主箕斗井提升设备大件起吊运输方案及实施

为了将提升设备大件起吊运输到安装现场,从方案比较到起吊受力分析,起吊索具车辆的选择,由于前期工作准备充分,最后顺利将提升设备大件起吊运输到安装现场。     

用独角拔杆起吊厂房主梁

详细介绍采用独角拔杆起吊厂房主梁的实施方法，并校核各起吊用具，方法实用、有效。     

八钢70t电炉厂房屋顶罩吊装方案的确定及实施

介绍了大型薄壳钢结构起吊方案及机具选定和起吊过程中问题的处理。     

基于Solid Works混铁炉箍圈起吊点的确定

利用Solid Works软件确定600t混铁炉中偏心箍圈的重心,进而根据力学知识分析确定起吊点位置。起吊点的合理选择,提高了生产效率,增加了生产制作的可靠性、安全性。     

浓缩机中心支架起吊检修方法探讨

文章就浓缩机中心支架的起吊检修方法进行分析，对生产实践中五种常见的检修方法进行比较，并推荐常规下既安全可靠又经济实用的一种起吊方法。     

一种新型吊具——内爪吊

本文介绍了一种新型的吊具－内爪吊，它是一种专用吊具，适用于起吊盘状物件。其特点是，内爪吊内起重机吊钩的升降来操作，通过内爪吊的杆系相互动作，来完成对物件的夹住，起吊和卸下。从而解决了常用吊具必须人工挂钩与脱钩这一难题。     

提高起重机工作可靠性的途径

桥式起重机在冶金企业承担着重要而繁忙的起吊任务,提高起重机工作的可靠性具有重要意义。     

双逆变变频调速技术在桥式起重机上的研究与应用

本文主要介绍了双逆变变频调速技术原理及在桥式起重机起吊电机控制系统的应用情况和效果。     

新型钢丝绳滴油润滑系统

<正>钢丝绳是起重设备不可缺少的重要零部件,也是设备的薄弱环节,使用中如果维护不足,就容易导致钢丝锈蚀、麻芯腐烂、油脂脱落或龟裂,以及内外部磨损,最终导致钢丝绳早期失效破坏,特别是在起吊重物时有钢丝绳绷断危险,造成起吊货物的损坏及其他损失与伤害。所以定期对钢丝绳进行润滑和清洁是非常重要的。目前,柳钢转炉炼钢厂起重机的卷筒和钢丝绳设备,采用传统手动人工上润滑油方式,     

一种移出铸坯的设备

正美国专利US8800636本发明提供了一种用于在铸造后移出铸铝坯料的设置。该设置包括一个有抓取装置的起吊设置和一个斜坡从铸坑延伸延至运输设置。起吊设置最好包括一个U形吊架,吊架由支柱和连接横梁组成。每根支柱都支撑在它自己的轮式底盘或者带轮小车上,连接横梁与支柱相连接是为了提高U形框架的强度。     

Construction of a Horizontally Curved Steel I-Girder Bridge. Part I: Erection Sequence

In the case of horizontally curved steel I-girder bridges, girder and cross-frame members are frequently detailed for erection in the no-load condition as a matter of convention. As a result, it is imperative that the erection sequence used to construct such bridges be comprehensively studied to ensure that the no-load condition can be achieved in the field and that significant superstructure component fit-up problems do not occur. The current research investigates the erection of a recently constructed horizontally curved steel I-girder bridge, in which significant difficulties were encountered during erection. The bridge erection is recreated through an analytical simulation using a detailed nonlinear finite element model. The analytical results demonstrate that a condition that closely resembles the no-load condition can be achieved in the field during construction with the proper implementation of temporary support structures; and that the difficulties encountered during the erection of the subject bridge superstructure could not be attributed to the erection scheme followed.     

