智能化节水水表设计

介绍了一种基于AT89S51单片机为控制核心的智能化节水水表的设计结构、功能、特性,阐述了水表测量电路、功能电路、储存电路、LCD显示电路和语音报警电路等硬件电路与软件流程的设计。

基于NB-IoT技术的物联网水表设计应用探讨

NB-IoT技术(窄带物联网技术),是当前智慧城市的核心技术,在水表设计领域展现出无与伦比的贡献和作用。本文基于NB-IoT技术的物联网水表设计应用为主要研究对象,针对NB-IoT技术的发展以及物联网水表的功能设计、系统设计、内容设计进行多角度、广范围、深层次的探索和剖析,围绕物联网水表的设计思想进行论述,为现代物联网水表的深入发展和有效拓展给予力所能及地帮助和支持。仅供参考。

基于ANSYS的水表塑料壳体应力分析及优化设计

应用ANSYS Workbench软件对水表塑料壳体的应力进行了模拟分析。对基础壳体进行分析,确定其应力情况,不断改进壳体中各个细节;挑选形变、应力较大的位置进行结构优化仿真计算,分析其应力变化,得出最佳修改方案,进而对实际壳体进行改进。耐压试验的结果表明,仿真值与实际试验值基本吻合,且整体变化趋势保持一致,强度完全优于基础壳体。数值模拟作为结构设计及优化的一种手段是切实可行的,能保证塑壳件在更加恶劣条件下依旧能够正常工作。

低功耗智能网络水表的设计

为实现远程自动计量用水量,提高水资源管理工作的效率和科学化水平,设计了一种集计量、计费、显示、管理及控制于一体的新型智能网络水表。通过网络通信技术与集中器、管理计算机联网,构成多功能低功耗用水量远程抄表系统。重点分析并阐述了以低功耗为出发点的智能网络水表的硬件及软件设计。

水表新产品快速试样技术的探索

对当前水表新产品的设计与样机试制工作中存在着诸如开发周期长、开发效率低、人工参与多等现状,提出了基于计算机辅助设计与仿真、虚拟装配与优化、快速加工与测量为主体的水表新产品、快速试样技术的观点和方法。

Optimal design of nanofiltration system for surface water treatment

Both reverse osmosis(RO) and nanofiltration(NF) membranes have been increasingly used for water purification and desalination. However, the salt rejection of NF membranes is quite different from that of RO membranes,which makes a significant distinction in their process designs. This work started from the performance investigation of a single NF membrane element and then focused on the process design of the NF system for surface water treatment. In experimental tests, it was found that the observed rejection of the NF element becomes nearly constant when the concentrate flow is large enough, while the membrane flux of the NF element is quite stable regardless of the water flow across the membrane surface. These findings can be used to instruct the process design of the NF system for surface water treatment. In process design, a two-stage arrangement is sufficient for the NF system to reach the highest water recovery, while the RO system requires a three-stage arrangement.

Synthesis of epichlorohydrin from 1,3-dichloropropanol using solid base

In this work, the synthesis of epichlorohydrin(ECH) from 1,3-dichloropropanol(DCP) by using solid sodium hydroxide(NaOH) is carefully investigated. Inert organic solvent, 1-octanol, is introduced to ensure reaction intensity under control. The reaction performances with respect to apparent kinetics and selectivity are determined to explore optimized reaction conditions and confirm potentials for enhancing productivity in one batch. The dissolution and liquid phase reaction mechanism and instant reaction assumption are proposed and verified through process analysis. A process design towards free additional water is schematically figured out to manipulate solid NaOH, by-product,and unreacted starting materials to realize a nearly closed circuit. This process allows high selectivity over 97% and complete DCP conversion at 323.2 K within a reaction time less than 20 min. Other advantages include near-zero wastewater emission, economically possible NaOH regeneration from NaCl, and robust operating condition window.

