Controlling the peripheral temperature of the blast furnace

Increase in FeO content lowers the initial melting temperature of primary slags in the blast furnace and prevents the formation of stable surface coatings. That increases the thermal loads on the coolers in the bosh and bosh extension and correspondingly increases the heat losses. The FeO content in the primary slags is determined by the indirect reduction. In the present work, means of reducing the thermal loads on the coolers in the bosh and bosh extension are assessed. Decrease in the gas temperature at the furnace periphery is accompanied by change in the degree of indirect reduction. Hence, the peripheral temperature may be regarded as an indicator of the degree of indirect reduction. A model of the gas temperature and the reducing effect of the gas at the furnace periphery is developed and may be used to optimize the thermal state of the furnace shaft in the peripheral zone.     

Development of a hyphenated microanalytical system for the investigation of leaching kinetics of heavy metals in environmental samples

A fast and convenient method for on-line monitoring of the extraction of heavy metals from solid (environmental) matrixes was developed. By the incorporation of microcartridges filled with dried and pulverized solid samples into the conduits of a flow system and appropriate selection of the liquid flowing through the cartridge, information about the degree of leaching and in particular of the kinetics of the leaching process are obtained. The method was optimized for determination of different metals of environmental concern using in-line detection by FAAS and ICPMS.     

Transport properties of natural gas through polyethylene nanocomposites at high temperature and pressure

Four titanium(IV) alkoxides, namely: Ti(IV) n-propoxide (1), Ti(IV) n-butoxide (2), Ti(IV) tert-butoxide (3), and Ti(IV) 2-ethylhexoxide (4), have been used as initiators in the bulk ring-opening polymerization (ROP) of ??-caprolactone (??-CL). The influence of the alkoxide group on the course of the ROP of ??-CL was investigated by means of ¹H-NMR and differential scanning calorimetry (DSC). The ¹H-NMR spectra confirmed that the ROP reaction of ??-CL proceeded via the widely accepted coordination-insertion mechanism for each of the four initiators. Isoconversional methods have been used to evaluate non-isothermal DSC data via the equations of Friedman, Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW). The kinetic studies showed that the polymerization rate for the four initiators (1-4) was in the order of 1?>?2????4?>?3. The lowest activation energies (40?C47, 42?C44, and 49?C52?kJ/mol for the Friedman, KAS and OFW methods respectively) were found in the polymerizations using Ti(IV) n-propoxide (1), while the highest activation energies (84?C107, 77?C87, and 80?C91?kJ/mol for the Friedman, KAS and OFW methods respectively) were obtained using Ti(IV) tert-butoxide (3). Differences in the rates of polymerization and the activation energies amongst the four initiators appeared to be governed mainly by the different degrees of steric hindrance in the initiator structure. These results represent important findings regarding the steric influence of the alkoxide groups on the kinetics of the ROP of ??-CL initiated by titanium(IV) alkoxides.     

Direct adaptive neural control of antilock braking systems incorporated with passive suspension dynamics

A direct adaptive neural network-based feedback linearization (NNFBL) slip control scheme for an antilock braking system (ABS) is presented. The NNFBL slip controller is developed to minimise the vehicle braking distance and to simultaneously improve its overall ride comfort and road handling. The comprehensive vehicle model incorporates the passive suspension dynamics, the dynamics of the electro-mechanical based braking system and air drag and wheel bearing friction. A feedforward, multilayer perceptron (MLP) neural network (NN) model that is well suited for control by discrete input-output linearization (NNIOL) is selected to represent the ABS with passive suspension. The NN model was trained using Levenberg-Marquardt optimization algorithm. The controlled signal was further boosted using a genetic algorithm generated gain. The effectiveness of the proposed controller is demonstrated by simulation results, in the presence of deterministic road disturbance input to the suspension and varying road conditions. The results are superior with respect to braking distance minimization and also to reference slip tracking, especially on the dry asphalt road.     

Antibacterial and antifungal effect of moringa (Moringa oleifera) seedmeal on marinated smoked African mud catfish (Clarias gariepinus)

The study assessed the antibacterial and antifungal effect of Moringa oleifera seed marinade on smoked Clarias gariepinus stored at ambient temperature for 15 days. Sixty C. gariepinus (15 kg) were gutted, washed, and randomly assigned in triplicate to five treatments containing 0, 5, 10, 15, and 20 g/kg M. oleifera seedmeal in 3.67 g/kg brine solution for 2 hr and later hot smoked for 24 hr. After smoking, the fishes were allowed to cool and packed separately in a transparent Ziploc polythene bag arranged in a box and kept at room temperature. Microbial load and diversity were conducted in the laboratory at 5 days intervals. The fungi isolated were Aspergillus flavus, Aspergillus niger, Saccharomyces cerevisiae, Alternaria alternata, Penicillium citrinium, Neurospora crassa, and Rhizopus stolonifer while Enterobacter spp., Staphylococcus spp., Proteus spp., Streptococcus spp., and Bacillus spp. were the identified bacteria. The optimum effective concentration of moringa seed marinade that acts as anti-bacteria was found best to be 11.2 g/kg of fish moringa marinade. While 12.08 g/kg exhibited the highest anti-yeast effect in C. gariepinus and 10.6 g/kg serves as antifungi. Thus, moringa seed marinade is safe to use as a natural edible food preservative that can protect smoked dried catfish from microbial spoilage.     

