Stress-Strain Relationships of Reinforcing Bars Subjected to Large Strain Reversals

National Science Foundation Research Grant GI 2993

Effects of Two-Dimensional Earthquake Motion on a Reinforced Concrete Column

National Science Foundation Research Grant GI 2993

Formation of oil droplets in plasticized starch matrix in simple shear flow

This paper describes the effect of simple shear flow on the formation of triglyceride oil droplets in a plasticized starch matrix. An in-house developed shearing device was used that enabled the application of controlled shear flow and rheological characterization of the native maize starch–triglyceride blends at shear stresses of up to 37 kPa. Due to the high viscosity of starch matrix, the viscosity ratio of the continuous starch phase and the dispersed triglyceride phase varied between 10-7 and 10-5. It was possible to create small droplets with a droplet diameter of 2.1 µm using simple shear flow only. An increase in shear rate had no influence on droplet diameter. However, an increase in oil content led to a vast increase in droplet diameter indicating the occurrence of coalescence. The results further show that the maximum stable droplet size in plasticized starch is significantly smaller (up to 100 times) than the predicted values for a Newtonian matrix. The differences of plasticized starch to Newtonian matrices are discussed in detail

Formulierung in festen Matrices: Dispergieren von Öltropfen in plastifizierten Stärkenmatrices

Emulgieren ist ein Fertigungsprozess, der aus der Lebensmittel-, Pharma- und Kosmetikindustrie nicht wegzudenken ist. Mit Hilfe moderner Emulgiertechniken lassen sich eine Vielzahl von Produkten herstellen. Die Neuauflage des Werkes „Emulgiertechnik" liefert hierfür das notwendige Wissen. Emulgierverfahren, aber auch die technologischen Grundlagen, werden anschaulich und praxisnah erläutert

Formulierung in festen Matrices: Dispergieren von Öltropfen in plastifizierten Stärkenmatrices

Emulgieren ist ein Fertigungsprozess, der aus der Lebensmittel-, Pharma- und Kosmetikindustrie nicht wegzudenken ist. Mit Hilfe moderner Emulgiertechniken lassen sich eine Vielzahl von Produkten herstellen. Die Neuauflage des Werkes „Emulgiertechnik" liefert hierfür das notwendige Wissen. Emulgierverfahren, aber auch die technologischen Grundlagen, werden anschaulich und praxisnah erläutert

Multi-scale structural changes of starch and proteins during pea flour extrusion

Dehulled yellow pea flour (48.2% starch, 23.4% proteins, d.b.), was processed by a twin-screw extruder at various moisture contents MC (18–35% w.b.), product temperature T (115–165 °C), and specific mechanical energy SME (50–1200 kJ/kg). Structural changes of extruded pea flour were determined at different scales by measurements of density (expansion), crystallinity (X-ray diffraction), gelatinisation enthalpy (DSC), starch solubility in water and protein solubility in SDS and DTE (SE-HPLC). Foam density dropped from 820 to 85 kg/m3 with increase in SME and T (R2 ≥ 0.78). DSC and XRD results showed that starch was amorphous whatever extrusion conditions. Its solubility in water augmented up to 50%. Increasing temperature from 115 to 165 °C decreased proteins soluble in SDS from 95 to 35% (R2 = 0.83) of total proteins, whereas the proteins soluble in DTE increased from 5 to 45% (R2 = 0.75) of total proteins. These trends could be described by sigmoid models, which allowed determining onset temperatures for changes of protein solubility in the interval [125, 146 °C], whatever moisture content. The SME impact on protein solubility followed similar trends. These results suggest the creation of protein network by Ssingle bondS bonds, implicating larger SDS-insoluble protein aggregates, as a result of increasing T and SME, accompanied by creation of covalent bonds other than Ssingle bondS ones. CSLM images suggested that extruded pea flour had a composite morphology that changed from dispersed small protein aggregates to a bi-continuous matrix of large protein aggregates and amorphous starch. This morphology would govern the expansion of pea flour by extrusion

Etho-ecological study of the Amazon River dolphin, <i>Inia geoffrensis</i> (Cetacea:Iniidae), and the dolphins of the genus <i>Sotalia</i> (Cetacea: Delphinidae) in Guamá River, Amazonia

The occurrence of dolphins in the Belém area, northern Brazil, has been poorly surveyed. In addition, there has been much speculation on the identity of cetaceans inhabiting these brackish waters. Vantage point observations conducted from September 2008 to October 2010 resulted in the observation of 44 groups of dolphins and 79 individuals. Among these, 56 were Inia geoffrensis (71%) and 23 Sotalia. In addition, 21 boat transects were conducted and recorded 50 individuals in 19 sightings. Among sighted during transects 36 were Sotalia (72%) and 14 were Inia. In both observation methods, Tasco Offshore binoculars were used and size and group composition and behaviour (feeding, resting, socializing, travelling and not identified) were recorded. All the categories of behaviour were recorded for Inia and Sotalia, except resting. The Inia group size ranged from one to four individuals, the solitary ones prevailing (57% in vantage point and 67% in boat surveys). Groups ranging from one to seven Sotalia dolphins were registered, in both observation methods. Boto calves were observed in September 2008 and 2009, and February 2010. In April 2010 two botos were sighted in courtship behaviour. Sotalia calves were found in March, May and December 2009. Botos frequently came closer to the right river margin, often entering the Igarapé do Tucunduba, usually in feeding behaviour. On the other hand, Sotalia was sighted in the main channel, or closer to the left margin, opposite to the observation point. Sotalia were observed in the rainy season, except for three sightings in the dry season