Semi-solid A356 alloy slurry for rheocasting prepared by a new process

To obtain the semi-solid slurry with uniform and fine structure morphology that satisfies the requirement of rheocasting process, a new process for preparing semi-solid Al alloy slurry was developed, in which local chilling was combined with low superheat pouring and slight electromagnetic stirring (LSPSEMS). The morphology and the size of primary α-Al in the A356 alloy slurry prepared with the new process, i.e., LSPSEMS with local chilling, were investigated using MIAPS image analyzing software, and the grain refinement mechanism was discussed. The results indicate that the semi-solid primary phase consists of particle-like or globular-like α-Al, and the morphology and grain size of primary α-Al in the slurry can be markedly improved by the new process. The fine primary α-Al distributes uniformly in the slurry, which satisfies the requirement of rheocasting. Compared with the alloy prepared by LSPSEMS, the average equal-area-circle grain diameter of primary α-Al in semi-solid A356 alloy ingot prepared by the new process is decreased from 85.6 μm to 68.8 μm at the central area, 112.6 μm to 77.6 μm at the transition area and is 84.7 μm in the edge area, respectively. The corresponding shape factor of primary α-Al is increased from 0.78 to 0.83, 0.54 to 0.77 and 0.28 to 0.59, respectively. In addition, the pouring temperature could be suitably raised from 620-630 ℃ of the traditional process to 650 ℃ using this technique, which is convenient for practical operation. The mechanism of grain refinement, in the new process, is that the local chilling quickens up the temperature decrease in the center of the melt. The nuclei could not grow up in a short time so the finer grains are formed in the melt.

Study on the mechanism of coal liquefaction reaction and a new process concept

The coal hydrogenation reaction process is simply considered as three steps.In the first step,the smaller molecules associated with coal structure units are released as some gases and water in the condition of solvent and heating.In this step,some weaker bonds of the coal structure units are ruptured to form free radicals.The radicals are stabi- lized by hydrogen atoms from donor solvent and/or H2.In the second step,chain reaction occurs quickly.In the process of chain reaction,the covalent bonds of coal structure units are attacked by the radicals to form some asphaltenes.In the third step,asphaltenes are hydrogenated form more liquids and some gases.In coal liquefaction,the second step of coal hydrogenation reaction should be controlled to avoid integration of radicals,and the third step of coal hydrogenation should be accelerated to increase the coal conversion and the oil yield.A new concept of coal liquefaction process named as China direct coal lique- faction (CDCL) process is presented based on the mechanism study of coal liquefaction.

A New Modified EWMA Control Chart for Monitoring Processes Involving Autocorrelated Data

Control charts are one of the tools in statistical process control widely used for monitoring,measuring,controlling,improving the quality,and detecting problems in processes in variousfields.The average run length(ARL)can be used to determine the efficacy of a control chart.In this study,we develop a new modified exponentially weighted moving average(EWMA)control chart and derive explicit formulas for both one and the two-sided ARLs for a p-order autoregressive(AR(p))process with exponential white noise on the new modified EWMA control chart.The accuracy of the explicit formulas was compared to that of the well-known numerical integral equation(NIE)method.Although both methods were highly consistent with an absolute percentage difference of less than 0.00001%,the ARL using the explicit formulas method could be computed much more quickly.Moreover,the performance of the explicit formulas for the ARL on the new modified EWMA control chart was better than on the modified and standard EWMA control charts based on the relative mean index(RMI).In addition,to illustrate the applicability of using the proposed explicit formulas for the ARL on the new modified EWMA control chart in practice,the explicit formulas for the ARL were also applied to a process with real data from the energy and agriculturalfields.

