Fuzzy approach for preliminary design of weak rock slopes in lignite mines

Rock slope failure modes are either driven by structurally controlled mechanisms (planar, wedge, or toppling failure) or lean upon the highly jointed or weak rock mass (circular failure). Developing practical tools for preliminary slope design is a popular topic among geotechnical society. This study proposes a practical methodology to predict a safe overall slope angle for weak rock slopes of lignite mines. Rock mass rating (RMR) and slope mass rating (SMR) classification systems can be remarkably misleading for weak rocks. Fuzzy modification was proven to improve rock and slope quality predictions. In addition, structurally controlled failures can be estimated more precisely. Later, a popular slope performance chart of Bieniawski that is based on RMR was modified by the fuzzy approach, and the computer models of a weak rock mass failure in a Turkish lignite mine are presented. The modified methodology was proven to be better suited to the weak rock conditions.     

Fast in situ copolymerization of PET/PEN blends by ultrasonically-aided extrusion

An ultrasonically-aided extrusion process was developed for fast in situ compatibilization of immiscible polymer blends. PET, PEN, and their 50/50 blend were ultrasonically extruded at various amplitudes. PET underwent homopolymerization and degradation, respectively, at ultrasonic amplitudes of 7.5 and 10 μm, while PEN underwent degradation at amplitudes of 5, 7.5, and 10 μm. MALDI-TOF mass spectrometry revealed greater amounts of hydroxyl and carboxyl terminated oligomers in ultrasonically treated PET and PEN, indicating their greater reactivity. Ultrasonic treatment at short residence time led to the enhancement of transesterification reaction in the PEN/PET blend, as shown by ¹H NMR and MALDI-TOF, indicating greater randomization with ultrasonic treatment. The latter was also observed through a shift in T_g that closely follows Gibbs-DiMarzio relation and an increase in viscosity of blend with treatment at an amplitude of 10 μm. No crystallinity was observed in the blend due to the already high level of transesterification introduced by extrusion without treatment. Accordingly, crystallinity, mechanical properties, oxygen permeability, and optical clarity of the blend were not influenced by ultrasonic treatment.     

Influence of gamma irradiation on growth and survival of Escherichia coli O157:H7 and quality of cig kofte, a traditional raw meat product

Cig kofte is a traditional Turkish food containing raw ground meat. Samples inoculated with Escherichia coli O157:H7 were irradiated at 0.5–6 kGy with a ⁶⁰Co source and stored at 4 and 25 °C. Total aerobic mesophilic count decreased with increasing irradiation doses, D₁₀ value was 0.83 kGy. Escherichia coli O157:H7 count decreased from 5.1 log₁₀ CFU g^?1 to an undetectable level (<1 log₁₀ CFU g^?1) after 1‐day storage at 4 °C following irradiation at 2 kGy, D₁₀‐value was 0.29 kGy. Irradiation doses up to 2 kGy did not affect sensory quality after 1 day. There was colour loss in samples irradiated at 2 kGy or above and stored for longer periods. Storage of the irradiated products at abused temperature must be avoided for safety assurance. Irradiation at 2 kGy has a great potential for extending the shelf‐life of cig kofte and assuring safety by decreasing the number of E. coli O157:H7 and other bacteria, but further studies with suitable package designs are needed to decrease quality degradation during extended storage.     

Effect of Sintering Duration on Some Properties of Pure Magnesium

Powder Metallurgy and Metal Ceramics - Tribological and physical properties of pure magnesium (Mg) are investigated during sintering for 2, 4, and 6 h at the temperature of 600°C. The pure...     

