bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects Concerning “Play” for the Promotion of Preschool Children with Severe Speech- and Language Impairment
Authors: Ullrich Dieter , Marten Magret
Published: March 2016

Speech and language abilities are of great importance for later participation in economical and social life. In Lower Saxony/Germany, severely speech-/language (SL) impaired children may obtain special treatment during preschool in a so-called “Sprachheilkindergarten” (STK), a kindergarten focusing on early SL therapy. Purpose: This work analyzes the role of play during SL-therapy at the STK and monitors the long-term development and success of SL-impaired children. Methods: Long-term development (up to 19 years) of 71 children, who were dismissed from a STK during 1993 and 2006, was investigated. Playing habits were observed in 21 children (male: n = 14, female: n = 7), who were treated at STK in the years 2011/2013. The study was designed as a register study. Results: Approximately 75% of the children attend a regular school or complete a standard professional training after being treated at the STK. Upon admittance, 100% of the children had severe SL impairment, in addition 75% of the children exhibit deranged, not age-appropriate playing behavior. Additionally, children often show indication of social-emotional problems. At dismissal from the STK, the children show measurable improvement of SL and playing abilities due to SL therapy and educational measures. But according to the present study there were no close statistical relations between play- and SL development. Conclusion: Due to active promotion and therapy, many children achieve to improve their SL and playing abilities. The apparent independent improvement of these skills allows them to catch up with other children in their age group. Potentially, this is the crucial aspect for a child’s long-term development as it profits from its peer group.
Aggregator-Based Interactive Charging Management System for Electric Vehicle Charging
Authors: Xia Mingchao , Lai Qingying , Zhong Yajiao , Li Canbing , Chiang Hsiao-Dong
Published: March 2016

With the ongoing large-scale implementation of electric vehicles (EVs), the exploration of a more flexible approach to maintain fair interaction between EVs and the power grid is urgently required. This paper presents an aggregator-based interactive charging management scheme adopting interruptible load (IL) pricing, in which the EV aggregator will respond to the load control command of the grid in an EV interactive mode. Charging managements are carried out according to battery state-of-charge and the EV departure time in EV charging stations. A power-altering charging (PAC) control method is proposed to dispatch the EVs charging fairly in a station and guarantee EV owners’ preferences. The method does not require classical iterative procedures or heavy computations; furthermore, it is beneficial for EVs to depart earlier than expected for reasons beyond keeping homeostatic charging. The proposed scheme, which is tested to charge individual EVs well according to its preference, was implemented as part of an “EV Beijing” project. The proposed management scheme provides new insight into EV charging strategy and provides another choice to EV users.
An Effective Approach towards the Immobilization of PtSn Nanoparticles on Noncovalent Modified Multi-Walled Carbon Nanotubes for Ethanol Electrooxidation
Authors: Geng Xi , Cen Yinjie , Sisson Richard , Liang Jianyu
Published: March 2016

In this article, we describe an effective method to tether Pt and PtSn nanoparticles (NPs) on polyelectrolyte modified multi-walled carbon nanotubes (MWCNTs) for ethanol electrooxidation. By using a polymer wrapping technique, positively charged polyethyleneimine (PEI) was attached onto carbon nanotubes (CNTs) to provide preferential linking sites for metal precursors. Well-dispersed Pt and PtSn nanocrystals (2–5 nm) were subsequently decorated on PEI-functionalized MWCNTs through the polyol reduction method. The successful non-covalent modification of MWCNTs was confirmed by Fourier transform infrared spectroscopy (FTIR) and Zeta potential measurements. Energy dispersive X-ray (EDX) spectrum indicates approximately 20 wt % Pt loading and a desirable Pt:Sn atomic ratio of 1:1. Electrochemical analysis demonstrated that the as-synthesized PtSn/PEI-MWCNTs nanocomposite exhibited improved catalytic activity and higher poison tolerance for ethanol oxidation as compared to Pt/PEI-MWCNTs and commercial Pt/XC-72 catalysts. The enhanced electrochemical performance may be attributed to the uniform dispersion of NPs as well as the mitigating of CO self-poisoning effect by the alloying of Sn element. This modification and synthetic strategy will be studied further to develop a diversity of carbon supported Pt-based hybrid nanomaterials for electrocatalysis.
Improved PNIPAAm-Hydrogel Photopatterning by Process Optimisation with Respect to UV Light Sources and Oxygen Content
Authors: Haefner Sebastian , Rohn Mathias , Frank Philipp , Paschew Georgi , Elstner Martin , Richter Andreas
Published: March 2016

