Matrix morphology and fibre pull-out strength of T700/PPS and T700/PET thermoplastic composites

The main objective of this fundamental study was to investigate effects of processing conditions and resulting matrix morphology on interfacial bond strength of fibre reinforced thermoplastic composites. Using a hot stage microscope, single fibre pull-out samples were produced with T700S high strength carbon fibre and two semicrystalline thermoplastic matrices, polyphenylene sulphide (PPS) and polyethylene terephthalate (PET), respectively. Processing temperatures and cooling histories were the major variables in sample preparation. The T700S fibre had no clear effect on the surrounding PPS and PET matrix morphology, as long as direct cooling at constant rates was selected. A transcrystalline phase around the fibres could be induced in the T700S/PPS system, if isothermal crystallization was carried out at 227°C. Fibre pull-out tests were conducted at room temperature and two basic failure paths were observed, i.e. debonding at the fibre-matrix interface and cohesive failure of the matrix close to the fibre surface. The results indicate that slow cooling rate and a resulting coarse spherulitic morphology around the fibres correlate with high interfacial shear strength. In fact somewhat higher strength values were obtained for samples with transcrystalline layers around the fibres.     

Laboratory aid and ultrasonography in the diagnosis of appendicitis in children

The purpose of this study was to evaluate the relationship between the number of yolk sacs and amnionicity in monochorionic twin pregnancies scanned early in the first trimester. We retrospectively reviewed images of all monochorionic twins scanned between 6 and 9.5 weeks' gestation and with pathologic or sonographic confirmation of chorionicity-amnionicity. Each film was reviewed for the number of yolk sacs present, as well as for the gestational age at which the amniotic membrane was first visualized. Twenty monochorionic-diamniotic pregnancies and two monochorionic-monoamniotic pregnancies met the criteria for inclusion in the study. In diamniotic pregnancies scanned at less than 8 weeks' gestation, only the yolk sacs were identified; none of the dividing amniotic membranes were detected. Two yolk sacs were identified in all but one case. In this case, although one yolk sac was seen at 6 weeks, follow-up scanning at 8 weeks revealed two yolk sacs. In each of the monochorionic-monoamniotic twin pregnancies, one yolk sac was seen at 9 weeks and a single amnion encircled both embryos. We conclude that the sonographic identification of two yolk scas in monochorionic twins enables us to make the diagnosis of diamniotic twins early in the first trimester, before the amniotic membrane can be imaged. The presence of one yolk sac should prompt a follow-up ultrasonogram to assign amnionicity definitively.     

Economics of liquid hydrogen from water electrolysis

Using the data from vendors and open literature, we have constructed a preliminary cost model to predict the cost of liquid hydrogen (LH₂) from water electrolysis. The model has been applied to two LH₂ plants. Both have a production rate of 10 886 kg day⁻¹. The first plant (Plant 1) consists of a tank-type electrolyzer and a liquefier and runs all day at the base-load (or equivalent base-load) power rate. The second (Plant 2) consists of a tank-type electrolyzer, a liquefier, a compressor, and storage vessels. The electrolyzer and the compressor shall run only during the off-peak hours at the off-peak power rate. However, the liquefier shall run all day at the base-load (or equivalent base-load) power rate. The costs of LH₂ from both plants are presented. Unless the base-load power rate is high and the off-peak power rate is substantially low, Plant 1 appears to be economically more feasible than Plant 2.     

The use of doped polyaniline as an electrode in the galvanic anodic protection of ferrous metals in industrial acid solutions

In order to investigate the galvanic anodic protection (GAP) of ferrous metals (such as 410, 304 and 316 stainless steels) in acid solutions by doped polyaniline (PANi), separate doped PANi powder-pressed electrodes with different surface areas (the area ratio of the PANi electrode to stainless steel is between 1:1 and 1:2) have been prepared. These were coupled with ferrous metal in the following solutions: 5 M sulphuric acid, 5 M phosphoric acid and industrial phosphoric acid (containing 5 M phosphoric acid and 0.05% chloride ion) to construct a galvanic cell, in which PANi is cathode while ferrous metal is anode. The results indicate that a PANi electrode with sufficient area can provide corrosion protection to stainless steel in these acidic solutions. A pilot scale coupling experiment was carried out. The results indicate that PANi is a promising material as an electrode for the anodic protection of ferrous metals in acidic solutions in industrial situations.     

Cloud analysis by modeling the integration of heterogeneous satellite data and imaging

This paper presents a computer-aided cloud-analysis approach by effectively modeling the integration of heterogeneous satellite-observed data and remote sensing images. First, automatic cloud detection and tracking methods are proposed to identify the georeferenced cloud objects in satellite remote sensing images. Then, a data integration modeling mechanism is designed to collect meaningful properties of those detected clouds by integrating the heterogeneous satellite-observed data and imaging into a unified cloud database. Finally, based on the integrated global data schema, a two-phase data mining method employing the decision tree algorithm is implemented to analyze and forecast the meteorological activities of all the cloud objects. Experimental results have shown that the proposed data integration model can effectively extract and synthesize all the useful information from heterogeneous data sources to generate a unified view of knowledge, on the basis of which the evolvement trends of clouds can be analyzed properly.     

地图中铁路、道路提取和恢复显示的方法

本文提出一种从军用地图中提取铁路、道路的半自动方法和自动恢复显示其在地图中标识方式的算法,从而进一步实现地图图形显示系统的多层次结构。     

β放射性气体浓度计的新分度方法

本文介绍β放射性气体浓度计的一种新的分度方法——泄漏元件排气法。其特点是一只元件可分度放射性气体浓度计的许多读出数(甚至是几个量程),操作方便。     

An empirical formula for the prediction of rain attenuation infrequency range 0.6 - 100 GHz

An empirical formula for calculating the extinction cross section (ECS) by raindrops over a broad frequency range is first derived based on extensive calculations made on a widely varying in mean radius of modified Pruppacher and Pitter (MPP) raindrop models ranging from 0.25 to 3.5 mm. The expansion coefficients in the empirical formula are determined by least-squares curve fitting of numerical data obtained by the volume integral equation formulation (VIEF). The formula satisfies the frequency and raindrop size dependence. Numerical results obtained from the empirical formula for calculating the ECS are generally in good agreement with those calculated by the VIEF for raindrops with mean radius varying from 0.25 to 3.5 mm in the frequency range from 0.6 to 100 GHz. The average error in the ECS is less than 10%. The formula thus provides a simple and inexpensive method for calculating the ECS of raindrops, which otherwise requires complicated and expensive methods of calculation. By implementing this empirical formula of ECS into the rain attenuation equation, a new numerically empirical formula for calculating the specific rain attenuation is also proposed. The validity of the empirical formula for calculating the specific rain attenuation is also checked by comparing the obtained results of specific rain attenuation with those obtained from Li et al.'s (1995) solution, Yeo et al.'s (1993) measurement, and Olsen et al.'s (1978) power-law equation