Isolation and characterization of two soil derived yeasts for bioethanol production on Cassava starch

Two ethanol-producing yeast strains, CHY1011 and CHFY0901 were isolated from soil in South Korea using an enrichment technique in a yeast peptone dextrose medium supplemented with 5% (w v^?1) ethanol at 30 °C. The phenotypic and physiological characteristics, as well as molecular phylogenetic analysis based on the D1/D2 domains of the large subunit (26S) rRNA gene and the internally transcribed spacer (ITS) 1 + 2 regions suggested that they were novel strains of Saccharomyces cerevisiae. During shaking flask cultivation, the highest ethanol productivity and theoretical yield of S. cerevisiae CHY1011 in YPD media containing 9.5% total sugars was 1.06 ± 0.02 g l^?1 h^?1 and 95.5 ± 1.2%, respectively, while those for S. cerevisiae CHFY0901 were 0.97 ± 0.03 g l^?1 h^?1 and 91.81 ± 2.2%, respectively. Simultaneous saccharification and fermentation for ethanol production was carried out using liquefied cassava (Manihot esculenta) starch in a 5 l lab-scale jar fermenter at 32 °C for 66 h with an agitation speed of 2 Hz. Under these conditions, S. cerevisiae CHY1011 and CHFY0901 yielded a final ethanol concentration of 89.1 ± 0.87 g l^?1 and 83.8 ± 1.11 g l^?1, a maximum ethanol productivity of 2.10 ± 0.02 g l^?1 h^?1 and 1.88 ± 0.01 g l^?1 h^?1, and a theoretical yield of 93.5 ± 1.4% and 91.3 ± 1.1%, respectively. These results suggest that S. cerevisiae CHY1011 and CHFY0901 have potential use in industrial bioethanol fermentation processes.     

Anneal temperature dependent Er/Tm energy transfer and luminescence from Er and Tm co-doped silicon-rich silicon oxide

The effect of the anneal temperature on the Er³⁺/Tm³⁺ energy transfer and subsequent Er³⁺/Tm³⁺ luminescence from Er/Tm co-doped, silicon-rich silicon oxide films are investigated. The anneal procedure necessary for optimum photoluminescence (PL) from the co-doped film is substantially different from that for only Er- or Tm-doped films. Analysis and modeling of PL intensity and time-resolved PL indicate that this higher optimum anneal temperature is due to the anneal temperature dependent Er-Tm interactions. In addition, the optimization of combined ultrabroad Er/Tm luminescence was discussed controlling Er-Tm interactions which is tailored by the change of Er/Tm doping ratio and anneal temperature.     

Effect of deformation induced transformation of ɛ-martensite on ductility enhancement in a Fe-12 Mn steel at cryogenic temperatures

Metastable ?-martensite (?-Ms) formed during a prior heat treatment of Fe-12Mn steel has been reported to transform into α-Ms during subsequent inelastic deformation. This deformation induced phase transformation (DIPT) from ?-Ms to α-Ms has been investigated in the present study within the framework of kinetics relation proposed based upon an internal variable theory of inelastic deformation. The ?-Ms phase was found to become more stable at lower temperatures to provide more prolonged DIPT from ?-Ms to α-Ms during an inelastic deformation at cryogenic temperatures, contrary to the case of austenite phase in various transformation induced plasticity steels being more stable at higher temperatures. This reversed stability-temperature relationship in Fe-12Mn steel appeared to provide a significant ductility enhancement at lower temperatures as well as significant strengthening effect.     

Cold Isostatic‐Pressured Silver Nanowire Electrodes for Flexible Organic Solar Cells via Room‐Temperature Processes

Transparent conducting electrodes (TCEs) are considered to be an essential structural component of flexible organic solar cells (FOSCs). Silver nanowire (AgNW) electrodes are widely used as TCEs owing to their excellent electrical and optical properties. The fabrication of AgNW electrodes has faced challenges in terms of forming large uniform interconnected networks so that high conductivity and reproducibility can be achieved. In this study, a simple method for creating an intimate contact between AgNWs that uses cold isostatic pressing (CIP) is demonstrated. This method increases the conductivity of the AgNW electrodes, which enables the fabrication of high‐efficiency inverted FOSCs that have a power conversion efficiency of 8.75% on flexible polyethylene terephthalate with no short circuiting occurring as the CIP process minimizes the surface roughness of the AgNW electrode. This allows to achieve 100% manufacturing yield of FOSCs. Furthermore, these highly efficient FOSCs are proven to only be 2.4% less efficient even for an extreme bending radius of R ≈ 1.5 mm, compared with initial efficiency.     