Poly-N-isopropylacrylamide (PNIPAAm) hydrogels, known for their sensor and actuator capabilities, can be photolithographically structured for microsystem applications. For usage in microsystems, the preparation, and hence the characteristics, of these hydrogels (e.g., degree of swelling, size, cooperative diffusion coefficient) are key features, and have to be as reproducible as possible. A common method of hydrogel fabrication is free radical polymerisation using a thermally-initiated system or a photoinitiator system. Due to the reaction quenching by oxygen, the polymer solution has to be rinsed with protective inert gases like nitrogen or argon before the polymerisation process. In this paper, we focus on the preparation reproducibility of PNIPAAm hydrogels under different conditions, and investigate the influence of oxygen and the UV light source during the photopolymerisation process. The flushing of the polymer solution with inert gas is not sufficient for photostructuring approaches, so a glove box preparation resulting in better quality. Moreover, the usage of a wide-band UV light source yields higher reproducibility to the photostructuring process compared to a narrow-band UV source.
Spatial Patterns of Heat-Related Cardiovascular Mortality in the Czech Republic
Authors: Urban Aleš , Burkart Katrin , Kyselý Jan , Schuster Christian , Plavcová Eva , Hanzlíková Hana , Štěpánek Petr , Lakes Tobia
Published: March 2016

The study examines spatial patterns of effects of high temperature extremes on cardiovascular mortality in the Czech Republic at a district level during 1994–2009. Daily baseline mortality for each district was determined using a single location-stratified generalized additive model. Mean relative deviations of mortality from the baseline were calculated on days exceeding the 90th percentile of mean daily temperature in summer, and they were correlated with selected demographic, socioeconomic, and physical-environmental variables for the districts. Groups of districts with similar characteristics were identified according to socioeconomic status and urbanization level in order to provide a more general picture than possible on the district level. We evaluated lagged patterns of excess mortality after hot spell occurrences in: (i) urban areas vs. predominantly rural areas; and (ii) regions with different overall socioeconomic level. Our findings suggest that climatic conditions, altitude, and urbanization generally affect the spatial distribution of districts with the highest excess cardiovascular mortality, while socioeconomic status did not show a significant effect in the analysis across the Czech Republic as a whole. Only within deprived populations, socioeconomic status played a relevant role as well. After taking into account lagged effects of temperature on excess mortality, we found that the effect of hot spells was significant in highly urbanized regions, while most excess deaths in rural districts may be attributed to harvesting effects.
Molecular Cloning and Expression Analysis of Eight PgWRKY Genes in Panax ginseng Responsive to Salt and Hormones
Authors: Xiu Hao , Nuruzzaman Mohammed , Guo Xiangqian , Cao Hongzhe , Huang Jingjia , Chen Xianghui , Wu Kunlu , Zhang Ru , Huang Yuzhao , Luo Junli , Luo Zhiyong
Published: March 2016

Despite the importance of WRKY genes in plant physiological processes, little is known about their roles in Panax ginseng C.A. Meyer. Forty-eight unigenes on this species were previously reported as WRKY transcripts using the next-generation sequencing (NGS) technology. Subsequently, one gene that encodes PgWRKY1 protein belonging to subgroup II-d was cloned and functionally characterized. In this study, eight WRKY genes from the NGS-based transcriptome sequencing dataset designated as PgWRKY2-9 have been cloned and characterized. The genes encoding WRKY proteins were assigned to WRKY Group II (one subgroup II-c, four subgroup II-d, and three subgroup II-e) based on phylogenetic analysis. The cDNAs of the cloned PgWRKYs encode putative proteins ranging from 194 to 358 amino acid residues, each of which includes one WRKYGQK sequence motif and one C2H2-type zinc-finger motif. Quantitative real-time PCR (qRT-PCR) analysis demonstrated that the eight analyzed PgWRKY genes were expressed at different levels in various organs including leaves, roots, adventitious roots, stems, and seeds. Importantly, the transcription responses of these PgWRKYs to methyl jasmonate (MeJA) showed that PgWRKY2, PgWRKY3, PgWRKY4, PgWRKY5, PgWRKY6, and PgWRKY7 were downregulated by MeJA treatment, while PgWRKY8 and PgWRKY9 were upregulated to varying degrees. Moreover, the PgWRKY genes increased or decreased by salicylic acid (SA), abscisic acid (ABA), and NaCl treatments. The results suggest that the PgWRKYs may be multiple stress–inducible genes responding to both salt and hormones.
On Solving the Fuzzy Customer Information Problem in Multicommodity Multimodal Routing with Schedule-Based Services
Authors: Sun Yan , Lang Maoxiang , Wang Jiaxi
Published: March 2016

