航空发动机喘振问题分析

本文通过分析喘振对发动机使用性能及发动机经济性能方面的影响,指出了发动机喘振形成的根本原因,喘振的形成及喘振对飞机的危害,通过对航空发动机喘振故障的监控与分析,大大提高了喘振故障的排除效率,同时发动机的可靠性也得到一定提升,对解决喘振故障提供了参考和借鉴。     

机组防喘振控制设计与实现

介绍了发生喘振的原因，喘振对机组和工艺生产的危害。介绍了防喘振变量得计算，各种喘振控制线的确定，防喘振控制的控制响应，控制方法和特点。     

防喘振阀的选型及动作时间探讨

针对压缩机在工业生产过程中的重要性,介绍压缩机防喘振阀门的选型及防喘振阀门动作时间的计算,通过简单的介绍,在选型过程中选择合适的阀门和合理的附件,从而满足防喘振阀门的要求,使压缩机避免喘振。     

离心压缩机喘振的预防及解决措施

离心压缩机是一种速度式压缩机,是工业生产中的关键设备。文章简要分析了离心压缩机喘振产生的原因、危害及喘振的判别,并提出了预防及解决喘振的措施,以供参考。     

浅谈离心泵防喘振技术

喘振问题一直都是困扰离心泵实现安全经济、平稳运行的难题。文章首先分析了喘振现象出现的原因,其次,就离心泵防喘振技术要点进行了深入的探讨,具有一定的参考价值。     

污水厂离心式鼓风机喘振原因分析及对策

针对兖矿集团国际焦化公司酚氰污水处理厂离心式鼓风机在使用过程中发生的喘振现象，对喘振产生的原因和影响喘振的主要因素进行了分析，提出了判断喘振的方法，并总结了几种消除喘振的解决方案，如采用变频器启动、采用出风管放气、降低好氧池的污泥浓度、保证管路畅通、改变鼓风机的“争风”状态、加强人员技能培训、定期维护保养等。     

导叶调节与防喘振控制中的解偶

介绍了离心鼓压缩机性能调节中,入口导叶调节与防喘振控制中的反向偶合的消解,因为离心鼓压风机由于入口导叶调节过程中是压力、流量双重参数控制,而防喘振控制也是压力、流量有此两参数的联全控制,在采用两者并联控制时,在运行防喘振线时,如果仍然保持并联独立的调节,就会加速喘振,为了避免了在防喘振线及以左时导叶调节与防喘振控制反向效果,就必须在导叶调节和防喘振控制时,加入合理有效的解偶控制,以达到优化智能可靠控制。本项目从问题的提出,到解决方案,内容进行了全面分析和解偶设计,并有实际应用与效益收益。     

浅谈离心泵防喘振技术

喘振问题一直都是困扰离心泵实现安全经济、平稳运行的难题。文章首先分析了喘振现象出现的原因，其次，就离心泵防喘振技术要点进行了深入的探讨，具有一定的参考价值。     

离心压缩机防喘振控制器的设计

主要介绍了离心压缩机防喘振控制器坐标的建立,以及防喘振控制体系的建立。     

离心式压缩机喘振分析及解决措施

论述了离心式压缩机喘振机理、影响因素、危害及判断,以及本车间气压机组发生喘振时的处理措施.     

变电站雷电侵入波在线监测系统测量误差分析

文章介绍了变电站雷电侵入波在线监测的意义和基本原理,包括对雷电侵入波电流和电压的监测,提出了一种基于CVT响应电流的侵入波在线监测方法,以克服现有研究存在的不足。     

浅析建筑物防雷措施中浪涌保护器的设计

针对如何正确选择浪涌保护器,提高建筑物防雷水平,文章概述了浪涌保护器的有关知识,阐述了浪涌保护器设计和选择的步骤。     

电子衡器的浪涌保护器设计应用

本文阐述了电子衡器产生浪涌电压的机理;介绍了浪涌保护器的特性及常用浪涌吸收保护器,并给出瞬态过电压分级保护措施以及分级保护器件使用。旨在解决电子衡器在浪涌电压和防雷环境中稳定工作问题。     

