Influence of Macromolecular Brushes with Polyimide Backbones and Poly(methyl methacrylate) Side Chains on Structure,Physical, and Transport Properties of Polyphthalamide

Composite films based on polyamide (poly(m-phenylene-iso-phthalamide)) (PA) and a brush-like polymer with polyimide (PI) backbone and side poly(methyl methacrylate) chains (PI-PMMA) were prepared by mixing individual solutions of PA and PI-PMMA and subsequent film casting. Macromolecular brushes with the same backbone length and density of side chains but with various lengths of side PMMA chains were synthesized via activator generated by electron transfer atom transfer radical polymerization. Interactions between PA and PI-PMMA, as well as distribution of PI-PMMA filler inside the PA matrix, were studied by viscometry, dynamic light scattering, differential scanning calorimetry, scanning electron microscopy, and IR spectroscopy. The mechanical properties of polymer samples were also investigated. Microphase separation was revealed in PA/PI-PMMA films. The length of side chains influences interactions between PA and PI-PMMA. At the same time, the degree of reduction in the rigidity parameters and in the elasticity parameter depends on the side chain length. Diffusion membranes were prepared on the basis of compositions with the best mechanical properties; these membranes proved to be highly efficient in pervaporation of methanol–hexane mixture. It was established that the fluxes and separation factors of the studied membranes are several times higher as compared to the corresponding characteristics of known commercial membranes. POLYM. ENG. SCI., 60:481–490, 2020. © 2019 Society of Plastics Engineers     

Behavior-based detection and classification of malicious software utilizing structural characteristics of group sequence graphs

Journal of Computer Virology and Hacking Techniques - In this work we present a graph-based approach for behavior-based malware detection and classification utilizing the Group Relation Graphs...     

Underapproximation of procedure summaries for integer programs

International Journal on Software Tools for Technology Transfer - We show how to underapproximate the procedure summaries of recursive programs over the integers using off-the-shelf analyzers for...     

Manganese ferrite-polyaniline hybrid materials: Electrical and magnetic properties

Magnetic MnFe₂O₄ nanopowders were synthesized by an original solvothermal method in the absence and in the presence of tetra-n-butylammonium bromide (TBAB) and Tween 80 (TW) as surfactants. Manganese ferrite/polyaniline (PANI) hybrid materials were synthesized by in situ polymerization of aniline on the surface of MnFe₂O₄ using ammonium persulfate as oxidant. The purpose of the study was to investigate the influence of the two surfactants on the properties of the MnFe₂O₄ powders and of their composites with PANI. The specific surface area, the cumulative surface area of pores and the cumulative volume of pores are influenced by the nature of surfactant in case of MnFe₂O₄ powders and are higher by comparison to those of the MnFe₂O₄/PANI hybrid materials. The values of saturation magnetization in case of MnFe₂O₄ powders are higher than those of the hybrid materials and are not influenced by the surfactant nature. These features revealed that MnFe₂O₄ powders can be efficiently used as adsorbents for the purification of wastewaters. The values of the electrical conductivity of the composites exhibit a significant increase in comparison to the MnFe₂O₄ powders and depend on the surfactant nature. The highest value of electrical conductivity was achieved by the composite obtained using Tween 80 as surfactant (σ_DC = 54.5·10^?5S?m^?1) which was close to that of PANI (σ_DC = 61.2·10^?5 S?m^?1). The fact that the magnetic and electric properties of the synthesized MnFe₂O₄/PANI composites can be changed by design, demonstrate the high potential of these materials to be used in magneto-electric applications.     

Orientated crystallization in drawn thermoplastic polyimide modified by carbon nanofibers

The solid state crystallization in drawn thermoplastic polyimide films is studied as a function of draw ratio (DR) under the effect of vapor grown carbon fiber nanoinclusions. The nucleating effect of the nanoinclusions coupled with the orientation effect of drawing generates a unique orientated layered lamellar structure, characteristic of smectic‐like mesophase. The degree of draw induced orientated crystallization increases with the content of nanoinclusions and with the DR, and is reflected in the mechanical behavior of the film. Generally, the Young's modulus and the yield point of the drawn crystalline films in the drawing direction are significantly higher compared with the noncrystalline counterparts. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Automatic speech recognition performance in different room acoustic environments with and without dereverberation preprocessing

The performance of recent dereverberation methods for reverberant speech preprocessing prior to Automatic Speech Recognition (ASR) is compared for an extensive range of room and source-receiver configurations. It is shown that room acoustic parameters such as the clarity (C50) and the definition (D50) correlate well with the ASR results. When available, such room acoustic parameters can provide insight into reverberant speech ASR performance and potential improvement via dereverberation preprocessing. It is also shown that the application of a recent dereverberation method based on perceptual modelling can be used in the above context and achieve significant Phone Recognition (PR) improvement, especially under highly reverberant conditions.     

Estimation of unknown speaker’s height from speech

In the present study, we propose a regression-based scheme for the direct estimation of the height of unknown speakers from their speech. In this scheme every speech input is decomposed via the openSMILE audio parameterization to a single feature vector that is fed to a regression model, which provides a direct estimation of the persons’ height. The focus in this study is on the evaluation of the appropriateness of several linear and non-linear regression algorithms on the task of automatic height estimation from speech. The performance of the proposed scheme is evaluated on the TIMIT database, and the experimental results show an accuracy of 0.053 meters, in terms of mean absolute error, for the best performing Bagging regression algorithm. This accuracy corresponds to an averaged relative error of approximately 3%. We deem that the direct estimation of the height of unknown people from speech provides an important additional feature for improving the performance of various surveillance, profiling and access authorization applications.     

高炉喷吹煤的气化产物新技术

降低焦比是降低铁水生产成本的最有效方法.按测算,高炉最低焦比可降至180～200kg/t.要达到这样的焦比,可以采用两种方法:在喷氧量为210～280kg/t情况下,喷煤量应达到300～400kg/t;喷吹脱CO2后经预热的高炉煤气和纯氧.钢铁联合企业煤气平衡的波动和高喷煤比时高炉回旋区的气化问题是这两种技术的主要制约因素.高炉喷吹煤的气化产物可以有效解决上述问题.该技术与传统喷煤工艺相比,能够提高喷吹比、降低焦比;可使用低级煤;不用把煤磨成细粉;在煤气化过程中可以进行脱硫处理;煤灰可以在该过程中去除掉.开发了一种安装在高炉风口处的煤的特殊气化装置,在乌克兰扎波罗热(Zaporozgstal)钢铁公司的高炉上进行了工业试验,计划喷吹305kg/t煤的气化物和105kg/t的氧气,预计可以将焦比从565kg/t降至305kg/t(如果炉料组成较好,焦比可进一步降至180～200kg/t),高炉利用系数提高50%,铁水生产成本降低10%,向大气放散的气体量将随焦比的下降而成比例地减少.该技术投资比传统喷煤系统低得多,投资回收期在一年以内.     

Urethrocystometry as a routine method for the objective evaluation of women with urinary incontinence

Over a 2-year period, 401 patients with urinary incontinence were examined at the Women's Clinics in Lund and Malm? and then investigated by urethral pressure profile measurement and simultaneous urethrocystometry. After full investigation the patients could be classified as follows: 214 (53.4%) had genuine stress incontinence, 48 (12.0%) had genuine urge incontinence, 41 (10.2%) had mixed incontinence, 20 (5.0%) had urgency-frequency, 6 (1.5%) had neurogenic incontinence, 9 (2.2%) had incontinence of uncertain aetiology, and 63 (15.7%) of the patients were apparently continent with normal urethral pressure profiles and urethrocystometrograms.