In this study, we combine the fuzzy customer information problem with the multicommodity multimodal routing with schedule-based services which was explored in our previous study [1]. The fuzzy characteristics of the customer information are embodied in the demanded volumes of the multiple commodities and the time windows of their due dates. When the schedule-based services are considered in the routing, schedule constraints emerge because the operations of block container trains should follow their predetermined schedules. This will restrict the routes selection from space-time feasibility. To solve this combinatorial optimization problem, we first build a fuzzy chance-constrained nonlinear programming model based on fuzzy possibility theory. We then use a crisp equivalent method and a linearization method to transform the proposed model into the classical linear programming model that can be effectively solved by the standard mathematical programming software. Finally, a numerical case is presented to demonstrate the feasibility of the proposed method. The sensitivity of the best solution with respect to the values of the confidence levels is also examined.
Cyclic Behavior of Mortarless Brick Joints with Different Interlocking Shapes
Authors: Liu Hongjun , Liu Peng , Lin Kun , Zhao Sai
Published: March 2016

The framed structure infilled with a mortarless brick (MB) panel exhibits considerable in-plane energy dissipation because of the relative sliding between bricks and good out-of-plane stability resulting from the use of interlocking mechanisms. The cyclic behaviors of MB are investigated experimentally in this study. Two different types of bricks, namely non-interlocking mortarless brick (N-IMB) and interlocking mortarless brick (IMB), are examined experimentally. The cyclic behavior of all of the joints (N-IMB and IMB) are investigated in consideration of the effects of interlocking shapes, loading compression stress levels and loading cycles. The hysteretic loops of N-IMB and IMB joints are obtained, according to which a mechanical model is developed. The Mohr–Coulomb failure criterion is employed to describe the shear failure modes of all of the investigated joints. A typical frictional behavior is observed for the N-IMB joints, and a significant stiffening effect is observed for the IMB joints during their sliding stage. The friction coefficients of all of the researched joints increase with the augmentation of the compression stress level and improvement of the smoothness of the interlocking surfaces. An increase in the loading cycle results in a decrease in the friction coefficients of all of the joints. The degradation rate (DR) of the friction coefficients increases with the reduction in the smoothness of the interlocking surface.
Erratum: Chen, F. et al. A Space View of Radar Archaeological Marks: First Applications of COSMO-SkyMed X-Band Data. Remote Sens. 2015, 7(1), 24–50
Authors: Chen Fulong , Masini Nicola , Yang Ruixia , Milillo Pietro , Feng Dexian , Lasaponara Rosa
Published: March 2016

In this paper [1], the author, Rosa Lasaponara, should have been numbered as 1 and 6, instead of only 6.[...]
A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems
Authors: Brunelli Davide
Published: March 2016

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.
Conversion Ratio between Botox®, Dysport®, and Xeomin® in Clinical Practice
Authors: Scaglione Francesco
Published: March 2016

Botulinum neurotoxin has revolutionized the treatment of spasticity and is now administered worldwide. There are currently three leading botulinum neurotoxin type A products available in the Western Hemisphere: onabotulinum toxin-A (ONA) Botox®, abobotulinum toxin-A (ABO), Dysport®, and incobotulinum toxin A (INCO, Xeomin®). Although the efficacies are similar, there is an intense debate regarding the comparability of various preparations. Here we will address the clinical issues of potency and conversion ratios, as well as safety issues such as toxin spread and immunogenicity, to provide guidance for BoNT-A use in clinical practice. INCO was shown to be as effective as ONA with a comparable adverse event profile when a clinical conversion ratio of 1:1 was used. The available clinical and preclinical data suggest that a conversion ratio ABO:ONA of 3:1—or even lower—could be appropriate for treating spasticity, cervical dystonia, and blepharospasm or hemifacial spasm. A higher conversion ratio may lead to an overdosing of ABO. While uncommon, distant spread may occur; however, several factors other than the pharmaceutical preparation are thought to affect spread. Finally, whereas the three products have similar efficacy when properly dosed, ABO has a better cost-efficacy profile.
Objective Classification of Rainfall in Northern Europe for Online Operation of Urban Water Systems Based on Clustering Techniques
Authors: Löwe Roland , Madsen Henrik , McSharry Patrick
Published: March 2016

This study evaluated methods for automated classification of rain events into groups of “high” and “low” spatial and temporal variability in offline and online situations. The applied classification techniques are fast and based on rainfall data only, and can thus be applied by, e.g., water system operators to change modes of control of their facilities. A k-means clustering technique was applied to group events retrospectively and was able to distinguish events with clearly different temporal and spatial correlation properties. For online applications, techniques based on k-means clustering and quadratic discriminant analysis both provided a fast and reliable identification of rain events of “high” variability, while the k-means provided the smallest number of rain events falsely identified as being of “high” variability (false hits). A simple classification method based on a threshold for the observed rainfall intensity yielded a large number of false hits and was thus outperformed by the other two methods.
Valx: A System for Extracting and Structuring Numeric Lab Test Comparison Statements from Text
Authors: Hao Tianyong , Liu Hongfang , Weng Chunhua
Published: March 2016

Objectives: To develop an automated method for extracting and structuring numeric lab test comparison statements from text and evaluate the method using clinical trial eligibility criteria text.

