ABSTRACT
Colemanite is a preferred boron mineral in industry, such as boric acid production, fabrication of heat resistant glass, and cleaning agents. Dissolution of the mineral is one of the most important processes for these industries. In this study, dissolution of colemanite was examined in water saturated with carbon dioxide solutions. Also, prediction of dissolution rate was determined using artificial neural networks (ANNs) which are based on the multilayered perceptron. Reaction temperature, total pressure, stirring speed, solid/liquid ratio, particle size, and reaction time were selected as input parameters to predict the dissolution rate. Experimental dataset was used to train multilayer perceptron (MLP) networks to allow for prediction of dissolution kinetics. Developing ANNs has provided highly accurate predictions in comparison with an obtained mathematical model used through regression method. We conclude that ANNs may be a preferred alternative approach instead of conventional statistical methods for prediction of boron minerals.
Subject(s)
Kinetics , Models, Theoretical , Neural Networks, Computer , Solubility , Algorithms , Boron/chemistry , Minerals/chemistryABSTRACT
OBJECTIVE: To evaluate the tuberculin response after bacille Calmette-Guérin (BCG) vaccination in preterm infants. METHODS: Thirty-five infants born at <35 weeks gestation were included in the study. An intradermal injection of 0.05 ml BCG vaccine was given to each infant at postnatal months 2-3. Tuberculin skin tests (TSTs) were done 8-12 weeks after vaccination using 0.1 ml of 5 TU purified protein derivative (PPD). The diameter of induration was measured 72 h later and > or =5 mm induration was taken as a positive response. RESULTS: The babies had a mean birth weight (SD) of 1650 (424) g, and a gestational age of 32.4 (2.1) weeks. The TST was positive in 20 (57%) of the infants. The mean body weight of the tuberculin-positive babies was significantly higher than the others at both vaccination and TST. No difference was found between groups concerning sex, birth weight, gestational age, intrauterine growth and postnatal age at BCG vaccination and TST. CONCLUSION: BCG vaccination in preterm infants at months 2-3 of postnatal life results in a high percentage of BCG scarring and 57% TST conversion. A positive tuberculin response was significantly related to the postnatal weight gain of the preterm infants.
Subject(s)
BCG Vaccine , Infant, Premature/immunology , Tuberculin Test , Tuberculosis, Pulmonary/prevention & control , BCG Vaccine/administration & dosage , Birth Weight , Female , Humans , Infant , Infant, Newborn , Injections, Intradermal , Male , Tuberculin/immunology , VaccinationABSTRACT
Integrated iron and steel plants generate large amounts of metallurgical slag, which usually contains some quantity of metals or mixtures of oxides that could be treated to be recycled in various applications. The conventional method for disposal of slags is dumping. However, it is possible to process the slags to be used in the production of metallic iron, or as an additive in cement making. In this study, a basic oxygen furnace (BOF) steelwork slag obtained from the Kardemir integrated iron and steel works, Karabuk, Turkey is used. A drum magnetic separator system with pre-engineered crucial processing parameters of drum revolution speed, drum radius, drum flesh thickness, and magnitude of the magnetic field applied is utilized, as these parameters have a competing influence on the results. Subsequently, the effects of slag grain size and the drum-blade gap are investigated in the separation efficiency of magnetic grains. It is found that collection of magnetic grains is improved by decreasing the grain size of slags and moreover, the collection of magnetic grains fraction is increased with an increase in the gap between the blades and drum.
Subject(s)
Magnetics , Metallurgy/methods , Refuse Disposal/instrumentation , Refuse Disposal/methods , Steel , Waste Products , Particle Size , TurkeyABSTRACT
Growth and aflatoxin production byAspergillus flavus (MAM-268 C17, TNS=98) on autoclaved coconut, black pepper, crushed red pepper, red pepper powder were studied. Coconut were found to be a better substrate for fungal growth, as well as aflatoxin production. Red pepper powder could be considered as a poor substrate for fungal growth. The amount of aflatoxin found in crushed red pepper under laboratory conditions is much less compared with coconut, black pepper and red pepper powder.