Effect of Oat β-Glucan on the Rheological Characteristics and Microstructure of Set-Type Yogurt

The oat β-glucan (OG) was added into set-type yogurt as a functional ingredient, in order to evaluate effects on the rheological characteristics and microstructure of set-type yogurt. When the OG concentration increased from 0 to 0.3%, the WHC gradually increased. At 0.3% OG, the set-type yogurt had the highest WHC of 94.67%. Additionally, the WHC continuously decreased, reaching the lowest WHC (about 80%) at 0.5% OG. When 0.3% OG was added, the highest score of sensory evaluation was about 85. The rheological result showed that the fermentation process went through the changes as follows: solid → liquid → solid → liquid. The addition of 0.3% OG decreased the fermentation time of set-type yogurt by about 16 min, making yogurt more inclined to be liquid. The acidity of set-type yogurt with OG was slightly higher. The result of microstructure showed that the addition of OG destroyed the three-dimensional network structure of yogurt, and some spherical aggregate particles could be clearly observed at 0.3% OG. Overall, this study provided a theoretical basis for the application of OG in set-type yogurt.

Three-Dimension Random Aggregate Generation of Numerical Concrete Model

The aggregate generation of concrete is one of the important problems in concrete mesoscopic mechanics. Firstly, the mesoscopic numerical model with spherical aggregates is obtained by the method of excluding the occupied space, and fully-graded concrete model of high aggregate content can be quickly generated. Then, based on the spherical aggregate model, the generation method of random convex polyhedral aggregates is proposed. Finally, a full-graded concrete model with spherical aggregates is shown in Case 1 and a cylindrical concrete model with random convex polyhedral aggregates is shown in Case 2. The result shows that the aggregates are equally distributed in the concrete models which can be used in the study of mesoscopic numerical calculation.

Morphology control of BiFeO3aggregatesviahydrothermal synthesis

The assembly of crystalline building units with specific shape-derived properties into aggregates is often required to broaden their practical applications because the properties of the building units can be fully integrated and used in the aggregates owing to their orientation. Herein, morphology-controlled BiFeO3aggregates composed of oriented crystalline building units were fabricatedviaa hydrothermal process without any additives, and the effects of the supersaturation conditions on the aggregation state were investigated. The supersaturation condition, controlled by varying the KOH concentration, was found to affect the shape of the crystalline building units. For lower supersaturation conditions, the morphology of the aggregates was found to be closely related to the shape of the fundamental building units, and the results indicated that oriented attachment occurred between specific crystal faces of the building units. Under a high supersaturation condition, the morphology of the aggregate did not reflect the shape of the building units and a monodispersed spherical aggregate was obtained. Further, the internal microstructures of the aggregates changed from homogeneous and dense to sparse core and dense shell structures with an increasing supersaturation condition. The formation mechanism of these morphology-controlled aggregates is discussed using microstructure analyses. The present approach to control the morphology of aggregates using the shape of the building units and aggregation kinetics could also be applicable for other microcrystalline aggregated systems in addition to BiFeO3.

The Effect of Paste Preparation and Annealing Temperature of ZnO Photoelectrode to Dye-Sensitized Solar Cells (DSSC) Performance

Dye-sensitized Solar Cells (DSSCs) have been successfully fabricated by using ZnO nanoparticles (NPs). The ZnO photoelectrode was prepared by using pastes solved in water-based and ethanol-based solvent. The ZnO NPs was synthesized by copresipitation method, prepared by reaction from Zinc Acetate with diethylene glycol (DEG). The obtained ZnO NPs has 13.93 nm particle diameter. Scanning Electron Microscopy (SEM) showed that ZnO NPs from monodisperse spherical aggregate with particle diameter of approximately 300nm. The band gap was found of 3.29eV. Variations of annealing temperature were carried out in photo-electrode fabrication. This work employs extracts from mangosteen pericarp as natural dye for fabrication of DSSCs. DSSCs were fabricated in sandwich structure with redox couple electrolyte I3-/I- and Pt-catalyst counter electrode. The best efficiency of 0.11% (Voc = 232.4 mV, Jsc = 111.6 µA/cm2, FF = 61.41 %) was obtained for DSSCs using ZnO photo-electrode prepared by ethanol-based paste and 200°C of annealing temperature.

Research on Properties of Coastal Natural Spherical Aggregate Concrete

Our country has a long coastline and there are a lot of natural pebbles in coastal region. Applying natural pebbles in concrete is of great engineering significance and prospect. To measure the performance of coastal natural pebbles concrete and study the effect of aggregate on concrete properties, this article put forward a new comparison conditionthe same slump constant and cement dosage based on properties of coastal natural pebbles concrete and crushed stone concrete. Prepare different strength concrete under this condition. The compressive strength of pebble concrete is 100.5%110.7% times of stone concrete. The bending strength and fatigue strength are 97.8%108.1%, 135.8%176.6% respectively. This explains good static and fatigue properties of coastal natural pebbles. Pebble concrete has significant fatigue strength advantages in cement concrete pavement and concrete member under dynamic loading.

STEREOLOGICAL ESTIMATES FOR ROUGHNESS AND TORTUOSITY IN CEMENTITIOUS COMPOSITES

Relatively weak interfaces between aggregate grains and the cementitious matrix initiate the damage evolution process leading to fracture. Coalescence between nearby interface cracks is promoted by the small nearest neighbour distances in a dense random packing of the aggregate. The fracture surface is therefore modelled as a dividing plane from which particles protrude. Assuming spherical aggregate, roughness is obtained as the global geometrical-statistical expression for the increase in fracture surface area due to a multitude of dome-like caps of various sizes. Transport phenomena in concrete are equally influenced by the aggregate, because traversing water-born molecules or ions have to go around the dense grains. This route is additionally promoted by the relatively high porosity in the interfacial transition zone. The planar and linear concepts of tortuosity in the transport path are analogous to those of roughness.