Self-organization in Models of Cyclically Sheared Suspensions

This thesis presents a study of random self-organized systems using computer-simulated models inspired by cyclically-sheared non-Brownian suspensions of monodisperse spherical particles in a density-matched fluid. When driven at low Reynolds number, such systems have vanishing thermal fluctuations and only short-range interactions between individual particles. Nevertheless, they show intriguing collective behaviors at large length scales, such as a strong suppression of fluctuations in the number density. Such self-organized hyperuniform states can useful in industrial applications where well-controlled states can ease the processing of such materials.In Chapter 2, we propose a new way of generating hyperuniform suspensions, by incorporating slow gravity-driven sedimentation into a cyclically-sheared suspension. The effect of self-compaction drives the particle system towards its critical state automatically. We thus achieve quality hyperuniform distribution without fine-tuning of the system parameters. Computer simulations were conducted that mimic an experimental setup, and we successfully demonstrated a process leading to hyperuniformity in the steady state in the simulations. To this end, we characterize the spatial structure in both real space and reciprocal space to bolster our findings. In Chapter 3, we were inspired by dynamical jamming fronts [1], which prompted us to conduct a detailed study of our sheared suspension system with sedimentation that shows a qualitatively similar propagating front. We conducted extensive measurements to better describe the compaction front in this dilute system that is far from jamming. We found that the density profile of the front is solely dependent on geometric parameters of the system; its surprisingly does not vary with the effective diffusion rate. To further investigate the formation of the compaction front, we conducted point perturbation simulations to extract a correlation length in homogeneous systems as the critical packing fraction is approached from below. We show that the scaling exponent of the compaction front width compares favorably with the correlation length from our point perturbation measurements, and could be consistent with either the directed percolation universality class or conserved directed percolation. In Chapter 4, we summarize this body of work and present an outlook for future directions

Hyperuniformity with no fine tuning in sheared sedimenting suspensions

Particle suspensions, present in many natural and industrial settings, typically contain aggregates or other microstructures that can complicate macroscopic flow behaviors and damage processing equipment. Recent work found that applying uniform periodic shear near a critical transition can reduce fluctuations in the particle concentration across all length scales, leading to a hyperuniform state. However, this strategy for homogenization requires fine tuning of the strain amplitude. Here we show that in a model of sedimenting particles under periodic shear, there is a well-defined regime at low sedimentation speed where hyperuniform scaling automatically occurs. Our simulations and theoretical arguments show that the homogenization extends up to a finite lengthscale that diverges as the sedimentation speed approaches zero.Comment: 11 pages, 6 figure

DON reduction of wheat grain without compromising the lab-scale milling properties of flour

Wheat bran was investigated to be the most commonly contaminated raw material by mycotoxins. However, there are no economical and practical pretreatment methods for industrial on-line application until now. The effect of light debranning on deoxynivalenol (DON) removal, polyphenol oxidase (PPO) activity and flour quality from lab-scale milling were performed. For on-line production, the DON concentration in wheat decreased 15.89% at debranning ratio of 1.2%. For lab experiment, the maximum DON removal for wheat and flour was 23.35% and 21.95%, respectively. However, the PPO activity, browning of dough sheet and flour qualities in lab scale exhibited no significant variation. Light debranning (1.2%) prior to milling could be efficiently applied to on-line wheat production

Effect of Different Debranning Degrees on the Qualities of Whole Wheat Flour and Chinese Steamed Bread

Abstract: Strong gluten, middle-strong gluten and middle gluten wheat were used as raw materials to obtain whole wheat flour by dry debranning process, and the effect of different debranning degrees on the quality of wheat kernel, whole wheat flour and Chinese steamed bread was evaluated. The results showed that the ash content, hardness index and thousand kernel weight of wheat kernels were decreased with increasing debranning degree by 0.17%, 1.0–1.5 and 1.74–1.82 g, respectively, whereas the volume weight was increased by 22.0–23.4 g/L. The contents of ash and damaged starch in whole wheat flour were decreased by 0.12%–0.14% and 1.0–2.1 UCDc, respectively; insoluble dietary fiber and total dietary fiber were decreased by 0.38%–0.49% and 0.13%–0.17%, respectively, while soluble dietary fiber was increased by 0.22%–0.33% with increasing debranning degree. Besides, the pasting properties of whole wheat flour were increased with increasing debranning degree, the stability time was prolonged by 0.3–0.7 min, and the degree of softening was decreased by 9–25 FU. The hardness, gumminess and chewiness of steamed bread were decreased by 732–1 114 g, 335–549, and 147–346 respectively, and the springiness and resilience were increased by 0.030–0.031, and 0.049–0.066, respectively. At the same time, the overall sensory score and L* value of steamed bread were increased, indicating that debranning treatment can significantly improve the rheological properties of whole wheat flour, and efficiently improve the quality of steamed bread

