Activation of anthracite combustion by copper acetate:mechanism,effect of particle size and introduction method

This paper addressed the efect of copper acetate on the combustion characteristics of anthracite depending on the fractional composition of fuel and additive introduction method.Anthracite was impregnated with 5 wt%of Cu(CH_(3)COO)_(2)by mechanical mixing and incipient wetness impregnation.Four anthracite samples of diferent fraction with d<0.1 mm,d=0.1-0.5 mm,d=0.5-1.0 mm,and d=1.0-2.0 mm were compared.According to EDX mapping,incipient wetness impregnation provides a higher dispersion of the additive and its uniform distribution in the sample.The ignition and combustion characteristics of the modifed anthracite samples were studied by thermal analysis and high-speed video recording of the processes in a combustion chamber(at heating medium temperature of 800℃).It was found that copper acetate increases anthracite reactivity,which was evidenced by decreased onset temperature of combustion(ΔT_(i))by 35-190℃and reduced ignition delay time(Δτ_(i))by 2.1-5.4 s.Copper acetate reduces fuel underburning(on average by 70%)in the ash residue of anthracite and decreases the amount of CO and NO_(x)in gas-phase products(on average by 18.5%and 20.8%,respectively).The mechanism for activation of anthracite combustion by copper acetate is proposed.

Effect of Water on Extractive Desulfurization of Simulated FCC Gasoline Using Ionic Liquid NMP-FeCl_(3)-H_(2)O

A series of novel aqueous ionic liquids(NMP-FeCl_(3)-nH_(2)O)were prepared and the effects of water in the aqueous ionic liquids on desulfurization rate and selectivity of simulated FCC gasoline were investigated.The results showed that adding a small amount of water into the ionic liquid NMP-FeCl_(3) could effectively improve the desulfurization rate and selectivity,and the optimal amount of water was equal to 5%-10% of NMP.Finally,the possible desulfurization mechanism activated by a small amount of water was proposed.

Activation of 2D MoS_(2) electrodes induced by high-rate lithiation processes

MoS_(2) is a highly promising material for application in lithium-ion battery anodes due to its high theoretical capacity and low cost.However,problems with a fast capacity decay over cycling,especially at the first cycles,and poor rate performance have deterred its practical implementation.Herein,electrodes comprised solely of few-layers 2D MoS_(2) nanosheets have been manufactured by scalable liquid-phase exfoliation and spray deposition methods.The long-standing controversy questioning the reversibility of conversion processes of MoS_(2)-based electrodes was addressed.Raman studies revealed that,in 2D MoS_(2) electrodes,conversion processes are indeed reversible,where nanostructure played a key role.Cycling of the electrodes at high current rates revealed an intriguing phenomenon consisting of a continuously increasing capacity after ca.100-200 cycles.This phenomenon was comprehensively addressed by a variety of electrochemical and microscopy methods that revealed underlying physical activation mechanisms that involved a range of profound electrode structural changes.Activation mechanisms delivered a capacitive electrode of a superior rate performance and cycling stability,as compared to the corresponding pristine electrodes,and to MoS_(2) electrodes previously reported.Herein,we have devised a methodology to overcome the problem of cycling stability of 2D MoS_(2) electrodes.Moreover,activation of electrodes constitutes a methodology that could be applied to enhance the energy storage performance of electrodes based on other 2D nanomaterials,or combinations thereof,strategically combining chemistries to engineer electrodes of superior energy storage properties.

Manganese oxide and derivative-modified materials in advanced oxidation processes:A review of modification enhancement and activation mechanisms

Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation efficiency.Fortunately,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its reactivity.Herein,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other support.The activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical pathways.The effects of pH,inorganic ions,and natural organic matter on degradation reactions are also discussed.Finally,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.

Microstructures of Sintered Mo-Cu Alloys with Mechanically Activated Powder

Mechanical activation and liquid phase sintering were used to manufacture high performance Mo-Cu alloy and develop new processes. The microsboctures and propefties of the alloy were investigated. The experimental results showed that: (1) the ball milled Mo/Cu powder has lamellar structure, (2) the microstructures of the sintered Mo-Cu alloy were homogenous composed structUres of adhesive phase Cu linking Mo grains, (3) Mo grains frequently strung or ga- thered in Cu phase, and (4) the full densities of Mo-Cu alloy was achieved through sintering and special densification process. As a result, the properties of the alloy are good enough to satisfy various requirements.

Mine tailings as a raw material in alkali activation: A review

The mining industry produces billions of tons of mine tailings annually.However,because of their lack of economic value,most of the tailings are discarded near the mining sites,typically under water.The primary environmental concerns of mine tailings are related to their heavy metal and sulfidic mineral content.Oxidation of sulfidic minerals can produce acid mine drainage that leaches heavy metals into the surrounding water.The management of tailing dams requires expensive construction and careful control,and there is the need for stable,sustainable,and economically viable management technologies.Alkali activation as a solidification/stabilization technology offers an attractive way to deal with mine tailings.Alkali activated materials are hardened,concrete-like structures that can be formed from raw materials that are rich in aluminum and silicon,which fortunately,are the main elements in mining residues.Furthermore,alkali activation can immobilize harmful heavy metals within the structure.This review describes the research on alkali activated mine tailings.The reactivity and chemistry of different minerals are discussed.Since many mine tailings are poorly reactive under alkaline conditions,different pretreatment methods and their effects on the mineralogy are reviewed.Possible applications for these materials are also discussed.

