bluuebunny/crossref_metadata_2025 huggingface dataset:
Mining Users' Intents from Logs
Authors: Khodabandelou Ghazaleh , Hug Charlotte , Salinesi Camille
Published: April 2015

Intentions play a key role in information systems engineering. Research on process modeling has highlighted that specifying intentions can expressly mitigate many problems encountered in process modeling as lack of flexibility or adaptation. Process mining approaches mine processes in terms of tasks and branching. To identify and formalize intentions from event logs, this work presents a novel approach of process mining, called Map Miner Method (MMM). This method automates the construction of intentional process models from event logs. First, MMM estimates users' strategies (i.e., the different ways to fulfill the intentions) in terms of their activities. These estimated strategies are then used to infer users' intentions at different levels of abstraction using two tailored algorithms. MMM constructs intentional process models with respect to the Map metamodel formalism. MMM is applied on a real-world dataset, i.e. event logs of developers of Eclipse UDC (Usage Data Collector). The resulting Map process model provides a precious understanding of the processes followed by the developers, and also provide feedback on the effectiveness and demonstrate scalability of MMM.
On The Reuse of Past Searches in Information Retrieval
Authors: Gutiérrez-Soto Claudio , Hubert Gilles
Published: April 2015

When using information retrieval systems, information related to searches is typically stored in files, which are well known as log files. By contrast, past search results of previously submitted queries are ignored most of the time. Nevertheless, past search results can be profitable for new searches. Some approaches in Information Retrieval exploit the previous searches in a customizable way for a single user. On the contrary, approaches that deal with past searches collectively are less common. This paper deals with such an approach, by using past results of similar past queries submitted by other users, to build the answers for new submitted queries. It proposes two Monte Carlo algorithms to build the result for a new query by selecting relevant documents associated to the most similar past query. Experiments were carried out to evaluate the effectiveness of the proposed algorithms using several dataset variants. These algorithms were also compared with the baseline approach based on the cosine measure, from which they reuse past results. Simulated datasets were designed for the experiments, following the Cranfield paradigm, well established in the Information Retrieval domain. The empirical results show the interest of our approach.
Relationship between Information Richness and Exchange Outcomes
Authors: Cai Shaohan , Jun Minjoon
Published: April 2015

The present study identifies the richness levels of various Internet media and empirically examines the moderating effects of Internet media richness (rich and lean media) and Internet communication governance mechanisms (legal contracts and relational norms) on the relationships between rich and lean information communication, and exchange outcomes. This study uses regression analysis to analyze data collected from 284 Chinese companies. The analysis reveals that: (1) Rich information exchange is effective when rich Internet media is frequently used. Conversely, the effectiveness of lean information exchange is not significantly affected by the frequent use of lean Internet media; (2) While lean information exchange is effective when legal contracts are extensively utilized as a governance mechanism, rich information exchange is effective when high levels of relational norms exist; and (3) Lean information exchange is effective when a high level of plural form governance (i.e., a combination of relational norms and legal contracts) exists.
Simulation Modeling and Analysis of Fire Fighting Operations in the State of Kuwait
Authors: Savsar Mehmet , Aleisa Esra
Published: April 2015

Emergency services, including firefighting operations, are complex processes and involve several activities in different stages that function together to achieve a main goal of preventing destruction in human life, property, and environment. This study uses discrete event simulation (DES) to model and improve firefighting operations in the state of Kuwait. The main objective is to reduce the response time required to reach an accident place. It is a life-saving criterion that needs to be considered. This study is conducted by collecting thorough data of fire operation department over a period of five years and accordingly creating a valid simulation model to analyse the system under current operational conditions nationwide. Analysis of variance (ANOVA) was used to identify factors that were statistically proven to have positive effects in reducing response time. A simulation model was used as a medium to carry out these experiments. The results of simulation model were validated at 95% confidence level. The effectiveness of the analysis is examined by incorporating related parameters from the ANOVA model into simulation model. The response time was reduced from seven minutes to three minutes on average per incident per fire station.
Flexible Pressure Sensor Based on Photo Paper-Molded Micro-Structural AgNWs/PDMS Electrode
Authors: Mo Li Xin , Hou Yu Qun , Zhai Qing Bin , Zhang Wen Guan , Li Lu Hai
Published: April 2015

The novel flexible pressure sensor with skin-like stretchability and sensibility has attracted tremendous attention in academic and industrial world in recent years. And it also has demonstrated great potential in the applications of electronic skin and wearable devices. It is significant and challenging to develop a highly sensitive flexible pressure sensor with a simple, low energy consuming and low cost method. In this paper, the silver nanowires (AgNWs) as electrode material were synthesized by polyol process. The polydimethylsiloxane (PDMS) was chosen as a flexible substrate and polyimide (PI) film as dielectric layer. The AgNWs based electrode was prepared in two methods. One is coating the AgNWs on photographic paper followed by in situ PDMS curing. Another one is suction filtration of the AgNWs suspension followed by glass slide transfer and PDMS curing. Then the capacitive pressure sensor was packaged in a sandwich structure with two face to face electrodes and a PI film in the middle. The sensitivity of the sensor as well as the micro-structure of the electrodes was compared and studied. The results indicate that the roughness of the electrode based on AgNWs/PDMS micro-structure plays an important role in the sensitivity of sensor. The as-prepared flexible pressure sensor demonstrates high sensitivity of 0.65kPa-1. In addition, the fabrication method is simple, low energy consuming and low cost, which has great potential in the detection of pulse, heart rate, sound vibration and other tiny pressure.
Fabrication of Ultrathin Free-Standing Ceramic Chips Based on Printing Technology
Authors: Kong Wen Wen , Gao Bo , Jiang Chun Ping , Chang Ai Min
Published: April 2015