Methods: Leveraging semantic knowledge from the Unified Medical Language System (UMLS) and domain knowledge acquired from the Internet, Valx takes seven steps to extract and normalize numeric lab test expressions: 1) text preprocessing, 2) numeric, unit, and comparison operator extraction, 3) variable identification using hybrid knowledge, 4) variable – numeric association, 5) context-based association filtering, 6) measurement unit normalization, and 7) heuristic rule-based comparison statements verification. Our reference standard was the consensus-based annotation among three raters for all comparison statements for two variables, i.e., HbA1c and glucose, identi -fied from all of Type 1 and Type 2 diabetes trials in ClinicalTrials.gov.

Results: The precision, recall, and F-measure for structuring HbA1c comparison statements were 99.6%, 98.1%, 98.8% for Type 1 diabetes trials, and 98.8%, 96.9%, 97.8% for Type 2 diabetes trials, respectively. The pre -cision, recall, and F-measure for structuring glucose comparison statements were 97.3%, 94.8%, 96.1% for Type 1 diabetes trials, and 92.3%, 92.3%, 92.3% for Type 2 diabetes trials, respectively.

Conclusions: Valx is effective at extracting and structuring free-text lab test comparison statements in clinical trial summaries. Future studies are warranted to test its generaliz-ability beyond eligibility criteria text. The open-source Valx enables its further evaluation and continued improvement among the collaborative scientific community.
STANDING SHOCK INSTABILITY IN ADVECTION-DOMINATED ACCRETION FLOWS
Authors: Le Truong , Wood Kent S. , Wolff Michael T. , Becker Peter A. , Putney Joy
Published: March 2016

Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either preshock deceleration or preshock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier & Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameter space where disks/shocks with outflows can be stable or unstable. In regions of instability, we find that preshock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental mode and overtones. Furthermore, we also find that preshock acceleration is always unstable to the zeroth mode and that the fundamental mode and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expands above ∼12 gravitational radii at the shock radius. In regions of stability, we demonstrate the zeroth mode to be stable for the velocity profiles that exhibit preshock acceleration and deceleration. Moreover, for models that are linearly unstable, our model suggests the possible existence of quasi-periodic oscillations (QPOs) with ratios 2:3 and 3:5. These ratios are believed to occur in stellar and supermassive black hole candidates, for example, in GRS 1915+105 and Sgr A*, respectively. We expect that similar QPO ratios also exist in regions of stable shocks.
Retour sur les travaux de la 14e Assemblée des Etats parties de la Cour pénale internationale : Qui sont les grands gagnants ?
Authors: Orenga Emilie , Rambolamanana Vony
Published: March 2016

Vendredi 12 janvier 2016, la Chambre d’appel de la Cour pénale internationale (la Cour) a porté un coup dur à l’accusation dans le procès du vice-président kényan William Ruto : les juges ont annulé à l’unanimité la décision autorisant l’utilisation rétroactive de témoignages, fragilisant considérablement le dossier de la Procureure. Si le sens de cette décision n’étonne pas en lui-même, le contexte dans lequel elle s’inscrit mérite une attention particulière. Pour comprendre la décision, il faut en effet se replonger dans les débats qui ont marqué la dernière Assemblée des Etats parties (AEP ou Assemblée), trois mois plus tôt. Le Kenya avait réussi à placer le procès de son vice-président au cœur des discussions, cherchant à interférer sur la procédure en cours devant la Chambre d’appel. Le présent article se propose donc de revenir, plus généralement, sur les travaux de cette Assemblée, la plus mouvementée depuis la création de la Cour.
Corporate Social Responsibility in Hotel Industry
Authors: Jhamb Rajesh , Singh Gurjit
Published: March 2016

Corporate Social Responsibility (CSR) is basically, what an organization does over and above the statutory requirement for the benefits of all the stakeholders of the society. In recent years, there has been a significant perception shift in the use of hotels. Hotels are being used for socializing, relaxation, business and so many other reasons. The hotel industry has to adapt themselves with the rapid social changes and creative relations and also face challenges of modern style and technology, green features and sustainability etc. The issues like garbage disposal, quality services to the customers, maintaining the flora and fauna of the area, culture heritages, respect the sentiments of the local areas residents' community, socials environment issues, etc. and are the main issues and challenges for the hotel industry in these days. This paper will take in account the above mentioned issues and challenges of hotel industries in the today's eras of liberalization, Privatization and Globalization and their impact on the growth of economic development in India.
Analysis of MRR and TWR on OHNS Die Steel with Different Electrodes Using Electrical Discharge Machining
Authors: Nallusamy S.
Published: March 2016

