非标准设备制作工程造价计算方法探讨

分析比较了现有4种非标准设备评估方法，在成本估算法的基础上，提出一套适用于非标准设备制作工程造价的计算方法，并介绍了其计算程序，指出此法准确度高，计算简便，应用面广。     

Quantitative study of the effect of electromagnetic field on scale deposition on nanofiltration membranes via UTDR

Ultrasonic time-domain reflectometry (UTDR) as an in situ, non-invasive real-time technique has been successfully utilized to quantify membrane fouling and cleaning. This study describes an existing ultrasonic technique for quantitative study of the effect of magnetic fields on CaCO₃ scale deposition on the membrane surface during crossflow nanofiltration (NF). The fouling experiments were conducted with CaCO₃ solution containing Ca²⁺ of 1.8 and 3 mmol/L. The experimental electromagnetic field (EMF) was 0.02 T. A commercial NF membrane and a highly sensitive ultrasonic sensor were used in all the experiments. Results show a good relationship between the ultrasonic measurements and the development of CaCO₃ scale on the NF membrane surface. An increase in the amplitude of differential signal with operation time results from the deposition of the CaCO₃ scale layer. In addition, the movement of the differential signal in the time domain observed is associated with an increase in the thickness of the fouling layer. The UTDR technique is capable of measuring the rate of fouling layer formation under different treatment conditions, i.e. with non-magnetic field (NMF) and EMF. Scale layer of deposited CaCO₃ obtained in the experiment with NMF is denser and thicker than that with EMF. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses imply that the magnetic treatment suppresses the formation of calcite crystals and prefers vaterite and aragonite. Furthermore, the ultrasonic technique is sensitive to the different fouling rate between experiments carried out with 1.8 and 3 mmol/L CaCO₃ solutions. The thickness of the fouling layer measured by weight measurement is consistent with that obtained by UTDR in real time. The thinner and less dense scale layer is the main reason for the slower flux decline. Overall, independent measurements such as the flux-decline data, SEM analysis and weight measurement corroborate the ultrasonic measurements.     

Enzymatic biosensor for nitrite detection based on direct electron transfer by CPO-ILEMB/Au@MoS2/GC

Journal of Applied Electrochemistry - A novel nitrite electrochemical biosensor is constructed by glassy carbon electrodes (GC) coated by chloroperoxidase (CPO) -Au nanoparticles-MoS2 nanoflowers...     

Evaluation of grinding wheel loading phenomena by using acoustic emission signals

In the industrial manufacturing field, machining is a major process. Machining operations involve grinding, drilling, milling, turning, pressing, molding, and so on. Among these operations, grinding is the most precise and complicated process. The surface condition of the grinding wheel plays an important role in grinding performance, and the identification of grinding wheel loading phenomena during the grinding process is critical. Accordingly, this present study describes a measurement method based on the acoustic emission (AE) technique to characterize the loading phenomena of a Si₂O₃ grinding wheel for the grinding mass production process. The proposed measurement method combines the process-integrated measurement of AE signals, offline digital image processing, and surface roughness measurement of the ground workpieces for the evaluation of grinding wheel loading phenomena. The experimental results show that the proposed measurement method provides a quantitative index from the AE signals to evaluate the grinding wheel loading phenomena online for the grinding mass production process, and this quantitative index is determined via some experiments in advance in the same grinding environment to help the monitoring and controlling of the grinding process.     

Triangulated surface flattening based on the physical shell model

Journal of Mechanical Science and Technology - Triangulated surface flattening plays an important role in the surface shape design of a complex product, such as a vehicle, a train and an air plane....     

Woodchip-sulfur packed biological permeable reactive barrier for mixotrophic vanadium (V) detoxification in groundwater

Science China Technological Sciences - Groundwater vanadium (V) (V(V)) contamination is ubiquitous in vanadium mining/smelting region and development of novel strategy for its remediation is of...     

COUPLING MODEL OF TWO PHASE FLOW IN A FRACTURE-ROCK MATRIX SYSTEM AND ITS STOCHASTIC FEATURE ANALYSIS

This study is concerned with developing a two-dimensional two-phase model thatsimulate the movement of non-aqueous phase liquid (NAPL) in a fracture-rock matrix system. Theintrinsic permeability and the fracture aperture are represented in the model via its Karhunen-Loeve expansion. Other parameters and the nodal unknowns, water saturations and waterpressures, are represented by their stochastic spectral expanions. The errors resulting fromtruncation of Karhunen - Loeve and polynomial chaos expansions to a finite number of terms areanalyzed. The eigenvalues of stochastic process is found out for any point in the special domain ofthe problem at any instant in time.     

多功能结构在固体火箭上的应用分析

为实现固体火箭轻质化设计,采用传统机械结构优化的方法能力十分有限。多功能结构优化设计方法,由于采用机、电、热一体化的系统工程级设计思路,为提升火箭整体性能开辟了一个全新的方向。介绍多功能结构设计方法及思路,结合一种新型箭载记录设备原型样机的研制,对多功能结构在固体火箭领域应用的前景进行深入探讨。     

计算机采掘计划自动编制系统的研究

在矿山采掘计划的编制中，需要考虑的相关因素很多，资源数据复杂，涉及面广，因此难以用人工实现这样复杂的计划编制工作，必须借助于现代计算机技术来完成。本文论述了采掘计划计算机编制系统的设计目标，基本结构与功能及所采用的数学模型。实际应用表明，该系统设计合理，运行稳定可靠，能满足矿山实际生产需要。     

矿山生产调度计算机多目标决策模型的研究

由于采矿工艺自身的特殊性,致使矿山企业的生产调度决策采用一般单目标规划模型很难满足要求,因此,必须采用多目标决策模型才能合理地解决这一问题。多目标规划方法是单目标方法的新发展,它将单目标规划下的绝对约束改变成非绝对函数目标,并按优先等级,不同程度地予以满足,因而它总能找到一个最优解。矿山生产调度模型的建立,除了必须遵循一般的步骤以外,还必须充分了解和掌握不同采矿方法的工艺要求,以便从中提取工艺要求控制变量,并确定其优先级别,建立指标偏离函数。