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1

Badania inżynieryjne nad bezpośrednią syntezą metylochlorosilanu w reaktorze fluidalnym wyposażonym w wielorurowy wymiennik ciepła z przegrodami segmentowymi

Qiang W., Zhengwei Z., Xu W., Lin G.

Przemysł Chemiczny

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2018

|

T. 97, nr 7

1144--1150

PL

Oceniono wpływ masowego natężenia przepływu chlorometanu i ciśnienia na stopień konwersji chlorometanu oraz na wydajność reakcji syntezy metylochlorosilanu w temp. 300°C, prowadzonej w reaktorze fluidalnym wyposażonym w wielorurowy wymiennik ciepła z przegrodami segmentowymi. Wzrost stopnia konwersji chlorometanu oraz wydajności reakcji syntezy metylochlorosilanu nie zawsze korelował z rosnącym masowym natężeniem przepływu chlorometanu przy stałym ciśnieniu w określonych warunkach pracy reaktora. Przy stałym masowym natężeniu przepływu stopień konwersji chlorometanu oraz wydajność syntezy metylochlorosilanu początkowo malały, a następnie wzrastały wraz z rosnącym ciśnieniem w układzie reakcyjnym. W konsekwencji zaobserwowano synergizm między masowym natężeniem przepływu chlorometanu oraz ciśnieniem, mający wpływ na stopień konwersji chlorometanu oraz wydajność syntezy metylochlorosilanu. Optymalną wydajność tej reakcji uzyskano przy ciśnieniu wynoszącym 0,30 MPa oraz masowym natężeniu przepływu chlorometanu równym 4,5 kg/h.

EN

The fluidized bed reactor with multiple tubular and segmented heat transfer was employed to study the effects of mass flow rate of MeCl and reaction pressure on the rate of MeCl conversion and the methyl chlorosilane yield at 300°C. The rate of MeCl conversion and the yield of Me2SiCl2 were not always increased with increasing mass flow rate of MeCl at constant reaction pressure under particular operating conditions. At constant mass flow rate, the rate of MeCl conversion and the yield of Me2SiCl2 decreased first, and then increased with increasing reaction pressure. Therefore, for the fluidized bed reaction system, a synergism between the MeCl mass flow and reaction pressure in effecting the MeCl conversion rate and the yield of Me2SiCl2 was obsd. The reaction pressure for optimum yield of Me2SiCl2 was 0.30 MPa and MeCl mass flow rate was 4.5 kg/h.

2

Operation Properties and Algebraic Application of Covering Rough Sets

Kong Q., Xu W.

Fundamenta Informaticae

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2018

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Vol. 160, nr 4

385--408

EN

Rough set theory is one of the most important tools for data mining. The covering rough set (CRS) model is an excellent generalization of Pawlak rough sets. In this paper, we first investigate a number of basic properties of two types of CRS models. Especially, we study the operation properties of the two types of CRS models with respect to the unary covering. Meanwhile, several corresponding algorithms are constructed for computing the intersection and union of rough sets and some examples are employed to illustrate the effectiveness of these algorithms.Finally, as an application of the operation properties of CRS, some basic algebraic properties of CRS are explored. It is evident that these results will enrich the theory of covering rough sets.

3

Digital volume correlation in an environment with intensive salt-and-pepper noise and strong monotonic nonlinear distortion of light intensity

Tu P., Bai Y., Xu W., Dong B., Ye S., Yang Q., Zhou Y.

Optica Applicata

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2017

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Vol. 47, nr 2

209--223

EN

Digital volume correlation is an image-based technique for internal 3D displacement and strain fields measurement or analysis widely used in the field of experimental mechanics. A widely used correlation function (criterion) of digital volume correlation is Pearson correlation function, which suffers from the problem of the acquired data being contaminated by salt-and-pepper noise and monotonic nonlinear distortion of the light intensity. In this work, a 3D correlation function called the Spearman correlation function is used to deal with those interferences. A numerical experiment shows that the performance of Spearman correlation function using integer-pixel registration in an environment with 10% salt-and-pepper noise is better than that of Spearman and Pearson correlation functions using sub-pixel registration in an environment with 1% salt-and-pepper noise. As the light intensity distortion is significant, the error of Pearson correlation function is considerable; meanwhile, the error of Spearman correlation function is small. In conclusion, Spearman correlation function is, in particular, practical and useful in digital volume correlation.