Distribution of Prestin on Outer Hair Cell Basolateral Surface

Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC electromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cuticular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface cisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.

Study on the mechanical activation of malachite and the leaching of complex copper ore in the Luanshya mining area, Zambia

Mechanical activation(MA) of malachite was carried out by dry planetary grinding(DPG) and wet Isa grinding(WIG) methods. When the rotational speed was increased to 400 r/min in DPG, the specific surface area of malachite reached the maximum and the particle size reached the minimum of 0.7–100 μm. Agglomeration occurred between mineral particles when the rotational speed was increased to 580 r/min in DPG.However, no agglomeration was observed among particles with sizes 0.4–3 μm in WIG. X-ray diffraction analysis showed that, at a 580 r/min rotational speed in DPG, the amorphization degree of malachite was 53.12%, whereas that in WIG was 71.40%, indicating that MA led to amorphization and distortion of crystal structures. In addition, in the Fourier transform infrared(FT-IR) spectra of activated malachite, the bands associated with –OH, CO_3^(2-)and metal lattice vibrations of Cu–O and Cu–OH were weakened, and a new H–O–H bending mode and peaks of gaseous CO_2 appeared, indicating that MA decreased the band energy, enhanced dihydroxylation, and increased the chemical reactivity of the malachite.Furthermore, the leaching behavior of copper ore was greatly improved by MA.

Microstructure and Properties of W-Cu Alloys Prepared with Mechanically Activated Powder

W-15% Cu (mass fraction) alloys were sintered with mechanically activated powder in order to develop new preparing processes and improve properties of alloys. The microstructures of the activated powder and the sintered alloy were observed. Properties such as density were measured. The results show that through mechanical activation, the particle size of the powder becomes finer to sub-micron or nanometer level, some copper was soluble in tungsten, and high density W-Cu alloys can be obtained by mechanically activated powder for its action to the activation sintering.

Integration of preparation of K,Na-embedded activated carbon and reduction of Zn-bearing dusts

Large amounts of solid wastes and flue gases are generated in iron and steel production process,probably leading to serious environmental pollution without duly handle.An innovative and green process of simultaneous reduction of zinc-bearing dusts and activation of low-rank coal was developed and its mechanism was clarified in this paper.Under the optimal conditions,the reduced zinc-bearing dusts containing low harmful elements(0.02%Zn,0.015%K and 0.03%Na)could be made as high-quality burden for blast furnace while the low-rank coal was transferred into K,Na-embedded activated carbon,which can be used as effective adsorbent for purification of SO_(2) and NO-containing flue gases.The solid wastes were successfully utilized to treat the flue gases through the process.The synergetic activation and reduction mechanism in the process was revealed.The coupling effect between reduction reactions of metal oxides in the dusts and activation reaction of carbon in the coal promoted the simultaneous reduction and activation process.In the meanwhile,part of the potassium and sodium from the zinc-bearing dusts could be adsorbed by the activated carbon and played a catalytic role in the activation process.

Effect of mechanical activation on TiC synthesis reaction in Al-Ti-C powder mixture

After milling in a high energy ball miller for various times, the synthesis reaction process of the Al Ti C powder mixture were investigated by difference thermal analysis (DTA) and X ray diffractometry (XRD). According to the patterns of reaction peaks on the DTA curves, the activation energy of each reaction was calculated. The experimental results of DTA show that the synthesis reaction of Al Ti C powder mixture can be enhanced after high energy milling. The longer the milling time, the lower the reaction temperature. The synthesis reaction of TiC is transformed from Ti+C→TiC to Al 3Ti+C→TiC+3Al with long period milling. Meanwhile, the activation energy of the reaction reduces with increasing milling time. The effect of milling time on reduced activation energy for low temperature region is more significant than that for high temperature region.

The performance and mechanism of iron-mediated chemical oxidation:Advances in hydrogen peroxide,persulfate and percarbonate oxidation

Many studies have successfully built iron-mediatedmaterials to activate or catalyze Fentonlike reactions,with applications in water and wastewater treatment being investigated.However,the developed materials are rarely compared with each other regarding their performance of organic contaminant removal.In this review,the recent advances of Fentonlike processes in homogeneous and heterogeneous ways are summarized,especially the performance and mechanism of activators including ferrous iron,zero valent iron,iron oxides,iron-loaded carbon,zeolite,and metal organic framework materials.Also,this work mainly compares three O-O bond containing oxidants including hydrogen dioxide,persulfate,and percarbonate,which are environmental-friendly oxidants and feasible for in-situ chemical oxidation.The influence of reaction conditions,catalyst properties and benefits are analyzed and compared.In addition,the challenges and strategies of these oxidants in applications and the major mechanisms of the oxidation process have been discussed.This work can help understand the mechanistic insights of variable Fenton-like reactions,the role of emerging iron-based materials,and provide guidance for choosing appropriate technologies when facing real-world water and wastewater applications.

