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1

Stability of air nucleus in liquid water and cavitation inception on marine engineering

Fu Q., Chen M., Wang X., Zhu R., Zhang G.

Polish Maritime Research

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2018

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S 3

111--119

EN

The micro air nucleus widely distributed in the ocean is a necessary condition for the cavitation of hydraulic machinery in seawater. In order to study the stability of air nucleus in seawater and cavitation inception, the computational domain of water molecules with air nucleus was studied using the method of molecular dynamics simulation, and the transient characteristics of air nucleus in liquid water were obtained. The key factors influencing nuclei stability were analyzed. The results showed that air nucleus with a certain mass could maintain the dynamic equilibrium in liquid water. The internal density of air nuclei had a critical value that allowed the nuclei to stably exist in water. The air nuclei mass was the decisive factor in its equilibrium volume in water, and the two were positively correlated. The internal density of air nuclei was negatively correlated with the nuclei radius when the nuclei was stable in water. Liquid surface tension was an important factor affecting the stability of the air nuclei. The larger the initial radius of nuclei, the smaller the water pressure, and the more likely the cavitation occurs.

2

System Design for Evenness Measurement of Raw Silk

Pan Q., Chen M., Hu Y., Zuo B.

Fibres & Textiles in Eastern Europe

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2018

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Vol. 26, no. 1 (127)

21--24

EN

The evenness of raw silk is one of its most valuable qualities. Seriplane inspection is a common test for raw silk evenness but is prone to human error and lacks accurate repeatability; the Uster evenness tester is another common approach but is costly and vulnerable to environmental factors. An image-based raw silk evenness detection system is proposed in this paper. The system is comprised of an image acquisition segment with a CCD image sensor, telecentric lens, light source, over feeding device, and raw silk winding device, plus an image processing segment tasked with threshold segmentation and morphology operations. Images of the raw silk are first captured with the image acquisition segment, then the images are processed by threshold segmentation and morphology processing; the diameters obtained in this segment are then used to calculate the variation coefficient (CV), which characterises the evenness of the raw silk. We conducted three experiments to test the stability, repeatability, and accuracy of the system. The results showed that the system proposed is stable, repeatable, and accurate.

PL

Równomierność surowego jedwabiu jest jedną z jego najcenniejszych zalet. Dotychczas powszechnie stosowane systemy kontroli równomierności jedwabiu są podatne na błąd człowieka i nie mają dokładnej powtarzalności, są kosztowne i wrażliwe na czynniki środowiskowe. W artykule zaproponowano system oceny równomierności jedwabiu oparty na analizie obrazu. Zaproponowany system składa się z segmentu akwizycji obrazu z przetwornikiem obrazu CCD, soczewką telecentryczną, źródłem światła, urządzeniem nadawczym i urządzeniem do nawijania surowego jedwabiu oraz segmentu przetwarzania obrazu, którego zadaniem jest progowa segmentacja i operacje morfologiczne. Obrazy surowego jedwabiu są najpierw przechwytywane przez segment pozyskiwania obrazu, następnie obrazy są przetwarzane przez segmentację progową i przetwarzanie morfologiczne; średnice uzyskane w tym segmencie są następnie wykorzystywane do obliczenia współczynnika zmienności (CV), który charakteryzuje równomierność surowego jedwabiu. Analiza otrzymanych wyników pokazała, że zaproponowany system jest stabilny, powtarzalny i dokładny.

3

Development of evaluation system of coastline resource in Dafeng

Chen M., Xu C., Chen H.

Polish Maritime Research

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2017

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S 2

181--187

EN

Coastline is one type of valuable non-renewable resources. From the perspective of economic theory, it can gather population, promote traffic construction, and then improve the level of international trade. The research object of this paper is the coastline resource in Dafeng area. Firstly, we have a brief summary of the existing coastline evaluation literature, then introduce the location and natural attributes of the coastline resources in Dafeng. Following that, the Analytic Hierarchy Process (AHP) model is used to build the economic evaluation index system based on the characteristics of coastline in Dafeng. Specially, this index system consists of 6 factors, and a total of 41 detailed indicators were chosen including water depth, GDP, etc. On this basis, we use the assignment method to quantify the weight of each index, and calculate the comprehensive score of coastline resource by using the YAAHP software. The final conclusion is as follows: The total score of economic evaluation of coastline resource in Dafeng is 0.87. Therefore, the coastline resource in Dafeng will eventually be constructed a unique coastal economic zone, where the implemented port industrial projects will include shipbuilding, logistics, mechanical processing etc.