4

Analysis of the start-up of natural bio-film colonization of constructed rapid infiltration system

Xu W., Yang J., Wang J., Jian Y., Tang M.

Polish Maritime Research

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2016

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S 1

32--35

EN

Abstract: this paper studied the start-up of natural bio-film colonization under the conditions where wet-to-dry ratio was 1:6, hydraulic load was 0.8m3/m2·d, and water temperature was 100C-150C, it took 25d in total to become mature, after the success of bio-film colonization, the removal rate of COD and NH4+-N can be stabilized at 80%, and the removal rate of NH4+-N can reach 90% above. The microorganism was divided into the following stages during bio-film colonization:1. Reversible adhesion of cell on the surface of the carrier, 2.Irreversible adhesion of cell on the surface of the carrier, 3.Division of cell adhering to the surface of the carrier and formation of microcolony adhering to the surface of the carrier, 4.Growth of microcolony adhering to the surface of the carrier to be mature bio-film with three-dimensional structure. The process of natural bio-film colonization can be judged comprehensively according to removal rate of NH4+-N and COD, effluent pH as well as color of microbial film.

5

Reconstruction of Wetland Zones: Physiological and Biochemical Responses of Salix variegata to Winter Submergence — A Case Study from Water Level Fluctuation Zone of the Three Gorges Reservoir

Miao L., Xiao F., Xu W., Yang F.

Polish Journal of Ecology

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2016

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Vol. 64, nr 1

45--52

EN

The Salix variegata Franch. seedlings planted in the Three Gorges Reservoir (TGR) water level fluctuation zone (WLFZ) could survive after experiencing several seasons of winter submergence. We investigated the recovery mechanisms of S. variegata seedlings planted at the elevation of 168 m and 172 m in the TGR WLFZ after winter submergence. The results indicated that winter submergence caused some impacts on S. variegata seedlings with increases of hydrogen peroxide (H2O2), superoxide anions radical (O2-.), and malondialdehyde (MDA) levels, and decreases of antioxidant enzymatic systems during recovery stage after winter submergence. However, further analyses of relative water content (RWC), pigment content, proline content, carbohydrate content and several other antioxidant enzymatic activities (catalase (CAT), guaiacol peroxidase (G-POD), and glutathione peroxidase (GSH-POD)) showed that S. variegata seedlings were well recovered after winter submergence. These results indicate that S. variegata possesses strong winter submergence tolerance and adaptation to the specific hydrological environment in the TGR WLFZ. Therefore, S. variegata should be popularized as native tree species during the revegetation in the TGR WLFZ.

6

Unidirectional Torsion Properties of Single Silk Fibre

Jiang S., Cao G., Cai G., Xu W., Li W., Wang X.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 3 (117)

26--30

EN

The unidirectional torsion properties of silk fibre were investigated on a purpose-built single fibre torsion tester. The torsional fracture angle and the number of cycles of torsion at breaking were recorded, and the effect of the gauge length and pretension together with the torsion speed on the torsion properties of single silk fibre was investigated in detail. Scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and a tensile tester were used to understand the morphology, structure and tensile properties of silk fibre after torsion deformation. SME photos show that silk fibre exhibits a ribbon-like profile after torsion, and fracture tends to occur at both ends of the silk fibre, where a larger number of twists can be observed. The crystallinity calculated from XRD spectra of silk fibre increases from 26.11% to 34.10% after torsion. The breaking stress and strain decreases slightly with an increase in the gauge length. The breaking cycle increases linearly with an increase in the gauge length, while the actual torsional fracture angle decreases gradually at the same time. The torsional fracture angle together with the breaking cycle decreases gradually as the pretension increases. The fracture angle together with the breaking cycle increases with an increase in the torsion speed. Understanding the unidirectional torsion properties of single silk fibre will benefit its further application in specific areas where the fibre will be subject to frequent torsion and deformation.

