bluuebunny/crossref_metadata_2025 huggingface dataset:
Electronic Government Services Adoption
Authors: Mensah Isaac Kofi , Mi Jianing
Published: October 2017

This study investigated the moderating impact of perceived service quality on the positive relationship between perceived usefulness of e-government services and intention to use e-government services. The Technology Acceptance Model (TAM) was applied as the theoretical foundation for the study. The research data collected was analyzed with SPSS while the graphical representation of the moderating effect was generated using the software known as Interaction version 1.7.2211. The results have demonstrated that perceived service quality of e-government services does not have any significant moderating effect on the positive relationship between perceived usefulness and intention to use e-government services. However, perceived service quality and perceived usefulness of e-government services were found to be positively significant in influencing the intention to use e-government services. The implications of this study are further discussed.
Evidences of Validity of The Brazilian Scale of Learner's Attitude Towards Distance Education Programs
Authors: Junior Francisco Antonio Coelho , Cortat Mariane , Flores Clarissa Leite , Santos Flávio Augusto Mendes , Alves Gleidilson Costa , Faiad Cristiane , Ramos Wilsa Maria , Rodrigues da Silva Alan
Published: October 2017

Online learning is one of the fastest growing trends in educational uses of technology. In this study, an instrument to measure the social attitudes of the Brazilian students based on distance education was developed and validated. The study population consisted of public administration undergraduate students that has been providing by distance education by University of Brasília, in Brazil. The sample of the study consisted of 590 Brazilian students. The scale has 41 items, with total Cronbach alpha coefficient of .94, and reliability coefficient (KMO) of .94. The correlations of each item with total point were between .30 and .79. A factor analysis was run using direct oblimin rotation for construct validity, resulting in 4 factors structure explaining 47.12% of total variability. These factors are “Personnel and Dispositional Aspects”, “Procedural Characteristics”, “Negative Affects” and “Internalization and habituation of usage”. Consequently, findings show that The Brazilian Attitude Scale towards Distance Education (BrazilASTDE) is a valid and reliable instrument.
Exploring Factors Affecting Users' Satisfaction Toward E-Learning Systems
Authors: Hammouri Qais , Abu-Shanab Emad
Published: October 2017

E-learning is emerging as the new phenomenon of modern education. Universities are adopting e-learning as a strategy for the improving the teaching/learning process. The primary question addressed in this paper is related to the factors influencing the adoption of e-learning. An integrated model was used to explore the factors influencing students' satisfaction with e-learning in Jordan. The model adopted five variables from the technology acceptance model, Delone and McLean model and the social cognitive theory to predict students' satisfaction with e-learning. A sample of 386 students was utilized and an instrument with 30 items was used. Results indicated that perceived ease of use, perceived usefulness, system quality, information quality, and computer self-efficacy are major factors influencing students' satisfaction. The coefficient of determination estimated to be 0.498, and yielded a full support of all proposed hypotheses. Conclusions and future work are reported at the end of this study.
Students' Acceptance of an Educational Videos Platform
Authors: Costa Carolina , Alvelos Helena , Teixeira Leonor
Published: October 2017

The Educast is an educational videos' platform that captures simultaneously video and digital support materials. This paper presents a study on the acceptance of Educast, by students, using the Technology Acceptance Model–TAM. The data was collected through a questionnaire applied to 54 students which results were analyzed using descriptive analysis and non-parametric tests. It was concluded that students expressed a positive attitude towards the variables Perceived Ease Of Use, Perceived Usefulness and Attitude Toward Using. The comparison between ratings assigned to the questionnaire items by the students who viewed video recordings and those that did not was performed, and it was found that the former showed higher levels of agreement with the referred items than the latter. It is considered that introducing some training before students have contact with Educast should be taken into account. The result of this work can be valuable not only for researchers on the Education area, but also for teachers that intend to use educational videos in their teaching/learning environment.
Optimized Packet Filtering Honeypot with Snooping Agents in Intrusion Detection System for WLAN
Authors: Kumar Gulshan , Saha Rahul , Singh Mandeep , Rai Mritunjay Kumar
Published: October 2017

Wireless LAN networks are considered to be widely used and efficient infrastructure used in different domains of communication. In this paper, we worked on Network Intrusion Detection System (NIDS) to prevent intruder's activities by using snooping agents and honeypot on the network. The idea behind using snooping agents and honeypot is to provide network management in term of monitoring. Honey pot is placed just after the Firewall and intrusion system have strongly coupled synchronize with snooping agents Monitoring is considered at packet level and pattern level of the traffic. Simulation filtered and monitor traffic for highlight the intrusion in the network. Further attack sequence has been created and have shown the effects of attack sequence on scenario which have both honey pot and snoop agent with different network performance parameters like throughput, network load, queuing delay, retransmission attempt and packet. The simulation scenario shows the impact of attack on the network performance.
Using Mobile Devices to Facilitate Student Questioning in a Large Undergraduate Science Class
Authors: Crompton Helen , Burgin Stephen R. , De Paor Declan G. , Gregory Kristen
Published: October 2017

