Dynamic distribution of contact stress of friction lining in the process of friction transmission

The dynamic distribution of contact stress of friction lining in the process of deep coal mine friction transmission was investigated in this study. Rope tensions during lifting and lowering were obtained using Simulink simulation models first. Then, correlation model of contact stress of friction lining was established. Subsequently, effects of the friction coefficient, lifting load, terminal mass ratio, maximum speed, maximum acceleration and acceleration rate on the dynamic distribution of contact stress were explored. The results show that the wrap angle of the friction pulley is divided into three, i.e. static, mixed, and friction angles, respectively. Furthermore, the friction angle decreases with the increasing coefficient of friction, and the increases of the terminal mass ratio induce expanding trends of overall ranges of the friction angle, which could result in rope skid accidents and unpredictable failure of friction lining

A CN-FDTD Scheme and Its Application to VLSI Interconnects/Substrate Modeling

In this paper, a two-dimensional (2D) Crank-Nicholason (CN) finite difference time domain (FDTD) method is proposed for VLSI interconnect/substrate characterization. Through rigorous truncation and dispersion error analyses, a guideline on using this technique is presented. Several iterative solvers are investigated to accelerate the solution of the CN-FDTD scheme. Numerical examples are given to demonstrate the accuracy and the efficiency of the proposed algorithm

Effects of the combination of loxoprofen sodium and sodium hyaluronate on osteoarthritis and knee function

Purpose: To determine the treatment efficacy of the combination of loxoprofen sodium and sodium hyaluronate in osteoarthritis (OA), and its role in knee joint function. Methods: 98 patients with OA admitted to Guang'an People's Hospital, Sichuan, China were allocated into control group (CNG, given loxoprofen sodium n, = 51) and study group (SG, given loxoprofen sodium and sodium hyaluronate, n = 47). Both groups were compared in terms of the levels of inflammatory factor, Lysholm, VAS, WOMAC scores, treatment effects, serum MDA, NO, SOD levels, adverse effects, and blood rheology indices. Results: The study group had higher SOD levels, and higher BALP and BGP than CNG (p < 0.05). SG had lower TRACP-5b and blood rheological indices than CNG (p < 0.05). The difference in the incidence of adverse reactions was not statistically significant between the two groups (p > 0.05). Conclusion: The combination of loxoprofen sodium and sodium hyaluronate effectively improves the function and blood rheological indices of knee joints. It reduces the occurrence of adverse reactions and the level of pain in patients with OA, and improves OA prognosis. However further clinical trials are required prior to application in clinical practice

Prediction of heat accumulation of symmetrical rubber buffer on track-type bulldozer

Symmetrical rubber buffers mounted on a tracktype bulldozer are used in passive damping for the reduction of vibrations. As heat accumulation due to hysteresis  may occur in continuous operation distributions of three typical cases were  evaluated by FEM. The simulation result shows that hysteresis–related heat  accumulation occurring near the contact region of the rubber pad remains unchanged in different cases. The maximum temperature in the case of  earthmoving somewhat exceeds the range. The value of cutting and bulldozing is below the range. The value of loosening obviously exceeds the range. The great conductivity gap of heat flux between steel and rubber, which caused the most  heat, was dissipated through the steel plate. Superficial temperatures were  measured with a non-contact thermometer for the convenience of calculation that revealed a fair agreement between simulation and measurement in the case of  earthmoving and cutting andbulldozing case. A lot of hysteresis-related heat  produced due to excessive load caused a large error

Impact of sub-grid variability of precipitation and canopy water storage on land and atmosphere hydrological processes

The sub-grid variability of precipitation and canopy water storage plays an important role in regulating the land-atmosphere interactions. This study develops a canopy hydrology scheme that considers the sub-grid variability based on a dynamic-statistical method. When implemented into the offline Community Land Model version 3 (CLM3), the scheme is fairly robust under different temporal resolutions. The model evaluation is conducted by comparing the simulated interception loss ratio (i.e., the interception loss as a fraction of precipitation) with field measurements at various sites over the globe. The comparisons demonstrate that the model with the new canopy hydrology scheme performs much better than the one with the scheme not considering the sub-grid variability of precipitation and canopy water storage. The improvement is more significant over the tropics where convective rain is dominant and vegetation is dense. By applying the new scheme into the offline CLM3 and the coupled Community Atmosphere Model version 3 (CAM3)-CLM3, the impact of sub-grid variability of precipitation and canopy water storage on the hydrological processes is investigated. The impact is much more significant over the tropics both in the offline CLM3 and the coupled CAM3-CLM3. However, hydrological processes in the offline CLM3 and the coupled CAM3-CLM3 response differently to the sub-grid variability of precipitation and canopy water storage. For example, the evapotranspiration decreases when the sub-grid variability is included in the offline CLM3, while it remains more or less the same in the coupled CAM3-CLM3. The differences in the impact of sub-grid variability result from the land-atmosphere feedbacks that modify the large-scale circulation and atmospheric instability. Cloud feedback plays an important role in propagating the impact from land surface to atmosphere.

