Drying behavior of sludge with drying accelerator

Abstract

For fuelization of high moisture content sludge, efficient sludge drying technique using a drying accelerator was investigated. In the experiment, drying accelerator types and drying conditions were changed and the effect of accelerator type and/or drying condition on sludge drying behavior was evaluated by analyzing drying characteristic curve. Depending on drying accelerator type, the addition of drying accelerator did not always exert superiority in drying rate, but sludge with added acrylic resin having low glass transition temperature (DA10) demonstrated significantly enhanced drying rate. Addition of surface activating agent (SAA) instead of resin type drying accelerator also enhanced the sludge drying rate. The highest drying rate was obtained by addition of DA10 and SAA together, and the sludge drying rate has significantly been augmented at the high drying temperature condition.     

Improved feedback modeling of transport in enlarging urban areas of developing countries

Toward the common issue of quick urban sprawls of many cities in developing countries today, this research incorporates the expectation-maximization (EM) algorithm into the feedback application process of a newly developed feedback model to improve the modeling studies of the urban transport prediction and planning for the developments of the cities with their urban areas enlarged in the future. By utilizing the survey data obtained in Jabodetabek metropolitan region of Indonesia in 2002, the study results numerically confirm that the iteratively computational calibrations to the K-factors for the newly urbanized areas of a developing city by employing the EM algorithm in the feedback process can truly improve the validity of the proposed feedback model’s application to effectively predict the urban transport developments of developing cities in the future.     

Preparation of griseofulvin nanoparticle suspension by high-pressure homogenization and preservation of the suspension with saccharides and sugar alcohols

Aim: We have attempted to micronize drug particles with a particle size of less than 100 nm and maintain the particle size of their suspension to improve the solubility and bioavailability of poorly water-soluble drugs. Furthermore, the method of freeze-drying nanoparticles was applied to maintain particulate nature of nanoparticles containing various saccharides and sugar alcohols for a long time. Method: Griseofulvin (GF)–lipid nanoparticle suspension is prepared using GF and a lipid by high-pressure homogenization. The particle size of the obtained GF–lipid nanoparticle suspension is maintained constant by freeze-drying. Result: The mean particle size of GF–lipid nanoparticles prepared by high-pressure homogenization is approximately 60 nm. The mean particle size remains less than 100 nm for 1 month. The GF–lipid nanoparticle suspension containing xylitol, trehalose, or sucrose is freeze-dried to maintain the particulate nature. The mean particle size of the rehydrated suspension is lower than that of the rehydrated suspension containing erythritol or lactose. In particular, it is new knowledge to have found that an aggregation is minimized by adding xylitol which is sugar alcohol. The minimum concentration of xylitol, trehalose, and sucrose required to maintain a constant particle size by rehydration is 3%, 3%, and 5% (w/v), respectively.     

Free-standing,roll-able,and transparent silicone polymer film prepared by using nanoparticles as cross-linking agents

A free-standing, roll-able, and transparent silicone-based polymer film with a tensile modulus of ca. 7.8 MPa and strain at the break point of 0.76% was successfully prepared by reaction between a reactive silicone oligomer with methyl- and methoxy-side groups and hydrophilic SiO₂ nanoparticles. First, SiO₂ nanoparticles were grafted with silicone chains by a controlled wet chemical sol–gel-type reaction with the reactive oligomers. The solvent of the resulting solution was evaporated to form a viscous suspension, casted into a film, and finally heat-treated at 100 °C and 150 °C. A hydrolysis and condensation reaction among silicone-grafted SiO₂ nanoparticles and free silicone oligomers in the final heat treatment resulted to produce free-standing, roll-able, and transparent silicone-based polymer film. The fact that the silicone film cannot be synthesized without the presence of SiO₂ nanoparticles suggests that these nanoparticles act as cross-linking agents of silicone components providing the improved mechanical properties to the composite film. The rate-controlled mixing and heating of the SiO₂ aqueous/alcohol suspension and the silicone oligomer/alcohol solution was found to be the key step in the synthesis of the free-standing transparent film. While rapid addition/mixing resulted in a fragile and opaque film, a transparent material was achieved when those solutions were slowly mixed. The effect of the synthesis process on the macroscopic and microscopic properties of the prepared films is discussed along with their formation mechanism.     

Control of water content by reverse micellar solutions for peroxidase catalysis in a water-immiscible organic solvent

The water content of a water-immiscible can be controlled using reverse micelles. We applied this reverse micellar system to improve the enzymatic activity of a surfactant-manganese peroxidase complex in toluene. Increasing the water content in toluene to 2 vol% using the reverse micelles resulted in the great improvement (10-fold) of the peroxidase activity.     

The effect of La oxide additive on the solubility of NiO in molten carbonates

A comprehensive analysis on a novel energy recovery system for reformate-based proton exchange membrane (PEM) fuel cell systems is presented. The energy recovery system includes a throttling valve, a heat exchanger, a compressor, and is coupled with a coolant loop for the fuel cell stack. The feed stock of the fuel reformer, which is primarily a mixture of water and fuel, is vaporized in the heat exchanger and is then compressed to a sufficiently high pressure before it is ducted into the fuel reformer. The analysis includes the throttling of two-phase fuel/water mixture and vaporization in the heat exchanger to obtain the temperature and pressure of the mixture at the inlet of the compressor. The results indicate that the power plant efficiency with the energy recovery system can be increased by more than 20% compared to that of a fuel cell power plant without the energy recovery system. Additionally, more than 25% of the waste heat generated by the fuel cell stack can be removed due to the energy recovery system, and the fuel burned for the fuel reforming purpose is reduced by more than 70%.