Asking scientific questions is the first practice of science and engineering listed in the Next Generation Science Standards. However, getting students to ask unsolicited questions in a large class can be difficult. In this qualitative study, undergraduate students sent SMS text messages to the instructor who received them on his mobile phone and via Google Glass. Using observations, coding of texts, and interviews, the researchers investigated the types and level of questions students asked and the perceptions of the instructor and TAs on how the messages were received. From the findings of this study, it is evident that students asked a wide variety of question types and levels. It would appear that important distinctions between voice and text questions are that: (a) a shy or insecure questioner can remain anonymous; (b) questions can be asked in an interactive, but not interruptive manner; (c) there is no time limit to answering questions; and (d) the record of questions on the instructor's phone can be used to guide revision of lecture notes for future semesters.
Deep Learning
Authors: Naylor Amanda , Gibbs Janet
Published: October 2017

This article presents results from an international collaboration between college students and pre-service teachers in Norway and the UK. This research is part of a large, international project exploring and developing the interrelationship between mobile technology and teachers' perceptions of teaching and learning. Data was collected for this study through an on-line survey of 37 pre-service teachers followed by six semi-structured, in-depth interviews. The data analysis revealed the themes of collaboration, authenticity and professional learning through the use of mobile technology in the data. The collaboration enabled the use of the affordances of mobile technology to enhance the pre-service teachers' professional learning and the data suggested that this enhanced their emergent conceptions of teaching and learning.
FLANN + BHO
Authors: Naik Bighnaraj , Nayak Janmenjoy , Behera H.S.
Published: October 2017

Among some of the competent optimization algorithms, nature inspired algorithms are quite popular due to their flexibility and ease of use in diversified domains. Moreover, balancing between exploration and exploitation is one of the important aspects of nature inspired optimizations. In this paper, a recently developed nature inspired algorithm such as black hole algorithm has been used with the functional link neural network for handling the nonlinearity nature of system identification. Specifically, the proposed hybrid approach is used to solve classification problem. The results of the hybrid approach are compared with some of the other popular competent nature based approaches and found the superiority of the proposed method over others. Also, a brief discussion on the working principles of the black hole algorithm and its available literatures are discussed.
Enhancement of TOPSIS for Evaluating the Web-Sources to Select as External Source for Web-Warehousing
Authors: Sinha Hariom Sharan
Published: October 2017

In this paper, the main concern is to evaluate the web-sources, which are to be selected as an external source for web-warehousing. In order to identify the web sources, they are evaluated on the basis of their multiple features. For it, Multi-Criteria Decision Making (MCDM) approach is used. In this paper, among all the MCDM approach, the focus is on “Technique for Order Preference by Similarity to Ideal Solution” (TOPSIS) approach and proposing an enhancement in this method. The traditional TOPSIS approach uses Euclidean Distance to measure the similarity. Here, Jeffrey Divergence has been proposed instead of Euclidean Distance to compute the similarity measure which includes asymmetric and symmetric distances during computation. Experimental analysis of both the variations of TOPSIS approach have been conducted and the result shows the enhancement in the selection of web sources.
Comparative Study of the Impact of CO2 Emission on Income
Authors: Allali M. , Tamali M. , Rahli M.
Published: October 2017

Emissions of global warming gases continue to rise as the world burns ever more coal, oil and gas for energy. The article, aims to run an investigation nexus between carbon dioxide (CO2) emission per capita and economic growth of energy consumption in over the period 1990-2100. To evaluate the impact of CO2 emission on relative variables, this study verifies that there is positive long-run relationship among CO2 emissions, Electric power consumption and Energy use. This paper also proves bi-directional causality between CO2 emission and electric power consumption (modeling the impact of CO2 emission on output especially in Algeria and because of the vast majority of natural gas is imported from Algeria to Morocco so the authors use the same model for Morocco and compare the results obtained and see what the different causes that influence these results). The policy makers may evaluate exogenous effect to seeking economic growth for global climate warming and to formulate energy policies.
Assessment of A Mobile Educational Coaching App
Authors: Shahidi Niousha , Tossan Vesselina , Cacho-Elizondo Silvia
Published: October 2017

This article explores which antecedents explain intentions to adopt a mobile coaching app. To that end, this study describes a coaching service designed to guide/encourage students throughout their studies in order to validate a new model of planned behavior based on the Technology Acceptance Model and the Goal-Directed Behavioral theory. The methodology included a short qualitative study and an online survey to examine the theoretical model which is based on scales tested in previous studies. The convenience sample is composed of students (Bachelor and Master/MBA) with the results analyzed using structural equation modelling to test the proposed model's causal structure. The results show different adoption patterns by gender and type of school.
Inter-Organizational Study of Access Control Security Measures
Authors: Yaokumah Winfred , Okai Eric Saviour Aryee
Published: October 2017

This study assesses the level of implementation and management of access control security measures among organizations. A survey was conducted and 233 responses were received from 56 organizations drawn from 5 major industry sectors of Ghana. This study focuses on the four access control clauses, namely access control policy, user access management, user responsibility and accountability, and system and application access control, which were adopted from ISO/IEC27002 international information systems security management standard. Overall, the results show that the organizations' level of implementation and management of access control measures were approximately 66.6% (Level 3 - well defined), indicating that access control measures were documented, approved, and implemented organization-wide. Moreover, the results show significant differences in the implementation and management of access control measures among the organizations. For all the access control measures, the financial and health care institutions outperform educational institutions and government public services.
Characterization of Squeeze Cast Mg Alloy AM50 Containing Ca Addition
Authors: Ren Lu Yang , Masoumi Mohsen , Hu Henry
Published: October 2017