A Study on Effects of Blade Pitch on the Hydrodynamic Performances of a Propeller by Using CFD

The main objective of this work is to use the CFD （Computational Fluid Dynamics） technique to study the effects of pitch ratio on the controllable pitch propeller＇s thrust characteristic. The propeller analyzed is at the following design condition： diameter of 3.65 m, speed of 200 rpm, blade number of 4, average pitch of 2.459 m, pitch ratio at 0.7 of 0.6737. The first stage involves the mesh generation and refinement on domain of the designed propeller. The second stage deals with the identification of initial and boundary conditions of the mesh-equipped module. In the final stage, various results are calculated and analyzed for pitch ratio affecting on the propeller＇s thrust characteristic. The achieved results are the basis design and improving efficiency of the controllable pitch propeller.

水表出户设计与设备选择中的有关问题

一、户外查表是对现代住宅设计的基本要求在国外的经济发达国家和地区,一般都不需要供水、供电、进气等有关管理人员进入居民住所去核查水、电、煤气的用量。而在国内目前入户查抄水表和煤气表仍是普遍现象。

Numerical simulation of effect of bionic V-riblet non-smooth surface on tire anti-hydroplaning

Inspired by the idea that bionic non-smooth surfaces(BNSS) can reduce fluid adhesion and resistance, and the effect of bionic V-riblet non-smooth structure arranged in tire tread pattern grooves surface on anti-hydroplaning performance was investigated by using computational fluid dynamics(CFD). The physical model of the object(model of V-riblet surface distribution, hydroplaning model) and SST k-ω turbulence model were established for numerical analysis of tire hydroplaning. With the help of a orthogonal table L16(45), the parameters of V-riblet structure design compared to the smooth structure were analyzed, and obtained the priority level of the experimental factors as well as the best combination within the scope of the experiment. The simulation results show that V-riblet structure can reduce water flow resistance by disturbing the eddy movement in boundary layers. Then, the preferred type of V-riblet non-smooth structure was arranged on the bottom of tire grooves for hydroplaning performance analysis. The results show that bionic V-riblet non-smooth structure can effectively increase hydroplaning velocity and improve tire anti-hydroplaning performance. Bionic design of tire tread pattern grooves is a good way to promote anti-hydroplaning performance without increasing additional groove space, so that tire grip performance and roll noise are avoided due to grooves space enlargement.

The Effect of Priming on Seed Performance of Chickpea （Cicer arietinum L.） under Drought Stress

In order to investigate the effect of priming on Chickpea seed performance under drought stress, a study was carried out at the Seed Research Laboratory of Razi University, Kermanshah, Iran. The experiment was a factorial with three factors arranged in a completely randomized design with four replications. The first factor was seed priming （control （untreated）, HB-101 （Completely organic herbal extracts, derived from the bark of dark cones）, KNO3 and distilled water）, the second was drought stress levels （0.0, -0.3, -0.6, -0.9, -1.2 MPa） and the third was chickpea cultivars （Arman and Azar）. Results indicated that for both cultivars germination percentage （GP）, mean germination rate （MGR）, radicle length （RL）, plumule length （PL） and seedling dry weight （SDW） were reduced when drought stress level were increased from 0 to -!.2 Mpa, although, the cultivars showed different responses to the increased drought stress level. For all of the traits under study, the best results due to the priming treatments were obtained at the drought stress levels higher than -0.6 or -0.9 MPa. So that, at the -1.2 MPa of drought stress level, GP, MGR, and SDW were increased 53.75, 0.49, and 13.85, respectively by HB -101 when compared with control. However, seeds primed with HB-101 showed better performance than those primed with distilled water and KNO3. In general, this study revealed that seed priming especially with HB-101 improved chickpea seed performance under drought stress condition. However, the improvements were more obvious at the higher levels of drought stress.

Analytical expressions for determining the stability of cohesionless soil slope under generalized seismic conditions

In recent major earthquakes, the researchers have found the need for consideration of vertical seismic acceleration for the stability analysis of the man-made and natural slopes. However, in most past studies, the performance of slopes has been assessed by accounting only the horizontal seismic component of the ground motion, without giving due weightage to the effect of vertical component. In the present study, analytical expressions are derived to determine the factor of safety, yield seismic coefficient and consequently the seismic displacement of cohesionless soil slope under combined horizontal and vertical components of the ground motion. The derivation uses the Newmark's sliding block approach, in which the soil slope with a planar failure surface within the framework of conventional pseudo-static analysis is assumed to follow the Mohr-Coulomb failure criterion. The effects of vertical seismic coefficient on the stability of cohesionless slope have been studied through a set of graphical presentations for a specific range of soil parameters. It is observed that overlooking the effect of the vertical component of the ground motion on factor of safety and the displacement while designing the slope may be detrimental, resulting in the slope failure. The general expressions presented in this paper may be highly useful in the field of earthquake geotechnical engineering practice for designing the cohesionless soil slopes under combined horizontal and vertical seismic loads.

