Correlations of in situ modulus of deformation with elastic modulus of intact core specimens and RMR values of andesitic rocks: a case study of the İzmir subway line

Bulletin of Engineering Geology and the Environment - The main purpose of this paper is to obtain the rock mass rating (RMR) from different methods considering either the elastic modulus of intact...     

Fractal parameter approach on weathering grade determination of Çeşme (Izmir, Turkey) tuffs

Tuffs, classified as weak rock to hard soil with respect to their strength, slake on exposure, hence engineering problems occur as they weather and loosen. Weathering grades were determined in the field and in the laboratory using petrographic, chemical, physico-mechanical, P-wave velocity, and slake durability measures. Strong correlations were found between chemical weathering index, average porosity and fractal parameters based on the slake durability test results. The shapes of the tuff particles before and after the slaking test were investigated using the fractal dimension method to explain numerically the variations of the surface characteristics of the test samples due to weathering. Two fractal parameters are proposed for the second and fifth cycles of the slake durability test. The study has shown that for assessing the weathering state of tuffs, the fractal dimension approach could be a more effective tool than other methods of weathering grade determination.     

TREATMENT OF WASTE PICKLING LIQUORS: PROCESS SYNTHESIS AND ECONOMIC ANALYSIS

An economic analysis was carried out for three different recycle/recovery options for waste pickling liquors from hydrochloric acid pickling baths in an existing small-mid scale plant presently neutralizing and discarding waste pickling liquors. The analysis was based on process synthesis and design, which were completed by using real plant data along with some experimental work. Three basic schemes were studied: the addition of metallic iron to convert unused hydrochloric acid to ferrous chloride recovery by evaporation and recycling of a large proportion of the unused acid, and removal of ferrous chloride by crystallization to enable the recycling of the unused acid. All three schemes were evaluated at the same concentration of ferrous chloride by-product, which can be directly sold or converted later to ferric chloride, which has a higher market value. Extrapolation of existing solubility data was verified experimentally, cost estimation was done for purchased equipment and utility requirement, and feasibility analyses of the process schemes were completed. Depending on the market demand for the by-product and the criteria chosen, metallic iron addition or evaporation found to be recommendable, while the relatively more expensive crystallization process was also found to bring improvement over the no-treatment alternative.     

Wet separation of wheat flours into starch and gluten fractions: the combined effects of water to flour ratio–dough maturation time and the effects of flour aging and ascorbic acid addition

The process of making a dough, allowing time for maturation, dispersing the dough in water and wet sieving/washing to obtain a protein fraction and starch milk was studied using response surface methodology by changing the water to flour ratio in dough making (400–710 g kg^?1), maturation time (45–660 s) and the type of flour. Two grades of bread wheat flour and durum clear flour were studied. The effects of aging at ambient temperature for up to 29 days and the addition of ascorbic acid at 100 or 500 mg kg^?1 flour on separation behaviour were also studied for freshly milled high‐grade (65% extraction) bread wheat flours at constant maturation time, 600 s, and at optimum farinograph water absorption value. The quantities and dry matter contents of the protein fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailings and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content. The fractional recoveries of dry matter and protein in the protein fraction, prime starch, tailings and decantate were calculated for each experiment. The acid values of flour oils were also determined on some aged flour samples. The results indicated superior separation characteristics in high‐grade wheat flour compared with lower‐grade flours. The water to flour ratio was more influential than maturation time within the range studied. Contrary to the initial expectation, no statistically significant effect of flour aging was observed in the studies with no additive, and ascorbic acid addition was not found to improve the wet separation behaviour, the separation behaviour becoming even worse at the 100 mg kg^?1 level. Acid value showed a slight increase with time. © 2002 Society of Chemical Industry     

Use of a spouted bed to improve the storage stability of wheat germ followed in paper and polyethlyene packages

Stabilization of wheat germ by heating in a spouted bed for 180–540 s with air at 140–200 °C was studied. The lipase activity decreased by 6–65%. Wheat germ processed at 200 °C for 360 s was ranked highest in sensory evaluation, described as having ‘a golden color’ and ‘nutty flavor’, and its lipoxygenase activity had decreased by 91.2%. This product and raw wheat germ were stored in paper, polyethylene and vacuum‐packed polyethylene pouches at 5 °C, room temperature (18–26 °C) and 40 °C, and the moisture contents, water activities, free fatty acid contents and peroxide values were followed for 20 weeks. The increases were faster in paper pouches than in the polyethylene ones; vacuum packaging in polyethylene did not bring about significant improvement. The peroxide values of raw samples exceeded 10 meq O₂ kg^?1 oil after 3–23 days while those of the processed samples stored at room temperature or 5 °C were still less than 10 after 20 weeks. The free fatty acid content and peroxide value changes were expressed by zero order kinetics, resulting in similar activation energies for the raw and processed samples. Copyright © 2005 Society of Chemical Industry     

Separation of bread wheat flours into starch and gluten fractions: effect of water temperature alone or in combination with water to flour ratio

Two different commercial bread wheat flours (BF‐I, 65% extraction and BF‐V, 86% extraction) were separated into gluten and starch milk by making a dough, allowing some time for maturation, dispersing the dough in water and wet sieving/washing. The effect of using of warm water (20–45 °C) for dough making and washing on separation was studied for BF‐I flour at 640 g kg^?1 water to flour ratio of and 300 s maturation time, and the separation was found to improve with increase in temperature. The combined effects of water temperature (20–50 °C) and water to flour ratio (640–780 g kg^?1 for BF‐I and 620–870 g kg^?1 for BF‐V) were studied at 600 s maturation time. The quantities and dry matter contents of the gluten fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailing and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content, and the fractional recoveries of dry matter and protein in the gluten fraction, prime starch, tailings and decantate were calculated. The results indicated the optimum point for BF‐I flour to be the combination of optimum farinograph water absorption and 40 °C. BF‐V showed very poor separation behaviour within the ranges studied. At the optimum farinograph water absorption the use of warm water for dough making and 20 °C water for washing steps was also tried, but no significant improvement over the 20 °C results was obtained. © 2002 Society of Chemical Industry