Metallographic analyses on microstructure of squeeze cast magnesium alloy AM50 with different levels of calcium addition are performed via optical microscopy (OM), and scanning electron microscopy (SEM). The OM results show the calcium has a grain refining effect on the base alloy AM50 with the level of Ca addition up to 2 wt.%. As the Ca content further increases, its grain refining effect becomes limited. The SEM observation reveals the addition of 2 wt.% Ca to the AM50 alloy leads to the formation of a continuous network of eutectic phases along grain boundaries while the discontinuous divorced secondary eutectic β-Mg12Al17 is present in the microstructure of AM50 containing also the primary α-Mg, and Mn-Al intermetallic particles. The elemental mapping by the energy dispersive spectroscopy (EDS) indicates the presence of the major alloying elements of Al and Ca along grain boundaries in the squeeze cast AM50 alloy with Ca addition.
Application of Swirl Brake in Pipeline Compressor System
Authors: Yang Lei , Zhang Xiao Long
Published: October 2017

According to level I and level II stability analysis of the API617 (7th edition), the stability of a natural gas pipeline compressor system is studied. It is found that the rotor bearing system is unstable. Therefore, adding swirl brake on the system is to improve the damping characteristics. The stability of the unit can meet the requirement of API617 dynamic design. The research demonstrates that the stability of compressor system is not solely determined by the rotor system, but the stator system is also an important factor. In particular, the swirl brake on the diaphragm can reduce the cross coupling stiffness generated by the seal, and it is significant to improve the stability of the compressor system.
Surface Layer Damage of Quartz Glass Induced by Ultra-Precision Grinding with Different Grit Size
Authors: Geng Zong Chao , Gao Shang , Kang Ren Ke , Dong Zhi Gang
Published: October 2017

Quartz glass is a typical hard and brittle material. During the manufacturing process of quartz glass components, ultra-precision grinding is widely used due to its high throughput and good dimensional accuracies. However, grinding will unavoidably induce large surface and subsurface damage. In this study, the surface and subsurface damage characteristics of quartz glass substrates ground by diamond wheels with different grit sizes were investigated in terms of surface roughness, surface topography, subsurface microcrack characteristic, and subsurface damage depth. Discussion was also provided to explore corresponding reasons of surface and subsurface damage induced by diamond grinding wheels with different grit sizes of #1500 and #2000. The experiment results showed that the surface roughness, surface damage, and subsurface damage depth induced by #2000 quartz glass was ground by #1500 diamond grinding wheel, and in ductile mode when ground by #2000 diamond grinding wheel.
Design and Analysis of Compound Multilayer Metamaterial Filter in THz Region
Authors: Pan Wu , Zhang Jun , Yu Xuan , Zeng Wei
Published: October 2017

A periodic microstructure with dielectric and metal layers is proposed to obtain a bandpass filter. The multilayer microstructure is compounded of ring cross slot and cross slot. The center frequency of the filter is 0.338THz with a 3dB bandwidth of 75.62GHz. The maximum insertion loss in the pass band reaches 0.60dB. The bandedge transitions of the rejection bands are 232dB/THz and 176dB/THz, respectively. Furthermore, the physical mechanism of near field distribution and the influence of two factors (the number of metal layer and dielectric layer) on the passband have been studied. Meanwhile, the frequency response is analyzed for different incident angles and polarizations. The frequency response characteristic is insensitive to the polarization, and a good performance for incident angle of the transmission is obtained. It can be applied to THz atmospheric communication system.
Modeling of the Electromagnetic Drive Torque on the Permanent Magnet in a Novel Drive Mechanism
Authors: Cao Feng Yu , Niu Mu Qing , Yang Yi Kun , Xie Bao Ying , Yang Bin Tang
Published: October 2017

Analytical models of vibration exciters and shakers are of great importance to their dynamic analysis and control. Furthermore, the modeling of the drive torque/force of the driving principle plays a key role in the modeling of an entire driving system. This paper aims to find a more detailed analytical model of the electromagnetic drive torque on the permanent magnet with a new shape in a novel driving mechanism. The proposed model contains all the related parameters instead of treating them as only one variable. Two methods of the permanent magnet installation are firstly introduced and compared. Based on the magnetic charge model, torque models of the bipolar cylindrical permanent magnet and partial bipolar cylindrical permanent magnet are then obtained. Thereupon then the final model with a composite shape is gained by combining the cylindrical and partial cylindrical ones. Moreover, all analytical models are verified by finite element method and it is found the final detailed model can characterize the electromagnetic drive torque in a high accuracy.
Visual Measurement Method for Target Size Based on Torque
Authors: Li Hai Hua , Chen Xiao Lin
Published: October 2017

With the rapid development of industrial technology, people have put forward higher requirements on the precision of process and assemblage for the part of the machine. In the process of accessory, a finish machining for the hole parts are generally necessary. There is greater impact on the processing accuracy because of the influence from the measurement methods, tool wear, lathe itself and other factors. In this paper, a regional centroid algorithm is proposed based on the visual measurement technology and mechanics principle. Firstly, the image of the workpiece is collected by the camera. And then the workpiece image is processed by the image processing technology. Thus, the torque of each pixel on the workpiece image contour relative to the center can be calculated. Finally, the detection and judgment of the part size is realized by the torque. Experiments show that this method can achieve accurate on-line detection for the inner diameter of the hole parts.
Single Photon Counting Discrimination Voltage Software
Authors: Deng Long Hu , Liu Wei Feng , Lu Yi Jia , Cheng Jia
Published: October 2017

