Excessive High Pressure Research Articles

Detrimental electrochemical behavior caused by excessive high pressure on Li-ion pouch-type full cell

Pressure on electrodes in cells is crucial for improving their active material density and electronic conductivity. A single-layer pouch cell (60 mAh) was fabricated to study the electrochemical effects of external pressures ranging from 0 to 3 MPa. The high-pressure cell at 3 MPa presented poor capacity retention owing to Li plating and pore-clogging on the graphite electrode. However, the optimized pressed cell did not hinder Li-ion transport in the graphite anode and underwent 200 cycles with 82 % capacity retention. External pressure impacts the contact between the electrodes and electrolyte; however, excessive pressure makes it difficult to supplement Li ions from the electrolyte into the graphite anode, resulting in increased polarization, electrolyte side reactions, and Li-metal deposition.

Effect of an impinging jet on the flow characteristics and thermal performance of mainstream in battery cooling of hybrid electric vehicles

The novel concept of impinging jet cooling, i.e., an active-passive air cooling strategy, was proposed to achieve improved battery thermal management in hybrid vehicles, and this method is supported by excess high pressure discharged air. To comprehensively realize the active-passive combined cooling behavior, a rectangular channel with a jet impingement hole was utilized to experimentally and numerically study the flow characteristics and thermal performance of the joint cooling mechanism. The numerical results were confirmed by the experimental data in this work, the maximum deviations of the offset and Nusselt numbers are 18.8% and 7.5%, respectively. The thermal transport performs much better under the interaction between the mainstream and impinging jet, i.e., the average Nusselt number and maximum Nusselt number can be increased by 0.43-16.55, 5.73-34.42, respectively, at inlet pressures of the impinging jet in the range of 1–6 bar. The values of Nu/Nu0/(f/f0) 1/3 are improved by 1.52–3.33. The jet fluid was deflected under the influence of the mainstream and a vortex can be induced, which is beneficial for the heat transfer performance. The jet fluid closely reached the heated plane at a relatively large volume flow rate and the heat transfer performance was excellent once the jet fluid touched the heated plane. The thermal boundary layer becomes thinned under the impact of the impinging jet but the magnitude of the reduction is relatively slight.

Gelation of chicken batters during heating under high pressure

The gelling process of chicken meat batters, which were heated (75 °C) under atmospheric pressure or high pressure (200/400 MPa), was investigated by determining the hardness of batter, residual denaturation enthalpy, microstructure, and protein secondary structure. The results showed that meat batters heated at 200 MPa showed a similar increase in hardness to heat-only samples, but meat batters heated at 400 MPa showed a texture decreasing tendency after a limited increase. High pressure disrupted the myofibrils, promoted protein denaturation and aggregation in the first stage of heating under pressure treatment. In the second stage of treatment, heating was the main driving force for protein gelation, which was disturbed by hindering the structural transformation of proteins in the presence of high pressure during heating. The effect of 200 MPa on muscle proteins was relatively gentle and had a less negative effect. Excessive high pressure should be avoided when applying heating under pressure for gel-type meat products processing. Industry relevanceHigh-pressure processing is increasingly applied in the meat industry. By combining high pressure with heating, their effects on texture improvement and microbial inactivation can be maximized. In this study, the influence of high pressure on the texture of meat products was analyzed, which showed that excessive pressure would significantly interfere with the thermal denaturation of the protein, thus adversely affecting the formation of the gel structure. High pressure at 400 MPa and above should be avoided when applying heating under pressure for gel-type meat products processing.

The Influence of Operation Pressure on the Long-Term Stability of Salt-Cavern Gas Storage

The operation pressure of underground salt-cavern gas storage directly affects its stability. Because of seasonal demand and other emergency reasons, the gas storage working pressures always change from high to low or from low to high cyclic variation. In order to analyze the effect of gas storage pressure changing on its long-term stability, considering the salt rock creep, a 3D finite element model was built using the software Abaqus. Moreover, the deformation and analyzed results of the storage under 0 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa, and 12 MPa and also circulating changes pressure operation were given in the 10-year creep. It concluded that how working pressures have effect on long-term stability of salt-cavern gas storage. The research results indicated that the long-term creep performance of underground salt cavern gas storage is affected by internal pressure, the smaller the internal pressure creep is, the more obvious the creep and the greater deformation of gas storage are. The greater the internal pressure is, the smaller the deformation of the gas storage is. The low pressure and excessive high pressure must be avoided during the operation of gas storage. These results have an important significance on determining the reasonable pressure of gas storage operation and ensure the long-term stability of gas storage.

Computer simulations of transient flow in a real city water distribution system

Several cases of computer simulation for transient flow have been conducted to demonstrate the transient effects in distribution system. Each case is simulated with specified scenarios. The results of computer model show that any changes of water demand can produce large pressure oscillation. If the change of demand is sudden, it will create many undesirable consequences such as backflow, excessive high pressure, or negative pulling pressure. The computer model utilized in this study has been found to be a promising simulation tool for the solution of transient flow in distribution system. Computer models have to be used for the design of distribution system subject to transient flow. Moreover, it can be used as an operational tool to protect the distribution system from the excessively high pressure, the column separation due to excessive negative pressure, or any undesirable incidents.

Follow-up Angiographic Results after MultiLink Coronary Stent Implantation

Background and Objectives:The objective of this study was to assess the in-hospital clinical outcome and 6 months follow-up angiographic results after flexible balloon expandable MultiLink coronary stenting. The impact of post-stenting excessive high pressure balloon dilation on late outcome is controversial. The other purpose was to investigate the impact of post-stenting high pressure balloon dilation (HPD group ≥14 atm) on clinical and angiographic outcome in comparison to moderate pressure dilation (MPD group <14 atm). Materials and Method:The MultiLink stents were implanted in 124 patients (mean age 58±9, M/F=94/30) with 128 lesions. Post-stenting high pressure balloon dilation was performed to have less than 10% of residual stenosis and smooth instent lumen without IVUS guidance. Results:The indications for stenting were elective in 88 lesions (69%), suboptimal angioplasty results in 27 lesions (21%), and bail-out in 13 lesions (10%). The incidence of in-hospital major adverse cardiac events was 1.6% and major vascular complication rate was 3.2%. The followup angiography was performed in 86 patients (69%) at 7.9±2.6 months. The angiographic restenosis rate was 22.7%. The acute gain of HPD group had a tendency to be higher than MPD group (HPD:MPD=2.33±0.51 mm:2.22±0.44 mm, p=0.08) and the late loss of MPD group had a tendency to be lower than HPD group (MPD:HPD=0.86±0.73 mm:0.95±0.84 mm, p=0.09). And the net gain and restenosis rate of both groups were similar respectively (HPD:MPD=1.38±0.94 mm:1.36±0.83 mm, p=ns, HPD:MPD=22.5%:22. 9%, p=ns). Conclusion:The MultiLink coronary stent system is a safe and effective device with high procedural success rate and also has the acceptable angiographic restenosis rate for the treatment of coronary artery disease. The post-stenting excessive high pressure balloon dilation might not be necessary during the deployment of MultiLink stent. (Korean Circulation J 1999;29(11):1169-1175)