Monolithic protective coatings for billet continuous casting machine tundishes

Conclusions Magnesia-spinellide refractory coatings for protection of tundish linings of brick refractory parts have been developed.The use of protective coatings makes it possible to increase the lining life by five heats, to decrease the refractory consumption by 1.6 kg per ton of steel, and to increase the productivity of billet continuous casting machines.Translated from Ogneupory, No. 7, pp. 49–52, July, 1984.     

The Effect of Bath Parameters on the Electrocrystallisation of Cox–Cu100−x Alloys on Stainless Steel Cathode

The electrocrystallisation of the alloys of Co_x–Cu_100?x onto stainless steel cathode was investigated by performing cyclic voltammetry (CV) to understand the mechanism of deposition. The deposit morphology and crystal structure of deposit were analysed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The kinetic parameters were obtained from the cathodic polarisation of the CV to predict the electron transfer mechanism in the process. The transfer coefficient value (α) of the kinetic parameter revealed that both cathodic and anodic processes were unsymmetrical. It was demonstrated that the current efficiency of the deposit increased from 96.8% at pH 4.0 to 99.2% at pH 7, and then it dropped to 89.7% at pH 8. Before the deposition of the Co–Cu alloy, the initial copper deposition occurred at ??0.24 V and peaked at ??0.66 V. This was followed by the deposition of the Co–Cu alloy at ??1.04 V, which occurred after the deposition potential of Cu²⁺ (??0.24 V) and Co²⁺ (??0.89 V). The current then increasesd with a small increment in applied potential due to subsequent diffusion-controlled copper reduction along with the co-deposition of Co. The variation in the kinetic parameters was also reflected in the current efficiencies, the deposit morphologies, the crystallographic orientations and the nucleation overpotential values. The percentage of cobalt content in the alloy was observed to decrease in at.% from 54.35% at pH 4 to 49.86% at pH 6 and further to 20.62% at pH 8. The structure of the deposited alloy confirmed the formation of a single solid solution phase having different planes such as (222), (311), (220), (200) and a sharp peak due to face-centred cubic structure with (111) plane. This strong peak along with other similar peaks were observed in all the XRD of the deposit obtained at pH 4, 6 and 8. The morphology of the deposit characterised by the SEM showed that the deposit changed from a bitter gourd to a regular cauliflower-like structure as the pH value changed from 4 to 8.

     

Comparison of ZnO and Ti-doped ZnO sensing membrane applied in electrolyte-insulator-semiconductor structure

In this paper, we demonstrate electrolyte-insulator-semiconductor devices for biochemical sensing applications prepared from ZnO and Ti-doped ZnO sensing membranes deposited on Si substrates by radio frequency sputtering. The structural, morphological, and compositional features of these deposited films with multitemperature annealing were studied using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. Sensitivity, linearity, hysteresis, and drift rate were measured to determine the sensing and reliability performance of all fabricated devices. Compared to the ZnO electrolyte-insulator-semiconductor (EIS), the Ti-doped ZnO EIS sensor annealed at 700 °C exhibits a higher sensitivity of 57.56 mV/pH, lower hysteresis of 2.79 mV, and lower drift rate of 0.29 mV/h. For Ti-doped ZnO, sensitivities of 3.62 mV/mM and 6.42 mV/mM were obtained for urea and glucose sensing, respectively. The improvements are owing to Ti-doping, which produces a rougher sensing surface, a well-crystallized grain structure, and thinner silicate and SiO₂ at the silicon-oxide interface.     

Owners perception on the adoption of building envelope energy efficiency measures in Swedish detached houses

The paper focuses on Swedish homeowners’ need for and perceptions about adopting building envelop energy efficiency measures. The paper is based on a questionnaire survey of 3059 homeowners (response rate of 36%) selected by stratified random sampling during the summer of 2008. The results showed that 70–90% of the respondents had no intention of adopting such a measure over the next 10 years. The main reasons for non-adoption were that homeowners were satisfied with the physical condition, thermal performance, and aesthetics of their existing building envelope components. A greater proportion of respondents perceived that improved attic insulation has more advantages than energy efficient windows and improved wall insulation, but windows were more likely to be installed than improved attic insulation. Respondents gave high priority to economic factors in deciding on an energy efficiency measure. Interpersonal sources, construction companies, installers, and energy advisers were important sources of information for homeowners as they planned to adopt building envelope energy efficiency measures. Policy measures to facilitate the rate of adoption of energy efficient building envelope measures are discussed.     

Formation of Calcium Titanate During Electroreduction of TiO2 in Molten CaCl2 Bath

The direct electrochemical reduction of a TiO₂ cathode in a molten CaCl₂ bath to produce titanium metal invariably results in the formation of CaTiO₃ as an intermediate product. To obtain even more insight into the formation of CaTiO₃, experiments are performed in open-circuit conditions as well as at a cell voltage of 2?V for different time periods. In this study, we examine the conversion of TiO₂ to CaTiO₃ in the molten CaCl₂ bath. Prolonged electrolysis experiments are conducted and the newly transformed phases are analyzed using X-ray diffraction (XRD). The formation of CaTiO₃ and its subsequent transformation to different species during reduction is discussed. An approach for preparing CaTiO₃ chemically by treating the TiO₂ electrode in CaCl₂ bath and subsequently reducing it by electrochemical means to produce titanium metal has been proposed.     