防雷电浪涌保护在低压供配电系统中的应用

在低压配电系统的安全保护措施中,防雷电浪涌保护起到的作用日益突出,尤其在雷电多发地区,防雷电浪涌保护直接影响到设备的安全运行和操作人员的生命安全。所以,如何在实践中做好防雷电浪涌的保护,已经成为当前电力建设中的重点课题。     

风暴潮灾害辅助决策系统研究

如何减少风暴潮灾害带来的损失是沿海城市发展中不可忽视的环节。基于Web服务建立风暴潮灾害辅助决策系统,对系统设计、系统模型和系统应用等进行了描述。风暴潮灾害辅助决策系统的建立对提升沿海城市在风暴潮灾害的应变水平具有重要的意义。     

我国棉花产业进口现状原因浅析

文章运用协整分析方法,阐述了我国棉产业进口状况,研究表明:价格差距拉大是导致棉花进口量大幅攀升的直接原因。     

Intermediated surge pricing

Although Uber and Lyft are known for their flexible “surge pricing,” they are surprisingly rigid in another way: each firm takes a constant percentage of passenger fare whether or not there is a surge. In this paper, I investigate the possible reasons for, and the impact of, this rigidity. I study a market in which a profit‐maximizing intermediary facilitates trade between buyers and sellers. The intermediary sets prices for buyers and sellers, and keeps the difference as her fee. Optimal prices increase when demand increases, that is, shifts right. If a demand increase is due to an increase in the number of ex ante symmetric buyers, then the intermediary's optimal percent fee decreases. If, instead, a demand increase is due to a reduction in the elasticity of demand, then the intermediary's optimal percent fee increases. In either case, if the intermediary keeps a constant percent fee regardless of shifts in demand, as is the case with Uber and Lyft, then surge pricing (i.e., the ratio of price during high demand to price during low demand) is amplified on one side of the market and diminished on the other side.     

THE ROLE OF INVENTORIES AND SPECULATIVE TRADING IN THE GLOBAL MARKET FOR CRUDE OIL

We develop a structural model of the global market for crude oil that for the first time explicitly allows for shocks to the speculative demand for oil as well as shocks to flow demand and flow supply. The speculative component of the real price of oil is identified with the help of data on oil inventories. Our estimates rule out explanations of the 2003–2008 oil price surge based on unexpectedly diminishing oil supplies and based on speculative trading. Instead, this surge was caused by unexpected increases in world oil consumption driven by the global business cycle. There is evidence, however, that speculative demand shifts played an important role during earlier oil price shock episodes including 1979, 1986 and 1990. Our analysis implies that additional regulation of oil markets would not have prevented the 2003–2008 oil price surge. We also show that, even after accounting for the role of inventories in smoothing oil consumption, our estimate of the short‐run price elasticity of oil demand is much higher than traditional estimates from dynamic models that do not account for for the endogeneity of the price of oil. Copyright © 2013 John Wiley & Sons, Ltd.     

Multilevel marketing: optimizing marketing effectiveness for high-involvement goods in the automotive industry

International Entrepreneurship and Management Journal - With a surge in communication channels increasing the complexity of today’s media landscape, companies face new challenges concerning...     

The effect of episodes of large capital inflows on domestic credit

This paper analyses the effect of capital inflow surges on the evolution of domestic credit. Using a panel of developed and emerging economies from 1970 to 2007, it is shown that in the two years following the beginning of a capital inflow surge the credit-to-GDP ratio increases by about 2 percentage points. The effect is reversed in the medium-term with the credit-to-GDP ratio decreased by almost 4 percentage points seven years after the initial surge. The paper also finds that the effect is different depending on the type of flows characterising the episode (debt vs. portfolio equity vs. FDI), with large capital inflows that are debt-driven having the largest effect. The results of the paper also suggest that the short-term effect of capital inflow surges on domestic credit depends on countries’ macroeconomic policy stances. In particular, it is found that this effect is lower in countries with higher real exchange rate flexibility and fiscal policy counter-cyclicality.