Effects of Cobalt on the Sintering Behavior of Mechanically Activated Tungsten Powder

Tungsten alloys were prepared with mechanically activated powder added microelement cobalt in order to im- prove the process and properties of alloys. Properties of alloys such as density, hardness and bending strength were me- asured. The results show that through mechanical activation, cobalt can accelerate the sintering process of these alloys. By the combination of mechanical activation and adding microelement cobalt, tungsten alloys with higher density and better properties can be obtained.

A Self-propagating high-temperature synthesis process for the fabrication of Fe（Cr）–Al2O3 nanocomposite

Self-propagating high-temperature synthesis(SHS)was used to fabricate a Fe(Cr)–Al2O3 nanocomposite.The composite was fabricated by the reactions between the powders of Fe,Fe2O3,Cr2O3,and Al.The effect of blending ratio and mechanical activation of the initial powders and the precursor compressing pressure on the microstructure of the final product was studied by optical microscopy,scanning electron microscopy,transmission electron microscopy,and X-ray diffraction.The significance of the effect of each of the aforementioned parameters on the quality of the composite(assessed by measuring the compressive strength and wear resistance)was determined using a full-factorial design of experiments method.The results showed that the best molar powder ratio that produced the most homogeneous product through a sustainable SHS reaction was Fe:Fe2O3:Cr2O3:Al=10:1:1:4.A lower Fe content caused the Fe(Cr)phase to melt and separate from the rest of the materials.

Investigating the Structurization Process of Iron Monosilicide Powders Obtained by High-Temperature Synthesis from the Preliminarily Mechanoactivated Burden

Raising the efficiency of production, for the most part depends on the use of secondary material resources, particularly such wastes as metallurgical slags of the operating plants. Huge quantity of such slags generates an urgent problem of their reasonable utilization with maximum extraction of valuable metals. The objective of the thesis is the development of an efficient technology for obtaining powder iron-monosilicon alloy by means of processing of iron and silicon containing dump slags on the basis of out-of-furnace aluminothermic reduction. Thus, structure of the obtained alloy strоngly depends on the state of the initial slags, on their correlation and on the amount of components contained in the complement of the burden. The structurization processes of the iron powder-like silicide obtained by the method of self-propagating high-temperature synthesis of the preliminarily mechano activated burden are investigated. The combination of these two methods allows to form unique materials and alloys, significantly reducing the power expenditure by applying the exothermal effect of the reactions, and to obtain a product with special physico-chemical properties. The results of the investigation are to obtain monophase iron silicide by preliminary mechano-chemical activation of the burden, containing a mixture of wastes of a certain composition obtained from metallurgical production—the Alaverdi copper-smelting and the Yerevan molybdenum factories, as well as KNO3 and CaO by combined aluminothermal reduction in the SHS regime. By the X-ray fluorescent method of analysis, the structurization process of the obtained alloy is studied. It is shown that, at the expense of preliminary mechano-chemical activation of the burden, a finer and homogeneous structure of powder-like iron silicide is formed.

Domain-Swapping as a Mechanism to Lock the Active Conformation of SARS-CoV Main Protease

The main protease (Mpro) of SARS-CoV plays an essential role in the extensive proteolytic processing of the viral polyproteins (pp1a and pp1ab), and it is an important target

Structure and dielectric properties of (1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3)

The solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system were produced by the conventional ceramic technology using mechanical activation of the synthesized product.It was found that in the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system at room temperature,a number of morphotropic phase transitions occur:rhombohedral!cubic!tetragonal!monoclinic phases.The introduction of a small amount of Na_(0.5)K_(0.5)NbO_(3) leads to an increase in the temperature stability of the dielectric properties of ceramics.A change in the relaxor properties of the solid solutions of the(1-x)Na_(0.5)Bi_(0.5)TiO_(3-x)Na_(0.5)K_(0.5)NbO_(3) system was shown.The increase in energy density and energy efficiency was found at additive 10 mol.%of Na_(0.5)K_(0.5)NbO_(3).

Glial Activation, A Common Mechanism Underlying Spinal Synaptic Plasticity？

Long-term potentiation(LTP)at synapses between primary afferents and spinal dorsal horn neurons induced by noxious electrical stimulation or injury of peripheral nerve is considered to underlie chronic pain[1].The mechanisms of the spinal LTP have been intensively investigated,since it was discovered in 1995[2].In recent years,spinal application

Crystal structure of full-length human glucagon receptor reveals novel receptor activation mechanisms

Subject Code:C05With the support by the National Natural Science Foundation of China,a team of scientists let by Profs.Wu Beili(吴蓓丽),Wang Mingwei and Jiang Hualiang from Shanghai Institute of Materia Medica,Chinese Academy of Sciences has determined the high-resolution atomic structure of a full-length class B