Thermal Decomposition Study of Isolated Lignin Using Temperature Modulated TGA

Abstract

Temperature modulated TGA (MTGA) was utilized to study the kinetics of lignin pyrolysis. Three industrial lignin preparations were investigated: softwood kraft lignin, hardwood kraft lignin, and Alcell lignin. Unlike conventional TGA, MTGA provides apparent activation energy (E _a ) distribution curve using a single experimental run in a relatively short experimental time. Under Hi-Res conditions using a dynamic heating rate, the activation energies were higher than those determined using a constant heating rate. Likewise, small sample masses provided higher activation energies than those run with large sample mass. These effects can be eliminated by using a relatively large sample mass, > 10 mg. In this study, we discuss the effect of MTGA conditions on calculating E _a distribution curves for lignin pyrolysis.     

Kinetics and mechanism of emulsion copolymerization. IV. Kinetic modeling of emulsion copolymerization of styrene and methyl methacrylate

Based on the micellar nucleation theory, a mathematical kinetic model for an unseeded emulsion copolymerization system is developed, where the radicals with and without electric charge are discriminated from each other in view of the role in the particle nucleation process. In order to demonstrate the validity and utility of this kinetic model, the experiments of the unseeded emulsion copolymerization of styrene (ST) and methyl methacrylate (MMA) are carried out varying the initial initiator (potassium persulfate) and emulsifier (sodium lauryl sulfate) concentrations and the monomer composition in the initial monomer feed, and various kinetic features observed are compared with the model predictions. It is concluded from this comparison that in this system, almost all the polymer particles are generated by the charged radicals stemming from the initiator, and further that this mathematical kinetic model can provide a satisfactory explanation of the various kinetic features observed.     

Mathematical modeling of porosity formation in solidification

Shrinkage porosity and gas porosity occur simultaneously and at the same location when conditions are such that both may exist in a solidifying casting. Porosity formation in a solidifying alloy is described numerically, including the possible evolution of dissolved gases. The calculated amount and size of the porosity formed in Al-4.5 pct Cu plate castings compares favorably with measured values. The calculated distribution of porosity in sand cast Al-4.5 pct Cu plates of 1.5 cm thickness matches experimental measurements. The decrease of the hydrogen content by strong degassing and the increase of mold chilling power are recommended to produce sound aluminum alloy castings. The calculated results for steel plate castings are in agreement with the experimental work of Pellini. The present modeling has clarified the basis of empirical rules for soundness and suggests that the simultaneous occurrence of shrinkage and gas evolution is an essential mechanism in the formation of porosity defects.     

Acquiring non-parametric scattering phase function from a single image

Computational Visual Media - Acquiring accurate scattering properties is important for rendering translucent materials. In particular, the phase function, which determines the distribution of...     

In-channel focusing of flowing microparticles utilizing hydrodynamic filtration

We present herein microfluidic systems to continuously focus the positions of flowing particles onto the center of a microchannel, which is indispensable to various applications for manipulating particles or cells such as flow cytometry and particle-based bioassay. A scheme called ‘hydrodynamic filtration’ is employed to repeatedly split fluid flows from a main stream, while remaining particles in the main stream. By re-injecting the split flows into the main channel, these flows work as sheath flows, focusing the positions of the particles onto the center of the microchannel without the help of sheath flows or complicated devices generating physical forces. In this study, we proposed two schemes, and compared the focusing efficiencies between the two schemes using particles 5.0 μm in diameter. Also, we confirmed that the flow speed did not affect the focusing efficiency, demonstrating the versatility and applicability of the presented systems. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Worktime control-dependent reductions in fatigue, sleep problems, and depression

We investigated the association between worktime control and fatigue, sleep problems, and depressive symptoms in a sample of daytime and shift workers. A total of 3681 permanent daytime workers and 599 shift workers completed a questionnaire designed to assess the above variables. Worktime control was evaluated in terms of both “control over daily working hours” and “control over days off”. Worktime control × work schedule × gender analysis of covariance, adjusted for age and employment status, showed overall reductions in incomplete recovery, insomnia symptoms, daytime sleepiness, and depressive symptoms with increasing levels of worktime control. However, no associations between control over daily working hours and insomnia symptoms were observed in women. The reductions appeared to be more evident for control over days off. These results remained consistent after adjustments for other potential covariates. The present findings indicate that increased worktime control and enhanced control over days off in particular, may be associated with favorable health outcomes.     

Criticality of cooperative society

Generally speaking, there are two types of interaction, synchronous interactions (N members interact simultaneously) and asynchronous interactions (each member interacts withN neighboring agents individually). The purpose of this paper is to consider the dynamics of the evolution of a cooperative society with synchronous interaction by focusing on the spatial size of the interaction. Asynchronous interaction is dealt with in the cumulative payoff of individual 2-interated prisoner's dilemma (2-IPD) games. The result has shown that an adequate spatial size for interaction promotes a highly cooperative society, but it gets more difficult for agents with synchronous interactions to achieve a cooperative society as it increases in size. This work was presented, in part, at the Sixth International Symposium on Artificial Life and Robotics, Tokyo, Japan, January 15–17, 2001     

Experimental Risk Estimation for Offshore Software Outsourcing

It is necessary to estimate the risk for strategic decision of offshore software outsourcing projects. In this paper we propose an experimental risk estimation method based on questionnaire for externalizing the know‐how of experienced project managers. Introducing three parts of questionnaire contents, this paper describes the estimation method and presents the implementation procedure. Focusing on five client companies, this paper reports five types of risk estimation methods considering the bias of respondents with different backgrounds, and discusses the Recall, Precision together with Accuracy of these estimation methods. This paper also applies the t‐test and vector analysis to study the bias in vendor countries, software types, as well as client companies. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.