Because the output signals of photon detectors are scattered under weak light, the single photon counting method uses pulse discrimination technique and digital counting technique to identify and count weak signals. Compared with analog recording technique, the single photon counting technique has the advantages of high signal-to-noise ratio and good anti drift performance. Discrimination voltage is an important part of single photon counting, which will greatly affect the signal to noise ratio (SNR). The selected process of discrimination voltage is very complicated, especially the number of photomultiplier tube spectral analysis system [1], discrimination voltage selection process more time-consuming. This paper presents a software for automatically searching voltage discrimination. The software can automatically measure the discrimination voltage of a plurality of photomultiplier tubes, greatly improve the efficiency and accuracy of screening voltage selection, and verify the effectiveness of the screening voltage software by calculating the signal-to-noise ratio.
A Multi-State HLL Approximate Riemann Solver for Solid/Vacuum Riemann Problem
Authors: Zhang Wei , Bai Jin Song , Sun De Jun
Published: October 2017

A new multi-state HLLD (‘‘D’’ stands for Discontinuities.) approximate Riemann solver for Riemann problem of nonlinear elastic solid is developed based on the assumption that a wave configuration for the solution that consists of five waves (two slow waves, two fast waves and a contact discontinuity) separating six constant states. Since the intermediate states satisfied with the Rankine-Hugoniot relations in this approximate Riemann system are analytically obtained, the HLLD Riemann solver can be constructed straightforwardly. The Piecewise Parabolic Method (PPM) is used directly to construct high-order finite-volume schemes. Numerical tests demonstrate that the scheme PPM coupled with HLLD is robust and efficient. It indicates that the scheme PPM+ HLLD can be useful in practical applications for the non-linear elasticity.
A Genetic Algorithm for Solving an Assembly Sequence Problem
Authors: Alharbi Fawaz Saad , Wang Qian
Published: October 2017

If a product has more than one component, then it must be assembled. The complexity of assembling a product is often subject to the number of assembly components that lead to possible assembly sequences in various forms. Also, it is widely understood that efficiency of assembling a product by reducing assembly times (therefore costs) is vital particularly for small manufacturing companies to survive in an increasingly competitive market. Ideally, it is helpful for determining an optimal assembly sequence of a product at the early design stage. Nevertheless, it may find inefficient using the heuristic approaches in acquisition of a quick solution in terms of an optimal assembly sequence with a minimal assembly time. By contrast, the study indicates that the genetic algorithm (GA) can be used as a cost-effective way for solving an assembly sequence optimisation problem of a product. This paper presents an investigation into a GA used for solving an assembly sequence problem of a ball pen. The study demonstrates that it can provide a quick solution in obtaining an optimal or near-optimal assembly sequence of the product for a small-sized company.
Application of Laser Additive Enhancing Technology in the Field of Cutting Tools
Authors: Ren Yuan , Wang Wen Tao , Ma Xin Qiang , Cheng Wei
Published: October 2017

Fe62 alloy coating was fabricated on the surface of #45 steel cutting edges with 2kW all-solid-state laser and powder feeding device. The substrate and forming layer are characterized by optical microscope and scanning electron microscope for microstructure, and tested by micro-hardness tester for micro-hardness. The results show that the forming layer combined with the substrate metallurgically. The microstructure of substrate is eutectoid ferrite and pearlite. The microstructure of layer is uniform and compact, with hard precipitation. The content of Cr, the hard phase generated element, at the grain boundary, is higher than that of grain inside and many hard phases were generated at the grain boundary. Compared with the substrate, the micro-hardness of forming layer increases by about 2 times. All these results show that application of laser additive enhancing technology in the field of cutting tools has larger potential.
Applying 2k Factorial Design to Study on Parameters Affecting Springback of Forming of Advanced High Strength Steel Sheets (AHSS)
Authors: Kesvarakul Ramil , Chianrabutra Chamaporn , Sirigool Watcharapong
Published: October 2017

Advanced high strength steels (AHSS) are widely used in the automotive industry due to their appropriate strength to weight ratio. This alloy has unique hardening behavior and variable unloading elastic modulus; however, the unavoidable obstacle of AHSS sheet metal forming is springback. The springback is a result of elastic recovery and residual stress. The aim of this study is to determine the proper process parameters enabling the reduction of the springback defects in AHSS forming process. This work was divided into two parts, regarding to the effects of numerical parameters and process parameter on forming AHSS. In this paper, a U-shape forming was used to examine the springback behaviors, such as springback angle, sidewall curl, and thickness, through an experiment. To achieve this purpose, 2k factorial statistical experimental design has been employed to investigate the parameters affecting the springback of forming in AHSS to find out the main effect in the springback reduction focusing on using as a guideline for die design. It showed that the blank holder force is the most influential parameter. The second is the punch radius. However, the blank holder force and punch radius is not simple to adjust in die design, the die radius becomes the important parameter to be used to reduce the springback angle.
Design and Analysis of High Absorber Based on Sub-Wavelength Grating Structure
Authors: Li Kun , Xiong Yu Qing , Cao Sheng Zhu , Zhang Kai Feng , Wang Hu , Zhou Chao
Published: October 2017

