Myth and reality of the hybrid desalination process

The paper discusses some misconceptions that have contributed to the continued use of thermal desalination processes and promotion of the hybrid desalination process for new plants being built or considered at Middle East locations. The misconceptions are examined both on the basis of fundamental thermodynamic principles and in terms of practical engineering parameters. The analysis shows that there is no economic or performance advantage in the installation of greenfield hybrid power/thermal desalination/ seawater reverse osmosis (SWRO) plants in preference to power/SWRO plants, because the latter would produce water more cheaply under all conditions and at all fuel costs, and would provide more operational flexibility than the former. The paper identifies situations where the hybrid desalination process can be fully justified: in existing power/desalination plants, where aging boilers and multistage flash (MSF) units need to be repaired or replaced, through retrofitting and repowering. In such situations, abandonment of the MSF process would result in a reduction in the power output of the plant. The paper refers to previous work which showed that the repowering of a typical existing power/desalination station with refurbishment/replacement of the MSF units, together with the addition of SWRO units, would result in a several-fold increase in the water and power output and a dramatic improvement in the fuel efficiency, without any additions to the existing seawater intake system. The paper emphasizes the importance of test stations/demonstration plants at existing power/desalination stations in the Middle East in order to obtain data and make improvements in the technology of higher temperature SWRO, with the feed obtained from the cooling water returning from the power plant condenser and the thermal desalination plant. The paper shows that the potential benefits would easily justify the investment in research and development required to validate this concept.     

Analysis of Minor Products in Linear Alkylbenzene Sulfonation. Comparison Between the Traditional Gravimetric Method and High Performance Liquid Chromatography (HPLC) Procedures Versus High Temperature Gas Chromatography (HT-GC)

During the sulfonation process of the linear alkylbenzene (LAB) other products like sulfones and anhydrides are also formed in addition to the linear alkylbenzene sulfonic acid (HLAS). Most of them are transformed in different degrees during the aging and hydrolysis steps of the overall sulfonation process [Moreno et al. (2003) J Surfactant Deterg 6(2):137–142]. The use of HPLC technique since 1988 and earlier the use of high temperature gas chromatography (HT-GC) enable the separation and quantification of all the components of the free oil (FO) of the sulfonic acids—anhydrides; LAB and sulfones. The purpose of this paper is to review the current knowledge about the free oil analysis and to discuss a new analytical procedure based on the HT-GC to quantify the free oil content. We will compare the results obtained using this new method with other analytical procedures (traditional gravimetry) and near infrared (NIR) spectroscopy.

3D Prussian blue/Pt decorated carbon nanofibers based screen-printed microchips for the ultrasensitive hydroquinone biosensing

Nowadays,water pollution has become more serious,greatly affecting human life and healthy.Electrochemical biosensor,a novel and rapid detection technique,plays an important role in the real-time and trace detection of water pollutants.However,the stability and sensitivity of electrochemical biosensors remain a great challenge for practical detections in real samples to the strong interferences derived from complex components and coagulation effects.In this work,we reported a novel three-dimensional architecture of Prussian blue nanoparticles (PBNPs)/ Pt nanoparticles (PtNPs) composite film,using 3D interweaved carbon nanofibers as a supporting matrix,for the construction of screen-printed microchips-based biosensor.PtNPs with diameters of～2.5 nm was highly dispersed on the carbon nanofibers (CNFs) to build a 3D skeleton nanostructure through a solvothermal reduction.Subsequently,uniform PBNPs were in-situ self-assembled on this skeleton to construct a 3D architecture of PB/Pt-CNF composite film.Due to the synergistic effects derived from this special feature,the as-prepared hydro-quinone (HQ) biosensor chips can synchronously promote both surface area and conductivity to greatly enhance the electrocatalysis from enzymatic reaction.This biosensor has exhibited a high sensitivity of 220.28 μA·L·mmol-1·cm-2 with an ultrawide linear range from 2.5μmol·L-1 to 1.45 mmol·L-1 at a low potential of 0.15 V,as well as the satisfactory reproducibility and usage stability.Besides,its accuracy was also verified in the assays of real water samples.It is highly expected that the 3D PB/Pt-CNF based screen-printed microchips will have wide applications in dynamic monitoring and early warning of ana-lytes in the various practical fields.     

