Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft

Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design.

The Inspection of Level Crossing Rails Using Guided Waves

Level crossing rails are high risk areas due to the combination of the limited effectiveness of current inspection methods and high corrosion rates which often exist.This paper discusses the current UK standard practices for the periodic inspection of level crossing rails using visual(VT)and conventional ultrasonic(UT)methods.The limitations of these methods are discussed and how these limitations affect the overall maintenance program for level crossings.A new inspection method,guided wave testing(GWT)is then described with particular emphasis on its advantages for inspecting level crossings.Finally,a review is given of the current Network Rail trial of GWT on level crossings using the G-Scan system,with representative results which demonstrate the effectiveness of GWT for this application.

Effects of Rare-earth and Microalloying Elements on the Microstructure Characteristics of Hypereutectoid Rails

We performed thermal simulation experiments of double-pass deformation of hypereutectoid rails with different microalloying elements at a cooling rate of 1℃/s and deformation of 80%to explore the influence of rare-earth and microalloying elements on the structure of hypereutectoid rails and optimize the composition design of hypereutectoid rails.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and other characterization techniques were employed to quantitatively analyzed the effects of different microalloying elements,including rare-earth elements,on pearlite lamellar spacing,cementite characteristics,and dislocation density.It was found that the lamellar spacing was reduced by adding various microalloying elements.Cementite lamellar thickness decreased with the refinement of pearlite lamellar spacing while the cementite content per unit volume increased.Local cementite spheroidization,dispersed in the ferrite matrix in granular form and thus playing the role of dispersion strengthening,was observed upon adding cerium(Ce).The contributions of dislocation density to the alloy strength of four steel sheet samples with and without the addition of nickel,Ce,and Ce–copper(Cu)composite were 26,27,32,and 37 MPa,respectively,indicating that the Ce–Cu composite had the highest dislocation strengthening effect.The Ce–Cu composite has played a meaningful role in the cementite characteristics and dislocation strengthening,which provides a theoretical basis for optimizing the composition design of hypereutectoid rails in actual production conditions.

Study on wear characteristics and authorized limits of switch rails of high-speed turnout

Purpose-It is quite universal for high-speed turnouts to be exposed to the wear of the stock rail of the switch rail during the service process.The wear will cause the change of railhead profile and the relative positions of the switch rail and the stock rail,which will directly affect the wheel-rail contact state and wheel load transition when a train passes the turnout and will further impose serious impacts on the safety and stability of train operation.The purpose of this paper is to provide suggestions for wear management of high-speed turnout.Design/methodology/approach-The actual wear characteristics of switch rails of high-speed turnouts in different guiding directions were studied based on the monitoring results on site;the authorized wear limits for the switch rails of high-speed turnout were studied through derailment risk analysis and switch rail strength analysis.Findings-The results show that:the major factor for the service life of a curved switch rail is the lateral wear.The wear characteristics of the curved switch rail of a facing turnout are significantly different from those of a trailing turnout.To be specific,the lateral wear of the curved switch rail mainly occurs in the narrower section at its front end for a trailing turnout,but in the wider section at its rear end when for a facing turnout.The maximum lateral wear of a dismounted switch rail from a trailing turnout is found on the 15-mm wide section and is 3.9 mm,which does not reach the specified limit of 6 mm.For comparison,the lateral wear of a dismounted switch rail from a facing turnout is found from the 35-mm wide section to the full-width section and is greater than 7.5 mm,which exceeds the specified limit.Based on this,in addition to meeting the requirements of maintenance rules,the allowed wear of switch rails of high-speed turnout shall be so that the dangerous area with a tangent angle of wheel profile smaller than 43.68 will not contact the switch rail when the wheel is lifted by 2 mm.Accordingly,the lateral wear limit at the 5-mm wide section of the curved switch rail shall be reduced from 6 mm(as specified)to 3.5 mm.Originality/value-The work in this paper is of reference significance to the research on the development law of rail wear in high-speed turnout area and the formulation of relevant standards.

Test and application of 60 kg·m^(−1) bainite rails for heavy-haul railway

Purpose-In order to develop high-strength,high-toughness and high-wear-resistance rails suitable for the development and application of heavy-haul railways.Design/methodology/approach-Based on the trial production of 60 kg·m^(−1) bainite rails,the Zeiss inverted optical microscope,transmission electron microscope and static hydraulic universal tester were used to test the microstructure and property of rail base metal and welded joints.Meanwhile,a trial laying of rails,wing rails of frogs and switch rails for turnouts was performed to systematically analyze their strength,toughness and wear resistance.Findings-The results show that the base metal of 60 kg·m^(−1) bainite rail is of a uniform microstructure,with a carbide-free bainite matrix,a few of stable residual austenite and M/A islands,and it features high hardness,good wear resistance and good strength-toughness balance.The welded joint is of a uniform microstructure and has good properties.Originality/value-A bainite rail,laid in a curve section of heavy-haul railway is able to serve for 48 months with a gross traffic tonnage of nearly 600 million tons,whose service life is more than one time longer than that of pearlite rail;the service life of the wing rail of frog and the switch rail for turnout with 60 kg·m^(−1) bainite rails is 3-4 times longer than that with U75V rails,and no serious damage occurs.The bainite rails also have strong peeling and spalling resistance.

