21 research outputs found
Development of Anhydrous Ethanol Purification: Reduction of Acetal Content and VaporâLiquid Equilibrium Study of the EthanolâAcetal Binary System
Treatment of welding electrode manufacturing plant wastewater using coagulation/flocculation-nanofiltration as a hybrid process
Foreign Banks are Branching out: Changing Geographies of Hungarian Banking, 1987â1999
Walking through the streets of Budapest in spring 1999 could have given you the following impression: the supermarkets (Spar), the milk products sold there (Danone, MĂŒller), and the property markets (OBI) come from different Western European countries such as the Netherlands, France and Germany. Almost all fast food restaurants (McDonalds, Pizza Hut, KFC) and many hotels (Hilton, Mariott) have their origins in the US; shoes and clothes offered in downtown are designed in Italy or France (Benetton, Marco Polo); medicine is predominantly produced in Switzerland (Novartis, Roche) and the banks as well as the car dealerships have their roots everywhere in the so-called Western world - usually including Japan and other Asian countries with major (car) companies - but not in Hungary itself...
Nanofiltration and electrodialysis: alternatives in heavy metal containing high salinity process water treatment
Development of Anhydrous Ethanol Purification: Reduction of Acetal Content and VaporLiquid Equilibrium Study of the EthanolAcetal Binary System
Navigated 3Dâultrasound versus conventional neuronavigation during awake resections of eloquent low-grade gliomas: a comparative study at a single institution
Decomposition kinetics of gaseous ozone in peanuts Cinética da decomposição do gås ozÎnio em amendoim
This study was conducted to evaluate the decomposition kinetics of gaseous ozone in peanut grains. This evaluation was made with 1-kg peanut samples, moisture contents being 7.1 and 10.5% wet basis (w.b.), placed in 3-liter glass containers. The peanut grains were ozonated at the concentration of 450 ”g L-1, at 25 and 35 ÂșC, with gas flow rates of 1.0 and 3.0 L min-1. Time of saturation was determined by quantifying the residual concentration of ozone after the gas passed through the grains to constant mass. The decomposition kinetics of ozone was evaluated after the grain mass was ozone-saturated. For the peanut grains whose moisture content was 7.1% (w.b.), at 25 and 35ÂșC and with flow rates of 1.0 and 3.0 L min-1, the values obtained for time of saturation of gaseous ozone ranged between 173 and 192 min; the concentration of saturation was approximately 260 ”g L-1. For the grains whose moisture content was 10.5% (w.b.), a higher residual concentration of gaseous ozone was obtained at 25 ÂșC, that of 190 ”g L-1. As regards the half-life of ozone, the highest value obtained was equivalent to 7.7 min for grains ozonated at 25 ÂșC, while for those with moisture content of 10.5% at 35 ÂșC, half-life was 3.2 min. In the process of ozone decomposition in peanut grains, temperature was concluded to be the key factor. An increase of 10 ÂșC in the temperature of the grains results in a decrease of at least 43% in the half-life of ozone.<br>Este trabalho foi desenvolvido com o objetivo de avaliar a cinĂ©tica de decomposição do ozĂŽnio em grĂŁos de amendoim. Para avaliar a cinĂ©tica de decomposição do gĂĄs, utilizaram-se amostras de 1 kg de amendoim, com teores de ĂĄgua de 7,1 e 10,5% base Ășmida (b.u.), acondicionadas em recipientes de vidro com capacidade de 3 L. Os grĂŁos de amendoim foram ozonizados na concentração de 450 ”g L-1, nas temperaturas de 25 e 35 ÂșC, e vazĂ”es do gĂĄs de 1,0 e 3,0 L min-1. Determinou-se o tempo de saturação, quantificando-se a concentração residual do ozĂŽnio apĂłs a passagem do gĂĄs pela massa de grĂŁos, atĂ© que a mesma se mantivesse constante. A cinĂ©tica de decomposição foi avaliada depois da saturação da massa de grĂŁos com o gĂĄs. Nessa etapa, obteve-se a concentração residual do ozĂŽnio, depois de perĂodos de repouso, durante os quais o gĂĄs reagia no meio poroso, e dessa forma, era decomposto. Um modelo cinĂ©tico de primeira ordem foi ajustado aos dados da concentração residual em função do tempo, apĂłs linearização. A partir dos valores da constante da taxa de decomposição, definida como a inclinação da reta referente ao modelo cinĂ©tico de primeira ordem linearizado, foi possĂvel obter a meia-vida do ozĂŽnio em grĂŁos de amendoim. Para os grĂŁos de amendoim com teor de ĂĄgua de 7,1% (b.u.), nas temperaturas de 25 e 35 °C, e vazĂ”es de 1,0 e 3,0 L min-1, os valores obtidos de tempo de saturação do gĂĄs permaneceram na faixa entre 173 e 192 min, com concentração de saturação de aproximadamente 260 ”g. L-1. Para os grĂŁos com teor de ĂĄgua de 10,5% b.u., obteve-se maior concentração residual do gĂĄs na temperatura de 25 ÂșC, sendo igual a 190 ”g. L-1. No que se refere ao tempo de meia-vida do ozĂŽnio, o maior valor obtido foi equivalente a 7,7 min para os grĂŁos ozonizados na temperatura de 25 ÂșC, enquanto para aqueles com 10,5% de teor de ĂĄgua, na temperatura de 35 ÂșC, foi de 3,2 min. Concluiu-se que, no processo de decomposição do ozĂŽnio em grĂŁos de amendoim, o fator determinante Ă© a temperatura. Observou-se que o aumento de 10 ÂșC na temperatura dos grĂŁos implica decrĂ©scimo de, pelo menos, 43% no tempo de meia-vida do gĂĄs