Investigations of yield stress,fracture toughness,and energy distribution in high speed orthogonal cutting

This paper presents a novel prediction method of the yield stress and fracture toughness for ductile metal materials through the metal cutting process based on Williams' Model [38]. The fracture toughness of the separation between the segments in serrated chips in high speed machining is then deduced. In addition, an energy conservation equation for high speed machining process, which considers the energy of new created workpiece surfaces, is established. The fracture energy of serrated chips is taken into the developed energy conservation equation. Five groups of experiments are carried out under the cutting speeds of 100, 200, 400, 800 and 1500 m/min. The cutting forces are measured using three-dimensional dynamometer and the relevant geometrical parameters of chips are measured with the aid of optical microscope. The experiment results show that the yield stress of machined ductile metal material presents an obviously increasing trend with the cutting speed increasing from 100 to 800 m/min while it decreases when the cutting speed increases to 1500 m/min further. Meanwhile, the fracture toughness between the chip and bulk material displays a slightly increasing tendency. In high speed machining, the fracture toughness of the separation between the segments in serrated chips also presents increasing trend with the increasing cutting speed, whose value is much greater than that between the chip and bulk material. In the end, the distribution of energy spent in cutting process is analyzed which mainly includes such four portions as plastic deformation, friction on the tool–chip interface, new generated surface and chip fracture. The results show that the proportion of plastic deformation is the largest one while it decreases with the cutting speed increasing. However, the proportions of energy spent on new created surface and chip fracture increase due to the increasing of both the chip's fracture area and the fracture toughness.     

Shape memory behavior of high strength NiTiHfPd polycrystalline alloys

Systematic characterization of the shape memory properties of a quaternary Ni_45.3–Ti_29.7–Hf₂₀–Pd₅ (at.%) polycrystalline alloy was performed in compression after selected aging treatments. Precipitation characteristics were revealed by transmission electron microscopy. The effects of aging temperature and time on transformation temperatures, recoverable and residual strains, and temperature and stress hystereses were determined by differential scanning calorimetry, constant-load thermal cycling experiments and isothermal strain cycling (superelasticity) tests. The crystal structure and lattice parameters of the transforming phases were determined from X-ray diffraction analysis. It was revealed that precipitation hardening significantly improved the shape memory properties of the NiTiHfPd alloy. Under optimum aging conditions, shape memory strains of up to 4% under 1 GPa were possible, and superelasticity experiments resulted in full strain recovery without any plastic deformation, even at stress levels as high as 2 GPa. The NiTiHfPd polycrystalline alloy exhibited very high damping capacity/absorbed energy (30–34 J cm^?3) and work output (30–35 J cm^?3), which were attributed to the ability to operate at high stress levels without significant plastic deformation and to a high mechanical hysteresis (>900 MPa) at temperatures ranging from 20 °C to 80 °C.     

光固化型压敏胶的研究

以丙烯酸及丙烯酸酯为单体 ,采用光敏固化制备压敏胶带。对单体配比、预聚物粘度、反应型添加剂及涂层厚度、固化时间等因素对制备工艺的影响进行了讨论 ,建立了光敏固化型压敏胶的制备工艺。     

SBS和APP树脂石油沥青防水卷材的研制

用ＳＢＢ或ＡＰＰ树脂改性的石油沥青所制成的防水卷材,具有良好的防水性能,抗高温变形能力和抗寒性能,正逐步替代ＰＶＣ煤焦油防水卷材。     

新型干法水泥生产线的粉磨系统

本文从粉磨物料的特性、产品的要求出发,结合近年来出现的新技术、新装备对干法水泥生产的主要粉磨设备及系统进行分析评述,提出各粉磨作业比较适宜的粉磨系统;生料粉磨应尽量采用辊磨系统;水泥粉磨以带辊压机或预粉磨的联合粉磨系统为优选方案;煤粉制备采用辊磨煤磨和带高效选粉机的风扫磨系统均可作为选择方案。     

High nitrogen carbon material with rich defects as a highly efficient metal-free catalyst for excellent catalytic performance of acetylene hydrochlorination

In this work,we developed a simple strategy to synthesize a carbon material with high nitrogen and rich carbon defects.Our approach polymerized diaminopyridine(DAP) and ammonium persulfate(APS).Following a range of different temperature pyrolysis approaches,the resulting rough surface was shown to exhibit edge defects due to N-doping on graphite carbon.A series of catalysts were evaluated using a variety of characterization techniques and tested for catalytic performance.The catalytic performance of the N-doped carbon material enhanced alongside an increment in carbon defects.The NC-800 catalyst exhibited outstanding catalytic activity and stability in acetylene hydrochlorination(C_2 H_2 GHSV=30 h~(-1),at 220℃,the acetylene conversion rate was 98%),with its stability reaching up to 450 h.Due to NC-800 having a nitrogen content of up to 13.46%,it had the largest specific surface area and a high defect amount,as well as strong C_2 H_2 and HCl adsorption.NC-800 has excellent catalytic activity and stability to reflect its unlimited potential as a carbon material.     

挖掘机用高压多路阀研制的关键技术

随着工程机械挖掘机行业的飞速发展,作为挖掘机液压系统的主要核心液压元件,高压多路换向阀研制的关键技术得到了越来越多的重视。结合某公司生产的中型挖掘机用高压多路换向阀,从设计、铸造、加工3方面阐述多路阀研制过程中的关键技术。