In order to obtain high quality ultrathin free-standing ceramic chips, a new manufacturing process based on the screen printing and the cold isostatic pressing process has been developed. 1) In this process, an ultrathin free-standing green sheet (less than 20 μm thick) can be achieved successfully as shown in Fig. 1. After sintering, an ultrathin free-standing ceramic chip (less than 20 μm thick) with good density uniformity, can be obtained as shown in Fig. 2. In addition, the thicknesses of the ultrathin chips can be adjusted by changing the printing parameters for different application requirements. Such process can significantly widen the scope and applicability of the ultrathin chips in many kinds of materials.
Preparation of Fe3O4 with Solvothermal Method and its Electrochemical Properties
Authors: Zhao Fu Yan , Ding Meng Ru , Chen Jie , Li Ya Ling , Li Lu Hai
Published: April 2015

This article describes a facile solvothermal method to prepare magnetite (Fe3O4) for electrode material using ethylene glycol (EG) as one of the raw material. The properties were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The as-prepared Fe3O4 as an electrode material was fabricated into supercapacitor and characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge measurements. The Fe3O4 particles disperse well and the size is about 50 nm. Saturation magnetization and coercive force of sample are 90.44 emu/g and 81.84 G, respectively. The specific capacitance is 50.2 F g-1 at 0.5 A g-1.
Investigation on Electrical Stress over Metal-Insulator-Metal (MIM) Structures Based on Compound Dielectrics for the Inkjet-Printed OTFT Stability
Authors: Mitra Kalyan Yoti , Sowade Enrico , Sternkiker Christoph , Martínez-Domingo Carme , Ramon Eloi , Carrabina Jordi , Baumann Reinhard R.
Published: April 2015

One of the greatest challenges in the field of printed electronics is the performance stability of the devices fabricated by the different printing technologies e.g. inkjet or gravure printing technology. The performance instability can be defined in terms of the device breakdown or by other effects like the emergence of leakage current under the constant high voltage inputs (especially the dielectric within the transistor architecture). The reasons behind this phenomenon can be various, but the most prominent indication can be detected from the materials used and the deposition methodology. For this purpose the herein work is presented, targeting on the all inkjet-printed organic thin film transistor (OTFT), but keeping the focus on the basic building block for fabricating inkjet-printed OTFTs. In this case it is the metal-insulator-metal (MIM) layer structure. Herein, the MIM structures are inkjet-printed, and then characterized optically and electrically. The dielectric layers for the MIM structures are printed using three different dielectric ink materials either individually 1) Single component system; or in combination with each other as in form of bi-layer stack 2) Multiple component system. The thickness of the printed dielectric layers is varied for these MIM structures. The electrical characterization is performed with respect to current vs. applied voltage and is done for a large number of iterations. The leakage current is of interest and shows a negative and positive trend towards the single component system and multiple component system for the dielectric layers in the MIM characterization structures respectively.
Modeling and Optimizing Industrial Inkjet Printhead for Printable Electronics Fabrication
Authors: Ma Lian Bo , He Mao Wei , Hu Kun Yuan , Zhu Yun Long
Published: April 2015

The most significant issues in printable electronics fabrication are the printing quality and efficiency delivered by drop-on-demand (DOD) industrial inkjet printhead. Aiming to characterize the nonlinear behaviors of piezoelectric inkjet printhead, the dynamic lumped element model (DLEM) is proposed to cast the original LEM into a time-varying and nonlinear fashion. At the same time , the PSO-based optimization for paramenters is incorporated in DLEM. Due to new characteristics, DLEM can accurately simulate the inkjet-printed nanosilver droplet formation process and effectively predicate optimal combinations of high-frequency driving waveform with high printing quality. From extensive experimental studies, the effectiveness and efficiency of the proposed DLEM is validated.
Conductive Improvement of Flexography Printed Silver Pattern by Water Washing
Authors: Fang Yi , Liu Wei , Xu Yan Fang , Li Lu Hai
Published: April 2015

This work demonstrates a simple method to improve the conductivity of flexography printed silver pattern by water washing. The flexography printed silver pattern was firstly dried in an oven under 120 celsius degree, then was placed into the deionized water. Heating post-treatment is used to enhance adhesion between the printed silver layer and the substrate film to prevent the detachment of the silver pattern during water washing. The method is compatible with the PET substrate and printed fine pattern of square and hexagon in room temperature. After 2 hour immersion in water under magnetic stirring, the printed silver pattern of square and hexagon show different conductive improvement of conductivity. The silver pattern of hexagon shape with water washing exhibits much better conductivity than the one wiped by lens wipe paper, as measured by using a multimeter. The confocal laser scanning microscope (CLSM) shows that the morphology of the two shapes of silver pattern was almost no changed, except a little decrease on the thickness of the silver layer.
Influence of Annealing of PCDTBT:PC70BM on the Performance of Polymer Solar Cells
Authors: Yan Shi , Lv Long Feng , Hou Yan Bing
Published: April 2015