Structural Investigations of La-2125 Mixed Oxide Superconducting System

Crystallographic studies on the (La_{2 – x} Nd _x )Ca _y Ba₂Cu_{4 + y} O _z [y = 2x; 0.0 x 0.5] samples are carried out using neutron diffraction technique. The analysis of the neutron diffraction patterns for the series of samples with 0.0 x 0.5 was done using Rietveld method. The La₂Ba₂Cu₄Oz (La-224, x = 0.0) system exhibits tetragonal phase and is a nonsuperconductor, which on addition of a CaCuO₂ rock salt like layer becomes superconducting. It is important to note the significant role played by Ca-doping in improvising the superconducting properties. Analysis of the structural data reveals that, as Ca concentration increases, the unit cell volume decreases while T _c increases with a maximum value of 78 K for y = 1.0. The detailed crystal structure for LaNdCaBCO series of samples has been studied in the light of changes in bond lengths with increase in Ca concentration and its role in turning on the superconductivity.     

Ultrathin wideband slot and patch FSS elements with sharp band edge characteristics

ABSTRACT

Two diverse applications of FSS as bandpass and bandstop filters with wideband and sharp band edge characteristics are investigated in this paper. The proposed design comprised of a tapered tripole element in aperture and patch type printed on either side of a dielectric material to act as bandpass and bandstop filters respectively. The structures are ultrathin in design; structures comprise two metallic layers, isolated by single thin substrates with a thickness of 0.027λ. In the case of bandpass, the structure shows a relative bandwidth (?1 dB) of 8.87% with insertion loss better than 0.2 dB at normal incidence. Whereas, in the case of bandstop, it shows 24.36% (?10 dB). Further, the parametric analysis is performed for obtaining optimal performance. Both structures in the proposed form have spectacular application in bandpass filtering (slot FSS) and electromagnetic shielding (patch FSS). Further, two design techniques are presented namely dielectric encapsulation and substrate integrated waveguide (SIW) based FSS structures to develop a periodic structure to cater the high power handling in microwave sources. Finally, a fabricated prototype along with experimental verification proves the validity of simulated results.     

An adopter-centric approach to analyze the diffusion patterns of innovative residential heating systems in Sweden

Innovation and diffusion of renewable energy technologies play a major role in mitigation of climate change. In Sweden replacing electric and oil heating systems with innovative heating systems such as district heating, heat pumps and wood pellet boilers in detached homes is a significant mitigation option. Using an adopter-centric approach, we analyzed the influence of investment subsidy on conversion of resistance heaters and oil boilers, and the variation in diffusion pattern of district heating, heat pumps and pellet boilers in Swedish detached homes. Results from questionnaire surveys of 1500 randomly selected homeowners in September 2004 and January 2007 showed that more than 80% of the respondents did not intend to install a new heating system. Hence, about 37% of the homeowners still have electric and oil heating systems. The government investment subsidy was important for conversion from a resistance heater, but not from an oil boiler. This is because homeowners currently replacing their oil boilers are the laggards, while those replacing resistance heaters are the ‘early adopters’. Economic aspects and functional reliability were the most important factors for the homeowners when considering a new heating system. There is a variation in the perceived advantages associated with each of the innovative heating systems and therefore, the diffusion patterns of such systems vary. Installers and interpersonal sources were the most important communication channels for information on heating systems.     

Rationally designed curcumin laden glycopolymeric nanoparticles: Implications on cellular uptake and anticancer efficacy

Overexpression of glucose transport proteins (GLUTs) plays a pivotal role in the survival of cancer cells. Hence, targeting GLUTs receptors using glucose-based polymers can fill up the lacuna of cancer treatment by confining the dissemination and accumulation of chemotherapeutic drugs on cancer cells. The present study addressed the preparation of glycohomopolymer (PMG), PEG-based di- (PEG-b-PMG) and tri-block (PMG-b-PEG-b-PMG) polymers using atom transfer radical polymerization and their potential in the development of novel nanoparticulate drug delivery system. Curcumin-loaded glycopolymer nanoparticles were fabricated by nanoprecipitation method and investigated for various physicochemical parameters such as particle size, zeta potential, polydispersity index, drug loading, morphology, and dissolution profile. Homoglycopolymer nanoparticles exhibited lower average particle size (240.16 ± 21.41 nm), higher zeta potential (−28.72 ± 4.25 mV), and entrapment efficiency (74.61 ± 5.03%) compared to their block copolymer counterparts. Optimized formulation exhibited diffusion and dissolution-controlled drug release behavior. In vitro cell line studies demonstrated significantly superior cytotoxicity, clonogenic inhibitory and cellular uptake potential in MCF-7 cells besides receptor recognizing property of optimized curcumin nanoparticulate formulation compared to free curcumin. These findings elucidate that curcumin homoglucopyranoside nanocarriers can be a promising drug delivery option for effective management of breast cancer. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48954.