Advection Flows‐Enhanced Magnetic Separation for High‐Throughput Bacteria Separation from Undiluted Whole Blood

A major challenge to scale up a microfluidic magnetic separator for extracorporeal blood cleansing applications is to overcome low magnetic drag velocity caused by viscous blood components interfering with magnetophoresis. Therefore, there is an unmet need to develop an effective method to position magnetic particles to the area of augmented magnetic flux density gradients while retaining clinically applicable throughput. Here, a magnetophoretic cell separation device, integrated with slanted ridge‐arrays in a microfluidic channel, is reported. The slanted ridges patterned in the microfluidic channels generate spiral flows along the microfluidic channel. The cells bound with magnetic particles follow trajectories of the spiral streamlines and are repeatedly transferred in a transverse direction toward the area adjacent to a ferromagnetic nickel structure, where they are exposed to a highly augmented magnetic force of 7.68 µN that is much greater than the force (0.35 pN) at the side of the channel furthest from the nickel structure. With this approach, 91.68% ± 2.18% of Escherichia coli (E. coli) bound with magnetic nanoparticles are successfully separated from undiluted whole blood at a flow rate of 0.6 mL h^?1 in a single microfluidic channel, whereas only 23.98% ± 6.59% of E. coli are depleted in the conventional microfluidic device.     

A word extraction algorithm for machine-printed documents using a 3D neighborhood graph model

Automatic character recognition and image understanding of a given paper document are the main objectives of the computer vision field. For these problems, a basic step is to isolate characters and group words from these isolated characters. In this paper, we propose a new method for extracting characters from a mixed text/graphic machine-printed document and an algorithm for distinguishing words from the isolated characters. For extracting characters, we exploit several features (size, elongation, and density) of characters and propose a characteristic value for classification using the run-length frequency of the image component. In the context of word grouping, previous works have largely been concerned with words which are placed on a horizontal or vertical line. Our word grouping algorithm can group words which are on inclined lines, intersecting lines, and even curved lines. To do this, we introduce the 3D neighborhood graph model which is very useful and efficient for character classification and word grouping. In the 3D neighborhood graph model, each connected component of a text image segment is mapped onto 3D space according to the area of the bounding box and positional information from the document. We conducted tests with more than 20 English documents and more than ten oriental documents scanned from books, brochures, and magazines. Experimental results show that more than 95% of words are successfully extracted from general documents, even in very complicated oriental documents. Received August 3, 2001 / Accepted August 8, 2001     

A line feature based SLAM with low grade range sensors using geometric constraints and active exploration for mobile robot

This paper describes a geometrically constrained Extended Kalman Filter (EKF) framework for a line feature based SLAM, which is applicable to a rectangular indoor environment. Its focus is on how to handle sparse and noisy sensor data, such as PSD infrared sensors with limited range and limited number, in order to develop a low-cost navigation system. It has been applied to a vacuum cleaning robot in our research. In order to meet the real-time objective with low computing power, we develop an efficient line feature extraction algorithm based upon an iterative end point fit (IEPF) technique assisted by our constrained version of the Hough transform. It uses a geometric constraint that every line is orthogonal or parallel to each other because in a general indoor setting, most furniture and walls satisfy this constraint. By adding this constraint to the measurement model of EKF, we build a geometrically constrained EKF framework which can estimate line feature positions more accurately as well as allow their covariance matrices to converge more rapidly when compared to the case of an unconstrained EKF. The experimental results demonstrate the accuracy and robustness to the presence of sensor noise and errors in an actual indoor environment.

Wideband Linear Frequency Modulated Waveform Compensation Using System Predistortion and Phase Coefficients Extraction Method

This letter presents an effective method to compensate for the wideband linear frequency modulated waveform errors using system predistortion coefficients. The coefficients can be readily extracted by measuring and analyzing the changing rates of the period of non-constant beat frequencies generated from a nonlinear system in the time domain. The amplitude distortion components are examined using the polynomial curve-fitting method. In order to experimentally validate the practical feasibility of the waveform generator and the predistortion coefficients extraction module, the waveform's amplitude ripple, range resolution, and peak sidelobe ratios are measured and analyzed. The measured amplitude ripple at 5.3 GHz is improved from 1.835 to 0.333 dB and from 2.793 to 0.75 dB within 50 and 85 MHz bandwidth, respectively. Finally, the range resolution is improved from 4.102 to 3.103 m for 50 MHz bandwidth and the peak sidelobe ratio is improved from 7.78 to 20.55 dB for 85 MHz bandwidth with the applied predistortion.     

Analysis of Orographic Precipitation on Jeju-Island Using Regional Frequency Analysis and Regression

The orographic effect is a common phenomenon in mountainous regions. Our goal is to analyze the orographic effect with quantile by regional frequency analysis and multiple regression. Multiple regression was used to develop models to estimate the amount and the spatial distribution of orographic precipitation in mountainous terrain using elevation, latitude, longitude, duration, and return period. Multiple linear regression analysis indicated that the model using the three parameters of elevation, latitude, and longitude, produces better results than four- or five-parameter models. Therefore, multiple nonlinear forms, the combination of the intensity-duration-frequency (IDF) relationship and the general linear regression form of orographic statistics were proposed to improve the accuracy of models. The models in this study showed an increase in accuracy of 18.31~86.27%. Moreover, these models produced good results in GIS analysis and were able to represent all cases examined in this study using only a few equations, in contrast to multiple linear models.