Electrical Discharge Machining is a machining method primarily used for hard metals or those that are impossible to be machined with traditional techniques. The experimental investigation of material removal rate and tool wear rate during machining of oil hardened non-shrinking steel with brass and copper electrodes using EDM machine was carried out in this paper. This investigation presents the analysis and evaluation of heat affected zones and surface finish of the work piece using different tool electrodes and varying the machine parameters. The commercial grade kerosene oil has been used as dielectric fluid. The effect of various important EDM parameters such as discharge current (Ip) 2 to12A, pulse duration (Ton and Toff) and sparking voltage (V) of 80±5% have been used to yield the response in terms of Material Removal Rate (MRR) and Tool Wear Rate (TWR). Further a detailed analysis of the heat affected regions was also been carried out by using scanning electron microscopy.
Classifying Spam Emails Using Artificial Intelligent Techniques
Authors: Roy Sanjiban Sekhar , Viswanatham V. Madhu
Published: March 2016

Spam emails have become an increasing difficulty for the entire web-users.These unsolicited messages waste the resources of network unnecessarily. Customarily, machine learning techniques are adopted for filtering email spam. This article examines the capabilities of the extreme learning machine (ELM) and support vector machine (SVM) for the classification of spam emails with the class level (d). The ELM method is an efficient model based on single layer feed-forward neural network, which can choose weights from hidden layers,randomly. Support vector machine is a strong statistical learning theory used frequently for classification. The performance of ELM has been compared with SVM. The comparative study examines accuracy, precision, recall, false positive, true positive.Moreover, a sensitivity analysis has been performed by ELM and SVM for spam email classification.
A Novel MCDM Approach for Simultaneous Optimization of some Correlated Machining Parameters in Turning of CP-Titanium Grade 2
Authors: Khan Akhtar , Maity Kalipada
Published: March 2016

The present work explores the application of a novel Multi-Criteria Decision Making (MCDM) based approach known as VIKOR analysis combined with Taguchi technique for simultaneous optimization of some correlated cutting variables in turning of commercially pure titanium grade 2 using uncoated carbide inserts. The experiments have been carried out according to Taguchi’s L27 orthogonal array. Three input variables viz. cutting speed, feed rate and depth of cut have been taken at three different levels. The impact of these cutting variables on cutting force, surface quality and material removal rate has been investigated. The optimal combination of machining parameters has been evaluated to minimize the cutting force and to maximize the surface finish and production rate using MCDM based VIKOR analysis method. ANOVA (analysis of variance) test has been performed to determine the most influencing cutting variable on overall quality measure i.e. VIKOR index (Qi). The optimal setting of machining variables has been shown using main effects plot for S/N ratio for Qi. The results of ANOVA exhibit that the cutting speed is the governing machining parameter followed by feed rate on overall quality index (Qi). The minimum (desirable) value of Qi is achieved at the parametric combination of v3-f1-d3 i.e. cutting speed (110 m/min), feed rate (0.08 mm/rev) and depth of cut (0.4 mm) respectively. The feasibility of the proposed methodology has been verified by conducting a confirmation test.
Effect of Ta Addition on Microstructure and Hardness of FeCrNiMnCoTax and Al0.5FeCrNiMnCoTax High-Entropy Alloys
Authors: Mohd Pauzi Siti Sarah , Harun Mohamad Kamal , Talari Mahesh
Published: March 2016

Phase formation, microstructure, and hardness properties of FeCrNiMnCoTax and Al0.5 FeCrNiMnCoTax high-entropy alloys (HEA) have been investigated and reported. In this study, FeCrNiMnCoTax and Al0.5FeCrNiMnCoTax high-entropy alloys (HEA) were synthesized using arc-melting technique in argon (Ar) atmosphere from high purity elements (x in molar ratio, x=0.2, x=0.4 and x=0.6). Ingots from arc-melting were homogenized for 24h at 900°C in Ar atmosphere. Dominant dendritic and inter-dendritic phases were identified from the electron micrographs of these HEA. The area of inter-dendrite region increased for both FeCrNiMnCoTax and Al0.5FeCrNiMnCoTax alloys with the increasing of Ta content. The major phases in both FeCrNiMnCoTax and Al0.5FeCrNiMnCoTax alloys were identified as FCC and BCC solid-solutions. Addition of Al in Al0.5FeCrNiMnCoTax alloys has resulted in precipitation of a minor phase which was identified as FCC-TaCr2 Laves phase. As the Ta content increased, hardness of FeCrNiMnCoTax and Al0.5FeCrNiMnCoTax alloys increased from 200.34 Hv to 345.10 Hv and 385.22 Hv to 570.86 Hv respectively. Furthermore, presence of Laves phase in Al0.5FeCrNiMnCoTax alloys has resulted in higher hardness values compared to Al free sample, and this higher hardness could be attributed to precipitation strengthening effect by Laves intermetallic phase formation.
Luminescence of Er3+/Nd3+ Co-Doped Lithium Niobate Tellurite Glass
Authors: Nurhafizah Hasim , Rohani Md Supar , Sahar M.R. , Ghoshal Sib Krishna
Published: March 2016