Bulk-heterojunction polymer solar cells (BHJ-PSCs) have attracted considerable attention because of their unique advantages of lightweight, low cost, mechanical flexibility and suitable for large-area fabrication [1–3]. In the last decades, much attention has been paid to the donor and acceptor system P3HT:PCBM, However, because of the relatively large bandgap of P3HT (∼1.9 eV) and the relatively small energy difference between the lowest unoccupied molecular orbital (LUMO) of PCBM and the highest occupied molecular orbital (HOMO) of P3HT, the photovoltaic performance of the PSCs based on P3HT:PCBM is still significantly lower than the inorganic solar cells. Recently more work has been done on the novel donor materials which have a reduced energy gap with an ability of harvesting more of the sun’s spectral emission and a high charge carriers mobility for charge transport. One of the most promising new donor polymer is poly [N-9"-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3' -benzothiadiazole)] (PCDTBT) with a HOMO level of 5.5eV which is 0.4 eV down-shifted than that of P3HT. When PCDTBT is blended with the fullerene acceptor PC70BM, it showed excellent photovoltaic performance with a power conversion efficiency of ∼ 6%. [6]
Synthesis and Mesophase of a Triphenylene-Based Discotic Liquid Crystal with Plastic Columnar Phase
Authors: Wang Jian Chuang , Zhang Shuai Feng , Zhang Chun Xiu , Wu Hao , Wang Yi Fei , Hao Xing Tian , Hong Feng , Zhang Ao , Pu Jia Ling
Published: April 2015

A novel triphenylene-based discotic liquid crystal 2, 3, 6, 7, 10, 11-hexabutylcarboxyltriphenylene was synthesized. The chemical structure was determined by 1HNMR and FT-IR spectrum, and its mesophase was investigated by DSC and POM methods. The compound showed classical texture of columnar plastic phase under POM at the mesophase temperature from175°C-185°C during cooling.
Graphene Oxide for Ink-Jet Printing Technology
Authors: Li Ya Ling , Guo Xi , Feng Xiao Juan , Li Lu Hai
Published: April 2015

In order to acquire a suitable ink for ink-jet printing technology, a graphene oxide ink was explored based on the GO aqueous dispersion. The GO dispersion was characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The average particle diameter and zeta potential of the GO dispersion was determined by zeta potential & particle size analyzer. The GO ink is composed of 1,2-propanediol, diethylene glycol monobutyl ether, glycerol, polyvinyl pyrrolidone (PVP) and GO dispersion. The surface tension and viscosity of the GO ink was tested by surface tension meter and rheometer. The GO ink was inkjet printed on polyethylene terephthalate (PET) substrate. The optimal inkjet printing parameters were obtained and the printing quality was characterized by confocal laser scanning microscopy. The results show that the GO ink is suitable for inkjet printing technology and the morphology of the GO film with one printing pass has good uniformity.
Monolithic Integration of a Flexible Micro Thermal Flow Sensor
Authors: Zhao Shuai , Zhu Rong
Published: April 2015

In this paper, a novel monolithically integrated flexible thermal flow sensor combining four resistors in a Wheatstone bridge including hot-film resistor, temperature-compensating resistor and two other balancing resistors on one chip is proposed in order to improve the system integration level and sensor performances, such as signal to noise ratio (SNR), power consumption and temperature compensation. Fabricating the sensor directly on a flexible polyimide printed circuit board (PCB) by incorporating printed circuit technique with micromachining sputter technique is adopted. A complete performance test on the flow sensor demonstrates its superiorities on power consumption, SNR and temperature drift, the error of which is eliminated from 43% to 8% over a range of ambient temperature (35–75°C).
Preparation and Characterization of Ultrafine Monodisperse Iron Oxide Nanoparticles by Solvothermal Method
Authors: Liu Cheng Mei , Zhao Yu Xia , Dong Jin , Li Lu Hai , Wei Yen , Han Lu
Published: April 2015

Using iron-oleate complex as a precursor, oleic acid as a stabilizer and 1-octadecene as a reductant, uniform-sized and highly monodisperse iron oxide nanoparitcles with different diameters were successfully synthesized via solvothermal method by changing reaction time. Transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), fourier transform infrared spectroscopy (FT-IR), physical property measurement system (PPMS) and dynamic light scattering (DLS) was used to characterize obtained iron oxide nanoparticles. These results indicated that iron oxide nanoparitcles with the diameter ranging from 4 to 8 nm can be controllably synthesized.
Dependence of Mechanical and Dielectric Properties on Temperature of Poly(Vinylidene Fluoride-Hexafluoropropylene)
Authors: Thetpraphi Kritsadi , Putson Chatchai , Muensit Nantakan
Published: April 2015

