烧结工序中转炉渣的优化利用

钢铁厂产生的矿渣中很大一部分来自氧气顶吹转炉(LD转炉)和吹氧转炉工序.LD工序的主要目的是将熔融的铁水和废钢转化为优质钢.在印度,每年产生的熔融钢渣超过400～450万t.总体看来,生产每吨钢会产生150～200 kg的钢渣,对这些钢渣的处理已经成为了严重的环境问题.金达尔钢公司是年产700万t的联合钢厂,每天产生钢渣3 200 t,其中2 000～2 500 t来自LD转炉.LD转炉渣中含有47.75%的CaO,22.0%的Fe以及8.22%MgO,由于CaO含量很高,LD转炉渣可直接替代烧结工序中的生石灰.目前在实验室范围已进行了一些研究,以确定烧结工序中所允许的LD转炉渣的最大投加量以及转炉渣的投加对烧结产率和性能的影响.实验中,LD转炉渣在烧结矿里的添加量从0依次到60 kg/t.随着添加率的增大,烧结料层温度的降低致使FeO含量降低,而烧结配矿中烧损的降低以及由于避免了石灰石煅烧过程带来的的重量损失,使得烧结产率上升.与此同时,LD转炉渣中缺少自由的CaO,使烧结矿强度及还原粉化指数变差,可参加反应的CaO的减少也导致了铁酸钙相减少,及残存Fe2O3自由相增加.试验结果最终得出:烧结矿中LD转炉渣的投加量为30～35 kg/t时,可获得预期的烧结矿性能.     

A simple decision tree-based disturbance monitoring system for VSC-based HVDC transmission link integrating a DFIG wind farm

Fault detection and classification is a key challenge for the protection of High Voltage DC (HVDC) transmission lines. In this paper, the Teager–Kaiser Energy Operator (TKEO) algorithm associated with a decision tree-based fault classi f ier is proposed to detect and classify various DC faults. The Change Identification Filter is applied to the average and differential current components, to detect the first instant of fault occurrence (above threshold) and register a Change Identified Point (CIP). Further, if a CIP is registered for a positive or negative line, only three samples of currents (i.e., CIP and each side of CIP) are sent to the proposed TKEO algorithm, which produces their respective 8 indices through which the, fault can be detected along with its classification. The new approach enables quicker detection allowing utility grids to be restored as soon as possible. This novel approach also reduces computing complexity and the time required to identify faults with classification. The importance and accuracy of the proposed scheme are also thor oughly tested and compared with other methods for various faults on HVDC transmission lines.     

Microwave Preparation of SiO2-B2O3-Na2O-K2O-CaO-Fe2O3-TiO2 Glass System

This study reports preparation of glass composition （54.50 wt.%） SiO2, （10.80 wt.%） B2O3, （14.20 wt.%） Na2O, （1.20 wt.%） K2O, （6.00 wt.%） CaO, （4.00 wt.%） Fe2O3 and （9.30 wt.%） TiO2 by melt quenching method using direct microwave heating and conventional resistive heating. Study of dielectric loss factor of the glass as function of temperature illustrated increasing loss factor above 370 ℃, 550 ℃, 650 ℃ and 900 ℃, indicating enhanced microwave absorption by the glass at above these temperatures. Chemical analysis results of both the glasses depicted more volatilization loss of volatile ingredients in conventional heating. The study of chemical durability was performed from leachate analysis describing less leaching of Na2O, K2O and other constituents from glass melted in microwave furnace. Glass transition temperatures （Tg） were found to be 576.3 ℃ and 569.5 ℃ for glass melted in conventional and microwave heating route, respectively. Laboratory experiment of glass melting utilizing microwave energy as an alternate heating source demonstrated 70%-75% electrical power saving.     

Differential scanning calorimetric study of curing of acrylated epoxy resin with benzoyl peroxide

The curing reaction of the acrylated diglycidyl ether of bisphenol-A (DGEBA) with benzoyl peroxide has been investigated by differential scanning calorimetry at three different heating rates. The overall cure kinetics were found to be first-order, with Arrhenius parameters E=83 kJ mol^?1 and In A = 16.5 min^?1, independent of the scan rate, up to at least 90% conversion.     

Estimation of riverbank soil erodibility parameters using genetic algorithm

Determination of the erodibility parameters, such as critical shear stress and erodibility coefficient, are necessary before estimating the annual bank erosion (or bank retreat) at river reaches. However, in many cases, the river site is inaccessible making it difficult to assess the soil parameters either by in situ tests or by laboratory experiments. In this study, Genetic Algorithm (GA)-based optimisation technique was used to estimate the erodibility parameters of middle reaches of the Brahmaputra River in India. Two approaches were followed. At first, erodibility parameters were estimated using daily stage records at a selected site. Secondly, based on the annual observed bank erosions (bank retreat) from satellite images, erodibility parameters were estimated in three different river reaches. All these results were compared with that from a previous study using in situ jet tests. Annual bank erosions (bank retreat) were estimated using the median values of the erodibility parameters. The results agree well with the average observed annual bank erosion of these river reaches. In addition, the effects of measurement errors and optimisation algorithms on the parameter estimation were analysed. Sensitivity analysis of the parameters in GA was evaluated and it was found that GA can be utilised in the data-scarce regions to estimate the average erodibility parameters.     

