zircon and thus biased toward high-temperature magmatic processes. In contrast, rutile, which grows or recrystallizes under lower-temperature conditions, allows reconstruction of the metamorphic history of source terranes. Here, we present the first rutile double-dating analysis, integrating U-Pb geochronology and (U-Th)/He thermochronology on individual grains to refine provenance understanding. Results from heavy mineral−enriched Neogene siliciclastic sediments of the Murray Basin in southeast Australia fingerprint an exotic central Australian source, implying long-distance multicycle sediment dispersal via intermediate sedimentary basins. Source-to-sink relationships support the billion-year influence of radiating pulses of sediment dispersal across the Australian continent from its denuding core.

Recent Advances in the Performance and Mechanisms of High-Entropy Alloys Under Low- and High-Temperature Conditions

High-entropy alloys, since their development, have demonstrated great potential for applications in extreme temperatures. This article reviews recent progress in their mechanical performance, microstructural evolution, and deformation mechanisms at low and high temperatures. Under low-temperature conditions, the focus is on alloys with face-centered cubic, body-centered cubic, and multi-phase structures. Special attention is given to their strength, toughness, strain-hardening capacity, and plastic-toughening mechanisms in cold environments. The key roles of lattice distortion, nanoscale twin formation, and deformation-induced martensitic transformation in enhancing low-temperature performance are highlighted. Dynamic mechanical behavior, microstructural evolution, and deformation characteristics at various strain rates under cold conditions are also summarized. Research progress on transition metal-based and refractory high-entropy alloys is reviewed for high-temperature environments, emphasizing their thermal stability, oxidation resistance, and frictional properties. The discussion reveals the importance of precipitation strengthening and multi-phase microstructure design in improving high-temperature strength and elasticity. Advanced fabrication methods, including additive manufacturing and high-pressure torsion, are examined to optimize microstructures and improve service performance. Finally, this review suggests that future research should focus on understanding low-temperature toughening mechanisms and enhancing high-temperature creep resistance. Further work on cost-effective alloy design, dynamic mechanical behavior exploration, and innovative fabrication methods will be essential. These efforts will help meet engineering demands in extreme environments.

Enhancing the Rheological and Filtration Performance of Water-Based Drilling Fluids Using Silane-Coated Aluminum Oxide NPs.

For optimizing the drilling efficiency, nanoparticles (NPs) specifically nanometal oxides have been used in water-based drilling fluids (WBDF). Nano metal oxides improve the rheological and filtration characteristics of the WBDF. However, dispersion instability among pristine nano metals shrinks the performance of the nanometal oxides due to high surface energy. Therefore, this study aims to utilize silane-coated aluminum oxide NPs (S-Al2O3) as an alternative to widely used pristine aluminum oxide (P-Al2O3) in water-based drilling fluids. The S-Al2O3 NPs were synthesized using 3-aminopropyl triethoxysilane (APTES). FTIR, XRD, and SEM analyses were carried out to examine the crystalline structure and surface morphology of NPs. Moreover, the rheological and filtration properties of nanowater-based drilling fluids were investigated at low-pressure and low-temperature (LPLT) conditions. The results of experiments revealed that S-Al2O3 NPs significantly upgraded the rheological properties compared to P-Al2O3 NPs. The S-Al2O3 NPs reduced plastic viscosity from 12.6 to 9.6 cP, apparent viscosity from 34.5 to 26.5 cP, and yield point from 46.5 to 39.5 lb/100 ft2. The gel strengths (10 s and 10 min) were reduced from 44.5 to 32 lb/100 ft2 and from 77 to 59 lb/100 ft2, respectively. Furthermore, S-Al2O3 NPs enhanced the filtration performance, achieving a 26% reduction in filtrate loss and forming a thinner, more impermeable mud cake than P-Al2O3 NPs. In conclusion, the application of S-Al2O3 NPs in water-based drilling fluid was found to be effective in improving the rheological properties and controlling the filtrate loss effectively under LPLT conditions. The utilization of silane-coated NPs used in this study will open new and novel doors of research in the fields of both drilling engineering and nanotechnology.

Research Progress on Effects of Antifreeze Components, Nanoparticles and Pre-Curing on the Properties of Low-Temperature Curing Materials

There are long periods of winter construction in China’s eastern and western Alpine regions. The decreased construction temperature adversely affects the workability, mechanical properties, and durability of cement-based materials and alkali-activated materials. Under low-temperature curing conditions, the hydration reaction of these materials slows down, resulting in limited strength development and reduced durability. In response to this problem, researchers have summarized three measures to improve performance: the use of anti-freezing components, nanoparticles, and pre-curing. The effects of anti-freezing components on the mechanical properties and micro-mechanism changes of Portland cement, sulphoaluminate cement, magnesium phosphate cement-based materials, and alkali-activated cementitious materials are organized. Additionally, the improvement of macro-micro properties in cement-based materials through mineral admixtures, nanoparticles, and hydrated calcium silicate seeds is summarized. The influence of pre-curing on the mechanical properties of cement-based materials is analyzed, focusing on the relationship between pre-curing time and the critical strength of frost resistance. Finally, existing research challenges are summarized, and future research directions are proposed, providing valuable references for the further development of materials and engineering applications.