The Drainage Exchange of Stormwater Potential in Flat Area Problems

Groundwater as an alternative source still does not contribute to the water supply in area of Parit Raja because of the limitation of water availability in the ground. This lacking of groundwater could be caused by the circumstance that the top layer of soil is dominated by compacted clay around 2 meters in which its permeability is small, so the water is difficult to infiltrate the ground. The recharge well technique was designed based on the flat area problems, layer of real condition, flow water table and low infiltration rate. Resistivity soundings were made at existing wells to assess the subsurface layers. Beside that, the past records on floods event, sub surface and surface studies were collected around study area as a preliminary studies. It was presented that the study area promised good prospects to increase the capability of groundwater and contribute to the drainage system by reducing the volume of rainfall runoff using the recharge well technique.

关于几个水表术语的理解

GB/T778.1-2018《饮用冷水水表和热水水表第1部分:量值要求和技术要求》、JJG162-2019《饮用冷水水表检定规程》和JJF1777-2019《饮用冷水水表型式评价大纲》不仅规范了水表行业的专业名词解释,而且给出了影响水表性能的主要因素的定义。本文从影响水表流量性能的几个主要定义出发,实验验证和通俗化归纳相结合,重新对其梳理,方便大家更深刻地理解,从而为从事水表设计研发、生产、检定、选型、施工和维保的相关人员提供一种参考。

A new variational inequality formulation for unconfined seepage flow through fracture networks

Darcy's law only applying to the flow domain is extended to the entire fracture network domain including the dry domain.The partial differential equation(PDE) formulation for unconfined seepage flow problems for discrete fracture network is established,in which a boundary condition of Signorini's type is prescribed over the potential seepage surfaces.In order to reduce the difficulty in selecting trial functions,a new variational inequality formulation is presented and mathematically proved to be equivalent to the PDE formulation.The numerical procedure based on the VI formulation is proposed and the corresponding algorithm has been developed.Since a continuous penalized Heaviside function is introduced to replace a jump function in finite element analysis,oscillation of numerical integration for facture elements cut by the free surface is eliminated and stability of numerical solution is assured.The numerical results from two typical examples demonstrate,on the one hand the effectiveness and robustness of the proposed method,and on the other hand the capability of predicting main seepage pathways in fractured rocks and flow rates out of the drainage system,which is very important for performance assessments and design optimization of complex drainage system.

In-situ electrochemical activation designed hybrid electrocatalysts for water electrolysis

Developing transition metal-based electrocatalysts with rich active sites for water electrolysis plays important roles in renewable energy fields. So far, some strategies including designing nanostructures, incorporating conductive support or foreign elements have been adopted to develop efficient electrocat- alysts. Herein, we summarize recent progresses and propose in-situ electrochemical activation as a new pretreating technique for enhanced catalytic performances. The activation techniques mainly comprise facile electrochemical processes such as anodic oxidation, cathodic reduction, etching, lithium-assisted tuning and counter electrode electro-dissolution. During these electrochemicaI treatments, the catalyst surfaces are modified from bulk phase, which can tune local electronic structures, create more active spe- cies. enlarge surface area and thus improve the catalytic performances. Meanwhile, this technique can couple the atomic, electronic structures with electrocatalysis mechanisms for water splitting. Compared to traditional chemical treatment, the in-situ electrochemical activation techniques have superior advantages such as facile operation, mild environment, variable control, high efficiency and flex- ibility. This review may provide guidance for improving water electrolysis efficiencies and hold promis- ing for application in many other energy-conversion fields such as supercapacitors, fuel cells and batteries.