Two regularity criteria for the 3D MHD equations

This work establishes two regularity criteria for the 3D incompressible MHD equations. The first one is in terms of the derivative of the velocity field in one-direction while the second one requires suitable boundedness of the derivative of the pressure in one-direction

Global regularity for the 2D MHD equations with mixed partial dissipation and magnetic diffusion

AbstractWhether or not classical solutions of the 2D incompressible MHD equations without full dissipation and magnetic diffusion can develop finite-time singularities is a difficult issue. A major result of this paper establishes the global regularity of classical solutions for the MHD equations with mixed partial dissipation and magnetic diffusion. In addition, the global existence, conditional regularity and uniqueness of a weak solution is obtained for the 2D MHD equations with only magnetic diffusion

Off-hour admission and mortality risk for 28 specific diseases: A systematic review and meta-analysis of 251 cohorts

Background: A considerable amount of studies have examined the relationship between off-hours (weekends and nights) admission and mortality risk for various diseases, but the results remain equivocal. Methods and Results: Through a search of EMBASE, PUBMED, Web of Science, and Cochrane Database of Systematic Reviews, we identified cohort studies that evaluated the association between off-hour admission and mortality risk for disease. In a random effects meta-analysis of 140 identified articles (251 cohorts), off-hour admission was strongly associated with increased mortality for aortic aneurysm (odds ratio [OR], 1.52; 95% confidence interval, 1.30-1.77), breast cancer (1.50, 1.21-1.86), leukemia (1.45, 1.17-1.79), respiratory neoplasm (1.32, 1.20-1.26), pancreatic cancer (1.32, 1.12-1.56), malignant neoplasm of genitourinary organs (1.27, 1.08-1.49), colorectal cancer (1.26, 1.07-1.49), pulmonary embolism (1.20, 1.13-1.28), arrhythmia and cardiac arrest (1.19, 1.09-1.29), and lymphoma (1.19, 1.06-1.34). Weaker (OR<1.19) but statistically significant association was noted for renal failure, traumatic brain injury, heart failure, intracerebral hemorrhage, subarachnoid hemorrhage, stroke, gastrointestinal bleeding, myocardial infarction, chronic obstructive pulmonary disease, and bloodstream infections. No association was found for hip fracture, pneumonia, intestinal obstruction, aspiration pneumonia, peptic ulcer, trauma, diverticulitis, and neonatal mortality. Overall, Off-hour admission was associated with increased mortality for 28 diseases combined (OR, 1.11; 95% confidence interval, 1.10-1.13).Conclusions: Off-hour admission is associated with increased mortality risk, and the associations varied substantially for different diseases. Specialists, nurses, as well as hospital administrators and health policy makers can take these findings into consideration to improve the quality and continuity of medical services

Maltose and Totally Impermeable Film Enhanced Suppression of Anaerobic Soil Disinfestation on Soilborne Pathogens and Increased Strawberry Yield

peer reviewe

AN EXPERIMENTAL STUDY ON HEAT TRANSFER PERFORMANCE OF JET IMPINGEMENT ARRAYS

Jet impingement cooling is an effective way for thermal management in electronics, prevailed over many other single heat transfer modes. In general, jet arrays are better than a single jet, enhancing jet cooling performance. However, the performance of jet arrays is strongly dependent on the jet configurations, e.g., adjacent jet interval and hole-to-surface distance. Thus, in this study, jet impingement cooling is investigated on a flat heating surface placed in a channel, including in-line double jet cooling, in-line three jet cooling, and in-line four jet cooling. It is known that the outlet configuration could influence the jet performance because of the cross flow effect, and herein the outlet is designed to have intermediate cross flow only. The local Nusselt number distribution is experimentally measured by the liquid crystal method. Then the effect of the adjacent jet interval on the jet cooling performance on the target surface is compared. It is found that the jet array indeed enhances heat transfer. For example, based on the results, it is seen that in comparison to cross flow cooling, the average Nusselt number is improved by 34% by the in-line double jet cooling, and correspondingly the maximum Nusselt number is enhanced by 51%

EXPERIMENTAL STUDY ON HEAT TRANSFER ENHANCEMENT OF AIR JET IMPINGEMENT FOR ELECTRONICS THERMAL MANAGEMENT

Jet impingement cooling was investigated on a flat heating surface placed in a flow channel, including single jet cooling, in-line double jet cooling, and combined crossflow and jet cooling; cross-flow cooling was a baseline for comparison. In addition, the in-line double jet cooling was explored with various jet distances. Local Nusselt number distribution was experimentally achieved by the liquid crystal method, and the measurements were carried out under various jet pressures ranging from 1 bar to 4 bar. It was found that heat transfer depends on the jet distance because one jet may produce a crossflow effect on the other jet, affecting the formation of longitudinal vortices which could enhance heat transfer. It was seen that in comparison to the crossflow cooling, the average Nusselt number is enhanced by 110%, 150%, and 380%by the single jet cooling, the in-line double jet cooling, and the combined cooling, respectively, and correspondingly the maximum Nusselt number is enhanced by 160%, 240%, and 540%, respectively. In the combined cooling, there is a deflection distance ranging from 0 mm to 10 mm depending on the jet pressure