The oil jet lubrication performance of a high-speed and heavy-load gear drive is significantly influenced and determined by the oil jet nozzle layout, as there is extremely limited meshing clearance for the impinging oil stream and an inevitable blocking effect by the rotating gears. A novel mathematical model for calculating the impingement depth of lubrication oil jetting on an orthogonal face gear surface has been developed based on meshing face gear theory and the oil jet lubrication process, and this model contains comprehensive design parameters for the jet nozzle layout and face gear pair. Computational fluid dynamic (CFD) numerical simulations for the oil jet lubrication of an orthogonal face gear pair under different nozzle layout parameters show that a greater mathematically calculated jet impingement depth results in a greater oil volume fraction and oil pressure distribution. The influences of the jet nozzle layout parameters on the lubrication performance have been analyzed and optimized. The relationship between the measured tooth surface temperature from the experiments and the corresponding calculated impingement depth shows that a lower temperature appears in a situation with a greater impingement depth. Good agreement between the mathematical model with the numerical simulation and the experiment validates the effectiveness and accuracy of the method for evaluating the face gear oil jet lubrication performance when using the impingement depth mathematical model.
Ten water-soluble ions (F À , Cl À , NO 2 À , NO 3 À , SO 4 2À , K + , Na + , NH 4 + , Ca 2+ , and Mg 2+ ) in PM2.5 samples were determined by capillary electrophoresis (CE) with a resonant capacitively coupled contactless conductive detector (RC 4 D). The main component of the background electrolyte (BGE) solution was 20 mM 2-morpholinoethanesulfonic acid (MES)/L-histidine (His) (pH ¼ 6.1). The modifiers of 1.5 mM 18-crown-6 and 20 mM CTAB were added to the BGE for the separation of cations and anions, respectively. The limit of detection for the ten ions is in the range of 3-20 mg L À1 . In the combination of dual-opposite end injection and end-to-end differential detection, simultaneous determination of the ten ions was performed in a BGE of 20 mM MES/His + 1.5 mM 18-crown-6 + 20 mM CTAB. A flow injection interface was employed for delay of sample injection without interrupting the electrophoresis. The negative peaks appeared in the early and later stages of electrophoresis increase the possibility of peak superposition in electropherograms. With two independent separation capillaries employed in end-toend differential detection, simultaneous determination of anions and cations was performed with optimized BGE and better peak separation.
The kinetic processes of zeolitic imidazolate framework-8 (ZIF-8) film growth and the adsorption of dichloromethane, trichloromethane and carbon tetrachloride on ZIF-8 film are monitored in real time.
With the decrease of primary resources in recent years, deep seabed mineral resources, especially the massive sulfides, are of extensive research significance. In this paper, firstly, the uniaxial compressive strength (UCS) test and triaxial compressive strength (TCS) test on the seafloor massive sulfides (SMS) samples from three different segments are conducted to obtain the key mechanical properties, including the cohesive force, internal friction angle, compressive strength, elastic modulus and Poisson’s ratio. Then, by leveraging the PFC3D code, the uniaxial and triaxial numerical simulations of SMS are performed. During this process, the micro properties in the simulation are altered through a calibration process until they match the macro properties of the SMS samples measured in the laboratory tests. Finally, the micro properties are applied to simulate the cutting process of single cutting pick and two adjacent cutting picks; meanwhile, the cutting force in the fragmentation process of SMS is monitored and collected. This research can provide some guidance for the mining simulation of SMS and effectively predicting the maximum force on the cutting pick.
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