Advanced Materials Research Vols. 875-877

Abstract: A variety of chemicals including foaming agents are used to aid in the protection of forest resources from the wild land fires. The fire-fighting foams (FFFs) are formulations composed principally of surfactants. As a part of Japanese national project, environmentally inert FFFs have been developed. There is an emerging need for testing the impacts of these FFFs on the living organisms composing the typical landscapes or eco-systems in Japan. In the present report, we aimed to describe our latest attempt for assessing both the short-tem and long-term impacts of FFFs in aquatic (fresh water) and semi-aquatic (wetland) eco-systems, by employing the laboratory-sized model assays (preliminary studies) and the biotope-based observation, respectively. In the biotope assays which was based on the observation in compact biotopes mimicking the fresh water environments and wetland, both the acute and long-term eco-toxic impacts of two FFFs (soap-based and synthetic detergent-based) were assessed. Spraying of synthetic detergent-based foam formula was shown to be more toxic compared to soap-based formula and mock water treatment.

Abstract: In Hard disk drive (HDD) industry, the demand for faster HDD with higher storage capacities had led to the use of a dual-stage servo system with a high precision PZT actuator. However, the PZT actuator is made of piezoelectric material which exhibits hysteresis. Hysteresis causes inaccuracies and oscillations in the system responses. In this paper, the hysteresis behavior is examined for a new high resolution (a few nanometers) PZT actuator fabricated for dual stage actuator. The new PZT actuator has the first resonance at a frequency twenty times higher than the first resonant mode of PZT actuator used at present in HDD. A generalized Prandtl-Ishlinskii (GPI) model is obtained by using curve-fitting with the examined hysteresis behavior. Then the inverse of the GPI model is extracted which can be used as the hysteresis compensator. Finally a model-free hysteresis compensator using adaptive Neural Network algorithm is being proposed for future research.

Abstract: NO_x is the major technical barrier to increase hot blast temperature and prolong campaign life of hot blast stove (HBS) at present. In order to restrain the amount of NO_x formation during combustion process in the HBS, the paper studies and analyses the generation mechanism of NO_x production, and calculates NO_x generation rate and amount in HBS by means of thermodynamic generation model. A new dome combustion stove is developed based on high temperature air combustion (HTAC) technology. A comparison on the combustion process and characteristic of conventional HBS and HTAC HBS is performed by application of CFD numerical simulation model. Temperature and concentration field distribution, flame shape and NO_x concentration distribution of two kinds of stove are calculated. The result shows quite symmetrical HTAC stove temperature field distribution. Under the same dome temperature, NO_x generation is 80ppm only, reduced by approximate 76% in comparison with conventional stove. HTAC HBS can obtain higher temperature, energy-saving, emission-reducing, and decrease NO_x emission efficiently, as well as realize long campaign life of HBS.

Abstract: The aim of experimental solution was to measure the thermal characteristics at predetermined locations in the experimental samples in HAZ during the welding process. To measure the thermal cycles were used thermocouples of suitable type. Location of thermocouple was settled in the welding process at the bottom of the experimental samples. Measured values were recorded directly into the computer by using a special program of universal measuring system QUANTUM X.

Abstract: Impact of wild-land fires to the ecosystem is highly complex. Damages to the ecosystem can be attributed not only to the direct impact of fire and release of toxic post-combustion gasses but also to the spraying of fire-fighting chemicals. Fire-fighting foam (FFF) agents are frequently applied for controls in wild-land fires including forest fire. However, effects of FFFs on the composition of the post-combustion gasses and the phytotoxicity of smoke derived from burning woods have not been determined to date. In the present study, with Fourier transform infrared spectroscopy (FT-IR), we have analyzed the chemical composition of the gasses derived from wood slices exposed to two distinct manners of combustion, namely, smoldering (gradual combustion without flame) and rapid burning (combustion with flame). Tested samples include slices of Japanese cedar, Japanese cypress, and Western hemlock. The amount of hydrocarbons, detected in the post-combustion gas such as methane, ethane, ethylene, propane, hexane, formaldehyde, acrolein and phenol, were higher in the gasses from smoldered samples. The major hydrocarbon found in the post-combustion gases processed in the presence of pilot flame was methane. Other hydrocarbons were hardly detectable. Addition of FFFs, namely, a soap-based FFF (designated as MK-08) and a detergent co cocktail-based FFF (Phos-chek) onto wooden slices resulted in slight increase in other hydrocarbons in the gasses derived from flame-driven combustion of wood slices. Interestingly, addition of Phos-chek drastically elevated the phytotoxicity of post-combustion gas derived from Western hemlock slices heated in the presence of pilot flame when assessed using the suspension cultured tobacco cells. In contrast, the soap-based FFF tested here did not alter the phytotoxicity of the post-combustion gasses, suggesting that soap-based FFF might minimize the impact of the fire-fighting activity to the living plants consisting the ecosystem in the forests and wild-land.