PL

Badania przeprowadzono za pomocą specjalnie zbudowanego urządzenia do badania skrętu włókien. Badano kąt przełomu oraz ilość cykli doprowadzających do zerwania. Sprawdzano również wpływ długości próbki oraz wstępnego naprężenia. Oceniono wpływ długości próbki wstępnego naprężenia, szybkości skrętu na właściwości wytrzymałościowe włókien jedwabnych. Stosowano SEM, XRD dla określenia morfologii i struktury włókien. Stwierdzono, że włókna jedwabne po badaniu wykazują formę podobną do taśmy. Na podstawie XRD stwierdzono, że krystaliczność wzrasta od ok. 26% do 34% po skręceniu. Naprężenie zrywające i odkształcenia zmniejszają się lekko przy wzroście długości próbki.

7

Soft Sensing Method Of LS-SVM Using Temperature Time Series For Gas Flow Measurements

Xu W., Fan Z., Cai M., Shi Y., Tong X., Sun J.

Metrology and Measurement Systems

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2015

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Vol. 22, nr 3

383--392

EN

This paper proposes a soft sensing method of least squares support vector machine (LS-SVM) using temperature time series for gas flow measurements. A heater unit has been installed on the external wall of a pipeline to generate heat pulses. Dynamic temperature signals have been collected upstream of the heater unit. The temperature time series are the main secondary variables of soft sensing technique for estimating the flow rate. A LS-SVM model is proposed to construct a non-linear relation between the flow rate and temperature time series. To select its inputs, parameters of the measurement system are divided into three categories: blind, invalid and secondary variables. Then the kernel function parameters are optimized to improve estimation accuracy. The experiments have been conducted both in the single-pulse and multiple-pulse heating modes. The results show that estimations are acceptable.

8

Multigranulation Decision-theoretic Rough Set in Ordered Information System

Li W., Xu W.

Fundamenta Informaticae

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2015

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Vol. 139, nr 1

67--89

EN

The decision-theoretic rough set model based on Bayesian decision theory is a main development tendency in the research of rough sets. To extend the theory of decision-theoretic rough set, the article devotes this study to presenting multigranulation decision-theoretic rough set model in ordered information systems. This new multigranulation decision-theoretic rough set approach is characterized by introducing the basic set assignment function in an ordered information system. It is addressed about how to construct probabilistic rough set and multigranulation decision-theoretic rough set models in an ordered information system. Moreover, three kinds of multigranulation decision-theoretic rough set model are analyzed carefully in an ordered information system. In order to explain probabilistic rough set model and multigranulation decision-theoretic rough set models in an ordered information system, an illustrative example is considered, which is helpful for applying these theories to deal with practical issues.

9

Incremental Computing Approximations with the Dynamic Object set in Interval-valued Ordered Information System

Yu J., Xu W.

Fundamenta Informaticae

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2015

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Vol. 142, nr 1-4

373--397

EN

Rough set theory has been successfully used in formation system for classification analysis and knowledge discovery. The upper and lower approximations are fundamental concepts of this theory. The new information arrives continuously and redundant information may be produced with the time in real-world application. So, then incremental learning is an efficient technique for knowledge discovery in a dynamic database, which enables acquiring additional knowledge from new data without forgetting prior knowledge, which need to be updated incrementally while the object set get varies over time in the interval-valued ordered information system. In this paper, we analyzed the updating mechanisms for computing approximations with the variation of the object set. Two incremental algorithms respectively for adding and deleting objects with updating the approximations are proposed in interval-valued ordered information system. Furthermore, extensive experiments are carried out on six UCI data sets to verify the performance of these proposed algorithms. And the experiments results indicate the incremental approaches significantly outperform non-incremental approaches with a dramatic reduction in the computational time.

10

Study on the Structure and Properties of Viscose/Wool Powder Blended Fibre

Li W., Ke G., Li G., Xu W.

Fibres & Textiles in Eastern Europe

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2015

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Vol. 23, no. 1 (109)

26--29

EN

Viscose/wool powder blended fibres with 0, 5, 10, 15 and 20% wool powder were produced with the method of wet spinning. SEM, FT-IR spectroscopy, WAXD and TG analysis were used to study the chemical composition and structure of viscose/wool powder blended fibre. The experimental results show that the macromolecule composition, aggregation structure, morphological structure and thermal properties of these viscose/wool powder blended fibres were similar, which mainly show the characteristics of viscose fibre. Absorption studies were carried out to investigate the protein characteristics of the blended fibre. The results showed that the affinity of the blended fibre to acid dye increased with the wool powder content.

