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Purpose – The purposes of this paper are to prepare the carbon nanotube (CNT) grease, to contrast the tribology properties of the CNT grease with the original grease and to find the lubricating mechanism of the CNT grease. Design/methodology/approach – The CNTs (single-wall and multi-wall) are added into the polyalphaolefin oils (DURASYN_166) to form stable and homogeneous CNT grease with potential heat transfer, conductive and lubricative properties. The friction of this new type of CNT grease was determined by wear experiments under three conditions: dry friction, with the base oil grease and with the CNT grease. Findings – The research is about the tribological properties of CNT greases; it shows better lubricating performance and wear resistance than the base oil grease. The performance improvement of CNT grease is owing to the unique hexagonal structure and the high thermal conductivity of CNTs. Originality/value – The paper documents that CNTs can obviously improve the lubricating effect of grease, and the lubricating mechanism of the CNT grease is also discussed.

The tribological behavior of novel 7.5 wt% carbon nanotube-based lubricant greases in PAO (polyalphaolefin) oil with and without 1.0 wt% MoS2, together with several other commercial greases such as calcium, lithium, were studied. The test results showed a marked reduction of frictional coefficient achieved by the CNTs based grease samples with an average benefit of around 30% compared to conventional greases. The steady state test under 1.00 GPa average contact pressure in a mixed lubrication regime and the fretting test showed the best results in terms of friction reduction obtained by CNTs greases. Steady state tests at higher average contact pressure of 1.67 GPa proved to have a lower friction coefficient for CNTs grease containing MoS2; otherwise CNTs grease without MoS2 showed an average value of CoF comparable to calcium and lithium greases, both in a boundary and a mixed regime. The protection against wear, a considerable decrease (−60%) of reference parameter was measured with CNTs grease with MoS2 (NLGI 2) in comparison with the worst conventional grease and −22% in comparison with the best conventional grease. The data indicated that our novel carbon nanotube greases show superior tribological properties and will have promising applications in the corresponding industry.

The coupling of solar cells and Li-ion batteries is an efficient method of energy storage, but solar power suffers from the disadvantages of randomness, intermittency and fluctuation, which cause the low conversion efficiency from solar energy into electric energy. In this paper, a circuit model for the coupling system with PV cells and a charge controller for a Li-ion battery is presented in the MATLAB/Simulink environment. A new three-stage charging strategy is proposed to explore the changing performance of the Li-ion battery, comprising constant-current charging, maximum power point tracker (MPPT) charging and constant-voltage charging stages, among which the MPPT charging stage can achieve the fastest maximum power point (MPP) capture and, therefore, improve battery charging efficiency. Furthermore, the charge controller can improve the lifetime of the battery through the constant-current and constant-voltage charging scheme. The simulation results indicate that the three-stage charging strategy can achieve an improvement in the maximum power tracking efficiency of 99.9%, and the average charge controller efficiency can reach 96.25%, which is higher than that of commercial chargers. This work efficiently matches PV cells and Li-ion batteries to enhance solar energy storages, and provides a new optimization idea for hybrid PV/Li-ion systems.

A facile and scalable method is reported to fabricate Si-graphene nanocomposite as anode material for Li-ion batteries (LIBs) with high capacity and capacity retention performance. The Si-graphene electrode showed an initial discharge capacity of 1307 mAh g−1 at a current rate of 0.1C. At the 25th cycle, the electrode retained a discharge capacity of 1270 mAh g−1, with an excellent capacity retention of 97%. At the 50th cycle, the electrode still retained high capacity retention of 89%. The improved capacity retention of Si-graphene anode compared with Si anode is attributed to the mechanical flexibility of graphene that compromises the volume expansion of Si during the lithiation/delithiation process. The electrochemical impedance measurement further confirms the enhanced electrical conductivity and the denser solid-electrolyte-interface of the Si-graphene electrode. This fabrication approach is cost-effective and easy to scale up compared to known techniques, making it a promising candidate for commercializing Si-based anode for LIBs.

Electronics depend on their ability to shed operational heat to maintain operating temperature. Inferior grease can create preventable problems in electronics. This is typically achieved through a thermal grease or paste. If this grease fails to dissipate heat or maintain thermal contact, then the equipment will have faults. Greases with less-than-optimal performance create excessive wear, heat, and reduced life expectancy. This can cause equipment failures and malfunctions at the most inopportune moments. Thermal greases are applied to Central Processors (CPU) and Graphics Processors (GPU) in avionics LRUs, computers, Solar panels, HVAC systems, and other electronics. A high-performance novel nano grease will shed excess heat and increase device life expectancy. The fabricated nano greases show improvements of up to 80% in thermal conductivity measurements. CPU testing resulted in a 100% decrease in the standard deviation of temperature variation from commercial greases.