Two kinds of high absorber were designed based on sub-wavelength grating structure for aluminum substrate. The absorption and electric field distribution of these two structures were calculated by using the finite difference time domain method. One absorber was obtained by using Al2O3/SiO2 double layers and Al rectangular sub-wavelength layer which has high absorption peaks both in TE polarization and TM polarization in infrared spectrum. Another absorber was a single layer structure with a triangular sub-wavelength grating structure which had a broadband absorption in TE polarization at spectral range of 300-1000nm.Simulation results showed that the absorption of this absorber increase and then decreases with the increasing of the height of sub-wavelength grating. The average absorption reached the maximum when the height of grating was 800nm.
Micro-Manufacturing Using Online 3D Printing
Authors: Chen Yi Ping , Yang Ming Der
Published: October 2017

As an additive manufacturing process, 3D printing provides conceptualizers and designers an opportunity to quickly produce physical components and concept models at reasonable costs. Such manufacturing is distinct from mass production involving traditional subtractive machining processes. This paper briefly describes microscale manufacturing involving a series of 3D-printing-related processes, including 3D modeling, 3D model slicing, printing, and production. Furthermore, specifications of 3D printers, a major component of the 3D printing process, impedes the entry of new micro-manufacturing businesses, such as the maximum printing volume, printing material, positioning accuracy, layer thickness, and price, were analyzed. In addition, online 3D printing service could be an alternative to overcome the difficulty of new entry to micro-manufacturing by a step-by-step instruction through internet. Commercially available online 3D printing services were surveyed and compared in material and cost in this paper.
Influence of NiO Nanoparticles on Magnetic Properties of Neodymium Doped Tellurite Glasses
Authors: Sahar Md Rahim , Mat Jan Nur Amanina
Published: October 2017

Series of glass samples with composition (72.5-x)TeO2-15MgO-10Na2O-2.5Nd2O3-xNiO where 1.0 ≤ x ≤ 2.5 mol% are prepared using melt quenching method. The glasses are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD spectra confirmed the amorphous nature of prepared glasses. TEM images manifest the existence of NiO NPs which are homogeneously distributed in the glass matrix. The magnetization M(H) curve reveals that the glass displays an anomalous hysteresis behavior at room temperature. It is observed that M(H) is dependent on the NiO content. The initial curve of magnetization lies positively as a function of the magnetic field under 1000 H (O.e).
Absorption and Raman Spectra of Dy3+ Doped Tellurite Glass: Combined Effects of Silver and Titanium Nanoparticles
Authors: bin Mohd Saidi Mohd Syamsul Affendy , Ghoshal Sib Krishna , Arifin Ramli , bin Roslan Mohamad Khairil
Published: October 2017

Obtaining enhanced up-conversion efficiency in rare earth ions doped inorganic glass by means of noble metal nanoparticles (NPs) embedment remains challenging. For the first time, we report the combined effects of silver (Ag) and titania (TiO2) NPs embedment on the structural and absorption characteristics of dysprosium (Dy3+) doped tellurite glass. Transparent and thermally stable glass samples were prepared using conventional melt quenching method and characterized via spectroscopic techniques. The production of the strong electric field in the proximity of Dy3+ ion due to the localized surface plasmon (LSP) of embedded metallic NPs was found to improve the glass absorption properties. The effects of bimetallic NPs in changing the structure and absorption properties were found to be better than singly included metallic NP (either Ag or TiO2). This improvement in the absorption behavior was attributed to the combined LSP resonance (LSPR) effects of Ag and TiO2 NPs which transferred strong local electric field into the Dy3+ ions positioned in their vicinity. The UV-Vis-NIR spectra revealed six absorption bands centerted at 1690, 1283, 1097, 904, 800 and 755 nm which were allocated to the transition from 6H15/2 ground state to various excited states (6H11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2 and 6F3/2) of Dy3+ ion. Furthermore, the Raman spectra of such bimetallic NPs included glass system exhibited Raman peak shift accompanied by intensity variations when compared to the glass system with only one type of NPs incorporation. This enhancement in the Raman signal was ascribed to the LSPR mediated mechansim. The synthesized glass comporition was asserted to be prospective for devices.
The Effect of Nd3+ Composition on Judd-Ofelt Analysis of Lithium Niobate Tellurite Glasses Codoped with Er3+
Authors: Hasim Nurhafizah , Rohani Md Supar
Published: October 2017