4

Copper recovery from waste printed circuit boards and the correlation of Cu, Pb, Zn by ionic liquid

Li F., Chen M.

Environment Protection Engineering

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2017

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Vol. 43, nr 4

55--66

EN

Waste printed circuit boards (WPCBs) contain not only harmful materials but also many valuable resources, especially metals, which attracts more and more attention from the public. In this study, a sulfonic acid functionalized ionic liquid ([BSO₃HPy]OTf) was used to recycle copper from WPCBs. Zinc and lead, represented as typical heavy metals, were chosen to study the leaching behavior and their relation to copper. Five factors such as particle size, ionic liquid (IL) concentration, H₂O dose, solid to IL ratio and temperature were investigated in detail. The results showed that copper leaching rate was high, up to 99.77%, and zinc leaching rate reached the highest value of 74.88% under the optimum conditions. Lead cannot be leached effectively and the leaching rate was mostly low than 10%, which indirectly indicated that [BSO₃HPy]OTf has a good selectivity to lead. Besides, the interaction of copper, lead and zinc was characterized macroscopically by means of statistical methods. The Spearman correlation analysis showed that copper and zinc had a highly positive correlation. Lead had little relation to copper, which to some extent indicated that the effect of zinc on copper leaching behavior was bigger than that of lead.

5

Effects of three pesticides on superoxide dismutase and glutathione-S-transferase activities and reproduction of Daphnia magna

Song Y., Chen M., Zhou J.

Archives of Environmental Protection

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2017

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Vol. 43, no. 1

80--86

EN

Applying pesticides to crops is one of the causes of water pollution by surface runoff, and chlorpyrifos, trifluralin and chlorothalonil are used respectively as insecticide, herbicide and fungicide for crop plants widely. To explore effects of three pesticides on aquatic organisms, superoxide dismutase (SOD) and glutathione S-transferase (GST) activities were determined after 24 h and 48 h exposure of D. magna with ages of 6–24 h to several low concentrations of chlorpyrifos (0.36, 0.72, 1.43, 2.86, 5.72 μg∙L−1), trifluralin (0.17, 0.33, 0.66, 1.33, 2.65 mg∙L−1) and chlorothalonil (0.09, 0.18, 0.36, 0.72, 1.43 mg∙L−1) respectively. Main reproductive parameters including first pregnancy time, first brood time, the number of first brood and total fecundity after 21 d exposures at the same concentrations of pesticides as described above were also measured. The results showed that the activities of GST increased in lower concentrations and decreased in higher concentrations after 24 h exposure to three pesticides, respectively. The activities of SOD showed the same changes after 48 h exposure. With the time prolonged, the activities of GST decreased while the activities of SOD increased. After 21 d exposure, the first pregnancy time and first brood time were delayed, while the number of the first brood and total fecundity per female decreased with increasing concentrations. These results corroborated that GST activity was more sensitive to those pesticides than SOD activity, and there was a significant relationship between total fecundity and pesticides-dose(r>0.94, n=6), GST activity after 48 h exposure and total fecundity after 21 d exposure (r>0.92, n=6).

6

Multi-grid model for crowd’s evacuation in ships based on cellular automata

Chen M., Han D.

Polish Maritime Research

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2015

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S 1

75--81

EN

In order to enhance the authenticity and accuracy simulation of passengers’ evacuation in ships, a new multi-grid model is proposed on the basis of cellular automata theory. By finer lattice the multi-grid model could enhance the continuity of passengers’ track and the precision of boundary’s qualification compared with traditional cellular automata model. Attraction, repulsion and friction are also quantized in the multi-grid model to present the impact of interaction force among pedestrians. Furthermore, crowd’s evacuation simulated by traditional cellular automata and multi-grid model in single exit room and typical cabin environment have been taken as examples to analyze crowd’s motion laws. It is found that the laws of passengers’ evacuation simulated by the two models are similar, and the simulation authenticity and accuracy is enhanced by the multi-grid model.

7

Matching relation between consumer’s psychology and digital goods rankings

Chen M., Wang Q., Liu H.

