Effect of Process Variables on Rice Flour Functional Properties, and Porous Structure Properties of Rice and Wheat-Based Leavened Food Products

Research background. Various processing techniques impart significant impacts on physicochemical and functional properties of rice flour and the quality of the final products. This study aims to modify rice flour from different treatment combinations and to select the best treatment combination in developing rice-wheat-based leavened food products. Experimental approach. Eight treatment combinations were applied on rice flour according to 23 factorial design considering three variables at two levels namely, pre-treatment for rice grain modification [heat-moisture treatment, dual modification treatment (soaking rice grains in a NaHCO3 solution followed by heat treatment)], grinding technique (dry grinding, wet grinding), and flour particle size (75-180 µm, <75 µm). Eight dough samples were prepared by mixing 50 g of rice flour from each treatment with 50 g wheat flour. Thereafter, the dough samples were subjected to fermentation and gelatinization under pressurized condition (externally applied 1.0 kg/cm2 initial air pressure condition) in a pressure adjustable chamber. Results and conclusions. Results rendered that rice flour sample that underwent heat-moisture treatment followed by wet grinding and particle size at 75-180 µm, impart to improve the leavened gas retention capacity and obtaining highly porous and better textured rice-wheat based leavened food products under 1.0 kg/cm2 externally applied initial air pressure condition. Novelty and scientific contribution. Rice flour can be modified according to the present method to improve functional flour properties and the textural and structural properties of rice-wheat based leavened food products. Also, conducting fermentation and gelatinization under pressurized condition is a novel food processing technique, which contributes in restricting the escape of leavened gas from rice-wheat composite dough mass.

Effect of Graphene nanoplatelets (GNP) reinforcement on grindability of zirconium diboride ceramics

The grindability of graphene nanoplatelets (GNP) reinforced ZrB2 was studied using resin bonded diamond grinding wheel under dry and wet conditions. A comparative study of grinding forces was performed at selected wheel surface speeds and depth of cuts for surface grinding. ZrB2-GNP showed lower normal grinding forces due to the reduced hardness. The presence of GNP reinforcement in ZrB2 resulted in lower tangential forces and reduced specific grinding energy due to the role of GNP as solid lubricant. The measured forces showed good correlation with the micro cutting model for ZrB2 and ZrB2-GNP under dry condition. The tangential forces showed same trend as normal forces at different depth of cuts and wheel surface speeds for both ZrB2 and ZrB2-GNP with average force ratios of 0.3 and 0.35 respectively. The presence of porosity in ZrB2 increased the normal grinding forces during wet grinding. Scanning Electron Microscope (SEM) images of the grinding chips indicated a mixture of both the ductile mode and the brittle mode of material removal with predominantly brittle fractured chips. Energy Dispersive Spectroscopy (EDS) confirmed the presence of GNPs in ZrB2-GNP grinding chips. The topography of the grinding wheel showed higher wheel loading after the dry grinding than that of wet grinding. The wet grinding resulted in relatively lower surface roughness (Ra values) compared to that of dry grinding.

Grindability study of hard to cut AISI D2 steel upon ultrasonic vibration-assisted dry grinding

Ultrasonic vibration-assisted dry grinding is a sustainable hybrid manufacturing technology that decreases the negative environmental impact of coolant, reduces manufacturing costs, and improves surface integrity. The present investigation analyses the mechanisms associated with ultrasonic vibration-assisted dry grinding of AISI D2 tool steel with an alumina grinding wheel. It also compares the influence of traditional dry grinding and traditional wet grinding modes with the ultrasonic vibration-assisted dry grinding mode at different ultrasonic vibration amplitudes. Ultrasonic vibration was applied to the sample in the longitudinal feed direction. Further, kinematics of the abrasive grit path during the traditional grinding and ultrasonic vibration-assisted dry grinding is presented schematically. In this research, the impacts of ultrasonic vibration amplitude as well as the depth of cut on the process yields such as ground surface topography, grinding force, specific grinding energy, force ratio, surface finish, microstructure, and hardness were investigated experimentally. Experimental results revealed that the highest decline in tangential and normal grinding forces in ultrasonic vibration-assisted dry grinding at ultrasonic vibration amplitude 10 µm and the reduction in surface roughness parameter ( Ra, Rq, and Rz) in ultrasonic vibration-assisted dry grinding was 43.23%, 42.59%, and 33.69%, respectively, in comparison to those in traditional dry grinding and 26.35%, 26.94%, and 27.48%, respectively, in comparison to those in traditional wet grinding. It was observed that ultrasonic vibration-assisted dry grinding is beneficial as the profile produced by ultrasonic vibration-assisted dry grinding has a comparatively flat tip, and profile points are shifted to the bottom of the mean line. This study is expected to assist ultrasonic vibration-assisted dry grinding of hard materials.

Monitoring of the Effect of Grinding Raw Material Mixture and Soaking on the Formation of Monoclinic Phases of Alite

The article monitors the effect of length of grinding in the process of homogenization of raw material mixture and soaking on the number of monoclinic phases of alite M1 and M3 in the sample using the Rietveld method. The wet grinding process in the water environment in the planetary mill PULVERISETTE 6 was chosen for the preparation of raw material mixture. Based on previous research in this area, two firing temperatures 1450 and 1550 °C with soaking of 30, 60 and 90 minutes were selected. The results showed the monoclinic phase M1 is more readily formed during coarser grinding, during which large crystals of M1 are formed. On the contrary, the monoclinic phase M3 is formed at a higher firing temperature, at a larger amount nuclei and finer grinding. The results show that the grinding time has an important effect on the rate of formation of monoclinic phases.