The modification of absorption characteristics in rare-earth doped tellurite glasses is important in photonics application. The Er3+/Nd3+ doped glasses of the form (69-x)TeO2–15Li2CO3–15Nb2O5–1Er2O3 -(x)Nd2O3 with x =0.2 and 0.6 mol% are successfully made by using conventional melt-quenching technique. The Judd-Ofelt analysis is to determine the local structure and bonding in the vicinity of rare-earth ions. The oscillator strengths are calculated from the absorption spectra and used to evaluate Judd-Ofelt intensity parameters (Ωλ, λ=2, 4 and 6). The values of Ω4 and Ω6 change with the increase of Nd3+ concentration is ascribed to the change in glass network structures. The values of Ω2 are increased from 1.53 to 37.13 (10-22) cm2 with the increase of Nd3+ concentration which indicate an increase in the covalent nature of Nd-O bond and less centrosymmetrical the ion sites. The decrease in τrad for each level with the increase of Nd3+ concentration signifies on how fast a particular level gets depopulated. The values of β for the transitions 4G5/2, 2G7/2 → 4I9/2, 2H11/2 → 4I9/2 and 4F9/2 → 4I9/2 are found to lie in between 99.6 to 100.0%.
Growth and Characterization of Titanium Doped Lithium Niobate Single Crystal Using Czochralski Technique
Authors: Hashim K.Z. , Rohani Md Supar , Kamaruddin Wan Hairul Anuar
Published: October 2017

A successful growth of the titanium-doped lithium niobate (Ti: LiNbO3) single crystal by Czochralski method is reported. By preserving an effective control of growth parameters such as maintaining accurate temperature gradient by controlling its output power and growth rate as well as wisely choosing the right pulling rate and speed rotation, the Ti:LiNbO3 single crystal successfully produced using Automatic Diameter Control-Crystal Growth System (ADC-CGS). The structural and optical analyses have been done by using X-ray Diffractometer (XRD), Differential Thermal Analyzer (DTA) and Ultraviolet-Visible (UV-Vis) spectroscopy. The crystallinity of the sample has been confirmed using XRD and DTA has been used to determine the crystal nature of the sample. The position of fundamental absorption edge was recorded via transmission spectra in UV and visible region.
Effects of the Gold Nanoparticles (AuNPs) on the Proliferation and Morphological Characteristics of Human Breast Cancer Cells (MCF-7) in Culture
Authors: Rosli Nur Shafawati , Abdul Rahman Azhar , Aziz Azlan Abdul , Shamsuddin Shaharum , Zakaria Nurul Sabihah
Published: October 2017

Ultrastructural characteristic and morphological changes of untreated and treated breast cancer MCF-7 cells were observed by energy-filtered transmission electron microscope (EFTEM). Morphological observation of MCF-7 after being treated with 13 nm, 50 nm, and 70 nm AuNPs, were looking unhealthy and dying out of the populace, the observed cells were more reduced and dying as treatment with 50 nm and 70 nm AuNPs. Cells detachment, clumping, shrunken, and dispersed cells in the culture medium and floating cells were also observed. The observed morphological changes increase in 50 nm and 70 nm AuNPs than in 13 nm AuNPs, which is less toxic to MCF-7 cells. The presented morphological analysis has established that 13 nm AuNPs showed less toxic to MCF-7 breast cancer cells. Whereas, control cells of MCF-7 were treated with only complete culture media, despite the duration of treatment, whereby the cells maintained most of their morphological features and observed to have a typical morphology of healthy cells that are well attached to the surface. These results indicate that AuNPs were clustered in the cells and there was no significant difference between images of different sizes of AuNPs observed in the cells, because the AuNPs always clustered together inside the cells.
Conductance and Capacitance Responses of Metal-Organic-Metal Structure Based Organic Semiconductor Thin Film
Authors: Tak Hoh Hang , Mohamad Khairul Anuar , Ghosh Bablu Kumar , Alias Afishah , Saad Ismail
Published: October 2017

In this work we have investigated the frequency and the bias voltage dependence of the electrical responses of organic structures based on poly (triarylamine) (PTAA) thin film using ITO/Organic/Al diode structure. The frequency-dependent and bias voltage-dependent conductance and capacitance were investigated using a precision LCR meter with wide frequency test (10 Hz – 100 kHz) and various bias voltages ranges (0.2 to 5.0 V), respectively. Investigation revealed that conductance was strongly dependent on the frequency and bias voltage-dependent. Conductance was inversely proportional to the capacitance among the frequency. Meanwhile, the capacitance and series resistance were dependent until a certain value at the low frequency region, but the capacitance and series resistance were independent at high frequencies.
Electrical Transport Properties and Magnetoresistance of Pr0.67Sr0.33MnO3-NiO Composites
Authors: Lim Kean Pah , Shaari Abdul Halim , Chen Soo Kien , Jumiah Hassan , Ng Siau Wei , Wan Jusoh Wan Nur Wathiq , Fadin N.F.M.
Published: October 2017

A series of polycrystalline bulk samples (Pr0.67Sr0.33MnO3)1-x/ (NiO)x were prepared by solid state reaction, and its structure, electrical transport and magnetoresistance properties were investigated. X-ray analysis showed that parent compound of Pr0.67Sr0.33MnO3 (PSMO) formed in single phase with crystal structure of orthorhombic while secondary phase of NiO can be detected with the addition of composite. The electrical properties showed that the resistivity increased with the addition of NiO due to enhancement of spin dependent-tunneling scattering across the artificial grain boundaries of NiO layer. Magnetic field dependence MR curve at various temperatures clearly indicates that extrinsic magnetoresistance had been enhanced due to addition of NiO as the artificial grain boundary.
Microwave Absorption Properties of Fe3O4-Graphene Nanohybrids
Authors: Ng Yau Thim , Kong Wei , Appadu Sivanesan , Kong Ing
Published: October 2017