Effect of diluents and/or fortifier on the glass fiber–epoxy composites

The glass fiber-epoxy composites were fabricated with the E-type glass cloth and diglycidyl ether of bisphenol A (DGEBA) using 12% diethylenetriamine (DETA) as catalyst on the basis of DGEBA. The properties were modified by incorporating diluents such as epoxidized 2,2,6,6-tetramethylolcyclohexanol (ETMC) and 1,4-butandioldiglycidyl ether (BDDE) with/without 20 parts per 100 g of a condensation product of phenyglycidylether and 4-hydroxyacetanilide (PGEHA) employed as fortifier. The characterization of these epoxy laminates includes resistance to chemical reagents, dynamic mechanical analysis, and mechanical properties like flexural strength, impact strength, and hardness. The dielectrical properties such as breakdown strength, dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tan δ) were estimated.     

Swelling and dye adsorption study of novel superswelling [Acrylamide/N-vinylpyrrolidone/3(2-hydroxyethyl carbamoyl) acrylic acid] hydrogels

Summary Super swelling acrylamide (Am)/N-vinylpyrrolidone (NVP)/3-(2-hydroxyethyl carbamoyl) acrylic acid (HECA) hydrogels were prepared by free radical polymerization of quaternary mixtures of Am, NVP, HECA and water. The hydrogels were used in experiments on swelling, diffusion and adsorption of some water-soluble monovalent cationic dyes such as Crystal Violet (CV), Malachite Green (MG) and Methylene Blue (MB). In the experiment of the adsorption of dyes from their aqueous solutions type-S adsorption isotherm were found. The diffusion of water within the hydrogel was found to have non Fickian character. The uptake of dyes within the hydrogel increased in the following order: MG > MB > CV. The binding ratio of the hydrogel/dye systems was gradually increased with the increase of HECA content in the AAm/NVP/HECA hydrogel.     

In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains, Escherichia coli DH5α, Micrococcus luteus and Staphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications. Biswarup Saha and Jaydeep Bhattacharya authors contributed equally.     

Application of Semi-Hertzian Approach to Predict the Dynamic Behavior of Railway Vehicles Through a Wear Evolution Model

Wear prediction due to the wheel-rail interaction in a railway vehicle has a significant role in the view of running stability (critical speed), dynamic performance and maintenance scheduling. In this article, we have focused on the estimation of wear distribution on the wheel profile through co-simulation between the vehicle and the wear evolution models, built in the multi-body simulation (MBS) software ADAMS (VI-Rail) and MATLAB environments, respectively. As the shape of the contact patches varies from elliptical to non-elliptical depending upon the contact patch location on the rail and the wheel, the contact forces/stresses are calculated by using a combined formulation of semi-Hertzian approach with modified FASTSIM. The wear distribution is obtained using Archard’s wear model. The wheel profiles are updated after calculating the wear depth for a particular distance travelled by the vehicle. The dynamic behavior of the vehicle with the worn wheel profile is utilized to predict additional wear during a further fixed distance of travel and this profile updating and dynamic simulation process is repeated. The vehicle’s dynamic performance and passenger comfort are evaluated for various levels of wheel wear.     

Improved tire tread compounds using functionalized styrene butadiene rubber-silica filler/hybrid filler systems

Automotive industry is currently looking for an eco-friendly tire with low rolling resistance coefficient (RRc), better traction, wear resistance, and fatigue properties. Presently, solution styrene-butadiene rubber (SSBR)-silica systems are pursued for balancing between traction and RRc. However, the interaction between SSBR and silica is not enough to give satisfactory results. Functionalized-SSBR (FSSBR) leads to better rubber-silica interaction due to introduction of polar groups in the polymer chain. The present study investigates the influence of FSSBR, highly dispersible (HD) silica, and its hybrid filler systems with organically modified nanoclay (ONC) and exfoliated graphene nanoplatelet (xGnP). Both M_H, and Δtorque were higher for the FSSBR-HD silica compound (S1) with the lowest change in storage modulus (∆G') value, due to higher polymer-filler interaction. S1 exhibited 16% ice traction and 12% wet traction improvement with 29% lower rolling resistance over SSBR-silica compound. S1 showed the best wet traction rating and wear resistance. Replacing small portion of silica by ONC and xGnP improved the properties further. At 5 phr of nanofiller, TEM images revealed well-dispersed nanofillers in the FSSBR matrix. The xGnP compound showed the least crack growth. For both the cases, abradability decreased with higher nanofiller amount, due to better reinforcement of the rubber.