Recently, pyroelectric polymers i.e. polyvinyledene fluoride (PVDF) and its copolymer of P(VDF-TrFE), including poly (vinylidene fluoride-hexafluoropropylene) - P(VDF-HFP) have been reconsidered greatly for energy conversion or energy harvesting. This work study the effect of temperature on mechanical and dielectric properties of thin film P(VDF-HFP). All samples were prepared by solution casting method then stretched and poled at 35 μm/s of velocity and 60 MV/m of electric field, respectively. The dielectric properties were determined by LCR meter varying on temperature (30°C to 155 °C) at 1 kHz. For mechanical properties were investigated by dynamic mechanical analysis (DMA) which explained the viscoelastic behavior and obtained a glass transition temperatures (Tg) of all samples. The range of operated temperatures is-100 °C to 100 °C in rate 5°C/min. The results showed a tiny shift of Tg among non-stretched, stretched, and polarized P(VDF-HFP) which is related to their degree of crystallinity and ability of polarization on dielectric behavior of sample. Correlation of the temperature dependence of mechanical and dielectric properties under stretching and poling of these polymers are also discussed.
Optical Property of Sb-Doped SnO2 Nanoparticle Thin Films by Sparking Process
Authors: Jintakosol Thanut
Published: April 2015

Undoped and Sb doped SnO2 nanoparticle thin films were synthesized by sparking process. The nanoparticles were continuously deposited onto the substrate by varying the number of sparking cycles ranging from 10-30 and the deposited film were subsequently annealed at 500 °C in tube furnace under air atmosphere for 1 h. The effect of Sb doped SnO2 nanoparticles thin film on their structure and optical characteristics were investigated. The optical properties of the nanoparticles thin films have been studied from transmission spectra. An average transmittance of the thin films decrease from 70% to 50% when the doping level increased from 0 to 7 %Sb doped SnO2. Opitical band gap energy of thin films were found to vary in range of 3.85-3.89 eV which the energy band gap decrease with the increasing Sb doping concentration. From the experimental data, the reduction of optical transmittance spectra in the antimony doped SnO2 thin films make it suitable for generation of window layer coating and prevent unwanted absorption in UV range.
Experimental Investigation on Electrical and Mechanical Characteristics of PVC Cable Insulation with Silica Nano Filler
Authors: Edison Selvaraj D. , Vijayaraj R. , Satheeshwaran U. , Nancy J. , Pugazhendhi Sugumaran C. , Raj Kumar M. , Ganesan J. , Geethadevi S. , Dinesh Kumar S.
Published: April 2015

Cables are an integral part of the power transmission and distribution network. As the voltage level increases, amount of insulation used in the cable increases. Therefore a need arises for a material with better insulation characteristics to be used in cables. The dielectric strength of cable insulation depends on many factors such as the existence of filler material in the insulation. In this work, laboratory studies on a new filler material for cable insulation have been conducted. The influence of Silicon dioxide (SiO2) filler on the dielectric and mechanical properties of polyvinyl chloride (PVC) cable were analyzed. Comparison is made between the result of measurement and the actual value of the pure specimen. From the results, it is shown that the filler material has improved the dielectric and mechanical properties of the cable insulation.
SB12 Assisted Synthesis of Nano CuO via Precipitation Method in Different Reaction Environments
Authors: Bozkurt Gamze , Bayrakçeken Yurtcan Ayşe , Özer Abdulkadir
Published: April 2015

In this study, CuO was synthesized via precipitation method by using Cu (CH3COO)2.H2O as precursor. KOH+NH3, KOH and NaOH were used as reactants and zwitterionic 3-(N,N-dimethyldodecylammonio) propane-sulfonate (SB12) as surfactant in the synthesis procedure. The samples were calcined at 500°C. All prepared CuO structures were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier Transform Infrared (FTIR) spectra, and scanning electron microscopy (SEM) techniques. Electrochemical characterization was performed by cyclic voltammetry (CV). CuO showed different nanostructures according to the characterization results. Furthermore, electrochemical properties of the resulting structures were investigated. The specific capacitances of the CuO structures in different environments were determined by using CV technique in the order of: KOH+NH3>KOH>NaOH.
Liquid Crystalline Epoxy Resin Cured with Azomethine Hardening Compounds
Authors: Choi Ho Kyoung , Choi Jae Hyun , Lee Hyeoung Seok , Na Jae Sik
Published: April 2015

Bisphenol of 4,4’-dihydroxy-N-benzylidene-4-aminophenol containing azomethine group was synthesized via condensation of an aromatic amine namely 4-aminophenol with p-hydroxybenz aldehyde. It’s epoxy derivate and epicholorohydrin produced the new liquid crystalline diglycidyl ether of 4,4’-dihydroxy-N-benzylidene-4-aminophenol. A new type of liquid crystalline epoxy and azoemthine hardening agent are characterized at 300°C for 10 min, using c11z as a catalyst. The chemical structures were confirmed by FT-IR,1H-NMR. The curing reaction with 4,4’-dihydroxy-N-benzylidene-4-aminophenol were carried out in the ratio of glycidyl ether of 4,4’-dihydroxy-N-benzy lidene-4-aminophenol/azomethine hardening 1:0.8. The degree of crystallinity studied by X-ray diffractometer, differential scanning calorimetry (DSC) and polarized optical microscope (POM).
Fabrication of Chitosan Nanofibers Scaffolds with Small Amount Gelatin for Enhanced Cell Viability
Authors: Kim Min Sup , Park Sang Jun , Gu Bon Kang , Kim Chun Ho
Published: April 2015

