石油化工机械设备安装施工常见问题与对策刍议

由于我国国民经济持续增长,对石油化工产品的需求量逐步上升,石油化工产业由此获得了巨大发展前景。石油化工在我国经济结构中处于十分关键的地位,石油化工行业是否良性运转,是否处于可持续发展的态势,最重要的是要拥有发达的石油化工机械。机械设备在石油化工生产中的作用十分关键,机械设备安装施工又是极为关键的部分。为保证我国石油化工行业的良性运转,机械设备需要在安全、稳定的环境下工作。因此,有必要针对机械设备安装施工工作进行分析与探讨,研究相关改进措施。

大站段体制下工务机械设备管理浅谈

铁路局直管段后,贵阳工务段管理线路长度由原来的100 km营运里程扩大到现在的800 km,维修作业主要采用机械化作业的新模式。在设备管理过程中,采用重视新设备应用、逐步完善设备管理制度、发挥车间的作用以及建立设备台账管理数据库等措施,提高了设备的利用率,节约了维修成本。

A new visco-elastic contact model of traveling wave ultrasonic motor with stator frictional layer

A new contact model of traveling wave ultrasonic motor （TWUSM） with a visco-elastic stator frictional layer was presented. In this model, the initial boundaries were revised, and the rotor revolution speed could he calculated iteratively. This model was compared with compliant slider and rigid stator model. The results of motor characteristics simulations showed that the motors based on this model would gain bigger stall torque. Then the friction and wear characteristics of two models were analyzed. The motors based on this model had lower coefficient of friction and better wear resistance.

Method of designing developable surface based on engineering requirement

The paper deals with the principle of envelope of a one-parameter plane family to design developable surfaces. Three methods of designing developable surfaces are presented. They are designing a developable surface based on one curve on it and its normal line, designing a developable surface based on two curves on it and designing a developable surface based on one curve and one surface. They meet the requirements of engineering fields.

Dynamic Bayesian Network Based Prognosis in Machining Processes

Condition based maintenance (CBM) is becoming more and more popular in equipment main-tenance. A prerequisite to widespread deployment of CBM technology and practice in industry is effective diagnostics and prognostics. A dynamic Bayesian network (DBN) based prognosis method was investigated to predict the remaining useful life (RUL) for an equipment. First, a DBN based prognosis framework and specific steps for building a DBN based prognosis model were presented. Then, the corresponding inference algorithms for DBN based prognosis were provided. Finally, a prognosis procedure based on particle filtering algorithms was used to predict the RUL of drill-bits of a vertical drilling machine, which is commonly used in industrial process. Preliminary experimental results are promising.

Clarification of abrasive jet precision finishing with wheel as restraint mechanisms and experimental verification

According to the critical size ratio for the characteristic particle size to film thickness between grinding wheel and work, the machining mechanisms in abrasive jet precision finishing with grinding wheel as restraint can be categorized into four states, namely, two-body lapping, three-body polishing, abrasive jet machining and fluid hydrodynamic shear stress machining. The critical transition condition of two-body lapping to three-body polishing was analyzed. The single abrasive material removal models of two-body lapping, three-body polishing, abrasive jet finishing and fluid hydrodynamic shear stress machining were proposed. Experiments were performed in the refited plane grinding machine for theoretical modes verification. It was found that experimental results agreed with academic modes and the modes validity was verified.

An Expert System Based on Multi-reasoning Mechanism for Port Machine Diagnosis

Expert system plays an important role in port machine diagnosis, which aims at automatic equipment test for higher availability and efficiency of port operations. In this study, a port machine diagnosis expert system is proposed based on multi-reasoning mechanism. Relying on the knowledge acquired from the experienced experts in the port machine engineering, the system builds a library of relative experience and a set of rules of reasoning and estimating. Multi-reasoning mechanism that simulates the decision-making process of domain experts is employed to achieve reliable diagnosis results. The reasoning machine integrates artificial neural network, uncertain decision making and decision tree, which complements each other by sustainable growing voting mechanism. The effect of this multi-reasoning mechanism is evaluated and validated by means of Matthew＇s Correlation Coefficient （MCC）. The system incorporating the mechanism is successfully designed, implemented and applied in Shanghai Port.

Four driving forces for the advance of dyeing and printing equipment

The year of 2017 saw an obvious improvement in the sector of China’s textile machinery industry and an increase of the main business income and gross profit.Besides,foreign trade in textile machinery products grew in number.

Application of Transfer Learningin Mechanical Equipment Intelligent Diagnosis:Literature Review

Accelerating the process of intelligent manufacturing and the demand for new industrial productivity,the operating conditions of machinery and equipment have become ever more severe.As an important link to ensure the stable operation of the production process,the condition monitoring and fault diagnosis of equipment have become equally important.The fault diagnosis of equipment in actual production is often challenged by variable working conditions,large differences in data distribution,and lack of labeled samples,etc.Traditional fault diagnosis methods are often difficult to achieve ideal results in these complex environments.Transfer learning(TL)as an emerging technology can effectively utilize existing knowledge and data to improve the diagnostic performance.Firstly,this paper analyzes the trend of mechanical equipment fault diagnosis and explains the basic concept of TL.Then TL based on parameters,TL based on features,TL based on instances and domain adaptive(DA)methods are summarized and analyzed in terms of existing TL methods.Finally,the problems faced in the current TL research are summarized and the future development trend is pointed out.This review aims to help researchers in related fields understand the latest progress of TL and promote the application and development of TL in mechanical equipment diagnosis.

Artificial molecular machines that can perform work

An artificial molecular machine consists of molecule or substituent components jointed together in a specific way so that their mutual displacements could be initiated using appropriate outside stimuli. Such an ability of performing mechanical motions by consuming external energy has endowed these tiny machines with vast fascinating potential applications in areas such as actuators, manipulating atoms/molecules, drug delivery, molecular electronic devices, etc. To date, although vast kinds of molecular machine archetypes have been synthesized in facile ways, they are inclined to be defined as switches but not true machines in most cases because no useful work has been done during a working cycle. More efforts need to be devoted on the utilization and amplification of the nanoscale mechanical motions among synthetic molecular machines to accomplish useful tasks. Here we highlight some of the recent advances relating to molecular machines that can perform work on different length scales, ranging from microscopic levels to macroscopic ones.