γ-Linolenic acid (GLA), a nutritionally important fatty acid in mammals, is synthesized by a Δ6 desaturase. Here, we report identification of PiD6, a new cDNA from the oleaginous fungus, Pythium irregulare, encoding a 459-amino acid protein that shares sequence similarity to carboxyl-directed desaturases from various species. Expression of PiD6 in yeast (Saccharomyces cerevisiae) revealed that it converts exogenously supplied linoleic acid into GLA, indicating that it encodes a Δ6 fatty acid desaturase. Expression of the desaturase in Brassica juncea under the control of the Brassica napus napin promoter resulted in production of three Δ6 unsaturated fatty acids (18:2-6, 9; 18:3-6, 9, 12; and 18:4-6, 9, 12, 15) in seeds. Among them, GLA (18:3-6, 9, 12) is the most abundant and accounts for up to 40% of the total seed fatty acids. Lipid class and positional analysis indicated that GLA is almost exclusively incorporated into triacylglycerol (98.5%) with only trace amounts found in the other lipids. Within triacylglycerols, GLA is more abundant at the sn-2 position.

The unique properties of as-obtained 1D nanomaterials can lead to applications in various fields such as electronics, magnetism, optics, and catalysis. [...]researchers working in the 1D nanomaterials are constantly striving to develop new fundamental science as well as potential applications.

Three-dimensional SiO2/nitrogen-doped graphene aerogels (SiO2/NGA) with different SiO2 loading masses have been synthesized by a facile hydrothermal route. This composite structure significantly increased capacity through surface and interface engineering, and the three-dimensional structure can greatly absorb the volume expansion of silica. When applied as the anode material for lithium-ion batteries (LIBs), the SiO2/NGA nanocomposite can deliver a specific capacity of more than 1000 mAh g−1 at a current density of 100 mA g−1 with long cycle stability. Moreover, it can also present an excellent capacity reversibility after the rate performance test. Further analysis reveals that the SiO2/NGA shows an enhanced contribution of capacitive charge mechanism and displays typical pseudocapacitive behavior. In this case, constructing nitrogen-doped aerogel composite is an effective direction for improving Si-based electrodes for potential applications as the electrode for LIBs.Graphic abstractThree-dimensional porous SiO2/nitrogen-doped aerogel (SiO2/NGA) was synthesized. This novel SiO2/NGA composite structure can effectively solving the problem of huge volume change during cycles as well as facilitate the fast diffusion of Li ions and Electronics, and thus achieve improved anode performance. As Li-ion batteries anode materials, which shows excellent electrochemical performance

The resistance of several pristine and functional single-wall carbon nanotubes (SWNTs) deposited and dried on interdigitated electrode (IDE) chips was investigated to better understand how functional groups influence their resistivity. Without the external electrical field, the resistance was generally increased for the sulfonated and fluorinated SWNTs but not for COOH-SWNTs. With a 3 V electric field applied during depositing, while no change in resistance was found for the purified pristine SWNTs, fluorinated SWNTs, COOH SWNTs, and Ni-SWNTs, a significant decrease in resistance was observed in sulfonated SWNTs and unpurified pristine SWNTs, which could be due to the alignment of SWNTs in an electric field. The alignment of the sulfonated SWNTs is most likely due to the charge of the sulfate functional group. It is interesting to note that the alignment was found in the unpurified pristine SWNTs but not in the purified pristine ones which have lessened resistivity. The lower resistivity in the purified pristine SWNTs may be due to the smaller number (<5%) of impurities. The significance of this research is that hydrophilic COOH-SWNTs could be a better candidate than the hydrophobic pristine SWNTs for being used in many applications, especially in polymer nanocomposites.

Capacitive deionization (CDI) is a relatively new technique that uses electric double layer (EDL) effects, high-affinity chemical groups, redox-active materials, and membrane capacitive electrosorption principle for the desalination. In this paper, hydrothermal synthesis of cobalt ferric oxide (CFO) metal oxide nanoparticles (NPs) coupled with the vacuum filtration method, or the freeze-drying method is used to fabricate high-performance nanocomposites: CFO-graphene, CFO-CNTs, and CFO-3DrGO. Two times of hydrothermal reaction methods were conducted to fabricate the CFO-3DrGO nanoengineered as a pseudocapacitive/EDL electrode. The results have demonstrated that the SAC of CFO-3DrGO/CFO (64.5 mg g −1 ) is greater than that of the CFO-graphene/CFO (55.16 mg g −1 ) and CFO-CNTs/CFO (21.5 mg g −1 ) due to the better surface area of the CFO-3DrGO nanocomposite (330 m 2  g −1 ). The higher surface area of the CFO-3DrGO is due to the porous and interconnected 3D structure of the 3DrGO, and it provides a larger surface area to form EDL capacitance. In addition, the added porous 3DrGO entangled with the spinel crystals (CoFe 2 O 4 ) in the composite allowed for a quick ion diffusion across the interconnected open macroporous structures.