Anaerobic Biodegradation Tests of Poly(lactic acid) under Mesophilic and Thermophilic Conditions Using a New Evaluation System for Methane Fermentation in Anaerobic Sludge

Anaerobic biodegradation tests of poly(lactic acid) (PLA) powder were done at the thermophilic (55 °C) and mesophilic temperature (35 °C) under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 °C) and 2.24% (at 35 °C)] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 °C. On the other hand, the PLA degradation started in 55 days at 35 °C and degradation rate was much slower than at 55 °C.     

Properties of bifunctional phosphonate fibers derived from chloromethylstyrene grafted polyolefin fibers

Bifunctional fibers containing phosphonate and sulfonate were derived from chloromethylstyrene grafted polyolefin fibers (PPPE-g-CMS) by phosphorylation and subsequent sulfonation reactions. It was clarified that phosphorylation of PPPE-g-CMS by Arbusov reaction is more suitable than one by the reaction with PCl₃ in the presence of AlCl₃, because the latter damaged fibers and gave phosphinate groups in addition to phosphonate ones. Then, bifunctional fibers containing phosphonate and sulfonate groups were prepared by sulfonation of monofunctional phosphonate fibers obtained via Arbusov reaction with chlorosulfonic acid. The metal ion selectivity of the bifunctional fibers was governed by both phosphonate and sulfonate groups. In addition, bifunctional fibers gave much more excellent kinetic performances in column-mode uptake of Cu(II) than the monofunctional phosphonate fibers and resin.     

Synthesis of TiN and TiC powders by a reduction/nitridation method using arc image heating

Journal of Materials Science Letters -     

INTEGRATED CONTROL FOR VEHICLE YAW MOTIONUSING DOUBLECOSTFUNCTION LQR

The front steering angle control and its integration with the direct yaw moment control are suggested to enhance the handling performance for heavyduty vehicles based on a 3D vehicle modelThe doublecostf unction LQR methodology (DLQR) which extends the concept and the applicable field of LQR to express the practical requirements more plainly,is proposed to determine the control input value:compensation value of front steering angle in the optimal model A simple autotuning proportion controller is employed in direct yaw moment control to regulate the moment timely The simulation results show that front steering angle control using DLQR,has good ability to achieve the desired steering output in the different running conditionsDLQR is more powerful to balance many factors effectively based on the explicit mathematics expression of the physics of the problem than LQR does     

基于自适应模糊神经网络的变压器油中水分含量检测的研究

针对变压器油中水分检测的非线性、耦合性和时变性,提出了一种基于自适应模糊神经网络的变压器油中水分含量的检测方法。     

Notch effect on creep–fatigue life for Sn–3.5Ag solder

This paper studies the creep–fatigue crack initiation and failure lives of Sn–3.5Ag solder notched specimens focused on the multiaxial strain at the notch root. Push–pull creep–fatigue tests were performed using three circumferential notched specimens using four kinds of creep–fatigue strain waveforms. Multiaxial strains at the notched section were calculated by finite element (FE) analysis under four kinds of creep–fatigue loading. Creep–fatigue damage laws were applied for evaluating the crack initiation and failure lives using the multiaxial strains obtained by the FE analysis. von Mises equivalent strain at the notch root estimated the crack initiation lives with a large scatter as well as the failure lives. Instead, the mean value of von Mises equivalent strain over the cross section of the notch root estimated the crack initiation and failure lives with a small scatter.     

CREEP-FATIGUE STUDIES UNDER A BIAXIAL STRESS STATE AT ELEVATED TEMPERATURE

In order to study creep-fatigue interactions under multiaxial stress states, both push-pull and reversed torsion low-cycle fatigue tests were carried out using an austenitic stainless steel, SUS 304, at 923 K in air. From the tests, it is concluded that the hold-times introduced at the peak strain reduce low-cycle fatigue lives in the push-pull mode, but in the torsional mode they were not so harmful. This difference in the hold-time effect is discussed from considerations of crack formation and propagation and the stress amplitude applied to the specimen. Both maximum principal strain range, Δε₁, and the von Mises' equivalent strain range, Δε_eq, provide a nearly adequate comparison base for the assessment of biaxial low-cycle fatigue lives in tests without strain hold-time but are inadequate for hold-time tests. An equivalent stress range, Δσ*, which includes the effect of the stress parallel to the fatigue crack and which was previously proposed by the authors for no hold-time tests, is applied to the hold-time tests in the biaxial stress state. It is found that Δσ* is a good parameter for the correlation of biaxial low-cycle fatigue data in both no hold-time and hold-time tests.