Chitosan and gelatin has attracted considerable interest owing to its advantageous biological properties such as excellent biocompatibility, biodegradation, and non-toxic properties. In this paper, we investigated the potential of chitosan/gelatin (Chi-Gel) nanofibers mat with enhanced cell viability for use as cell culture scaffolds. The surface morphology, mechanical properties, and initial contact angle analysis of Chi-Gel nanofibers mat were evaluated. The proliferation of human dermal fibroblast cell (HDFs) on Chi-Gel nanofibers mat was found to be approximately 20% higher than the pure chitosan nanofibers mat after 7 days of culture. These results suggest that the Chi-Gel nanofibers mat has great potential for use tissue engineering applications.
Composite with Aren Fiber (Waste of Starch Fiber) as an Insulator and Sound Reducer
Authors: Sudarsono  , Huda Saiful , Yuniwati Murni , Purnawan
Published: April 2015

In this research, waste of Aren fiber is utilized for raw material of composite. This aren fiber composite is used for insulator and sound absorber. The Aren composite is manufactured by pressing technique of mixture of aren, resin and hardener occur for 24 hours. The composites made from aren composite are tested in term of thermal conductivity and ability of sound absorber. The research aims to study an effect of resin to fiber ratio, size of Aren fiber to thermal conductivity, and sound absorber ability of aren composite material. The result shows that the optimum thermal conductivity of Aren composite is found to be 0, 3950 kcal/m h0C. This composite is obtained with resin-fiber ratio of 7:1, fiber length of 1 cm, 10% hardener, and pressure of 70 kg/mm2. Meanwhile, for optimum sound absorber composite is obtained with resin-fiber ratio of 6:1, fiber length of 2 cm, 10% hardener, and pressure of 70 kg/mm2. The composite has noice reduction of 40,1 dB and transmission loss of 46,1 at frequency of 500 Hz.
Manufacturing and Mechanical Property Evaluations of PLA/Carbon Fiber/Glass Fiber Composites
Authors: Lin Jia Horng , Huang Chien Lin , Chen Chih Kuang , Liao Jo Mei , Lou Ching Wen
Published: April 2015

This study uses carbon fiber (CF) and glass fiber (GF) as reinforcement for polylactic acid (PLA) fiber, and their mixtures are melt-blended into PLA/CF/GF composites. Mechanical properties of the composites are evaluated by applying a tensile test, a flexural test, and an impact test, and the dispersion of fibers is observed by using a scanning electron microscopy (SEM). The test results show that the increasing content of CF results in a greater strength in the composites while the increasing content of GF provides the composites with greater modulus. The combination of both CF and GF contributes to a certain level of mechanical strength and also decreases the production costs for the composites.
Organic/Inorganic Acoustic-Absorbing/Thermal Insulating Fiber-Reinforced PU Composite Foam Boards
Authors: Lin Jia Horng , Chuang Yu Chun , Huang Chen Hung , Li Ting Ting , Lou Ching Wen
Published: April 2015

As technology expands rapidly, scientific productions have become an indispensable part for human daily life. Hence, human begin to value environment comfort and functional property. This study purposes to add reinforcing materials, carbon fiber and glass fiber, into polyurethane (PU) foam solvent, and to form PU foam composite board after foaming and curing process. The foaming density and reinforcing fiber were altered during process. The burst strength, acoustic absorption and thermal conductivity of resulting organic/inorganic fiber-reinforced PU composite foam boards were evaluated. Result displays that, 5 wt% additions of carbon fibers improved burst strength and thermal insulation, and maintained the original acoustic absorbing characteristic.
Preliminary Study of Puncture-Resisting Needle-Punched 3D Composites with Varying Reinforcements
Authors: Lin Jia Horng , Li Ting Ting , Lin Mei Chen , Lin Jan Yi , Lou Ching Wen
Published: April 2015

Logistics industry becomes the mainstream with promotion of life quality. The selection of delivery type and aging is subjected to limitations of packaging materials. In order to protect from product’s damage, this study purposes to use recycled high-strength fibers, including high-strength PET fiber, and Kevlar fibers, and thermal bonding PET fiber as well as glass fabric forming needle-punched 3D composite. For comparison of varying reinforcement on mechanical property, thermal bonding and water polyurethane impregnation are used to reinforce the 3D composite which is composed of nonwoven fabrics and glass fabrics. Result shows that, mechanical property from water polyurethane impregnation displayed much higher than that from thermal bonding. Thermal bonding remarkably improved burst strength and static puncture resistance. Therefore, 3D composite impregnated with water polyurethane reaches higher puncture protection level.
Development of Epoxy/BN Composites with High Thermal Conductivity for Metal-Core Printed Circuit Board (MCPCB)
Authors: Choi Jae Hyun , Choi Bong Goo , Lee Min A. , Na Jae Sik
Published: April 2015

The epoxy composites with high thermal conductivity for metal-core printed circuit board (MCPCB) can be prepared by varnish coating and a hot press method. Alumina filler of plate-like shape was used as primary micro-filler, while plate-like alumina filler, h-BN, a-BN and s-BN filler were used for blending into the plate-like alumina filler as the secondary filler. Results showed that the secondary fillers a-BN and s-BN loaded epoxy composites have higher thermal conductivity than alumina filler single-loaded composites. Also, BN filler has high thermal conductivity, but h-BN filled epoxy composite has lower thermal conductivity than alumina filled epoxy composite. The decrease of voids in epoxy composite are very important, and the filler shape and surface modification is also necessary to achieve high thermal conductivity in epoxy composite for MCPCB
Comparative Efficiency of Artificial Neural Network to Predict Spring-Back Value in U-Bending Process of High Strength Steel
Authors: Songkroh Arkhom , Sresomroeng Bhadpiroon
Published: April 2015