Process synthesis for the separation of coal-to-ethanol products

The coal-to-ethanol process,as the clean coal utilization,faces challenges from the energy-intensive distillation that separates multi-component effluents for pure ethanol.Referring to at least eight columns,the synthesis of the ethanol distillation system is impracticable for exhaustive comparison and difficult for conventional superstructure-based optimization as rigorous models are used.This work adopts a superstructure-based framework,which combines the strategy that adaptively selects branches of the state-equipment network and the parallel stochastic algorithm for process synthesis.High-performance computing significantly reduces time consumption,and the adaptive strategy substantially lowers the complexity of the superstructure model.Moreover,parallel computing,elite search,population redistribution,and retention strategies for irrelevant parameters are used to improve the optimization efficiency further.The optimization terminates after 3000 generations,providing a flowsheet solution that applies two non-sharp splitting options in its distillation sequence.As a result,the 59-dimension superstructure-based optimization was solved efficiently via a differential evolution algorithm,and a high-quality solution with a 28.34%lower total annual cost than the benchmark was obtained.Meanwhile,the solution of the superstructure-based optimization is comparable to that obtained by optimizing a single specific configuration one by one.It indicates that the superstructure-based optimization that combines the adaptive strategy can be a promising approach to handling the process synthesis of large-scale and complex chemical processes.

Comprehensive Evaluation of Flower Border Application Value of New and Superior Plants in Hefei Area

An analytic hierarchy process(AHP)was employed to assess the applicability of 18 new and superior varieties of flowers in Hefei City flower border applications.A total of 12 indicators were selected from three distinct aspects of adaptability,ornamental characteristics and use traits,in order to establish a comprehensive evaluation model.The results demonstrate that grade I(J≥2.685)exhibits excellent application value,encompassing six species of plants,such asHydrangeamacrophylla‘Endless Summer’;grade II(2.684≤J≤2.420)is also of notable application value,encompassing five species of plants,such asCallistemonrigidus;grade III(2.419≤J≤2.615)is of average application value,including five species of plants,such asCrocosmiacrocosmiflora;grade IV(J≤2.16)is of relatively poor application value.The evaluation results may be utilized as a theoretical reference for the promotion of new and superior varieties in the flower border of Hefei.

New Antenna Array Beamforming Techniques Based on Hybrid Convolution/Genetic Algorithm for 5G and Beyond Communications

Side lobe level reduction(SLL)of antenna arrays significantly enhances the signal-to-interference ratio and improves the quality of service(QOS)in recent and future wireless communication systems starting from 5G up to 7G.Furthermore,it improves the array gain and directivity,increasing the detection range and angular resolution of radar systems.This study proposes two highly efficient SLL reduction techniques.These techniques are based on the hybridization between either the single convolution or the double convolution algorithms and the genetic algorithm(GA)to develop the Conv/GA andDConv/GA,respectively.The convolution process determines the element’s excitations while the GA optimizes the element spacing.For M elements linear antenna array(LAA),the convolution of the excitation coefficients vector by itself provides a new vector of excitations of length N=(2M−1).This new vector is divided into three different sets of excitations including the odd excitations,even excitations,and middle excitations of lengths M,M−1,andM,respectively.When the same element spacing as the original LAA is used,it is noticed that the odd and even excitations provide a much lower SLL than that of the LAA but with amuch wider half-power beamwidth(HPBW).While the middle excitations give the same HPBWas the original LAA with a relatively higher SLL.Tomitigate the increased HPBWof the odd and even excitations,the element spacing is optimized using the GA.Thereby,the synthesized arrays have the same HPBW as the original LAA with a two-fold reduction in the SLL.Furthermore,for extreme SLL reduction,the DConv/GA is introduced.In this technique,the same procedure of the aforementioned Conv/GA technique is performed on the resultant even and odd excitation vectors.It provides a relatively wider HPBWthan the original LAA with about quad-fold reduction in the SLL.

Research on new beneficiation process of low-grade magnesite using vertical roller mill

We investigated whether the vertical roller mill can be efficiently used in the beneficiation of low-grade magnesite and whether it can improve upon the separation indices achieved by the ball mill.We conducted experiments involving the reverse flotation and positive flotation of low-grade magnesite to determine the optimum process parameters,and then performed closed-circuit beneficiation experiments using the vertical roller mill and ball mill.The results show that the optimum process parameters for the vertical roller mill are as follows:a grinding fineness of 81.6wt%of particles less than 0.074 mm,a dodecyl amine(DDA)dosage in magnesite reverse flotation of 100 g·t?1,and dosages of Na2CO3,(NaPO3)6,and NaOL in the positive flotation section of 1000,100,and 1000 g·t?1,respectively.Compared with the ball mill,the use of the vertical roller mill in the beneficiation of low-grade magnesite resulted in a 1.28%increase in the concentrate grade of MgO and a 5.88%increase in the recovery of MgO.The results of our causation mechanism analysis show that a higher specific surface area and greater surface roughness are the main reasons for the better flotation performance of particles ground by the vertical roller mill in the beneficiation of lowgrade magnesite.