Production of biscuits by substitution with different ratios of yellow pea flour

To promote the commercialization of yellow pea flour (YPF) due to its nutritional benefits. Four biscuits with different YPF ratio (10%–50%) were conducted to explore the optimal addition percentage. The effects of YPF on the rheological and baking performance of biscuits were performed. The results showed that the substitution ratio of YPF and milling methods had a critical impact on the rheological properties of dough. The dough stability decreased gradually while a softening degree increased with YPF ratio increased. In a term of biscuits, the dimensions of length (L), width (W), thickness (T) and color (L*) of biscuits reduced as YPF addition ratio increased, while colors (a* and b*) and hardness apparently increased. In addition, milling methods had a great influence on the texture and sensory evaluation of four biscuits. The dimensions and color parameters of biscuits from fine flours were larger than that from coarse flours, whereas hardness from fine flours was relatively softer, indicating flour with fine particle size could accelerate the extension and expansion of dough network, and improve Maillard reaction during baking. The highest sensory score for short and tough biscuits was obtained given at YPF ratio of 30% without compromising the qualities of biscuits

Lignin, sugar, and furan production of industrial hemp biomass via an integrated process

Traditional pretreatment of lignocellulosic biomass is often accompanied by washing and disposal of wastewater, which leads to overuse of water and loss of by-products. The objectives of this study were to validate the potential of an acid-base integrated process for simultaneous sugars, furans, and lignin production without washing and wastewater discarding. The difference in conversion performance among different biomass resources was also demonstrated. Parallel acetic acid (HOAc, pH = 2.25) and sodium hydroxide (NaOH, pH = 13.46) pretreatments followed by solid and liquid integration were applied to four genotypes of industrial hemp (Cannabis sativa L.) biomass that were harvested from two planting locations (Haysville and Manhattan, KS). Results showed that genotype, planting location, and their interaction had notable influences on biomass composition and its conversion to bioproducts but exhibited different trends. Glucan content of biomass from Haysville, ranging from 47.29 to 50.05%, were higher than those of 42.49–48.38 % from Manhattan with the lowest being Vega (Manhattan) and the highest being Hlukouskii (Haysville). Xylan and lignin contents in all the hemp genotypes were 11.70–13.88 % and 10.45–15.14 %, respectively. The integration process effectively rendered the pH of the integrated filtrate and slurry to approximately 4.80. The highest lignin recovery of 73.13 g/kg biomass was achieved by Rigel from Manhattan. Fourier transform infrared spectroscopy (FTIR) characterization showed that only lignin derived from Vega (Haysville) and Anka (Manhattan) was comparable to the commercial alkali lignin. Retaining monosaccharides (2.24–3.81 g/L) enhanced sugar concentrations (glucose: 40.40–45.71 g/L; xylose: 7.09–8.88 g/L) and conversion efficiencies (glucose: 71.19–77.71 %; xylose: 45.42–52.03 %). Besides, furans including 0.79–1.25 g/L of hydroxymethylfurfural (HMF) and 0.99–1.59 g/L of furfural coupling with 1.96–2.95 % and 10.00–14.65 % conversion efficiencies, respectively, were obtained in the final hydrolysate. Biomass from Haysville produced relatively higher glucose concentrations than those from Manhattan. Based on mass balance, the most productive genotype was Rigel. This study offers essential information to reduce water and chemical overconsumption and to understand the effects of genotype and planting location on biomass valorization

Bioconversion of industrial hemp biomass for bioethanol production: A review

Industrial hemp (Cannabis sativa L.) with robust drought-resistant features has excellent agronomic and pharmaceutical characteristics. As the federal prohibition on hemp cultivation was lifted, its valorization in various aspects is highly required. This review aims to summarize the potential of hemp biomass for bioethanol production. Chemical compositions of hemp biomass were evaluated as compared with those of corn fiber, corn stover, and sorghum bagasse. Several representative pretreatment technologies used for hemp biomass were summarized in terms of sugar recoveries, lignin removal, and sugar and ethanol yields. This review presents numerous technical barriers attributed to insufficient fermentable sugar and ethanol concentration during the conversion processes. Also, innovative research approaches (pretreatment optimization, co-fermentation of hexose and pentose, increasing potential sugar loading) in overcoming these challenges were critically reviewed. This review would promote future research on the utilization of hemp biomass for biofuel applications

Model predictive control strategy in waked wind farms for optimal fatigue loads

With the rapid growth of wind power penetration, wind farms (WFs) are required to implement frequency regulation that active power control to track a given power reference. Due to the wake interaction of the wind turbines (WTs), there is more than one solution to distributing power reference among the operating WTs, which can be exploited as an optimization problem for the second goal, such as fatigue load alleviation. In this paper, a closed-loop model predictive controller is developed that minimizes the wind farm tracking errors, the dynamical fatigue load, and and the load equalization. The controller is evaluated in a mediumfidelity model. A 64 WTs simulation case study is used to demonstrate the control performance for different penalty factor settings. The results indicated the WF can alleviate dynamical fatigue load and have no significant impact on power tracking. However, the uneven load distribution in the wind turbine system poses challenges for maintenance. By adding a trade-off between the load equalization and dynamical fatigue load, the load differences between WTs are significantly reduced, while the dynamical fatigue load slightly increases when selecting a proper penalty factor.Comment: Accepted by Electric Power Systems Researc