High strength steel (HSS) was used as raw material in the automotive industry, which required lightweight and high strength, such as chassis and etc. However, the strength and hardness of the steel are relatively high, leading to the low permeability and large spring-back occurring after forming operation. As a result, the work piece is not shaped desire. This research proposes neural network for predicts the spring back values, in U-bending process, that the materials were differences in mechanical properties, such as SPFH590 (JIS) and SPEC980Y (JIS). In the experiment, the input factors for predictable data consists as the punch radius (RP), die radius (Rd), clearance (Cl) and counter punch force (Fc). After that, the input data were analyzed relation with spring-back values by the Pearson Correlation of One-tailed. Next, It was selected by Leave-one-out and k-fold Cross validation (K-fold and LOOCV), to improve efficiency of the prediction process. Moreover, the result was a measurable performance with Root Mean Square Error (RMSE) technique, equal to 0.788 and 2.10 respectively. In the final analysis, the neural network is effective to predict the Spring-back values of SPFH590 (JIS) rather than SPEC 980Y (JIS) in U-bending process.
Increasing the Reactivity of the Mineral Powders by Modifying
Authors: Yadykina Valentina V. , Gridchin Anatoly M. , Trautvain Anna Ivanovna , Khoroshikh Alexander Sergeyevich
Published: April 2015

The present work contains information on control processes of interaction in the system "organic binder - mineral filler" by mechano-chemical water-repellency treatment of the latter with the purpose of expansion of a raw-material base in the production of road-building composites from man-made materials.
Application of a-SiO2 Rich Additives in Cement Paste
Authors: Pokorný Jaroslav , Pavlíková Milena , Navrátilová Eva , Rovnaníková Pavla , Pavlík Zbyšek , Černý Robert
Published: April 2015

The effect of a-SiO2 of various origin on the properties of cement paste with incorporated different silica containing materials is experimentally studied in the paper. For the applied a-SiO2 materials, basic physical and chemical properties are accessed, together with their chemical composition. Amount of amorphous phase of SiO2 in particular siliceous materials is determined using XRD analysis. Matrix density, bulk density, total open porosity, compressive and bending strength are measured for all developed pastes with incorporated a-SiO2 containing materials, together with initial and final setting time of fresh mixtures. The obtained data give evidence on a high and fast reaction activity of tested siliceous materials which results in a significant improvement of porosity and mechanical strength of a-SiO2 modified cement pastes.
Modeling of Externally Prestressed Beams until Fracture in Non Linear Elasticity
Authors: Adjrad Arezki , Bouafia Youcef , Kachi Mohand Said , Dumontet Hélène
Published: April 2015

In this paper, we present an analytical model to analyze reinforced and prestressed concrete beams loaded in combined bending, axial load and shear, in the frame of non linear elasticity. In this model, the equilibrium of the beam is expressed by solving a system of equations, governing beams equilibrium, based on the stiffness matrix of the beam, which connects the load vector to the node displacements vector of the beam. It is built from the stiffness matrix of the section which takes into account a variation of the shearing modulus (depending on the shear variation) instead of assuming a constant shearing modulus as in linear elasticity. For the internal tendons, the stiffness matrix is completed by the terms due to the prestress effect in flexural equilibrium and by the balancing of one part of the shear by the transverse component of the force in the inclined cables.
Modeling the Behavior of the Fiber Reinforced Concrete by Damage Mechanics
Authors: Belhadj Naima , Bouafia Youcef , Smahi Rebiha
Published: April 2015

The damage mechanics allows a detailed modeling of reinforced concrete’s degradation phenomenon. The theory of isotropic damage leads to quite satisfactory results in the description of both in the local and the global behavior. It is within the scope of this work to provide a model of damage based on the non-linear mechanical behavior of fiber concrete. This model takes into account the ductile nature of the observed during testing of material and direct tension after cracking. The modeling will be done while checking the principles of damage mechanics using the fundamentals of continuous mechanics of materials to propose a law of damage variation in unidirectional compression and tension. Confrontations with experimental test results are established.
Measurement and Numerical Simulation of Deformation of Pre-Stressed Masonry
Authors: Kozielova Marie
Published: April 2015

Contribution deals with laboratory measurements of deformations in the place exposed to local load caused by additional pre-stressing and its comparison with numerical simulation. The measurements are made at the masonry brick corner built in the laboratory equipment. The laboratory equipment was designed at Faculty of Civil Engineering VŠB – TU Ostrava for measurement tri-axial stress-strain conditions in masonry. The masonry structure of the brick corner is imposed on the vertical load and pre-stress is applied through two bars. The values of deformation from pre-stressing are sensed by potentiometer sensors. Numerical simulation of the brick corner is based on the finite element method using appropriate software and then the results are compared with those of experimental testing. For numerical simulation were used material linearity and material non-linearity of model. On the basis of these results it should be possible to improve the models and come closer to achieving an accurate and at the same time, simple procedure for the design of pre-stressed masonry.
Phase Change Materials: A Prospective Solution for Surface Layers of Building Envelopes
Authors: Pavlík Zbyšek , Trník Anton , Pavlíková Milena , Fořt Jan , Černý Robert
Published: April 2015