New process development and process evaluation for capturing CO2 in flue gas from power plants using ionic liquid[emim][Tf2N]

Using the ionic liquid[emim][Tf2N]as a physical solvent,it was found by Aspen Plus simulation that it was possible to attempt to capture CO2 from the flue gas discharged from the coal-fired unit of the power plant.Using the combination of model calculation and experimental determination,the density,isostatic heat capacity,viscosity,vapor pressure,thermal conductivity,surface tension and solubility of[emim][Tf2N]were obtained.Based on the NRTL model,the Henry coefficient and NRTL binary interaction parameters of CO2 dissolved in[emim][Tf2N]were obtained by correlating[emim][Tf2N]with the gas–liquid equilibrium data of CO2.Firstly,the calculated relevant data is imported into Aspen Plus,and the whole process model of the ionic liquid absorption process is established.Then the absorption process is optimized according to the temperature distribution in the absorption tower to obtain a new absorption process.Finally,the density,constant pressure heat capacity,surface tension,thermal conductivity,and viscosity of[emim][Tf2N]were changed to investigate the effect of ionic liquid properties on process energy consumption,solvent circulation and heat exchanger design.The results showed that based on the composition of the inlet gas stream to the absorbers,CO2 with a capture rate of 90%and a mass purity higher than 99.5%was captured.These results indicate that the[emim][Tf2N]could be used as a physical solvent for CO2 capture from coal-fired units.In addition,the results will provide a theoretical basis for the design of new ionic liquids for CO2 capture.

High Spatial Resolution Mapping of Dykes Using Unmanned Aerial Vehicle(UAV) Photogrammetry: New Insights On Emplacement Processes

Remote sensing has played a pivotal role in our understanding of the geometry of dykes and dyke swarms on Earth,Venus and Mars(West and Ernst,1991;Mege and Masson,1995;Ernst et al.,2005).Since the 1970’s

Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques

Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.

NEW PROGRESS IN MINERAL PROCESSING——REPORT ON FIRST INTERNATIONAL CONFERENCE ON MODERN PROCESS MINERALOGY AND MINERAL PROCESSING

The first International Conference on Modern Process Mineralogy and Mineral Processing, organized by the Nonferrous Metals Society of China and hosted by Beijing General Research Institute of Mining and Metallurgy,was held on September 22-25,1992,in Beijing,China.About 350 scholars and experts from 25 countries and regions showed up at the conference and 130 papers were presented,among them 98 papers are of mineral processing.Some of the papers given in mineral processing are summed up as follows.

A new,sustainable process for synthesis of ethylene glycol

In conventional heterogeneous catalytic process, the activation of C-H bond remains a grand challenge. It is even more difficult to activate the inert C-H bond with other functional groups （e.g. OH） in the same molecule, remaining intact [1]. Although the transformation of C1 species （e.g. CO, CO2, CH4 and CH3OH） into C2 molecules （e.g. C2H4, C2HsOH and HOCH2CH2OH） via C-C coupling has been a hot research topic but the yield of aimed product is still needed to be improved. Ethylene glycol （EG） is a versatile chemical with many important applications, in particular for the manufacture of polyesters, predominantly poly（ethylene terephthalate） [2]. Recently, Wang, Deng and co-workers at Xiamen University cleverly designed a new process for the conversion of methanol to ethylene glycol, in which the EG selectivity can reach 90% （Eq. （1）） [3].

Critical Materials Institute develops new acid-free magnet recycling process

A new rare-earth magnet recycling process developed by researchers at the Critical Materials Institute (CMI) dissolves magnets in an acid-free solution and recovers high purity rare earth elements. For shredded magnet-containing electronic wastes, the process does not require pre-processing such as pre-sorting or demagnetization of the electronic waste.

