Sleeve deformation in a three-roller screw-rolling mill

The screw rolling of steel pipe in a three-roller mill is considered. Given the differences in the unitforce distribution within the deformation region, a method is developed for calculating the deformation parameters in sleeve rolling on a long mandrel. A method is presented for calculating the reduction and contact surface area of the metal and the roller, in the region where the diameter of the sleeve is reduced and in the region where the wall thickness is reduced. Account is taken of the tangential flow of metal into the gaps between the rollers, which is characteristic of the rolling of thin-walled pipe when the ratio of the diameter and the wall thickness is D_pi/S_pi > 8. The results are intended for industrial use in the production of pipe with D_pi/S_pi = 8–15, when the tolerances are ±6% on the wall thickness and ±0.5% on the diameter. The results provide a better understanding of the production of thin-walled pipe on screw-rolling mills.     

Asymmetric neural control systems in human self-regulation.

Reviews the literature on the neurotransmitter substrates controlling motor readiness, showing that these substrates produce qualitative changes in the flow of information in the brain: Dopaminergic activation increases informational redundancy, whereas noradrenergic arousal facilitates orienting to novelty. Evidence that these neurotransmitter pathways are lateralized in the human brain is consistent with the left hemisphere's specialization for complex motor operations and the right hemisphere's integration of bilateral perceptual input. Principles of attentional control are suggested by the operational characteristics of neural control systems. The affective features of the activation and arousal systems are integral to their adaptive roles and may suggest how specific emotional processes dynamically regulate cognitive function. (4? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

管材钢中氧分析试样制备方法探讨

以氧含量均匀性较好的厚壁无缝钢管WB36、P92等材料为例, 确定了适合工厂大批生产条件下的管材钢中氧分析试样的制备方法。考察了样品质量、试样加工磨削进给量、放置时间、清洗时间这些因素对分析结果的影响, 结果表明, 当样品剪切质量为1.0 g、加工磨削进给量0.1毫米/行程、超声清洗时间为2 min、制备完成后1 d内分析效果最佳。选取内蒙古北方重工集团生产的厚壁管P92材料, 按照方法制备后测定, 与钢铁研究总院(CISRI)制备后测定值一致, 再现性限为0.000 70%～0.000 84%。     

Production of thin-walled pipe on a system with a three-roller mill

The manufacture of thin-walled pipe on a three-roller screw-rolling mill is described. The optimal reduction on the reduction mill is noted, and a formula is given for the aperture. A rolling technology for the rear end of the pipe without triangulation is outlined.     

Asymmetric spin-echo imaging of magnetically inhomogeneous systems: theory, experiment, and numerical studies

The ability of the asymmetric spin-echo (ASE) pulse sequence to provide different degrees of spin-echo (SE)-type and gradient-echo (GE)-type contrast when imaging media containing magnetic inhomogeneities is investigated. The dependence of the ASE signal on the size of magnetic field perturbers is examined using theory, computer simulations, and experiment. A theoretical prediction of the ASE signal is obtained using the Anderson-Weiss mean field theory, the results of which are qualitatively supported by computer simulations and experimental studies. It is shown that the ASE sequence can be used to tune the range of perturber sizes that provide the largest contributions to susceptibility contrast effects.     

需求依赖库存的生产库存系统的最优控制

针对现实生活中存在的库存刺激需求的现象,建立了生产库存系统的最优控制模型.模型中生产率和价格为控制变量,库存为状态变量,并且生产率是有界的,需求率同时依赖于库存和价格.运用最大值原理对模型进行求解,根据模型参数的不同取值,获得了三种可能的解,并对其进行了详细分析.最后将模型应用于具体算例,得到了系统状态的具体变化过程,通过与需求不依赖于库存的情形相比较,得到了需求依赖于库存所产生的影响.     

数字孪生五维模型及十大领域应用

为解决特种变压器生产车间实时化管控弱、调度决策能力差、过程监控不直观、运行态势不明朗的问题,从特种变压器车间的数字孪生建模、知识信息融合、运行可靠性分析和可视化表达等方面入手,探讨了一种特种变压器车间数字孪生系统的新型体系架构;阐述了基于“5维度-4视角”模型、高性能算力孪生引擎及沉浸式可视化技术的数字孪生建模表达方法;研究了数字孪生车间指标体系的构建方法以及车间知识信息与数字孪生的融合方法;基于层次分析理论和关联熵方法,构建了一种基于复合物元信息熵的车间数字孪生系统可靠性分析模型;最后,以某特种变压器生产车间为应用案例,基于上述方法和模型,结合实际生产过程开发了原型数字孪生系统,实现了特种变压器车间的多维多尺度实时智能管控,验证了该方法的合理性和有效性.     

A deterministic model for the economic evaluation of broiler production systems

A deterministic model for the economic evaluation of broiler production and the derivation of economic values in broiler breeding was developed and tested. The model distinguishes four production stages: multiplier breeder, hatchery, commercial grower, and processor. The processor is included to determine relationships for the price per kilogram of live weight and the quality of the carcass, either on a "whole sale" or "further processed" base. Quantity of product output for the system is fixed by a predetermined amount of kilogram carcass of final product broilers finished by the commercial grower. Profitability of production and cost prices per unit product for subsequent stages can be calculated. Exogenous parameters are easily changeable in order to calculate profitability and cost prices for different production levels or production circumstances. Economic values can be derived considering influences of changes in genetic merit for performance traits on profitability or cost price, for integrated and nonintegrated production systems. By changing exogenous parameters, the model can also be used to analyze profitability or derive economic values for other meat-type poultry, such as turkey.     

Asymmetric Flow in Symmetric Supercritical Expansions

A theory presented previously by the writer explained the asymmetric flow patterns occurring in symmetric rectangular expansions with subcritical flow. The theory is extended in the present paper to supercritical flows, in which the hydraulic jump is one of the flow features. The theory is shown to agree with available observations. Transverse oscillatory conditions are discussed in terms of a dynamic instability that can accompany static stability. The ranges for which experimental data are available with which to test the theory are identified, making it apparent where additional data would be useful for the full range of the problem. The phenomenological understanding provided by the present paper is important to the development of stabilization measures. In addition to stabilization by submergence, the hydraulic jump should be amenable to stabilization by other referenced methods, including various vane configurations and pipe communication between the eddy regions.     

Facial composite production: A comparison of mechanical and computer-driven systems.

Computer-driven systems for constructing composite faces of suspects (E-fit; Mac-a-Mug) have largely replaced mechanical systems (Photofit; the Identikit) in police use, yet little is known of their comparative effectiveness in rendering an accurate likeness. Participants (N?=?24) constructed 2 of 4 familiar or unfamiliar faces, for one of which they used Photofit and for the other, E-fit. A likeness of each face was made first under target-absent conditions and then with photographs of the target present. The accuracy of the resulting composites was assessed by familiarity ratings, names elicited, and matching accuracy. The computer-driven system showed consistent superiority only when a familiar face was constructed in the presence of photographs; when participants worked from memory, E-fit was no better than Photofit. The implications of these findings for theories of face retrieval and the operational use of composites are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimizing the production of steel with reduction by aluminum,in casting and rolling systems

Data on the metallurgical defects in pipe show that they may be due to nonmetallic oxide inclusions. Analysis of the formation of oxide inclusions from smelting to the continuous casting of steel shows that, in order to reduce the incidence of such defects, additional measures must be taken in the smelting and ladle treatment of the steel. Such measures reduce the content of oxide inclusions in the steel by half. The benefits of this approach are confirmed by the reduced rejection rate of the pipe on account of defects associated with the presence of nonmetallic inclusions.