A Phase Change Material (PCM) based on paraffinic wax encapsulated in polymer shell is used for improvement of the heat storage capacity of commercially produced dry plaster, originally developed for both exterior and interior hand application. The composition of PCM modified plasters is designed with respect to the workability of fresh mixtures. Characterization of applied PCM is done using the measurement of particle size distribution, powder density, and matrix density. For the newly developed composite plasters, basic physical properties, mechanical properties, and thermal properties are accessed, whereas a specific attention is paid to the Difference Scanning Calorimetry (DSC) analysis. Using DSC measurement, temperatures of phase change transitions and phase changes enthalpies are identified. The obtained results show that the temperature induced phase change can be used for the release and storage of thermal energy in buildings, which can be beneficially utilized for saving the energy spent for the achievement of the indoor thermal comfort.
Synthesis of Poly(ethylene glycol)-Block-Poly(lactide) via Sequential Ring-Opening Polymerization Technique for Preparing Micellar Carriers
Authors: Chen Chih Kuang , Lin Wen Jen , Chen Guan You , Lin Yu Te , Jhu Rong Siou , Lin Jia Horng
Published: April 2015

With the advancement of nanotechnology and material chemistry, micelles have emerged as one of the most attractive carriers for anticancer drug delivery. In this study, a newly developed polymerization technique termed as “sequential ring-opening polymerization (SROP)“ was used to synthesize poly (ethylene glycol)-block-polylactide-block-polylactide (PEG-PLA-PLAs). Utilizing the features of SROP, well-controlled chain length of two different PLA blocks by using PEG as initiator can be achieved. Two types of PEG-PLA-PLAs, PEG-PLA11-PLA11 and PEG-PLA18-PLA18, were successfully synthesized and characterized. Having amphiphilic properties, PEG-PLA-PLAs were used to form micelles through self-assembly. The effects of PLA length on the resultant micelles were thoroughly investigated.
Morphological, Photocatalytic and Bactericidal Properties of ZnO Powders Prepared by a Precipitation Method
Authors: Suwanboon Sumetha , Klubnuan Sarunya , Amornpitoksuk Pongsaton , Bangrak Phuwadol
Published: April 2015

Structural, optical and photocatalytic properties of ZnO powders prepared by a precipitation method were systematically investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffuse reflectance measurement and UV-Vis absorbance measurement. The antibacterial activity was tested by a broth microdilution method. All calcined ZnO powders exhibited a hexagonal wurtzite structure. The ZnO powders formed various shapes depending upon the concentration of n-propylamine used. The Eg value of ZnO powders depended upon defect concentration. The photocatalytic property of ZnO powders depended on the particle shape and defect concentration. The best photocatalytic efficiency of 100% was observed from the ZnO powders prepared at R = 2 after irradiating by the blacklight for 90 min. All ZnO powders can damage only S. aureus and the agglomerated sheet-like ZnO powders prepared at R = 2 showed the best antibacterial property with a MIC value of 1.5625 mg/mL.
Research on the Energy Conservation and Emission Reduction Technologies in First Washing Wastewater
Authors: Yu Ying Han , Yue Guan Hua , Wang Qi
Published: April 2015

In recent years, large amounts of wastewater are mostly discharged directly to environment without being properly treatment in many washing industry, bringing tremendous damage to the environment. From the perspective of reducing energy consumption of washing waste water treatment, the first washing wastewater containing the highest pollutant concentration are tested properly, the second and third washing wastewater could be recycled. In this research, the treatment effects of six coagulants are tested, the appropriate coagulant and an economic treatment scheme of first washing wastewater are developed according to the characteristics of wastewater. Adopting the method of centralized treatment, by which we can reduce water consumption and carbon emissions and can be used in the small and medium-sized enterprise of washing industry.
Erosion-Corrosion of Carbon Steel and Alloys in Ammonium Hydrosulfide Solutions
Authors: Jin Hao Zhe , Wang Kuan Xin , Ren Hai Yan , Ou Guo Fu
Published: April 2015

The rotary experiment apparatus was built to study the erosion-corrosionresistance of carbon steel, 15CrMo steel, duplex stainless steel 2205, nickel based alloy 825 and stainless steel 316L which are commonly used in the sour water environment of refinery. Based on the electrochemical test, the carbon steel and alloys corrosion rates in different ammonium hydrosulfide concentration, fluid velocity and temperature were obtained. The corrosion products film morphology was analyzed by scanning electron microscope (SEM) to find the reasons for corrosion rates difference of carbon steel and alloys. The results showed that the corrosion rates of carbon steel and alloys were increasing with fluid velocity, ammonium hydrosulfide concentration and temperature increase, when the velocity exceeds 6 m/s the corrosion rates essentially unchanged. The maximum corrosion rate of carbon steel at 60 °C and 10 wt% ammonium hydrosulfide concentration was as high as 6.5 mm/year, while the nickel based alloys 825 and stainless steel 316L were less than 1.5 mm/year. The corrosion product films of carbon steel and 15CrMo steel was loose and cracking which can easy to fall off from the substrate when subjected to fluid impact and the corrosive media can easily penetrate into the bottom of corrosion product and continue to corrode substrate. However, the corrosion film of nickel based alloys 825 and stainless steel 316L was dense and tightly bonded to substrate making it has a good corrosion resistance.
Friction and Wear Behaviors of GCr15 Steel under Dry Friction and Grease Lubrication
Authors: Su Bing , Zhang Shuo
Published: April 2015