RadRails

开发Rails应用需要写的代码非常少，Rails对代码的划分又很明晰，不管寻找、修改还是新写代码都可谓易如反掌，所以对IDE的依赖也就少了很多。笔者在习惯了用VI写Ruby程序（非Rails应用）之后，对IDE的挑剔就更是降到了最低。不过即便如此，最近一年多在几个不同的Ruby／Rails项目上工作，

Ruby On Rails在中医药数据共享平台的应用

Ruby on Rails(简称ROR)是一个Web应用程序框架,以其能快速开发而备受敏捷开发实践者的推崇,它包含的重要概念有MVC模式、DSL、习惯约定优于配置、生成器、低重复等.以一个实际课题"中医药数据库共享平台"为例,研究如何应用ROR技术来满足一个实际需求的项目,涉及的技术有MVC模式、RESTful SOA、AJAX、Lighttpd&FCGI等.

基于Rails的RESTful Web Service研究与实现

随着Web服务的快速发展,基于REST(Representational State Transfer)风格的Web Service越来越受到业界的关注。在实现RESTful Web Service的众多框架中,Rails完整实现了MVC并对RESTful Web Service的开发作了极大的封装和简化,使得开发人员用Rails实现RESTful Web Service变得容易。对RESTful Web Service特征和Rails框架结构进行了概述,分析了Rails实现RESTfulWeb Service的原理,在此基础上结合实例给出了基于Rails的RESTful Web Service以及RESTful Web Service客户端的开发步骤和方法,并且利用Ruby进行了实现。

基于Ajax on Rails的WebGIS应用

运用目前两种炙手可热的Web开发技术:AJAX和Ruby on Rails为WebGIS提供一个新的解决方案,AJAX技术作为一种新兴的网络技术比传统页面刷新模式具有更好的性能和友好的用户体验,不过在建立大量的Javascript的代码基础上的,本文通过对AJAX on Rails原理进行分析,运用Ruby on Rails的动态性和敏捷性使AJAX模式带来的程序量大、首页加载时间长的缺陷得到改善,进一步提高程序性能。在实现环节上,在该平台上结合使用Google Maps API,以GXmlHttp在Rails上实现了AJAX的WebGIS关键应用。

Ruby on Rails框架研究与应用

介绍了Rails平台,研究了Ruby on Rails架构拓扑,阐述了Ruby on Rails架构的原理和优势。

基于Rails和jQuery的Web应用程序敏捷开发

随着网络的日益普及,对电子商务和电子政务的需求日趋丰富,越来越多的企业和政府部门都希望将日常管理逐步信息化和网络化。在这种背景下,如何快速构建网页应用程序,以最短的时间,最少的投资,取得最好的效果,成为Web应用开发人员迫切希望解决的问题。本文提出了一种开发方法,用Rails框架快速开发web应用的功能,用jQuery完善Web应用界面,实现web应用程序的快速开发。

基于Ruby on Rails的粮食安全监测预警系统设计与实现

在分析了基于Ruby on Rails开发Web应用程序的优势基础上,设计出了粮食安全监测预警系统,并介绍了系统的总体设计和技术实现.通过系统给出的有效的、简明的预测结果来指导决策,防止粮食生产偏离正常发展轨道或出现危机.

一种新兴的Rails开发框架的应用研究

Rails是一个使web应用的开发、部署和维护变得更容易的新兴框架。通过与传统的WEB开发框架的比较,着重挖掘Rails框架的开发优势、核心体系结构及其关键技术,并通过在线购物系统原型(POSS)的具体开发实例,验证了在Ralis框架下开发应用的敏捷性、方便性等卓越的开发效率。同时,针对该框架下不支持中文显示和数据传输效率低等问题,给出了相应的解决方案。这些技术上的改进在一定程度上优化了Rails框架,对于促进该框架的推广和应用具有一定的实际意义。

Ruby on Rails与Struts+Hibernate架构之比较分析

Ruby on Rails是一个基于Ruby语言构建的全新Web应用程序架构,为Web应用程序开发提供了一种极其快捷的途径,正在和已经引起业界相当的兴趣.在给出了Ruby on Rails与轻量级J2EE架构Struts+Hibernate关键特性的基础上,从前端控制器、动作和模型,持久性框架三个方面对两种架构进行了比较.

一种在ruby on rails中图片上传与处理的方法

以SNS、BLOG等为代表的web2.0应用中,经常需要上传图片,而且要对图片进行缩放处理,得到缩略图。使用ruby on rails开发框架,通过attachment_Fu插件可以方便地实现所有这些功能。这大大提高了web应用的开发效率,符合用户对web2.0应用持续开发、持续改进、持续创新的要求。

基于Ruby on Rails的WEB开发新技术

新Web开发框架Ruby on Rails的迅速兴起引起了开发社区的关注,它大大提高了开发者开发可信赖的干净的应用程序的效率。本文分析了Web应用与开发领域的发展状况,将Rails的核心观念与传统框架进行对比,探讨其迅速流行与成功的原因及未来的前景。

一种复杂Rails系统架构优化方法

本文将介绍一种Rails系统架构优化方案，将复杂的Rails单一系统拆分成相互协作的多个轻量级应用集群，从根本上解决Rails系统在处理复杂的业务时代码臃肿、开发效率降低、难以维护与部署等问题。

无数据库模型在rails的form_for表单中的应用

rails的Active Model作为模型可以应用于不需要数据库存储数据的场合。经过定制,它可以很好地在form_for表单中工作。

用rails中的before_action简化身份验证

网站的身份验证代码很多时候都是重复的,并且和功能代码混杂在一起。用before_action则可以简化代码。

Rails2．0前瞻

随着RailS2．0 RC1的发布，Rails2．0开始离我们越来越近了。实际上，Rails2．0的基本功能在RC1中已经确定，因此我们也可以尽快地一睹Rails2．0的风采，了解新的特性，为以后的迁移做好准备。