Achieving tuneable photoluminescence via controlled co-doping of rare earth ions in lithium niobate based glasses are challenging. A series of Er3+/ Nd3+ co-doped tellurite glasses of composition (70-x-y) TeO2 – 15 Li2CO3 – 15 Nb2O5 – (x) Er2O3 – (y) Nd2O3 with x = 0; 1.0 mol % and 0 ≤ y ≤ 1.0 mol % are prepared using melt quenching technique. The influence of co-dopants on the emission properties is analyzed and discussed using partial energy level diagram of rare earth ions. The dopants concentration dependent physical properties such as refractive index, molar volume, density, polarizability and molar refractions are determined. The down-converted luminescence spectra for 2G9/2 à4I9/2 transition reveal a strong green emission band centred at 497 nm is attributed to the energy transfer from erbium to neodymium ion. The emission spectra exhibit five prominent peaks centred at 497, 539, 553, 616 and 634 nm corresponding to the transitions from 2H11/2, 4S3/2 and 4F9/2 excited states to the ground state of Er3+ ion and the transitions from 2G9/2, 2G7/2, 2H11/2 and 4F9/2 excited states to ground state of Nd3+ ion. The highest intensity is achieved for x = y = 1.0 mol%. The excellent luminescence response suggests that our glasses may be nominated for solid state lasers and other photonic applications.
The Sintering Effect of Lanthanum-Calcium Manganite Doping on Microstructure and Non-Linear Coefficient of Zinc Oxide Varistor
Authors: Ghazali Mohd Sabri Mohd , Nawawi Mohamed Fitri Mohamed , Zulkifli Mohamad Azman , Abdullah Wan Rafizah Wan , Zakaria Azmi
Published: March 2016

The zinc oxide based varistor are widely used as circuit protective devices by literally absorbs these dangerous surges and spikes or grounding this unwanted magnitudes. In this research, zinc oxide is added with 0.5 mol % CaMnO3 as an additive and 0.2 mol % of rare earth doped of lanthanum oxide. Citrate-gel method is used as fabrication method. Complex compound undergoes sintering process which varied at 900 °C, 950 °C and 1000 °C, while, the sintering time are setting at 1 hour and 2 hours. Thermo gravimetric analysis (TGA) shows the forming of CaMnO3 at 334-1000 °C. Fourier Transform Infrared (FTIR) spectra proved that the functional group present are.-O-H, C-H and C-O. The surface morphology with the grains size below 1μm was observed by Scanning Electron Microscopy (SEM). The α varistor ceramics was calculated from data analysis of I-V characteristics obtained through a Source Measure Unit (Keithley 236). The calculation of α is done by using Origin Pro8.0 software. I-V characteristic shows the value of α in the range of 1.00 to 4.05.
The Structural and Conductivity Characterization of P2O5-MgO-TiO2-Li2O Glass Ceramic Embedded with Nickel Nanoparticles
Authors: Abd Rahman S.F. , Sahar M.R.
Published: March 2016

Melt quenching technique (MQT) has been used to prepare the series of 75P2O5-17MgO-(3-x)TiO2-5Li2O glasses doped Nickel nanoparticles (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0), which was converted into glass-ceramic through heat treatment at 350 °C. In this study, the effects of NiO nanoparticle addition and heat treatment on microstructure were investigated through DTA and XRD. The frequency-dependent electrical data were used to study the conductivity mechanism. Preliminary experimental results from DTA measurement showed that the stability of the glasses are increased when the increment of TiO2 in the glasses. The XRD results showed the completely amorphous products were prepared by MQT and crystallite structured of glass ceramic were obtained via further heat treatment. Upon the increment of temperature, conductivities increased significantly.
Influence of Erbium Doping on Dielectric Properties of Zinc Borotellurite Glass System
Authors: Zulkefly Siti Shafinas , Kamari Halimah Mohamed , Abdul Azis Muhammad Nor Azlan , Wan Yusoff Wan Mohd Daud
Published: March 2016