Preparation and gas transport properties of dual‐layer polysulfone membranes for high pressure CO2 removal from natural gas

Permeability, sorption, and plasticization behaviors of dual‐layer composite membrane were studied. Polysulfone containing 10.7 wt % glycerol as additive was used for preparing a microporous membrane support. A thin top selective layer was prepared using diethylene glycol dimethyl ether as casting solvent. The overall performance of the membrane was evaluated using Scanning Electron Microscopy, and permeation and sorption tests at pressure up to 50 bar. The prepared membrane displayed high permeability at low pressure which gradually decreased with increase in pressure. Permeability of CO₂ was determined to be 84.97 Barrer at 2 bar. Membrane did not show any plasticization tendency up to the experimental pressure of 40 bar. Plasticization pressure and permeability at plasticization pressure were estimated to be 41.07 bar and 6.03 Barrer, respectively. The improved performance of the membrane is associated to the synergistic properties of the two layers prepared from different formulations of the same polymer. Thus, the dual‐layer flat sheet configuration displayed a potential in high pressure CO₂ removal from natural gas. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40924.     

Polarized Ferroelectric Polymers for High‐Performance Perovskite Solar Cells

In hybrid organic–inorganic lead halide perovskite solar cells, the energy loss is strongly associated with nonradiative recombination in the perovskite layer and at the cell interfaces. Here, a simple but effective strategy is developed to improve the cell performance of perovskite solar cells via the combination of internal doping by a ferroelectric polymer and external control by an electric field. A group of polarized ferroelectric (PFE) polymers are doped into the methylammonium lead iodide (MAPbI₃) layer and/or inserted between the perovskite and the hole‐transporting layers to enhance the build‐in field (BIF), improve the crystallization of MAPbI₃, and regulate the nonradiative recombination in perovskite solar cells. The PFE polymer‐doped MAPbI₃ shows an orderly arrangement of MA⁺ cations, resulting in a preferred growth orientation of polycrystalline perovskite films with reduced trap states. In addition, the BIF is enhanced by the widened depletion region in the device. As an interfacial dipole layer, the PFE polymer plays a critical role in increasing the BIF. This combined effect leads to a substantial reduction in voltage loss of 0.14 V due to the efficient suppression of nonradiative recombination. Consequently, the resulting perovskite solar cells present a power conversion efficiency of 21.38% with a high open‐circuit voltage of 1.14 V.     

Hidden Markov model for human to computer interaction: a study on human hand gesture recognition

Human hand recognition plays an important role in a wide range of applications ranging from sign language translators, gesture recognition, augmented reality, surveillance and medical image processing to various Human Computer Interaction (HCI) domains. Human hand is a complex articulated object consisting of many connected parts and joints. Therefore, for applications that involve HCI one can find many challenges to establish a system with high detection and recognition accuracy for hand posture and/or gesture. Hand posture is defined as a static hand configuration without any movement involved. Meanwhile, hand gesture is a sequence of hand postures connected by continuous motions. During the past decades, many approaches have been presented for hand posture and/or gesture recognition. In this paper, we provide a survey on approaches which are based on Hidden Markov Models (HMM) for hand posture and gesture recognition for HCI applications.     

Transesterification of methyl myristate in a continuous reactive distillation column: simulation and experiment

The transesterification of methyl myristate with isopropanol to methanol and isopropyl myristate is presented. This reactive system is suitable for reactive distillation and is used for the investigation carried out in this paper. A simulation model for the steady state and dynamic simulation of the reactive distillation processes was developed. For the validation of this model experiments were carried out. Based on dimensioning calculations, a 6 meter high reactive distillation column (0.1 m i.d.) with 22 bubble cap trays and a total liquid holdup of about 10 litres was constructed and built up. The stationary results obtained from the column show a good comparison between the simulated and the experimental concentration and temperature profiles. The experimentally determined dynamic time constants and sensitivities of the temperature profile of the column could be reproduced very well by the simulation tool developed.     

Comparative studies on the effects of casting solvent on physico‐chemical and gas transport properties of dense polysulfone membrane used for CO2/CH4 separation

The effects of casting solvents on the physico–chemical and transport properties of polysulfone membranes were investigated. Comparative analysis of the properties of membranes prepared from a new solvent (diethylene glycol dimethyether, DEG) and other commonly used solvents (1‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, dimethyl sulfoxide and N,N‐dimethylformamide) were performed using gas permeation, X‐ray diffraction, scanning electron microscopy, thermogravimetric, and Fourier transform infrared spectroscopy analyses. The degree of polymer–solvent interaction was evaluated using the solvent molar volume, and Hansen and Flory–Huggins parameters. Membrane prepared from DEG displayed a relatively higher permeability of 29.08 barrer and CO₂/CH₄ selectivity of 23.12 compared to membranes prepared from other solvents. This improved performance was attributed to the better interaction between the DEG solvent and polysulfone than other solvents that were considered. DEG has the highest molar volume of 142.280 cm³/mol and the lowest Flory–Huggins parameter of 0.129. Thus a thorough evaluation of polymer–solvent interaction is very crucial in preparing membranes with optimum performance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42205.