Evaluation of Two Sets of Sorghum Bagasse Samples as the Feedstock for Fermentable Sugar Recovery via the Calcium Capturing by Carbonation (CaCCO) Process

Abstract: Sorghum bagasse samples from two sets (n6 and bmr6; n18 and bmr18) of wild-type and corresponding “brown midrib” (bmr) mutant strains of sweet sorghum were evaluated as the feedstock for fermentable sugar recovery via the calcium capturing by carbonation (CaCCO) process, which involves Ca(OH)₂ pretreatment of bagasse with subsequent neutralization with CO₂ for enzymatic saccharification. Saccharification tests under various pretreatment conditions of the CaCCO process at different Ca(OH)₂ concentrations, temperatures or residence periods indicated that bmr strains are more sensitive to the pretreatment than their counterparts are. It is expected that variant bmr6 is more suitable for glucose recovery than its wild-type counterpart because of the higher glucan content and better glucose recovery with less severe pretreatment. Meanwhile, bmr18showed higher scores of glucose recovery than its counterpart did, only at low pretreatment severity, and did not yield higher sugar recovery under the more severe conditions. The trend was similar to that of xylose recovery data from the two bmr strains. The advantages of bmr strains were also proven by means of simultaneous saccharification and fermentation of CaCCO-pretreated bagasse samples by pentose-fermenting yeast strain Candida shehatae Cs 4R. The amounts needed for production of 1 L of ethanol from n6, bmr6, n18, and bmr18samples were estimated as 4.11, 3.46, 4.03, and 3.95 kg, respectively. The bmr strains seem to have excellent compatibility with the CaCCO process for ethanol production, and it is expected that integrated research from the feedstock to bioprocess may result in breakthroughs for commercialization.     

Investigation of the Influence of Small Hole on the Fatigue Crack Growth Path

The goal of this paper is to investigate the fatigue crack growth (FCG) path in 7075-T6 aluminum alloy affected by small hole. The codes ANSYS and FRANC3D are jointly used to compute the stress intensity factors and predict the FCG path. The predicted results show that the fatigue crack turns its growth direction toward the hole. The different locations and sizes of single hole have different influences on the FCG paths, while two symmetrically distributed holes have no effects on the FCG path. The predicted FCG paths are validated by the related FCG test results.     

Self-assembled poly(ethylene glycol) methyl ether-grafted gelatin nanogels for efficient delivery of curcumin in cancer treatment

Curcumin (CUR) is a natural active ingredient that attracted much attention for its chemotherapeutic activity against tumors without causing toxicity in healthy cells. However, it has certain limitations for being used in chemotherapy such as low aqueous solubility and hydrolytic instability in the physiological environment. In this study, self-assembled poly(ethylene glycol) methyl ether-grafted gelatin (Gel-mPEG) nanogels were fabricated as delivery systems to improve the applicability of CUR in cancer treatment. CUR-loaded Gel-mPEG nanogels exhibited desired size range, relatively colloidal stability, and provided enhanced CUR stability in aqueous solutions. Especially, they showed significant high CUR loading capacity and better anticancer activity than free CUR as compared to previously reported CUR-loaded nanogels according to the best of our knowledge. Moreover, the in vitro release of CUR from the nanogels was controlled and prolonged up to 96 h. These results demonstrated that Gel-mPEG nanogels are the promising modality for the efficient delivery of CUR in cancer treatment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47544.     