The physiology of erection

The majority of contemporary knowledge on the physiology of erection was assembled during the past thirty years. Today we consider erection as a multifactorial process. Mechanically it can be compared to an electromechanically controlled hydraulic system. Its function is conditioned by a number of mutually coordinated processes. As to nervous processes they include autonomous (parasympathetic and sympathetic) innervation, as well as somatic innervation (sensory and motor pathways). The control function is exerted by spinal as well as cerebral centres. As to mediators, in particular acetylcholine, nitrous oxide (NO) released from the endothelium are involved, noradrenaline, VIP (vasoactive intestinal polypeptide), CGRP (calcitonin gene-related peptide) and prostaglandins. The most important roles in the phase of erection are played by nitrous oxide and VIP. Erection can be either reflex erection, psychogenic or nocturnal or morning. It usually takes place in six stages (at rest, latent, the tumescence stage, complete erection, rigid erection and subsequently the stage of detumescence). Except for neurohumoral mechanisms an essential prerequisite for the development of erection are the arterial supply of the genital and the so-called venoocclusive mechanism. Erection takes the following course (simplified): erotogenic stimuli lead to the stimulation of the parasympathetic nerve-->vasodilating substances are released-->the s inusoids are filled with blood (tumescence stage)-->the venoocclusive mechanism starts to work: thus complete erection occurs. Then the contractions of the musculature of the perineum compress the proximal portions of the corpora cavernosa: this leads to rigid erection. Detumescence which occurs as a rule after ejaculation) is due to released noradrenaline (active stage) and the reduced tonus of the smooth muscles of the blood vessels (released endothelin and neuropeptide Y). Knowledge of the physiological mechanisms of erection made clinical diagnosis of their disorders and successful treatment of some forms of impotence possible.     

Bridge Falsework Productivity—Measurement and Influences

One principal element of the construction cost of a cast-in-place prestressed box girder concrete bridge is the erection of falsework. This paper presents the results of the analysis of labor-hours and quantity of work in erecting the falsework for 20 such bridges. Analysis of the bridge data has shown that the best productivity for falsework erection occurs when constructing a low structure on relatively flat ground. Location and design factors such as steep slopes, traffic openings, and tall structures, as well as such construction techniques as the use of cranes or lifts and the type of bent material selected, can reduce falsework erection productivity (measured through installation data for setting of pads, constructing bents, setting stringers, and rolling out the soffit) by over 50%. A belief network diagram was constructed to show graphically the falsework erection productivity influences identified through a study of the 20 bridges. With the collection of additional data, the belief network can be used to calculate a total falsework erection productivity value based on dozens of combinations of influencing factors.     

The erection pill

The introduction of sildenafil (Viagra) for the treatment of erection disorders has received much international attention. In the USA the prevalence of severe erection disorder amounts to 10% for men aged 40-70 years, which is much higher than was expected, in the Netherlands as well. This is probably due to embarassment with the condition and the absence of simple treatment. With the advent of sildenafil the problem of erection disorder is now openly discussed. An interview investigation in Leiden, the Netherlands, showed that two-thirds of men with erection problems (n = 200) who volunteered to participate in a relevant study, had consulted to a physician before; one-third of the volunteers were interested in using an erection pill, one-third also in other treatments, and one-third wanted to be treated by any method. These figures indicate that most men already take their problem seriously. As age is the main contributing factor to erection disorder, the safety of sildenafil in the elderly is a point of concern. Nitrate use is an absolute contraindication, poor cardiovascular condition is a relative contraindication. Sildenafil will probably become the drug of choice for the treatment of erection disorder. It constitutes a major step forward.     

Erection of Cable-Stayed Bridges Having Composite Decks with Precast Concrete Slabs

For the construction of composite steel-concrete decks of cable-stayed bridges, methods of erection and analysis have to be applied that, upon completion of the deck, accurately yield the prescribed dead load configuration of the deck regarding geometry and forces. During deck erection, no unwanted bending moments should be locked into the composite sections when the concrete slab is connected to the steel substructure. Such locked-in moments would bend the deck, cause concrete creep that is difficult to predict, and introduce the risk of deviations from the desired deck alignment and the corresponding distribution of forces. This paper presents a simple and practical method of erection and erection analysis for composite decks with precast concrete slabs. A two-step tensioning procedure of the stay cables is proposed that minimizes the effects of unwanted locked-in moments, making it easy to predict the geometry of the erection stages and to yield the desired dead load configuration of the deck. The method was successfully applied for the erection of the Ting Kau bridge in Hong Kong, a cable-stayed bridge of 1,200 m in length having a composite deck with a precast deck slab.     