Glasses of the system {[ (TeO2)70 (B2O3)30]70 (ZnO)30}100-y (Er2O3)y containing different concentration of Er2O3 (ranging from 0 to 5 mol %) was prepared from melt-quenching technique. The structural changes were studied by XRD analysis and FTIR analysis. The XRD pattern shows the glasses are amorphous. The higher concentration of Er2O3, the more unit of TeO3 would transform to TeO4 and formation of B-O vibrational groups. The density and molar volume was obtained attribute to non-bridging oxygen (NBO) and are found the density and molar volume of the glass system are increasing. The densities range from 3630 kg/m3 to 3960 kg/m3. The dielectric constant ε’ and dielectric loss factor ε’’ which were characterized in the frequency range 10-2 – 106 Hz over temperature range 50°C – 200 °C, show a larger value at lower frequency and higher temperature (above 110°C ). The results of dielectric response measurement show that interfacial polarization at low frequency, and orientation polarization at intermediate and high frequency.Keywords: Dielectric properties; Activation Energy; Rare Earth; Polarization; Non-Bridging Oxygen;
Preparation of SiO2-Na2O-CaO-P2O5 Glass-Ceramic from Waste Materials and Heat Treatment Effects on its Morphology
Authors: Pallan Nur Fadilah Baharuddin , Matori Khamirul Amin , Hashim Mansor , Lim Way Foong , Quah Hock Jin , Fauzana A.N. , Rosnah N. , Khiri M.Z.A. , Farhana S. , Zainuddin Norhazlin , Zarifah Nadakkavil Alassan , Nurzilla M. , Hafiz Mohd Zaid Mohd , Loy C.W. , Zamratul M.I.M.
Published: March 2016

Currently, many researchers interested studying waste materials to recycle them or reuse them in new products. From the sustainable perspective development, it is necessary to implement new technologies to help reduce waste and thus minimize the environmental problems associated with disposal. In this study, the preparation of SiO2-Na2O-CaO-P2O5 (SNCP) glass-ceramic is composed of Soda Lime Silicate (SLS), Clam Shell (CS), Na2CO3 and P2O5 in the ratio of 50: 25: 20: 5 respectively. The waste materials that were used for fabricate glass-ceramic are SLS and CS. All the compounds were mixed to fabricate the SNCP glass-ceramic through solid state reaction. The samples were investigated through X-ray diffraction (XRD), field emission microscope (FESEM) and density measurement. The samples were sintered at temperature 550°C, 650°C, 750°C, 850°C until 950°C. The main phase obtained from XRD analysis is Sodium Calcium Silicate, Na2CaSiO4 with cubic crystal system at 550°C. The highest intensity phase of the diffraction peak is (220) and at the angle 33.7°. There was new peak presence at right side of the main phase Na2CaSiO4, which belong to Silicon Phosphate, SiP2O7 at 650°C and 750°C.When heat treatment increased at 850°C - 950°C, the main phase is Combeite, Na4Ca4(Si6O18) at diffraction peak (220) with rhombohedral crystal system which is assigned to high crystallization temperature (Tc). The density of samples increases at 550°C - 750°C and decreases when heat treatment 850°C - 950°C. Sample density decreases at heat treatment 850°C - 950°C due to increases of sample lattice parameter. FESEM analysis showed that the grain size and porosity increased when the heat treatment increased.
Microstructure of Barium Cerate-Zirconate Ceramics Prepared by a Two-Step Sintering Technique
Authors: Othman Nurul Wahida , Osman Nafisah , Ramli Azliana , Safian Suhaida Dila
Published: March 2016

Ceramic materials based on cerate-zirconates have potential application as a solid electrolyte in electrochemical devices such as fuel cells and hydrogen sensors. To become a good electrolyte, the material must exhibits high density sample with homogenize grain size. In this study, we systematically investigated the microstructure of Ba (Ce,Zr)O3 pellet as a function of sintering temperature. The calcined powder was compressed to become a pellet using hydraulic press with pressure of 5 tons for 5 min. Two-step sintering (TSS) process was applied for the densification of Ba (Ce,Zr)O3 pellet. The first temperature profile was fixed at T1 = 1400°C and the second temperature profile was varied from T2 = 1150°C, 1200°C, 1250°C, 1300°C and 1350°C, respectively. The sintered sample at T2 = 1350°C showed the highest density compared to others. Its relative density was 82.50%. The lowest density was 64.38% for the sintered sample at T2 = 1150°C. However, the densification of pellet showed an irregular behavior at T2 = 1300°C. It might be related to the de-densification phenomenon due to the presence of carbonate species in the calcined powder. Microstructure of the fracture sintered pellet as observed by a scanning electron microscope (SEM) showed the grain size of the samples was in the range of 149.2–336.4 nm. For a comparison, green pellet and pellet prepared with conventional sintering step (CSS) were also discussed in this study.
An Evaluation of Microstructure and Hardness Properties of Zr Added FeNiAlCoCr High Entropy Alloys
Authors: Razuan Rafidah , Harun Mohamad Kamal , Talari Mahesh
Published: March 2016

