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Lauric acid sodium salt and cetyltrimethyl ammonium bromide as compound modifiers, surface modified potassium borate lubricant additives were prepared by plasma assisted ball milling as well as characterized and analyzed by scanning electron microscope (SEM), infrared spectrometer (FT-IR) and thermal analyzer (DSC-TG). Meanwhile, the high temperature tribological properties in low alkali marine cylinder oil were studied, and the antifriction self-repair mechanism was discussed. The results indicate that the potassium borate powder and modifiers are micro-zone melted and rapidly refined by the coupling effect of plasma thermal effect and mechanical milling of steel balls during plasma assisted ball milling for 10 h, and the average particle size of the primary particles is 100-300 nm. As the chemical action of ion pair in modifiers, the potassium borate powder adsorbs and chemically bonds with —CH2 and —CH3 organic molecular groups, which realize the lipophilic modification and a good dispersity in FEOCY 54 low alkali marine cylinder oil of the power. In the process of friction, potassium borate particles continuously adsorb and deposit on the friction surface by the effect of electric charge, and the rolling lubrication and anti-wear deposition films are formed in the metal contact area. At the same time, the friction surface reacts with potassium borate powder to produce Fe2O3, Fe3O4 and B2O3 boundary lubricating films that have the effect of antifriction and anti-wear, which greatly improves the high temperature tribological properties of marine cylinder oil.

Improving the high-temperature stress rupture properties of Inconel 718 (IN718) alloys is crucial for enhancing aircraft engine performance. By using the laser powder bed fusion (LPBF) technique, IN718 alloys were crafted at varying volumetric energy densities (VED) in this study. The dendrite growth mode, reinforcing phase distribution and high temperature stress rupture properties of various VED samples were investigated. The results showed that the stress rupture life and the uniform elongation of the samples both first increased and then decreased with the increase in VED. When the VED was 60 J/mm3, the maximum rupture life and elongation of the sample were 43 h and 3.8%, respectively. As the VED increased, the angle of dislocation in the dendrite decreased while the spacing between primary dendrite arms increased, resulting in an increase in the size and volume fraction of the Laves phase. Following a heat treatment, the δ phase would nucleate preferentially around the dissolved Laves phase causing an increase in the volume fraction of the δ phase with the increase in VED. The creep voids readily formed around the δ phase are distributed along the grain boundaries, while the inhomogeneous δ phase and fine grains facilitated crack initiation and propagation. Furthermore, a significant quantity of the δ phase consumed the Nb element, thereby hindering adequate precipitation in the γ″ phase and causing cracks. [ABSTRACT FROM AUTHOR]

To improve the lipophilicity of ZnO nanopowder in lubricating oil and analyze the surface modification mechanism, stearic acid, oleic acid, and HTAB-SL were selected as surface modifiers. ZnO nanopowders were prepared and modified in a single step by dielectric barrier discharge plasma assisted ball milling for 10 h. The ZnO nanopowder was characterized and analyzed by SEM, FTIR, TG-DSC, x-ray diffractometer, x-ray photoelectron spectroscopy, lipophilicity determination, COF test, etc. The results showed that the size of ZnO nanopowder was 40–100 nm. The results also revealed that the lipophilic groups –CH2 and –CH3 of modifier were successfully modified by ZnO nanopowder. Meanwhile, hydroxyl groups –OH of ZnO nanopowder chemically adsorbed with hydrophilic carboxyl groups –COO– of modifier. The lipophilicity of modified ZnO nanopowder was significantly increased. The COF of oil sample with modified ZnO nanopowder was smaller than that of oil sample with unmodified ZnO nanopowder. The modification mechanism was attributed to the coupling action of plasma, modifier, and mechanical forces of ball milling. The research demonstrated that modified ZnO nanopowder is more suitable as lubricating additive. [ABSTRACT FROM AUTHOR]