Primary Study of a Settling Fiber Particle in a Particle Cloud

Fiber particles have some unique behaviors due to their special shapes, which are important to those related industries. When a single fiber is in a particle cloud, its behavior will be influenced by others around it. Hence, the behavior of an isolated fiber particle will be different from that in a particle cloud, such as aggregation, orientation, and drag coefficient. However, little information is available on these phenomena, especially drag coefficient. Therefore, this article focuses on the settling process of a fiber particle in a particle cloud. Experiments were conducted to observe the settling behavior of fiber particles and to determine the drag coefficients of an isolated fiber particle in a particle cloud. The relationship between drag coefficient, orientation, and Re for different fiber particles is obtained, which is independent of volume concentration. It is further observed that the aspect ratio has little influence on the drag coefficients of fiber particles. By comparison, it is noticed that these relationships are similar to those found for an isolated single-fiber particle. Furthermore, the orientation of a fiber particle in a particle cloud fluctuates around the stable horizontal orientation in the same way as a single-fiber particle, but returns to the steady state more quickly.     

Application of the Box–Behnken design to the optimization of process parameters in foam cup molding

Currently, foam molding technologies are widely adopted for most bra styles, which demonstrate the incomparable advantages in the contemporary intimate apparel industry. The determination of proper molding conditions, such as molding temperatures and length of time on the basis of cup sizes and styles, is crucial in achieving the required cup shape with high stability, which is regarded as the most challenging part of the molded bra making process. To determine the optimal process parameter settings, numerous process trials are generally required to evaluate the molding variables and their interactions. This study proposes a novel systematic methodology to identify the optimal molding process parameters based on design of experiment (DOE) and a parameterization-based remesh method to evaluate the 3D shape conformity of molded cups. By solving the regression equation obtained from a Box–Behnken design (BBD) and analyzing the response surface plots, the results prove that molding temperature has greater influence than the length of the dwell time on the 3D shape conformity of molded cups. The optimal molding conditions can be determined for the cup depths of different sized mold heads, which are validated by the experimental results.     

The Nucleation Potency of In Situ-Formed Oxides in Liquid Iron

Metallurgical and Materials Transactions A - The nucleation potency of iron oxides was verified experimentally through nucleation undercooling of liquid iron using aerodynamic levitation technology...     

Multiplier design for extended strict positive realness and its applications

Given a stable square plant G ₁(s), based on linear matrix inequality (LMI) method, necessary and sufficient conditions are presented for the existence of a stable multiplier G ₂(s) such that G ₁(s)G ₂(s) is extended strictly positive real (ESPR). Furthemore, for uncertain plants, the corresponding problems are considered and solved. An application to the study of dichotomy for pendulum-like systems is also presented. Examples are given to illustrate the results.     

Rolling Bearing Fault Feature Extraction Based on Bacteria Foraging Optimization

Resonance demodulation technology has been widely applied in the fault diagnosis of rolling bearings because of the high sensitivity, the high reliability, and the effective identification of early damage. Its process includes collecting vibration signals, filtering, envelope demodulation analysis, and judge fault condition, while filtering as the key link directly affects the accuracy and efficiency of fault diagnosis based on resonance demodulation technology. So, there is an important problem in the resonance demodulation technology, which is how to select the optimal filter band rapidly to ensure the least amount of noise in the filter signal. To solve this problem, this paper applies bacteria foraging optimization algorithm (BFO) in the selection of the optimal filtering band. The kurtosis is used as evaluation function to judge the quality of the filter signals. Through the loop operation of three operators (migration, breeding, and chemotaxis), the algorithm converges to the global optimal solution quickly. In the last part of the paper, the feasibility and effectiveness of the application of BFO are tested by simulation signals and practical signals, and the relative merits of the application are concluded.     

Connectivity preservation for multi-agent rendezvous with link failure

This paper proposes a new connectivity-preserving protocol in terms of rectangle-like regions. The protocol consists of a set of distributed control rules; their working together guarantees the network connectivity as well as rendezvous of a discrete-time multi-agent system. It is assumed that all agents share a common minimum sensing radius, but the information exchange may suffer from link failure and recovery. Consequently, the interaction topology is in fact directed and time-varying. By rigorous mathematical arguments, we show the effectiveness and robustness of the protocol in the presence of alignment errors in local coordinate orientations of agents and measurement errors in relative positions of neighbors. We also present simulations to demonstrate the effectiveness of the theoretical results.