Magnetite (Fe3O4)-graphene nanohybrids having three different weight ratios of magnetite to graphene were synthesized by a facile in-situ deposition method. The combination of dielectric properties of graphene and magnetic properties of magnetite makes the nanohybrids an ideal choice of material for microwave absorption applications. In regards to that, the electromagnetic properties and microwave absorbing characteristics were investigated in a frequency range of 1-18 GHz. The reflection loss (RL) reaches a minimum of-40.44 dB at 6.84 GHz with a thickness of 7 mm for the sample containing 73 wt·% of Fe3O4. The bandwidth corresponding to the RL below-10 dB is 7.05 GHz. The as-prepared Fe3O4-graphene nanohybrids showed good microwave absorption ability in the low frequency band (C-band) which can be ascribed to improved impedance matching characteristics, enhanced interfacial polarizations as well as the magnetic loss contributions. Moreover, the frequency related to minimum RL could be tuned by varying the weight ratios of magnetite to graphene.
Impact of Annealing Time on the Optical Response of Zinc-Boro-Tellurite Glass
Authors: Mahraz Zahra Ashur , Sahar Md Rahim , Ghoshal Sib Krishna
Published: October 2017

Annealing time dependent optical properties of melt-quench synthesized Er3+-doped (0.5 mol%) zinc-boro-tellurite (ZBT) glasses containing silver (Ag) nanoparticles (NPs) (1.0 mol%) are reported. Heat treatment (HT) durations are varied to control NPs growth. Reduction of NPs sizes from 12.7 to 6.6 nm for HT time beyond 6 hr at 410 °C is ascribed to their diffusion limited growth. Surface plasmon resonance bands evidenced at 550 and 580 nm are red shifted. Luminescence intensity enhancement is majorly attributed to the local field effect of Ag NPs and quenching is due to the energy transfer from NPs to Er3+. Present glass compositions are promising for the development of photonic devices.
Fabrication and Characterization of Bi1.6Pb0.4Sr2Ca2Cu3-xFexOy Superconductor
Authors: Suazlina M.A. , Azhan H. , Syamsyir S. Akmal , Azman K. , Razali W.A.W. , Norihan Yahya , Mohamed Ruziana , Yusainee S.Y.S.
Published: October 2017

This paper reports the properties of Bi-2223 superconductors that had been doped with Fe2O3 at Cu-site of the system. It was prepared in bulk form using high purity oxide powders via solid state reaction technique with intermediate grinding. A series of x = 0.00, 0.02, 0.04, 0.06, 0.08 and 0.10 of Fe were stoichiometrically added to the well balanced of Bi1.6Pb0.4Sr2Ca2Cu3-xFexOy in order to trace the effect of Fe doping. Hence, electrical resistivity, X-ray diffraction and Field Emission Scanning Electron Microscopy have been carried out to assess the effects of Fe doping. These measurements indicate that Fe doping decreased the critical temperature and degrade the formation of high Tc phase compared with the undoped sample. The orthorhombicity parameters were increased due to substitution of Cu 3+ ion by Fe 2+ ion.
Effects of Calcination Temperature on Microstructure and Superconducting Properties of Y123 Ceramic Prepared Using Thermal Treatment Method
Authors: Dihom Mustafa Mousa , Shaari Abdul Halim , Baqiah Hussein , Al-Hada Naif Mohammed , Chen Soo Kien , Azis Raba’ah Syahidah , Awang Kechik Mohd Mustafa , Abd-Shukor Roslan
Published: October 2017

Thermal treatment method was employed to produce YBa2Cu3Ox superconductor ceramic. The effects of calcination temperature at 850 °C, set A, and 910 °C, set B, for 24 h followed by sintering at 930, 950 and 980 °C, were investigate using X-ray diffraction (XRD), scanning electron microscope (SEM) and four point probe measurement. The orthorhombic structure appears after calcination at 850 and 910 °C beside small amount of impurity phase such as Y2BaCuO5 (Y211). The samples exhibited metallic behaviour and the critical temperature, TC(R=0), increases with increasing sintering temperature. The TC(R=0) of samples calcined at 910 °C is higher than that of sample calcined at 850 °C. The highest TC(R=0), 87 K, was found for sample sintered at 980 °C of set B. An increase in grain size and homogeneity was observed as the sintering temperature increases. The set B sample sintered at 980 °C showed compact grains, which could result in the highest Tc (R=0).
EIS and FTIR Characterisation of NaI-NaN(CN)2 Solid Electrolyte Prepared by Mechanical Milling
Authors: Yusof M.K.H.M. , Ahmad Azizah Hanom
Published: October 2017

Conductivity of sodium based solid electrolyte xNaI-(100 - x)NaN(CN)2 with various compositions (0 ≤ x ≤ 70) were investigated by Electrochemical impedance spectroscopy (EIS) method in order to determine the conductivity value. Maximum conductivity of 10-4 S cm-1 was obtained for sample with 10 wt.% NaI. The improved conductivity could be due to presence of dicyanamide as an anionic-bridging ligand compound that provided conducting pathway for rapid Na+ ion conduction. The binary sodium solid electrolyte system was prepared by ball milling method with 200 rpm for 2 hours in order to promote ultra-fine size reduction and introducing defects in the crystal structure thus assisting rapid ionic mobility via hopping. Results obtained from Fourier transform infrared spectroscopy (FTIR) characterisation showed some changes in infrared spectrum peak appearance within wavenumber region of 2200 – 2500 cm-1 that had proven some weak intermolecular interaction at the terminal N (nitrile) atoms of the dicyanamide.
Thermal Analysis of 1-Ethyl-3-Methylimidazolium Trifluoromethanesulfonate Ionic Liquid to PEO-NaCF3SO3 Polymer Electrolyte
Authors: Mohd Sapri Mohd Noor Zairi , Ahmad Azizah Hanom , Mahat Mohd Muzamir
Published: October 2017