PL

Wyprodukowano włókna wiskozowe z dodatkiem sproszkowanej wełny w ilości 0,5, 10, 15 i 20% metodą mokrego przędzenia. Do badań składu chemicznego i struktury zastosowano SEM, FTIR, WAXD i analizę TG. Wyniki wykazały, że skład makromolekularny, struktura agregatowa i morfologiczna oraz właściwości termiczne włókien były podobne, z dominacją właściwości włókien wiskozowych. Przeprowadzono badania absorpcji dla zbadania oddziaływania proteiny w otrzymanych włóknach. Stwierdzono, że powinowactwo mieszanek włókien do kwaśnych barwników zwiększa się ze wzrostem zawartości proszku wełnianego.

11

Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

Hongbo Y., Meiling C., Xu W., Hong G.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1357--1359

EN

The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs) was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC) methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min) on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

12

The Development of Drilling Engineering Monitoring System Using Wireless Sensor Networks

Yang G., Ma Z., Xu W., Huang X., Zhou J.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1b

37--40

EN

In order to avoid defects of existing drilling engineering monitoring and alarming system, such as the sensors and cable which are difficult to be installed and easy to be damaged, this paper present a new embedded drilling engineering monitoring system which is based on Wireless Sensor Network(WSN) and Wireless Local Area Networks(WLAN). The system is consists of the data acquisition subsystem, duty room controller, tool-pusher room controller and engineer room controller. It acquired the data and exported control commands by WSN. The tool-pusher room controller and engineer room controller are communicated with the duty room controller by WLAN for remote monitoring. For the special field drilling environment, the system achieves the acquiring, transmission, the export of control commands and remote monitoring of drilling data.

PL

Obecnie stosowany system monitorowania I alarmowania w technice wiercenia posiada szereg wad związanych z czujnikami i kablami, które trudno instalować i łatwo uszkodzić. Zaprezentowany w opracowaniu nowy system pozwala na uniknięcie tych wad. Oparty jest o bezprzewodową sieć czujnikową (WSN) oraz bezprzewodową sieć lokalną (WLAN). System obejmuje gromadzenie, transmisję danych i przekazywanie sygnałów sterowania oraz zdalne monitorowania danych wiercenia.

13

Design and Research on Passive Controller for Three-phase Voltage-source PWM Rectifier

Xie Y., Xu W., Zhang Y.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

68--70

EN

This paper designs crude oil electric dehydration pulse power rectifier control system based on passivity-based control theory. This paper deduces the mathematical model of PWM rectifier on the basis of Euler-Lagrange (EL) Equation, proves passivity stability of PWM rectifier, deduces passivity-based control laws of the system and PWM modulation laws, and finally completes design of PWM rectifier controller.

PL

W artykule opisano sterowanie dla prostownika pracującego w systemie do dehydratacji ropy naftowej metodami elektrycznym, o impulsowym poborze mocy. Algorytm oparty został na teorii pasywności. Zaprezentowano, oparty na równaniach Euler’a-Lagrange’a model matematyczny prostownika. Przedstawiono opracowane algorytmy sterowania i modulacji oraz dowód stabilności pasywnej urządzenia.

14

The structure of a general materials genome approach to the design of new steel grades for specific properties

Xu W., LU Q., Xu X., van der Zwaag S.

