Consistent Forcing Scheme in the Simplified Lattice Boltzmann Method for Incompressible Flows

Considering the fact that the lattice discrete effects are neglected while introducing a body force into the simplified lattice Boltzmann method (SLBM), we propose a consistent forcing scheme in SLBM for incompressible flows with external forces. The lattice discrete effects are considered at the level of distribution functions in the present forcing scheme. Consequently, it is more accurate compared with the original forcing scheme used in SLBM. Through Taylor series expansion and Chapman-Enskog (CE) expansion analysis, the present forcing scheme can be proven to recover the macroscopic Navier-Stokes (N-S) equations. Then, the macroscopic equations are resolved through a fractional step technique. Furthermore, the material derivative term is discretized by the central difference method. To verify the results of the present scheme, we simulate with multiple forms of external force interactions including the space- and time-dependent body forces. Hence, the present forcing scheme overcomes the disadvantages of the original forcing scheme and the body force can be accurately imposed in the present scheme even when a coarse mesh is applied while the original scheme fails. Excellent agreements between the analytical solutions and our numerical results can be observed.     

Growth modulation of angular deformities with a novel constant force implant concept-preclinical results

PurposeVarus-valgus deformities in children and adolescents are often corrected by temporary hemi-epiphysiodesis, in which the physis is bridged by an implant to inhibit growth. With standard implant solutions, the acting forces cannot be regulated, rendering the correction difficult to control. Furthermore, the implant load steadily increases with ongoing growth potentially leading to implant-related failures. A novel implant concept was developed applying a controlled constant force to the physis, which carries the potential to avoid these complications. The study aim was to proof the concept in vivo by analyzing the effect of three distinct force levels on the creation of varus deformities.MethodsThe proposed implant is made of a conventional cerclage wire and features a twisted coil that unwinds with growth resulting in an implant-specific constant force level. The proximal medial tibial physes of 18 lambs were treated with the implant and assigned to three groups distinct by the force level of the implant (200 N, 120 N, 60 N).ResultsThe treatment appeared safe without implant-related failures. Deformity creation was statistically different between the groups and yielded on average 10.6° (200 N), 4.8° (120 N) and 0.4° (60 N) over the treatment period. Modulation rates were 0.51°/mm (200 N), 0.23°/mm (120 N) and 0.05°/mm (60 N) and were constant throughout the treatment.ConclusionBy means of the constant force concept, controlled growth modulation appeared feasible in this preclinical experiment. However, clinical trials are necessary to confirm whether the results are translatable to the human pathological situation.     

Health dynamics shape life-cycle incomes

This paper empirically investigates the long-run effects of major health improvements on income growth in the United States. To isolate exogenous changes in health, the econometric model uses quasi-experimental variation in cardiovascular disease mortality across states over time. Based on data for the white population, the results show that there is a causal link between health and income per person, and they provide novel evidence that health dynamics shape life-cycle incomes. Life-cycle income profiles slope more strongly at the beginning and at the end of work life in 2000 than in 1960, indicating that age becomes a more prominent determinant of income dynamics over this period. The channels for this transformation include better health, higher educational attainment, and changing labor supply.     

A demand-smoothing incentive for cesarean deliveries

We study the demand-smoothing incentives for private hospitals to perform c-sections. First, we show that a policy change in Chile that increased delivery at private hospitals by reducing the out-of-pocket cost for women with public insurance increased the probability of a c-section by 8.6 percentage points despite private hospitals receiving the same price for a vaginal or cesarean delivery. Second, to understand hospitals’ incentives to perform c-sections, we present a model of hospital decisions about the mode of delivery without price incentives. The model predicts that, because c-sections can be scheduled, a higher c-section rate increases total deliveries, compensating the forgone higher margin of vaginal deliveries. Finally, we provide evidence consistent with the demand-smoothing mechanism: hospitals with higher c-section rates are more likely to reschedule deliveries when they expect a high-demand week.     

海警人员核化生威胁防护装备发展策略研究

分析了国内海警部队执法时面临的核化生威胁的特点,总结了国内外核化生防护装备发展现状及在洗消、救治等方面的应用情况。针对目前海上核化生防护存在的问题,基于对我军现有核化生装备防护效能的评估,提出构建海警部队核化生防护装备体系及核化生威胁防护装备训练演练体系的发展策略,为海警部队核化生防护装备适应未来执勤任务提供参考。     

一种肌电控制假手的新型自适应增力机构

介绍一种用于肌电控制假手的新型自适应切换增力机构。对比现在国内外的各种假手增力机构，它不用超越离合器，因而更为简单、可靠、耐用。它不仅为广大的上肢残疾患者带来福音，也是康复器械上的一大革新     

抗剪切力镍钛记忆合金髌骨爪的设计与临床应用

目的研制能够抗剪切力的镍钛记忆合金髌骨爪,用于髌骨骨折的治疗。方法利用镍钛记忆合金的生物特性和髌骨的解剖特征以及髌骨骨折后膝关节活动时骨折端受力情况,设计一种符合髌骨解剖学特征和同时具有抗张力和抗剪切力的形态记忆髌骨爪。临床应用髌骨骨折41例。平均随访2.1年。结果抗剪切力记忆合金髌骨爪能够起到有效的生物固定,将记忆应力加压于骨折端,形成三唯记忆接骨,防止因骨折端产生的剪切力而出现髌骨上下错位,保证了膝关节的正常活动。骨折平均愈合时间为1.8月,关节活动度正常。结论抗剪切力镍钛记忆合金髌骨爪是治疗髌骨单纯骨折的一种有效的技术和方法。