Health-related effects and improving extractability of cereal arabinoxylans

Arabinoxylans (AXs) are major dietary fibers. They are composed of backbone chains of -(1–4)- linked xylose residues to which -l-arabinose are linked in the second and/or third carbon positions. Recently, AXs have attracted a great deal of attention because of their biological activities such as their immunomodulatory potential. Extraction of AXs has some difficulties; therefore, various methods have beenusedto increase the extractability ofAXs withvaryingdegrees of success, suchas alkaline, enzymatic, mechanical extraction. However, some of these treatments have been reported to be either expensive, such as enzymatic treatments, or produce hazardous wastes and are non-environmentally friendly, such as alkaline treatments. On the other hand, mechanical assisted extraction, especially extrusion cooking, is an innovative pre-treatment that has been used to increase the solubility of AXs. The aim of the current review article is to point out the health-related effects and to discuss the current research on the extraction methods of AXs

Design and analysis of spring parallel variable stiffness actuator based on antagonistic principle

Human-machine collaboration is an inevitable development trend of robots, and the variable stiffness joints of robots has been increasingly investigated by researchers. The variable stiffness joint based on the antagonism principle has received extensive attention, where its variable stiffness actuator mainly including nonlinear elastic components and antagonistic force pairs are the research hotspots. In this paper, a spring parallel variable stiffness actuator (SPVSA) based on a novel variable stiffness principle is proposed, in which the linear spring is arranged in parallel with the antagonistic force, so that the elastic components are no longer involved in the antagonism. The variable stiffness actuator effectively eliminates the antagonistic effect of the elastic components and improves the shock absorption and energy storage capacity. And based on the passive and active stiffness adjustment modes, the variable stiffness speed can be effectively improved. Meanwhile, the use of extremely ultralight springs and wire ropes simplifies the structure of the actuator and reduces the quality and size of the joints. In this paper the model design, related theoretical analysis and simulation analysis of SPVSA are carried out. And the effectiveness and advancement of SPVSA are verified by experiments. (C) 2019 Elsevier Ltd. All rights reserved

Nonlinear Vibration Analysis of Machine-Tool Guideway System with Clearance

Abstract. This paper studies hysteretic effect of machine-tool guideway system with clearance, establishes the nonlinear dynamics model of guideway system with symmetric clearance, and obtains the equivalent damping and equivalent stiffness coefficients using asymptotic method. With the use of time-domain graph, frequency-domain graph, phase trajectory figure, Poincare section figure, bifurcation diagram, and lyapunov exponent figure, the dynamics response of damping and external vibration frequency effect on system is studied. The result shows that the period, double-period and chaos movement will occur when the system parameters change in certain range

Nonlinear Vibration Analysis of Machine-Tool Guideway System with Clearance

Abstract. This paper studies hysteretic effect of machine-tool guideway system with clearance, establishes the nonlinear dynamics model of guideway system with symmetric clearance, and obtains the equivalent damping and equivalent stiffness coefficients using asymptotic method. With the use of time-domain graph, frequency-domain graph, phase trajectory figure, Poincare section figure, bifurcation diagram, and lyapunov exponent figure, the dynamics response of damping and external vibration frequency effect on system is studied. The result shows that the period, double-period and chaos movement will occur when the system parameters change in certain range