Computer Methods in Materials Science

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2013

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Vol. 13, No. 3

382--394

EN

In this work we review and reformulate a general alloy design methodology based on thermodynamic and kinetic principles, employing the genetic algorithm as the optimization scheme. The new approach relies on two key concepts: the ‘translator’ and the ‘creator’. The ‘translator’ is the conversion of the desired (thermo-)mechanical properties into required microstructures using known microstructure-property relationships. The ‘creator’ translates quantifiable microstructural parameters into metallurgical and economical parameters, i.e. composition, heat treatment parameter and cost, again employing established metallurgical principles. In the case of well defined ‘translator’ and ‘creator’ functions the model allows simultaneous, human intervention free optimization of alloy composition and key heat treatment parameters, i.e., austenitization temperatures and ageing temperatures, so as to fulfill multiple design criteria and eventually to achieve the desired microstructure. The elementary version of the model, not defining the ‘translator’ or ‘creator’ modules explicitly has applied to the design of ultra high strength (UHS) stainless steel and was validated by experiments on prototype alloys. The model was subsequently extended to take into account the alloying cost by adding a cost factor to various alloying elements, and is shown to provide valuable guidelines to the design and modification of alloy compositions and has the capacity to optimize strength and material cost in an integrated manner. In this manuscript the new conceptual approach to alloy design is reformulated in a more generic and abstract manner and new extensions of the model to the design of high temperature resistant steels (both creep steels and fire resistant steels) and abrasion resistant steels are discussed, and some preliminary results are shown.

PL

W pracy omówiono metodę projektowania stopów wykorzystującą zasady termodynamiki i kinetyki i stosując algorytmy genetyczne w procedurze optymalizacyjnej. Metoda polega na zastosowaniu dwóch głównych pojęć: translatora i kreatora. Translator jest zamianą wymaganych własności termomechanicznych na wymaganą mikrostrukturę, wykorzystując znane zależności między tymi parametrami. Kreator stosuje ustalone zasady metalurgiczne i zamienia ilościowe parametry mikrostruktury w parametry metalurgiczne i ekonomiczne, tzn. skład chemiczny, parametry obróbki cieplnej i koszty. W przypadku dobrze zdefiniowanych funkcji translatora i kreatora model pozwala na równoczesną optymalizację, z interwencją człowieka,dla składu chemicznego oraz dla parametrów obróbki cieplnej, tzn temperatury austenityzacji i temperatury starzenia. W ten sposób spełnione są różne kryteria projektowania i ostatecznie uzyskiwana jest wymagana mikrostruktura. Podstawowa wersja modelu, która nie definiuje modułów translatora i kreatora w sposób jawny, została zastosowana do projektowania stali nierdzewnych o podwyższonej wytrzymałości (ang. Ultra High Strength - UHS). Otrzymane wyniki zostały zweryfikowane doświadczalnie. Następnie model został rozszerzony i uwzględniono koszt dodatków stopowych poprzez wprowadzenie czynnika kosztów dla różnych pierwiastków stopowych. W ten sposób uzyskano cenne wskazówki dla projektowania i modyfikacji składu chemicznego i możliwość optymalizacji w sposób zintegrowany wytrzymałości materiału i kosztów jego wytwarzania. W niniejszej pracy to podejście zostało dalej uogólnione i stworzono nowe rozszerzenie modelu dla projektowania stali żaroodpornych, stali odpornych na pełzanie w wysokich temperaturach i stali odpornych na zużycie ścierne. Zamieszczone zostały wstępne wyniki uzyskane z nowej wersji modelu.

15

Preparation of Al Nanoparticles and Their Influence on the Thermal Decomposition of RDX

Hou C., Geng X., An Ch., Wang J., Xu W., Li X.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 1

123--133

EN

Aluminum (Al) nanoparticles were prepared by the DC arc plasma method in order to study the influence of Al nanoparticles on the thermal decomposition of cyclotrimethylenetrinitramine (RDX). The Al powder was characterized by TEM, BET, XRD, and LSA, and the thermal decomposition of RDX and RDX/nanometer Al were examined by DSC. Based on the DSC curves, the thermal decomposition parameters of the samples were calculated and compared. The results showed that the particles of Al are homogeneous and fine, and that the surface is smooth. The TEM results showed that the nanoparticles are spherical, with an average diameter of approximately 60 nm. The peak temperature of RDX decomposition decreased by 4.36 K at the heating rates of 5, 10, and 20 K/min after the addition of nano-Al powder, and the activation energy for decomposition decreased by about 11 kJ/mol. Furthermore, the critical explosion temperature was also reduced. These observable changes indicate that Al nanoparticles act as catalysts for the thermal decomposition of RDX.