Abstract: The high demand of smaller and compact size of MOSFETs has leads to desirable for ultra shallow junction formation with low sheet resistance and good electrical performances. These two characteristics are required to suppress short channel effects and to increase the efficiency of device. In this paper, Pre-amorphise implantation (PAI) PMOS with different doses of Boron and the basic PMOS structure are done by using ATHENA and the performance of devices is compared by using ATLAS software package from Silvaco TCAD. Comparison done in electrical characteristic, I-V curve Ion and Ioff has showed PMOS with PAI technology with low boron doses resulted in increasing electrical performance characteristic.

Abstract: A novel wet electrostatic precipitator used carbon fiber membrane as collector electrodes was designed for effective control of fine aerosol. The volt-ampere (V-I) characteristics of 3k，6k and 12k carbon fiber membrane with four kinds of typical discharge electrode were investigated to seek the ideal form of corona electrode. The results showed that 12k carbon fiber membrane obtained a higher corona current in the same voltage.

Abstract: In recent decades several industrial activities polluted the soil, which caused the accumulation of heavy metals to an extent greater than the natural concentration. This is mainly typical of countries, where mining and industry plays or has played an important role in the economy. The utilization of these lands is an economic interest, since locating the contamination, controlling its spreading and maintaining the area has costs. One of the methods for remediation is phytoextraction, during which heavy metals, especially harmful to water and soil, are removed from the soil by plants capable of accumulating contaminants. However, during the combustion of these plants their heavy metal content is replaced into the formed gaseous and solid combustion remains, so the hazard, composition and treating method of these remains must be defined by the appropriate examinations. In this article we present some part of the results of this research, where we examine the gaseous and solid pollutant content of flue gas formed during combustion, as well as the heavy metal content of fly ash. We made two different experiments for domestic and semiplant usage. We have used oak and poplar from a heavy metal contaminated area in both experiments. The domestic examination was conducted in a 7 kW hearth with a closed combustion chamber, the semiplant examination was carried out in a 0,5 MW capacity furnace equipped with an automatic fuel feeding system and a cyclone dust extractor. We have measured the composition of flue gas in both firing experiments with a HORIBA PG-250 type portable gas analyzer, in the case of the analysis of heavy metal content of fly ash DX4 EDAX EDS microprobe of an AMRAY 1830 I scanning electron microscope and ICP-AES, using a 720 ES instrument was used. Based on our results, it can be determined, that the combustion device used to burn biomass grown on heavy metal polluted areas – brownfield lands – must make it possible to separate fly ash from the flue gas and allow the handling of solid burning residues.

Abstract: Recently, a novel approach to a highly sensitive and quantitative detection of rare earth element (REE) ions including La³⁺, Eu³⁺ and Tb³⁺, by the polymerase chain reaction (PCR) technique, has been reported. The detection of REE ions is based on the catalytic nature of REE ions targeting the deoxyribonucleic acid (DNA), thus monitoring of the ions can be achieved by reading the level of intact DNA by PCR. Despite of its high sensitivity (at ppb to ppt levels), the conventional PCR-based REE detection protocol requires certain length of time (1-2 hours). In the present study, we modified the PCR-based REE detection protocols by employing the high-speed PCR, and performed the automated and rapid detection of La₃₊ in small-sized aqueous samples within 5min.

Abstract: Advanced Grid Stiffened(AGS) composite cylindrical shells are widely used in aerospace industry. This study analyzes the buckling loads for various types of grid structures of AGS composite cylindrical shells. The grid structures are classified as Angle-grid, Iso-grid, Kagome-grid, Ortho-grid, Orthotropic-grid and the characteristics had been analyzed for each grid type. In this study, the various types of grid structure were designed that weight of the whole structure keeps a constant. Under the condition of constant-weight, design variables such as grid angle, number of the grid, h/t ratio of the grid were controlled, and buckling loads of the grid structures were analyzed. The results were analyzed for each type of grid and each design variable of the structures. This study was performed through finite element method and the accuracy of the analysis was verified by previous studies. Finally, buckling modes were analyzed with the thickness of the skin. The selection for the most appropriate design variables had been verified for each grid type and the result can be applied to the optimization of grid structure design, and is also very helpful for reducing the computational cost and obtaining optimization values more accurately.