Densities and Viscosities of Oleic Acid at Atmospheric Pressure

The densities of oleic acid were measured over the temperature range from (293 to 459) K at atmospheric pressure using a densimeter based on the modified hydrostatic weighing method. The dynamic viscosities of the same oleic acid sample were measured using a capillary viscometer (VPZ-2 m) in the range from (293 to 363) K at atmospheric pressure. The combined expanded uncertainty of the density, atmospheric pressure, viscosity, and temperature measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15%, 1.0%, 3.5%, and 15 mK, respectively. The values of uncertainty for density and viscosity include the effects of purity and calibration (total expanded uncertainty). These experimental data were used to develop wide-range correlations for the density and viscosity based on theoretically confirmed Arrhenius–Andrade and Vogel-Tamman-Fulcher (VTF) models. The value of the glass temperature ( T _g= 179.78 K.) for the oleic acid was estimated using the VTF parameters derived from the present viscosity measurements. To additionally validate the reliability of the measured density data, the same oleic acid samples were measured using the pycnometric method. The present study showed that the densities measured using the modified hydrostatic weighing densimeter (HWD) agree with the values obtained using the pycnometric method within 0.09% for Sample 1 and 0.25% for Sample 2.     

基于PLC实现矿山计量称重自动化控制的改进措施

对矿山计量箕斗的PLC自动化控制提出相关改进措施，实现称重校准，并在实际应用过程中不断完善措施，方便工人操作，减少设备维护量，对提高产量和生产效益核算的准确度具有重要意义。     

Determination of protoberberine alkaloids in Coptidis Rhizoma by novel extraction and high-performance liquid chromatography

An alternative, effective, and solvent-free microextraction method has been developed using weighing paper as the adsorbent for five protoberberine alkaloids from the methanolic extract of Coptidis Rhizoma (C. Rhizoma). Several variables influencing extraction efficiency were optimized. 1.0?×?1.0?cm glassine weighing paper was employed for the isolation of the analytes followed by high-performance liquid chromatography. Under the optimum conditions, the limits of detection were between 0.2 and 0.4?ng/mL with enrichment factors from 41–47. The calibration curves were linear across the concentration ranges examined with correlation coefficients exceeding 0.992. All relative standard deviations were less than 10.0%. The method was employed for the determination of the analytes in C. Rhizoma. Berberine, palmatine, coptisine, epiberberine, and jatrorrhizine were present at concentrations between 9.62?±?0.87?mg/g and 0.48?±?0.05?mg/g.     

X射线称重原理与实现方法

通过对X射线产生原理的理解,设计了一种新型称重设备,扩展了X射线应用技术领域,并主要针对工程上的实现,如结构特点、电气原理等进行了简单阐述。     

《电子称重仪表》新老国标的对比

本文对比了电子称重仪表新旧国标的差异,介绍了新国标中部分条款修改的原因和依据。     

Design of Vibrating String Pressure Sensor

The vibrating string pressure sensor is designed according to the working surroundings and conditions.This sensor is used for the weighing of the fixed-quantity bucket loader in the main shaft lifting systems of coal mines.The design of the sensor has been introduced in detail.Calibrations and errors of the sensor theoretical formula have also been analyzed.     

基于PLC控制的氧化剂自动过筛和称量系统

阐述了一套基于PLC和现场总线技术的氧化剂自动过筛和称量系统,该系统基于西门子PLC和工业控制计算机,采用现场总线技术,实现了氧化剂过筛和称量的远程隔离操作,提高了工作效率,保障了操作人员的身体健康和生命安全.     

产品流水线自动称重喷印系统

为产品流水线提供了一套自动称重喷印系统方案.该方案由电子秤、喷码机和数据传输模块组成,具有在产品流水生产线上对产品进行快速称重和喷印重量、生产日期等信息的功能,节省了人力物力,提高了流水线的生产效率.     

HZS60型混凝土搅拌站的调整

针对工程施工中常用的HZS60型混凝土搅拌站进行了介绍,着重阐述了该搅拌站称重系统的检查、调整方法及重载调试,并探讨了该搅拌站混合料传输时胶带跑偏的原因及处理办法,以期指导实践。     

赛摩拉姆齐给料机控制器XR2105的使用与维护

分析赛摩拉姆齐给料机控制器XR2105在锅炉中应用出现故障的原因,介绍处理意见,并阐明维护工作的重要性,对于日常使用操作具有指导意义.