16

Distribution Networks State Estimation Based on Topological Contraction and Quality Tag

Huang Y., Liu D., Xu W., Yu W.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 5b

1-6

EN

By processing a set of raw measurement data, it provides a real-time system state solution which is the basis of the advanced applications. Currently, the incomplete and poor quality of measurement data is the key factor to impacting state estimation of distribution network. With the help of decision tree theory, the bad data identification method which combines the historical data and remote data from IDP (Integrated Data Platform) and a data processing method is proposed. Algorithm uses the laws of the distribution network data logic to determine the logic of the distribution network. With the help of the theoretical framework of decision tree we can establish the data quality assessment system and fix those bad data so as to increase the quality of the input data. On the basis of data evaluation and fixing, by collecting grid-based data of distribution network and using topology analysis and contracting technology, we can contract the actual network to the state estimation calculation network which meets the observation demand. Quality labels are used to modify the weight of the least squares state estimation algorithm to improve the accuracy of state estimation. Based on the status of data in city distribution network, a proper measurement data detecting and fixing method as well as topology contracting method is proposed. Two real cases of certain central power supply area in Shanghai have verified the effectiveness and feasibility of the method.

PL

W artykule zaproponowano metody badania stanu sieci dystrybucyjnej w czasie rzeczywistym. Metodę zilustrowano na przykładzie dwóch obszarów sieci zasilającej w Szanghaju.

17

Analysis of Markov Boundary Induction in Bayesian Networks: A New View From Matroid Theory

Feng D., Chen F., Xu W.

Fundamenta Informaticae

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2011

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Vol. 107, nr 4

415-434

EN

Learning Markov boundaries from data without having to learn a Bayesian network first can be viewed as a feature subset selection problem and has received much attention due to its significance in the wide applications of AI techniques. Popular constraint based methods suffer from high computational complexity and are usually unstable in spaces of high dimensionality. We propose a new perspective from matroid theory towards the discovery of Markov boundaries of random variable in the domain, and develop a learning algorithm which guarantees to recover the true Markov boundaries by a greedy learning algorithm. Then we use the precision matrix of the original distribution as a measure of independence to make our algorithm feasible in large scale problems, which is essentially an approximation of the probabilistic relations with Gaussians and can find possible variables in Markov boundaries with low computational complexity. Experimental results on standard Bayesian networks show that our analysis and approximation can efficiently and accurately identify Markov boundaries in complex networks from data.

18

Prediction of cohesion energy of polymers using topological indices

Xu J., Chen B., Liang H., Xu W., Cui W.

Polimery

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2009

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T. 54, nr 1

19-25

EN

The quantitative structure-property relationship (QSPR) study of the cohesion energy (Ecoh) values for a training set of 60 polymers was carried out using only topological indices as input parameters. A general four-parameter correlation was obtained to predict Ecoh values by stepwise multilinear regression analysis (MLRA), with squared correlation coefficient (R2) equal to 0.9775 and standard error of estimation (s) 2455J/mol. The mean relative error (MRE) of Ecoh prediction was 5.82%. The stability of the proposed model was validated using Leave-One-Out cross-validation, randomization experiments and external test set. The model requires only topological indices for the predictions and its advantage is relative ease in calculation of descriptors which makes it easy to apply.

PL

Dotyczącą energii kohezji (Ecoh) ilościową zależność struktura-właściwości (QSPR - quantitative structure-property relationship) wykorzystano do określenia wartości Ecoh wzorcowej serii 60 polimerów z zastosowaniem w charakterze parametrów wejściowych wyłącznie wskaźników topologicznych. Uzyskano ogólną czteroparametrową zależność [równanie (6)] pozwalającą na prognozowanie Ecoh metodą krokowej wieloliniowej analizy regresji (MLRA - stepwise multilinear regression analysis) z kwadratem współczynnika korelacji R2=0,9975 i ze standardowym błędem oznaczania s=2455J/mol (tabele 1 i 2, rys. 1). Średni błąd względny (MRE) tego oznaczania wynosił 5,82% (rys. 2). Trwałość omawianego modelu oceniono wykorzystując sposób walidacji krzyżowej w wariancie Leave-One-Out (LOO) (rys. 3, tabela 3) oraz testu prognozowania Ecoh serii polimerowych próbek zewnętrznych (tabela 5, rys. 4). Określono również istotność poszczególnych parametrów występujących w wyprowadzonej 4-parametrowej zależności (tabela 4). Pozwala ona na wiarygodne prognozowanie wartości Ecoh na podstawie wyłącznie wskaźników topologicznych a jej dodatkową zaletą użytkową jest możliwość uniknięcia skomplikowanych obliczeń.