Energy efficiency of data centers (DCs) is of great concern due to their large amount of energy consumption and the foreseeable growth in the demand of digital services in the future. The past decade witnessed improvements of the energy efficiency of DCs from an extensive margin—a shift from small to large, more efficient DCs. Improvements from the intensive margin, that is, from more efficient operation, would be critical in limiting the energy consumption and environmental impact of DCs in the upcoming period. Machine learning algorithms have advantages in optimizing the operation of DCs to improve energy efficiency as they have shown the potential of discovering control strategies not found by traditional method, and producing working condition‐dependent control strategies. This study proposes ready‐to‐use machine learning methods with practical details to decrease the most commonly used energy efficiency metric—power usage effectiveness in DCs. We achieved an accurate prediction by properly selecting the features used in the proposed prediction models established by neural network, light gradient boosting machine, recurrent neural network, and random forests. The proposed approaches are implemented in one of the largest hyperscale DCs in China—Tencent Tianjin DC, to optimize the set points of controllable variables in the cooling system and to detect and adjust the unreasonable working conditions in the modular data centers. The lower bound of PUE reduction was 0.005 with the proposed approaches, leading to about 1500 MWh (0.24% of the total designed electricity consumption of this DC) of energy saved per year in this hyperscale DC. The proposed methods have the potential to be transferred to DCs of similar scale, and the framework of our work could serve as a guide for machine learning‐based optimization of environmental indicators in other complex product/service systems. [ABSTRACT FROM AUTHOR]

Large‐area fabrication and stacking of various nanometer‐thick functional layers from solutions is essentially important for the construction of flexible thin‐film optoelectronic devices, but very challenging. The existing fabrication methods suffer from either non‐uniformity caused by the coffee‐ring effect or serious solution waste (excess of 90% for spin coating), and are hard to scale up and create stacks. Here, it is shown that centrifugal casting is a universal, scalable, and efficient method to fabricate uniform nanometer‐thick films and their stacks of various materials. The coffee‐ring effect is effectively suppressed, the solution utilization ratio is higher than ≈61%, and the films/stacks show a smooth surface/high‐quality interface. Using this method, flexible quantum dot light‐emitting diode displays with uniform luminance in a large lighting area of ≈115 cm2 that have not been achieved even on rigid substrates by the existing methods, are realized. This efficient and low‐cost solution processing method paves a way for large‐area fabrication of various flexible thin‐film optoelectronic devices. [ABSTRACT FROM AUTHOR]

In human body, alveoli are the primary sites for gas exchange which are formed by the dilation and protrusion of bronchioles at the end of the lung, and the rapid gas‐exchanging process in the alveoli ensures normal life activities. Based on the unique structures and functions of alveoli, it is necessary to study the regulation mechanism of its formation, respiration, and apoptosis. Herein, a class of reversible addition−fragmentation chain transfer (RAFT)‐derived amphiphilic triblock copolymers, PEO‐b‐P(DEAEMA‐co‐FMA)‐b‐PS is designed and synthesized. Due to the amphiphilic and gas‐responsive segments, these triblock copolymers can self‐assemble in aqueous solution and undergo the morphological transition from nanotubes to vesicles under gas stimulation; meanwhile, in the cycles of CO2/O2 stimulation, these vesicles can further realize the volume expansion and contraction, eventually rupture. The gas‐driven morphological transformations of these aggregates successfully imitate the formation, respiration, and apoptosis of alveoli, and provide an essential basis for revealing the life phenomena. [ABSTRACT FROM AUTHOR]

Immune checkpoint blockade (ICB) has achieved groundbreaking results in clinical cancer therapy; however, only a subset of patients experience durable benefits. The aim of this study was to explore strategies for predicting tumor responses to optimize the intervention approach using ICB therapy. Methods: We used a bilateral mouse model for proteomics analysis to identify new imaging biomarkers for tumor responses to ICB therapy. A PET radiotracer was synthesized by radiolabeling the identified biomarker-targeting antibody with 124 I. The radiotracer was then tested for PET prediction of tumor responses to ICB therapy. Results: We identified galectin-1 (Gal-1), a member of the carbohydrate-binding lectin family, as a potential negative biomarker for ICB efficacy. We established that Gal-1 inhibition promotes a sensitive immune phenotype within the tumor microenvironment (TME) for ICB therapy. To assess the pre-ICB treatment status of the TME, a Gal-1-targeted PET radiotracer, 124 I-αGal-1, was developed. PET imaging with 124 I-αGal-1 showed the pretreatment immunosuppressive status of the TME before the initiation of therapy, thus enabling the prediction of ICB resistance in advance. Moreover, the use of hydrogel scaffolds loaded with a Gal-1 inhibitor, thiodigalactoside, demonstrated that a single dose of thiodigalactoside-hydrogel significantly potentiated ICB and adoptive cell transfer immunotherapies by remodeling the immunosuppressive TME. Conclusion: Our study underscores the potential of Gal-1-targeted PET imaging as a valuable strategy for early-stage monitoring of tumor responses to ICB therapy. Additionally, Gal-1 inhibition effectively counteracts the immunosuppressive TME, resulting in enhanced immunotherapy efficacy., (© 2024 by the Society of Nuclear Medicine and Molecular Imaging.)