The objective of this study is to investigate the effect of ionic liquid to PEO-NaCF3SO3 solid polymer electrolyte. Sodium ion conducting polymer electrolyte films consisting of Polyethylene oxide (PEO) as a polymer host, Sodium trifluoromethanesulfonate (NaCF3SO3) as doping salt and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMiTF) as ionic liquid has been prepared by solution cast technique. Different amounts (5, 10, 15, 20, 25 and 30 wt. %) of EMiTF will be added to the optimized polymer-salt composition to develop PEO - NaCF3SO3 – EMiTF polymer electrolyte. Difference Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) indicated that the crystalline degree and the weight loss % of the electrolyte decrease with increasing the wt. % of the EMiTF respectively. The ionic transference number was found in the value of 0.95 which suggests that ions are the charge carriers.
Conductivity of Yittria-Stabilized Zirconia Nanostructure Electrolyte for Solid Oxide Fuel Cell Application by Using RF Magnetron Sputtering
Authors: Jaffar S.Y. , Wahab Yussof , Muhammad Rosnita , Othaman Z. , Ibrahim Zuhairi , Nayan N. , Tan R.K.
Published: October 2017

Yttria-stabilized zirconia (YSZ) thin films were deposited successfully using RF magnetron sputtering. The substrate had been used are sapphire glass. A pure ceramic of Zr-Y is synthesized and processed into a planar magnetron target which is reactively sputtered with an Argon-Oxygen gas mixture to form Zr-Y-O nanostructure. The aim of this research is to study the conductivity and roughness YSZ thin film by using RF magnetron sputtering by varying the temperature deposition parameter. By lowering the YSZ thin film into nanostructure would enable for SOFC to be operate at lower temperature below 400°C. The YSZ nanostructure were controlled by varying the deposition parameters, including the deposition temperature and the substrate used. The crystalline of YSZ structure at 100W and temperature 300°C. The surface morphology of the films proved that at 300°C temperature rate deposition showed optimum growth morphology and density of YSZ thin films. Besides, the high deposition subtrate temperature affected the thickness of YSZ thin film at 80nm by using surface profiler. A higher rate of deposition is achievable when the sputtering mode of the Zr-Y target is metallic as opposed to oxide. YSZ is synthesizing to obtain the optimum thin film for SOFC application.
Physical and Mechanical Characteristics of Porous SS316L for Biomedical Implant
Authors: Mat Noor Fazimah , Jamaludin Khairur Rijal , Ahmad Sufizar
Published: October 2017

Porous materials with open and interconnected pores are very interesting for biomedical applications as it provides a good base for the formation of bone ingrowth naturally. Besides, it also allows for body fluid transportation through the interconnected network. Therefore, in this work, foam replication method has been used to produce porous SS316L. The SS316L slurries were prepared by ball milling and mechanical stirring method. The polyurethane (PU) foam has been used as a sacrificial template. Sintering process was carried in a high vacuum furnace at 1200°C, 1250°C and 1300°C. The overall results show that increasing the sintering temperature from 1200°C to 1300°C and the using of different slurry mixing methods did not significantly affect the physical and mechanical properties of the porous SS316L produced. The density, porosity percentage and compression strength found for this porous SS316L were in the range of 1.35g/cm3-3g/cm3, 62% - 83%, and 30.6MPa-79MPa respectively. The SEM images also show that the microstructure of this porous SS316L mostly consisted of open and interconnected pores. Therefore, these results are very promising for biomedical implant application.
Effects of Gamma Radiation on the Elastic Properties of Thulium Doped Zinc Borotellurite Glass
Authors: Hasnimulyati Laoding , Halimah Mohamed Kamari , Azmi Zakaria , Shaari Abdul Halim , Ishak Mansor
Published: October 2017

Effects of gamma radiation on the elastic properties of {[(TeO2)0.7(B2O3)0.3]0.7[ZnO]0.3}0.99{Tm2O3}0.01 (thulium doped zinc borotellurite glass) were investigated. Glass samples were prepared using the melt-quenching technique. Density and ultrasonic velocity of glasses before and after irradiation process were measured using Electronic Densimeter MD-300S and Ritec Ram-5000 Snap System, respectively. Next, elastic moduli and Poisson’s ratio of the glasses were calculated. Atomic ring size of the glass network was also calculated to support the attained results. Results show that density varied after radiation and maximised at 20 kGy. This is attributed to the breaking and rearrangement of chemical bonding in the glass network due to radiation. Furthermore, all elastic parameters exhibited an increasing trend that indicated the strengthening of the glass samples as well as increment of its rigidity. Besides that, atomic ring size was found to decrease as radiation dose increased. This indicate that compaction of glass network took place as the samples were exposed to gamma rays which in turn contributed to the elevation of elastic moduli of the prepared glass.