Foundations of Computing and Decision Sciences

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2015

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Vol. 40, No. 2

107--117

EN

The development of digital goods has profoundly changed the economic relationship and trading methods. Among all the digital goods recommendation information, ranking information is of prominent significance. The rankings impact consumers positively as they make decisions on buying digital products. We serve rankings and consumer psychologies as the object of this study, and will offer references and suggestions for the customization of the mobile terminal. Combining factor and cluster analysis, we subdivide the rankings into three groups first based on consumers’ values and lifestyles: reputation ranking, consumption behavior ranking and purchase intention ranking. Then, we use a correspondence analysis method to conclude the matching relationship between different types of rankings and various consumption psychology groups.

8

Particle swarm optimization based fuzzy clustering approach to identify optimal number of clusters

Chen M., Ludwig S. A.

Journal of Artificial Intelligence and Soft Computing Research

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2014

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Vol. 4, No. 1

43--56

EN

Fuzzy clustering is a popular unsupervised learning method that is used in cluster analysis. Fuzzy clustering allows a data point to belong to two or more clusters. Fuzzy c-means is the most well-known method that is applied to cluster analysis, however, the shortcoming is that the number of clusters need to be predefined. This paper proposes a clustering approach based on Particle Swarm Optimization (PSO). This PSO approach determines the optimal number of clusters automatically with the help of a threshold vector. The algorithm first randomly partitions the data set within a preset number of clusters, and then uses a reconstruction criterion to evaluate the performance of the clustering results. The experiments conducted demonstrate that the proposed algorithm automatically finds the optimal number of clusters. Furthermore, to visualize the results principal component analysis projection, conventional Sammon mapping, and fuzzy Sammon mapping were used.

9

A novel forward problem solver based on meshfree method for electrical impedance tomography

Hu G., Chen M., He W., Zhai J.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 2a

234--237

EN

In this paper the meshfree method is developed to solve the forward problem for electrical impedance tomography. Differing from finite element method and finite volume method, there is no mesh generation in meshfree method, which is easier to realize and more propitious to be developed as an adaptive procedures for image reconstruction. Numerical simulation results are presented and compared with the results of analytical solution. It is observed that the obtained results are consistent with the results of analytical solution.

PL

W artykule zaproponowano nowa metodę tomograficznej analizy impedancji w której nie generuje się oczek jak na przykład w metodzie elementów skończonych. Dzięki temu uzyskuje się łatwiejsza analizę, w tym także metodami adaptacyjnymi.

10

Adsorption of nitrate from aqueous solution onto modified cassava (Manihot esculenta) straw

Li W., Mo W., Kang C., Zhang M., Meng M., Chen M.

Ecological Chemistry and Engineering. S

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2012

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Vol. 19, nr 4

629-638

EN

The performance of a new anion exchanger prepared from raw cassava straw (RCS), for the removal of nitrate from aqueous solutions was evaluated in this study. The cassava straw was modified by epichlorohydrin in the presence of pyridine. The influencing factors, adsorption kinetics, and thermodynamics model of nitrate adsorption onto the modified cassava straw (MCS) were studied. The results showed that the zeta potentials of RCS and MCS were -20.5 mV and +37.3 mV, nitrogen contents (N %) of RCS and MCS were 0.43 and 4.96%, respectively. The best nitrate removal results was reached at 0.2 g of adsorbent dosage and pH range of 6.0÷12.0. The modified cassava straw adsorbed nitrate(V) quickly, reaching equilibrium within 30 minutes. The kinetics of nitrate adsorption at different initial concentrations (25, 50 and 75 mg/dm3) all fit a second order reaction. The adsorption rates were controlled by both membrane diffusion and intra-particle diffusion. The adsorption data fit the Freundlich adsorption isotherm and the Langmuir adsorption isotherm. The maximum adsorption capacity was 2.14, 2.00 and 1.81 mmol/dm3 at 293, 303, and 313 K, respectively.