19

Thermoplastic film from superfine wool powder

Wang X., Xu W., Li W., Wang X. G.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 2 (73)

82--86

EN

In this paper a research work is described in which superfine wool powder was plasticised by glycerol and hot-pressed into a kind of thermoplastic film. SEM photos show that the powder is moulded into a smooth surface and is conglutinated into a continuous phase in the cross-section of the film. The glycerol content, moulding pressure, temperature and moulding time were changed in the moulding process. The sizes and thickness aw well as tensile strength, modulus, breaking elongation and breaking energy of the films were also tested to investigate the thermoplasticity and mechanical properties of the films. The best moulding techniques included a glycerol content of 30%, a moulding pressure of 5 MPa, a temperature of 160 °C and a moulding time of 5 minutes.

PL

W artykule przedstawiono badania , w których super drobny pył wełniany był plastyfikowany gliceryną i prasowany na gorąco dla otrzymania termoplastycznych błon. Fotografie SEM wskazują, że pył został stopiony i przetworzony w folie o gładkiej powierzchni oraz przekroju poprzecznym charakterystycznym dla fazy ciągłej. W trakcie badań zmieniano zawartość gliceryny, ciśnienie wywierane podczas topienia, temperaturę i czas obróbki. Dla wykonanych folii określano wielkość cząstek, grubości folii, wytrzymałość, moduł, wydłużenie przy zerwaniu oraz energię zrywania. Pozwoliło to na określenie termoplastyczności folii i ich właściwości mechanicznych. Najlepsze wyniki uzyskano przy zawartości gliceryny 30%, ciśnieniu 5Mpa, temperaturze 160 0C i czasie obróbki 5 min.

20

Circumferential Compliance of Small Diameter Polyurethane Vascular Grafts Reinforced with Elastic Tubular Fabric

Yang H., Xu W., Ouyang C., Zhou F., Cui W., Yi C.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 6 (77)

89--92

EN

Small diameter vascular grafts were fabricated from pure Polyurethane (PU), as well as PU reinforced with a weft-knitted tubular fabric. Textured polyester and Spandex blend yarns were used for knitting on a purpose-built weft-knitting machine. The circumferential compliance properties of the reinforced composite vascular grafts were compared with those of the tubular fabric itself and the pure PU vascular grafts. The elasticity and strength of the reinforced vascular grafts were improved in the radius compared with the tubular fabric. The strength of the reinforced vascular grafts was 5 10 times that of the pure PU vascular grafts. Expanding the tubular fabric to increase the inner diameter of the reinforced vascular graft increased the graft’s strength and initial modulus, but the difference was reduced as the PU content was increased. For grafts of the same inner diameter, increasing the PU content increased the thickness and strength of the graft wall, which led to a general increase in the strength and initial modulus of the composite vascular grafts. The new composite vascular grafts combine the good elasticity and blood-proof properties of PU with the strength and stability of weft-knitted fabrics.

PL

Poliuretanowe protezy naczyniowe o małej średnicy zostały wyprodukowane z czystego poliuretanu jak również z poliuretanu wzmocnionego rządkowymi dzianinami rurkowymi. Dla wyprodukowania dzianin stosowano mieszaninę teksturowanych przędz poliestrowych i przędzy Spandex, które przerabiano na specjalnie wykonanej rządkowej maszynie dziewiarskiej. Właściwości obwodowe protez naczyniowych z rurkowymi dzianinami rządkowymi były porównywane z właściwościami czystych protez poliuretanowych. Okazało się, że właściwości elastyczne i wytrzymałościowe wzmocnionych protez były lepsze od protez konwencjonalnych. Wytrzymałość była większa pięciokrotnie od protez nie wzmocnionych. Zwiększenie średnicy dzianiny rurkowej powoduje wzrost wytrzymałości protezy i jej modułu początkowego ale różnica się zmniejsza przy wzroście udziału poliuretanu. Nowe wzmocnione kompozytowe protezy naczyniowe łączą w sobie dobrą elastyczność i kompatybilność poliuretanu z krwią oraz wytrzymałością i stabilnością rządkowych dzianin rurkowych.