A NEW HEAT-TREATMENT PROCESS FOR 2014 ALUMINUM ALLOY AND ITS MECHANISM

The plan of heat-treatment process for 2014Al alloy is designed using orthogonal method, the heat-treatment experiments are made and the mechanical properties are tested according to the designed plan. The effect of solid solution temperature, ageing temperature, ageing time on microscopic mechanism of the mechanical properties of the 2014Al alloy is studied using microscope, transmission electron microscope. The best heat treatment process of the 2014Al alloy is developed. The experimental results indicate that the strength σb, yield stress σ0.2, percentage elongation δ of the alloy reach separately 490～500 MPa, 450～490 MPa, 10～12％ adopting the new heat treatment process. Compared with GB, the strength increases 20～30％, the percentage elongation increases 30～40％. The mechanism of the new heat-treatment process is also discussed.

A New Synthesis Process of Highly Efficient and Low Toxic Fungicide Difenoconazole

A new synthesis method of difenoconazole is studied.Difenoconazole is prepared from m-dichlorobenzene by Friedel Crafts reaction,cyclization,bromination,nucleophilic substitution and etherification.The new process improves the selectivity of the reaction and simplified the pu-rification process.The total yield of this process is 84%,which provides a green and economical synthetic route for industrialization.

Preliminary Studies on Evaluation and Change Trends of Dominant Components in New Types of Tobacco Sheets by Thick Pulp Process

[Objectives]This study was conducted to deeply understand the effects of production process on the quality of new types of tobacco sheets with different flavors.[Methods]Based on the pilot production process of thick pulp method,four different flavors of tobacco sheets were sampled at several links in the production process,for the detection of the contents of the main components in the samples,including propylene glycol,glycerol,menthol and glyceryl triacetate,so as to explore the change trends of various components in the thick pulp process.[Results]The change laws of propylene glycol and glycerol contents had a very high similarity,showing a trend of first decreasing and increasing then.The changes of menthol content and glyceryl triacetate content were greatly affected by the specific flavor formula.As one of the indexes of the new tobacco evaluation system,the alcohol-to-ester ratio data need to be further improved in the actual production and application process.[Conclusions]This study provides basic data support for improving the quality of tobacco sheets.

The New Standards System for Processing Food to Be Proved

It is reported that the work of re-structuring the frame of China national standards system for processing food has been finished with the print and distribution of 2004-2005 Development Plan of National Standards for Food (hereinafter Plan).

新质生产力的科学内涵、构成要素和制度保障机制

科学把握新质生产力的内涵需要回到其形成和发展的社会历史背景中。本文遵循历史唯物主义的分析逻辑,从技术形态、发展阶段和人类社会生产力演进三个层面,探寻新质生产力的丰富内涵;通过对劳动过程的剖析解构新质生产力的构成要素,并分析其对社会再生产过程的影响;最后考察经济制度对新质生产力形成的重要作用。我们认为,新质生产力是新一轮产业技术革命及其战略性新兴产业集群形成的生产力,是新时代实现高质量发展必需的一类生产力,要融合提升传统生产力,展现新时代新活力。新质生产力的形成将对新时代社会生产组织方式和社会再生产过程产生重要影响。为形成新质生产力培育动力不仅要坚持创新驱动发展,还要依靠全面深化改革激发内生活力。中国共产党的领导是我国形成新质生产力的独有优势和根本保障。

新型电力系统数据跨域流通泛安全边界防护技术

新型电力系统建设涉及多业务系统、多部门、多方主体间进行海量、异构数据的交互和共享,电力数据的内外部网络环境与安全形势日趋复杂化,数据流通的脆弱性风险加剧。首先,分析新型电力系统下数据流的类型与特性,概括电力数据流通安全防护面临的新形势;其次,基于专用数据处理器(DPU)的高性能流量编排和多功能安全网关能力,构建面向电力数据跨域流通安全增强的泛安全边界,凭借数据面可编程技术沟通网络安全与数据安全双维度安全能力,提出基于DPU的数据跨域流通协同防护技术应用方案;最后,阐释DPU在不同电力通信网络层次的部署方式、价值与关键技术,分析现阶段DPU在电力领域应用存在的挑战。