PL

Dokonano oceny wydajności nowego wymieniacza anionowego, wytworzonego ze słomy surowego manioku (RCS), w usuwaniu azotanów z roztworów wodnych. Słomę manioku zmodyfikowano za pomocą epichlorohydryny w obecności pirydyny. Zbadano kinetykę adsorpcji, czynniki wpływające oraz model termodynamiczny adsorpcji azotanów na zmodyfikowanej słomie manioku (MCS). Wyniki pokazały, że potencjały zeta RCS i MCS wynosiły -20,5 mV i +37.3 mV, zawartości azotu (% N) w RCS i MCS wynosiły odpowiednio 0,43 i 4,96%. Najlepsze wyniki usuwania azotanów uzyskano, wykorzystując 0,2 g adsorbentu, w zakresie pH 6,0÷12,0. Zmodyfikowana słoma manioku szybko adsorbowała azotany(V), osiągając stan równowagi po 30 minutach. Kinetyka adsorpcji azotu z roztworów o różnych stężeniach początkowych (25, 50 i 75 mg/dm3) wskazuje na reakcję II rzędu. Szybkość procesu adsorpcji kontrolowała zarówno dyfuzja membranowa, jak i dyfuzja cząsteczkowa. Dane doświadczalne opisano za pomocą modeli izotermy Freundlicha i izotermy Langmuira. Maksymalne pojemności sorpcyjne wynosiły 2,14, 2,00 i 1,81 mmol/dm3 w temperaturach odpowiednio 293, 303 i 313 K.

11

Real-time mask-division technique based on DMD digital lithography

Luo N., Gao Y., Chen M., Yu L., Ye Q.

Optica Applicata

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2010

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Vol. 40, nr 1

239--248

EN

Digital lithography technique is a promising tool for the fabrication of binary optical element. In this paper, we present the mask-division technique to improve the lithography quality. A piece of high-frequency mask is divided into several pieces of low-frequency binary masks. Then they are imaged on the photoresist successively by using the DMD-based lithography system. Based on the theory of partial coherent light, the intensity distribution in image plane has been simulated. The grating masks with period of 4 žm have been fabricated by using the mask-division technique. Experimental results demonstrate the feasibility of the proposed method as an effective technique for advancing the edge sharpness.

12

Syntheses and characterization of pH-sensitive hydrogel from poly(.gamma.-glutamic) acid

Yao B., Yang C., Zhang K., Ni C., Song H., Ni Z., Chen M.

Materials Science Poland

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2009

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Vol. 27, No. 1

319--327

EN

Novel pH-sensitive hydrogels were prepared through crosslinking of poly(.gamma.-glutamic) acid (.gamma.-PGA) by using 1,4-butanediol diglycidyl ether as a cross-linker, tetraethylammonium bromide as a catalyst, and reacting in DMSO. The dependence of the swelling ratio of the hydrogels on pH values, ionic strength and cross-linking degree was investigated. It was found that the pH-sensitive range was clearly extended through introducing multiple hydrogen bonds to the hydrogel network during the preparation. The swelling ratios of ?-PGA hydrogels increased with the increase in pH of the aqueous solution from 2 to 9. The swelling of the .gamma.-PGA hydrogels was firstly controlled by the ionization of carboxyl groups in the hydrogels within the pH range from 2 to 5, and then controlled by breaking of the multiple hydrogen bonds in the hydrogels within the pH range from 5 to 9. The swelling ratios of .gamma.-PGA hydrogels were also strongly dependent on the ionic strength of the medium and cross-linking degree of the hydrogels. Increasing the ionic strength and the crosslinking degree resulted in a decrease in the swelling ratio of the hydrogels.

13

Study on the experiments of the relationship between the geometric dimensions of flexural vibration disk and its vibration characteristics

Yuan Y., Ma Y., Chen M., Wang D., Zhao B.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

255--258

EN

Purpose: The vibration characteristics of flexural vibration disk in ultrasonic honing system were studied systematically through experiments. Design/methodology/approach: The vibration of flexural vibration disk was tested using the acoustic system of ultrasonic honing. Findings: The results showed that the amplitude of vibration disk increases with the reducing of its thickness, when the disk was thin disk (the ratio between the thickness and radius was less than or equal to one fifths) the vibration of disk was flexural vibration, the good vibration effect could be obtained. The maximal amplitudę could reach 20.5μm,at the same time, the number of the wave crests and size could be obtained. There exist amplifying characteristics in the vibration of the disk. When the diameter of disk was not changed, the resonant frequency would decrease with the reducing of the thickness of disk. The resonance could be excited at different frequencies. The corresponding maximal amplitude value provides certain reference value for the dimensional design and application of flexural vibration disk. Research limitations/implications: From analysis, the ratio between diameter and thickness of flexural vibration disk has direct effect on amplitude. The rational diameter and thickness of flexural vibration disk should be selected according to specific machining conditions and the size requirements of the whole honing equipment during the course of design of ultrasonic honing acoustic system. Originality/value: The studied on relationship between geometric dimensions of flexural vibration disk and its vibration characteristics were made.