The elasto-plastic impact analysis of functionally graded circular plates under low-velocities

In this study, three-dimensional elasto-plastic analysis of functionally graded (FG) circular plates under low-velocity impact loads is presented. The FG circular plate is composed of ceramic (SiC) and metal (Al) phases, varying in a predetermined fashion through the plate thickness. The elasto-plastic behaviour of the FG circular plate is described by the TTO model. In the analyses, the ceramic phase is taken to be an isotropic elastic material whereas the metal phase is taken to be elasto-plastic material in accordance with the TTO model. The locally effective material properties were evaluated using homogenization method which is based on the Mori–Tanaka scheme. The effects of compositional gradient exponent and impactor velocity on the elasto-plastic impact response of the FG circular plates are investigated, and results are presented graphical form. The compositional gradient exponent and impactor velocity have significant effects on the elasto-plastic impact response of the FG circular plates. The elasto-plastic impact response of FG circular plates is similar to those of homogeneous plates. Therefore, the TTO model can be used to describe the mechanical behaviour of FG plates beyond the elastic range, assuming that the material response is essentially governed by the spreading of plasticity in the metal phase.     

Inactivation of yeasts in grape juice using a continuous dense phase carbon dioxide processing system

The effects of dense phase CO₂ processing parameters, including temperature (25 and 35 °C), CO₂ concentration (0, 85 and 170 g kg⁻¹) and pressure (6.9, 27.6 and 48.3 MPa), on yeast survival and sensory properties of grape juice were investigated. The dense phase CO₂ process resulted in more than a 6 log reduction in yeast population. As the CO₂ to juice concentration, temperature and pressure increased, the inactivation rate increased. CO₂ in the supercritical state was more effective in inactivating yeast than in the subcritical state. The process did not cause detectable flavor degradation. Dense phase CO₂ processing can be an effective non‐thermal alternative process for pasteurization of grape juice. Copyright © 2005 Society of Chemical Industry     

Utilising grape juice processing by-products as bulking and colouring agent in white chocolate

In this study, grape pomace (mixture of grape seeds and skins) powder (GPP), obtained from grape processing, was used at different concentrations [10.0 (GPP10), 20.0 (GPP10) and 30.0 (GPP10) g/100 g] in white chocolate formulation for the partial replacement of sucrose. The results indicated that GPP addition at a higher concentration (>10.0 g/100 g) significantly affected the particle size, moisture content, texture and flow behaviour of white chocolate samples (P < 0.05). However, using GPP at a concentration of 10.0 g/100 g had advantages for physicochemical and flow properties. As expected, under simulated in vitro digestion conditions, the bioaccessibility of total phenolic compounds in saliva, gastric juice and intestinal juice for GPP10 samples was significantly higher than the control (P < 0.05). In conclusion, results of the study showed that it was possible to partially replace the sucrose with GPP at a concentration of 10.0 g/100 g in white chocolate formulations.     

Investigation of using possibility of grape pomace in wafer sheet for wheat flour substitution

In this study, grape pomace (GP), a by-product consisting of grape skins and seeds rich in dietary fibres and polyphenols, was used in wafer sheets at different concentrations [5.00 (GP5), 10.0 (GP10), and 15.0 g 100 g⁻¹ (GP15)] for the partial replacement of wheat flour (WF) and improve the functionality of wafer sheets. The GP inclusion at concentrations higher than 5.00 g 100 g⁻¹ significantly affected the texture of sheets as well as the flow behaviour of batters, resulting in softer sheets and more viscous batters (P < 0.05). Moisture contents did not significantly change after GP addition (P > 0.05). After the addition of GP, the L* values decreased and the a* values increased, making the wafers darker (P < 0.05). Moreover, under simulated in vitro digestion conditions, the bioaccessibility of total phenolic compounds in saliva, gastric juice, and intestinal juice was significantly higher than control even at the lowest GP concentration (P < 0.05). Regarding sensory properties, only smoothness and crispness were significantly affected by GP addition, and samples were found to be crisper with higher concentrations of GP. In conclusion, it is possible to partially replace the WF in wafers with GP at a concentration of 5.00 g 100 g⁻¹ to develop a product with higher functionality and nutrient content.