The sliding friction and wear behaviors of GCr15 steel against GCr15 steel under dry friction and grease lubrication were investigated on a reciprocating friction and wear tester consisting of a ball-on-disc friction pair. The morphologies of the worn surfaces of discs were analyzed by means of scanning electron microscopy (SEM). The result shows that GCr15 steel friction coefficient decreases with the increase of load, and the wear rate decreases with the time going by. There exist larger wear volumes on the friction surface under dry friction, while the wear volumes are relatively minor under grease lubrication. The SEM analysis agree with such results.
Synthesis, Crystal Structure and Optical Properties of Silver Complex with 2-Amino-4-Methylthiazole
Authors: Xue Rui Ting , Sun Wei Song , Yu Si Rong
Published: April 2015

The complex of 2-amino-4-methylthiazole with silver [Ag (C4H6N2S)2.(CH3)2CO] had been synthesized and characterized by elemental analysis, FT-IR and UV-vis spectra. Crystals of the complex were obtained through solvent diffusion method and the structure had been determined by single crystal X-ray diffraction. The nonlinear optical properties were investigated with the density functional theory method. The calculated results show that the complex has high hyperpolarizability of 316.8×10-30esu and the metal irons play an important role for the nonlinear optical properties.
Research on Plasticizing Properties and Mechanism of PVA
Authors: Hao Xi Hai , Wen Shu
Published: April 2015

Taking glycerol as the plasticizer, through its effect on melting and crystallization of PVA, this paper researches on the plasticizing properties and mechanism of PVA, and provides experimental and theoretical basis for the realization of PVA’s melt processing. Research Methods: Matching samples respectively, mix each sample in an electric high-speed mixer with a mixing temperature of 80 °C. And then, put each sample in a Banbury mixer, mixing for 10 minutes with a rotational speed of 45rm/min. Take out each sample to analyze its characterization and do some tests, including infrared analysis, DSC test, X-ray diffraction test, and rheological curve measurement. Experimental Results: After adding glycerol, there exist two more absorption peaks near the point of 1621cm-1 in the PVA infrared spectrum, and the crystallization peak at 1267cm-1 is decreased gradually. In the DSC chart, when the amount of glycerol increasing to 16.67%, the melting point of PVA is decreased to 212 °C, and its melting range is 191 °C-223 °C. Under this condition, the melting range has been completely separated from the decomposition temperature range. X-ray diffraction shows that glycerol is added no significant effect on the diffraction angle of the PVA, the diffraction peak intensity decreased significantly increases the degree of dispersion. Under the same temperature, with the shear rate increasing, the shear viscosity has a downward trend; as the temperature increases, the shear viscosity and shear stress of the system are gradually decreasing. Conclusion: Glycerol may lower the melting temperature because it can improve the segmental mobility of PVA and reduce the crystalline regions. However, the amount of glycerol should not be too much, or the plasticizing effects will be drastically reduced because of the separation. The research also find that a certain amount of glycerol used alone cannot reduce the decomposition temperature but decrease the melting temperature, which still cannot meet the melt processing conditions. The excessive glycerol can easily be precipitated from PVA, resulting in the product surface being oily and crisp.
Improved Stabilities of Lipase by Immobilization on Eupergit C
Authors: Wang Bin , Zhang Chun Yong , Hu Xiu Ying , Ma De , Su Li , Zhou Quan Fa
Published: April 2015

Lipase is frequently used for catalyze wide non-natural substrates in order to obtain enantio- and regioselectivie substrates. This study evaluates the stabilities of lipase by immobilization on Eupergit C. The immobilized lipase had improved stability at 60oC for 60 h compared to the free lipase 1 h at 60oC. Immobilization resulted in an increase in pH stability over a range of 7.0 - 9.0 and about 54 days for half-life of storage at 4oC. The tolerance of lipase to organic solvents was also improved by immobilization, and the immobilized lipase showed activating activity when exposed to hydrophobic solvents.
The Structure and Stability of C20 Dimer
Authors: Dai Ting Ting , Huo Pei Ying , Yu Ji Cai , Liu Huan , Song Yan Xia , Zhang Xiu Rong
Published: April 2015

The possible geometrical and electronic structures of C20dimer are optimized by using the density functional theory at B3LYP/LANL2DZ level, stable structure of C20dimer are obtained. The stability of the ground state structure have been studied. The results showed that: there was a slight expansion in carbon cage of C20 dimer ; its chemical stability and thermal stability have been improved.
Heat Transfer Model of Larch Bark Particles Pyrolysis
Authors: Sun Ya Wei , Cheng Yi , He Liang , Li Rui
Published: April 2015

A novel model for larch bark pyrolysis was established by combine dimensions, shapes, boundary conditions, pyrolysis gas diffusion, particle size and reaction heat expression. It overcomes the shortages of early models which are short of expression of the reaction heat and application conditions. By introducing the kinetic equations and shape factor, the model was simulated by commercial software. The simulation results indicated that the pyrolysis time of particles is increasing by particle size, the best size for larch pyrolysis is 0.8 mm under 775K.