Cyanogenesis in somatic embryos and plantlets of cassava (Manihot esculenta Crantz)

A protocol was established for high frequency cyclic somatic embryogenesis and plant regeneration for the cassava variety PRC 60a. Linamarin content and linamarase activity were determined in various tissues of secondary somatic embryos and regenerated plants. Neither linamarin nor linamarase activity were detected in embryogenic callus and somatic embryos. The stems and leaves of regenerated plants, however, contained variable amounts of linamarin and linamarase activity whereas, in the root tissues, only linamarin was detected. This study suggests that the pathway for linamarin biosynthesis may be absent or not switched on in the embryogenic callus and somatic embryos. This system would be useful for investigating cyanogenesis in cassava. © 1999 Society of Chemical Industry     

Manufacturing and impact behavior of syntactic foam

Syntactic foam made of glass hollow microspheres and epoxy vinyl ester resin is manufactured by using a new manufacturing method and its impact behavior is studied in terms of protection parameters. Experimental results for impact force and stress as functions of specimen diameter were found to be in reasonable agreement with predictions based on a model. Also, some compression properties of the foam were investigated. It was found that there is similarity in compressive failure mode between pseudostatic and impact loadings. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1324–1328, 2000     

Self-Healing Cs3Bi2Br3I6 Perovskite Wafers for X-Ray Detection

Self-healing of defects imposed by external stimuli such as high energy radiation is a possibility to sustain the operational lifetime of electronic devices such as radiation detectors. Cs₃Bi₂Br₃I₆ polycrystalline wafers are introduced here as novel X-ray detector material, which not only guarantees a high X-ray stopping power due to its composition with elements with high atomic numbers, but also outperforms other Bi-based semiconductors in respect to detector parameters such as detection limit, transient behavior, or dark current. The polycrystalline wafers represent a size scalable technology suitable for future integration in imager devices for medical applications. Most astonishingly, aging of these wafer-based devices results in an overall improvement of the detector performance—dark currents are reduced, photocurrents are increased, and one of the most problematic properties of X-ray detectors, the base line drift is reduced by orders of magnitude. These aging induced improvements indicate self-healing effects which are shown to result from recrystallization. Optimized synthetic conditions also improve the as prepared X-ray detectors; however, the aged device outperforms all others. Thus, self-healing acts in Cs₃Bi₂Br₃I₆ as an optimization tool, which is certainly not restricted to this single compound, it is expected to be beneficial also for many further polycrystalline ionic semiconductors.     

Routing state reduction in multicast protocols

To improve the scalability of multicast protocols, a simple yet novel technique, called the dynamic overlap tree path (DOTP), is proposed. According to the simulation results, the overall average forwarding state-table size can be reduced by ~30%     

Very long chain fatty acid methyl esters in transesterified palm oil

Some unidentified minor compounds have been observed in the residue from short-path distillation of transesterified palm oil that are not detected in the original palm oil. A method combining short-path distillation to enrich the unknowns with fractionation using solid-phase extraction is described. The fractionated components were identified using GC coupled with MS. The transesterified palm oil was found to contain methyl esters of up to C₃₂ carbon atoms. In the very long chain FAME with carbon numbers ≥20, both even and odd carbon numbers accounted for 0.26 wt%, with C₂₄ and C₂₆ being the major ones present in the residue after short-path distillation of transesterified palm oil.     

Ultimate load analysis of pretensioned inverted T-beams with circular web openings

The provision of transverse openings in floor beams to facilitate the passage of utility pipes and service ducts not only results in a more systematic layout of pipes and ducts, it also translates into substantial economic savings in the construction of a multi-storey building. In this paper, ultimate load analysis of statically loaded simply supported pretensioned inverted T-beams with circular web openings is presented. Major findings relevant to ultimate load analysis of pretensioned beams with circular web openings are summarized. An attempt has been made to answer the frequently asked questions related to ultimate load analysis on multiple circular web openings. It has been shown that the analysis method for pretensioned beams with multiple large circular web openings can be further simplified without sacrificing rationality.     

Fatigue Growth Analysis of Pre Induced Surface Defects Using Piezoelectric Wafer Based Impedance Method and Digital Image Correlation System

Defects in real mechanical, industrial and aerospace structures frequently have complex shapes. Most real structures are typically prone to multiple fatigue cracks and their propagation can be monitored by observing changes in the structural stiffness resulting from strength reduction as a function of the number of loading cycles. In addition, strain variations on the structural surface can be captured using digital equipments. The present work monitors two specimens (AISI 4340 steel) with electrode sparked hemispherical defects on their surfaces. Multiple-cracks emanating from these defects, under fatigue cyclic loading were monitored using piezoelectric wafer based electromechanical impedance (EMI) technique, and digital image correlation (DIC) system. EMI technique uses signature comparison of healthy and damaged state of the structure to depict the occurrence of crack and its growth. Images of DIC system captures initial sightings of surface hair-line cracks from the corners of machined defects and their propagation till merging. Thus, a signature analysis based technique such as EMI and image processing technology such as DIC were found to complement each other to expedite the prediction of early crack and their appearance on the surface.     

基于MPSO-LM算法的车用电池组SOC预测

在对车用氢镍电池组进行了不同工况和温度下的充放电实验,获取了大量能真实反映电池动态行为和特征的实验数据的基础上,建立了一个Back-propagation神经网络的车用动力电池组的仿真模型,实现对电池SOC的预测.为提高BP算法的训练速度和估算精度,设计了一种将改进粒子群算法(MPSO)与Leyenberg-Marquardt(LM)算法组合使用的混合算法(MPSO-LM)用于优化训练BP神经网络.仿真结果表明.所提议的MPSO-LM算法比BP算法更有效.具有较快的收敛速度和较高的预测精度.测试结果中97%数据达到5%的误差或更小.     

DBSC-Based Grayscale Line Image Vectorization

Vector graphics plays an important role in computer animation and imaging technologies. However present techniques and tools cannot fully replace traditional pencil and paper. Additionally, vector representation of an image is not always available. There is not yet a good solution for vectorizing a picture drawn on a paper. This work attempts to solve the problem of vectorizing grayscale line drawings. The solution proposed uses Disk B-Spline curves to represent strokes of an image in vector form. The algorithm builds a vector representation from a grayscale raster image, which can be a scanned picture for instance. The proposed method uses a Gaussian sliding window to calculate skeleton and perceptive width of a stroke. As a result of vectorization, the given image is represented by a set of Disk B-Spline curves.