Impact of sub-grid variability of precipitation and canopy water storage on land and atmosphere hydrological processes

The sub-grid variability of precipitation and canopy water storage plays an important role in regulating the land-atmosphere interactions. This study develops a canopy hydrology scheme that considers the sub-grid variability based on a dynamic-statistical method. When implemented into the offline Community Land Model version 3 (CLM3), the scheme is fairly robust under different temporal resolutions. The model evaluation is conducted by comparing the simulated interception loss ratio (i.e., the interception loss as a fraction of precipitation) with field measurements at various sites over the globe. The comparisons demonstrate that the model with the new canopy hydrology scheme performs much better than the one with the scheme not considering the sub-grid variability of precipitation and canopy water storage. The improvement is more significant over the tropics where convective rain is dominant and vegetation is dense. By applying the new scheme into the offline CLM3 and the coupled Community Atmosphere Model version 3 (CAM3)-CLM3, the impact of sub-grid variability of precipitation and canopy water storage on the hydrological processes is investigated. The impact is much more significant over the tropics both in the offline CLM3 and the coupled CAM3-CLM3. However, hydrological processes in the offline CLM3 and the coupled CAM3-CLM3 response differently to the sub-grid variability of precipitation and canopy water storage. For example, the evapotranspiration decreases when the sub-grid variability is included in the offline CLM3, while it remains more or less the same in the coupled CAM3-CLM3. The differences in the impact of sub-grid variability result from the land-atmosphere feedbacks that modify the large-scale circulation and atmospheric instability. Cloud feedback plays an important role in propagating the impact from land surface to atmosphere.

Preparation of GO/PAM Continuous Adsorption Medium and its Dynamic Adsorption Properties for Methylene Blue

A continuous and structured porous adsorbent named GO/PAM was synthesised by one-step copolymerization of graphene oxide (GO) and acrylamide (AM) in amorphous region initiated by redox agent consisting of hydrogen peroxide (H2O2) and ascorbic acid (VC) at -20°C. The dynamic adsorption characteristics of methylene blue (MB) in GO/PAM structured adsorption medium were investigated. With the introduction of GO which rich in —OH and —COOH groups, the adsorption capacities were 178.65 mg/g~201.58 mg/g. Structured continuous adsorption medium was prepared by one-step polymerization of crystallization, in order to replace traditional bulk resin and ion exchange resin in the treatment of printing and dyeing wastewater

The Use of Remote Sensing-Based ET Estimates to Improve Global Hydrological Simulations in the Community Land Model Version 5.0

Terrestrial evapotranspiration (ET) is a critical component of water and energy cycles, and improving global land evapotranspiration is one of the challenging works in the development of land surface models (LSMs). In this study, we apply a bias correction approach into the Community Land Model version 5.0 (CLM5) globally by utilizing the remote sensing-based ET dataset. Results reveal that the correction approach can alleviate both overestimation and underestimation of ET by CLM5 over the globe. The adjustment to overestimation is generally effective, whereas the effectiveness for underestimation is determined by the ET regime, namely water-limited or energy-limited. In the areas with abundant precipitation, the underestimation is effectively corrected by increasing ET without the water supply limit. In areas with rare precipitation, however, increasing ET is limited by water supply, which leads to an undesirable correction effect. Compared with the ET simulated by CLM5, the bias correction approach can reduce the global-averaged relative bias (RB) and the root mean square error (RMSE) by 51.8% and 65.9% against Global Land Evaporation Amsterdam Model (GLEAM) ET data, respectively. Meanwhile, the correlation coefficient (CC) can also be improved from 0.93 to 0.98. Continentally, the most substantial ET improvement occurs in Asia, with the RB and RMSE decreased by 69.7% (from 7.04% to 2.14%) and 70.2% (from 0.312 mm day−1 to 0.093 mm day−1, equivalent to from 114 mm year−1 to 34 mm year−1), and the CC increased from 0.92 to 0.99, respectively. Consequently, benefiting from the improvement of ET, the simulations of runoff and soil moisture are also improved over the globe and each of the six continents, and the improvement varies with region. This study demonstrates that the use of satellite-based ET products is beneficial to hydrological simulations in land surface models over the globe