Engineering the Tower and Main Span Construction of Stonecutters Bridge

Stonecutters Bridge is the second longest cable-stayed bridge in the world and the first major bridge with a twin-box girder superstructure. It has a number of innovative structural features which made the construction of the bridge a significant challenge. This paper describes the fabrication and erection procedures for the bridge towers and the main span superstructure. These were developed in close interaction between the contractor and his construction engineering consultant to ensure a safe and effective construction. A stage-by-stage analysis was set up to model every step of the main span erection. The results were first used in the verification analyses to establish the adequacy of the permanent works throughout construction. In parallel, extensive wind tunnel testing as well as numerical analyses were performed to ascertain the effects of typhoon wind loads on the structure. The structural deformations predicted by the erection analysis were incorporated into a comprehensive geometric control procedure. This paper describes the construction methodologies developed and the related engineering input. It outlines studies undertaken to achieve an effective construction, ensure structural adequacy of all erection stages, ascertain an acceptable aerodynamic performance of the bridge, and exercise full control over the bridge geometry throughout erection.     

Steel Girder Stability during Bridge Erection: AASHTO LRFD Check on L/b Ratios

The erection of steel plate girders during the construction process of a steel bridge is a complex operation, which is often left to the contractor and/or the subcontractor to plan and execute. Rules of thumb have been developed through experience to check the lateral torsional buckling of the steel girder during erection using the maximum L/b (unbraced length/compressive flange width) ratio, below which no lateral torsional buckling would occur. Although the L/b ratio check has proven to be useful and convenient on-site, it is necessary to provide a more rational basis for the rules of thumb, and find the maximum L/b ratios by checking the lateral torsional buckling failure of girders under erection according to the latest AASHTO LRFD code. A series of parametric studies were conducted on cantilever and simply supported girders under self-weight as well as self-weight plus wind load, in order to: (1) check the rules of thumb on L/b ratios and (2) determine the effects of girder flange width, flange thickness, web depth, web thickness, and yield strength on the maximum L/b ratio and girder stability during erection. From the results, rules of thumb were modified for girders with common shapes, and it was obvious that (1) self-weight plus wind load controls the girder stability during erection in most cases and (2) flange width and web depth have the most effects on the maximum L/b ratio and girder stability during erection.     

可逆轧机测速问题与对策

结合电气安装，调试工作实践，对速度检测在轧机生产中的意义，有关直流测速发电机在测速方面存在的总是和要求及其在安装、等方面所采取的对策进行了论述，并对轧机自动控制系统的相关技术的发展作了概述。     

Construction of a Horizontally Curved Steel I-Girder Bridge. Part II: Inconsistent Detailing

The erection of horizontally curved steel I-girder bridges tends to be more complex than the erection of straight steel I-girder bridges. The erection of a curved steel I-girder bridge can be further complicated when the cross-frame members and girders are detailed inconsistently in an effort to force bridge components into some desirable geometric condition. Inconsistent detailing involves the intentional specification of cross-frame members that are either too long or too short to align with girder connector plates properly so as to force the girders into a given position, resulting in connection misalignments that must be resolved by applying external forces to the bridge components. The current research investigates the erection of a recently constructed horizontally curved steel I-girder bridge and highlights the fact that practice of inconsistent detailing can lead to very formidable and costly fit-up problems in the field; especially when girder sizes are large.     

Systematic control of claw health in cows raised in loose housing systems for the total year

This study was designed to investigate whether experimental diabetes in rats could functionally affect reflexogenic erection. Erection was elicited by means of electrical stimulation of the dorsal nerves of the penis and recorded as intracorporeal pressure. Rats were examined 1, 3 and 6 months after diabetes induction by streptozotocin. Three and 6 month diabetes caused a significant decrease of latency for erection and a slower phase of detumescence when compared to age-matched controls. In addition, a trend for a lower developed intracorporeal pressure was present in the 6 month diabetes group. Our results indicate that experimental diabetes is associated with alterations of reflexogenic erection.