14

Preparation of new polyorganosiloxane acrylate and the properties of UV-cured acrylate compositions containing it

Liu H., Chen M., Xu K., Wang Z.

Polimery

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2004

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T. 49, nr 6

404-407

EN

A new polyorganosiloxane acrylate (POSA) has been obtained as a result of Michael addition reaction of polyorganosiloxane modified with cyclohexylamine with methyl end groups (MCAPS) and hexanediol diacrylate (HDDA). 1H NMR and FT-IR methods confirmed the course of a reaction of N-H groups of MCAMPS with acrylic groups of HDDA. POSA has been used to modification of UV-cured epoxy-acrylic system (HDDA + butyl acrylate + epoxy-diacrylate resin). It has been stated that even small POSA content (1-1.5 wt. %) causes significant changes of surface properties of cured coatings. Namely, contact angle and its hysteresis increase, gloss decreases while final hardness does not change. Using XDS method it was showed that POSA selectively concentrated on the surface of cured coatings.

PL

W wyniku reakcji addycji Michaela z udziałem modyfikowanego cykloheksyloaminą poliorganosiloksanu z końcowymi grupami metylowymi (MCAPS) oraz diakrylanu heksanodiolu (HDDA) otrzymano nowy akrylan poliorganosiloksanowy - POSA [równanie (1)|. Metodami 1H NMR (rys. 1) oraz FT-IR potwierdzono przebieganie reakcji grup N-H MCAMPS z grupami akrylowymi HDDA. Związek ten użyto do modyfikacji układu epoksydowo-akrylowego (HDDA + akrylan butylu + żywica diakrylanowo-epoksydowa) utwardzanego pod wpływem promieniowania UV. Stwierdzono, że już niewielka zawartość POSA (1-1,5 % mas.) powoduje bardzo istotne zmiany właściwości powierzchniowych utwardzonych powłok. Mianowicie, zwiększa się kąt zwilżania (rys. 2) i jego histereza (rys. 4) oraz oporność powierzchniowa, maleje połysk (tabela 1), natomiast końcowa twardość nie ulega zmianie (rys. 5). Metodą rentgenograficzną (XDS) wykazano, że POSA koncentruje się selektywnie na powierzchni utwardzonych powłok (rys. 3).

15

Preparation and properties of UV-curable acrylate compositions containing silicon

Liu H., Chen M., Zhang X., He T., Wang Z.

Polimery

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2004

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T. 49, nr 3

168-172

EN

Some di- and triacrylates were subjected to Michael addition reaction with N-cyclohexyl-gamma-aminopropylmethyldimethoxysilane (CAMS). FT-IR method has been used to follow the course of the reaction of -NH group in CAMS with double bond in an acrylate. Post-reaction mixtures obtained underwent UV-curing in the presence of a photoinitiator (2-hydroxy-2,2-dimethyl-1-phenylethane-1-one, trade name "Darocur 1173") and formed thin films on the glass or plastic substrate. Dependence of the thermal stability of cured material on its initial composition was characterized using thermogravimetric method. There were determined the effects of non-reacted acrylic groups' part in the post-reaction mixture as well as of irradiation time (crosslinking degree) on hardness and brittleness of the coatings cured. Silicon atoms presence in the compositions improves their elasticity but deteriorates thermal stability.

PL

Szereg di- i triakrylanów poddano reakcji typu addycji Michaela z N-cykloheksylo-gamma-aminopropylometylodimetoksysilanem (CAMS) (tabela 1). Przebieg reakcji grup -NH w CAMS z podwójnym wiązaniem w akrylanach śledzono metodą FT-IR (rys. 1 i 2). Uzyskane mieszaniny poreakcyjne ulegały wobec fotoinicjatora (2-hydroksy-2,2-dimetylo-1-fenyloetan-1-onu o nazwie handlowej "Darocur 1173") utwardzeniu pod wpływem promieniowania UV tworząc cienkie błony na podłożu szklanym lub tworzywowym. Metodą termograwimetryczną scharakteryzowano zależność termostabilności utwardzonych kompozycji od ich wyjściowego składu (rys. 3, tabela 2). Określono wpływ udziału nieprzereagowanych grup akrylanowych w mieszaninie poreakcyjnej i czasu napromieniania (stopnia usieciowania) na twardość oraz kruchość utwardzonych powłok (tabela 1). Obecność atomów krzemu w kompozycjach polepsza ich elastyczność, lecz pogarsza termostabilność.