High Entropy Alloy (HEA) with at least 5 elements with equimolar ratios were developed to investigate the characteristics of Zr added in FeNiAlCoCrZrx (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0). HEAs were prepared by arc melting technique in Ar atmosphere and were remelted five times to ensure homogeneity. The microstructure and phase constitution of these alloys are examined by X-Ray diffraction (XRD) and Scanning Electron Microscope (SEM). The results show that addition of Zr to FeNiAlCoCr HEA resulted in multiple solid solution phases viz., BCC1, BCC2, FCC1 and FCC2 as evidenced by XRD patterns. Furthermore, presence of both BCC and FCC phases at higher Zr additions suggests that Zr did not preferentially promoted the solidification of either BCC or FCC phase. It can be observed from the FESEM micrographs that with different Zr additions, solidified microstructures of FeNiAlCoCrZrx alloys varied between completely eutectic microstructures to proeutectic and eutectic phase mixtures. From FESEM micrographs it can be suggested that different Zr contents have resulted in different solidification modes. Hardness of Zr added samples is higher compared to base HEA which is FeNiAlCoCr. It was observed that hardness values are higher when proeutectic phases were present compared to completely eutectic FeNiAlCoCrZr alloy (x=0.1).
Role of Ionics Surfactant in Synthesizing Cerate-Zirconate Ceramic Powder
Authors: Mazlan Nurul Asyikin , Osman Nafisah , Md Jani Abdul Mutalib , Yaakob Mohd Hafiz
Published: March 2016

BaCe0.54Zr0.36Y0.1O2.95 (denoted as BCZY10) ceramic powder was synthesized by a modified sol-gel method using metal nitrate salts as precursors. The samples were prepared using two different types of surfactants which are cationic surfactant of hexadecyldimethylammonium bromide (HTAB), nonionic surfactant of polyoxyethylene (10) oleyl ether (Brij 97), and sample without surfactant as a control. All samples were labeled as S1, S2, and S3 respectively. They were dried and calcined at T=325 °C and T=1100 °C accordingly. Chemicals bonding of the compound were analyzed using Fourier transform infrared (FTIR) spectrometry and their phase formation was identified by X-Ray Diffractometer (XRD). All the dried samples showed the adsorption peak at 3200-3700 cm-1 that related to the overlapping of OH stretching originated from –OH terminal group and N-H stretching vibrations. The peaks appeared at 1620-1640 cm-1 can be assigned to C=O stretching and at 1380-1450 cm-1 can be attributed for N-H bending vibration. The adsorption peak ≈500 cm-1 of metal-oxygen bond for all the calcined samples became pronounces indicating that the metal complexes were transformed to metal oxides. XRD results confirmed that S2 and S3 formed a single-phase of Ba (Ce,Zr)O3 perovskite type-oxide and S1 consists of multi-phases compound which are dominated by BaCeO3, and BaZrO3. Therefore, the used of different type of surfactant was found to give a significant effect on the synthesizing single-phase of BCZY10 ceramics compound.
Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) Perovskite Nanorods by Template Synthesis
Authors: Habiballah Anisah Shafiqah , Mahmud Abdul Hadi , Osman Nafisah , Md Jani Abdul Mutalib
Published: March 2016

Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) is a ceramic perovskite-type oxide that has attracted growing attention due to its high catalytic activity, mixed ionic/electronic conductivity and giant magnetic resistance. Improvement in the properties of BSCF can be achieved by tailoring its architecture such as nanoparticles (powdered form), nanotubes or nanorods as these nanostructured materials posses high surface-to-volume ratios with high sensitivity to surface adsorption and reactions. However, most of the studies conducted by means of conventional solid-state reaction methods or with wet chemistry techniques regularly produced BSCF in loose powdered form, non-uniform and the particle size is hard to be controlled. Herein in this work, an investigation on a synthetic approach using highly ordered nanoporous anodic aluminium oxide (AAO) as a template, focusing on the fabrication of BSCF perovskite nanorods is demonstrated. Sol-gel method is used to prepare the BSCF precursor solution or sol followed by filling the AAO template with the sol at different immersion time of 1 hr, 12 hrs and 24 hrs. After the following drying and calcination steps, the morphological structure and composition of the synthesized BSCF nanorods inside the AAO templates are examined by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) analysis. The micrograph showed BSCF nanorods are successfully synthesized at immersion time of 24 hrs with the diameter of nanorods embedded in the AAO template is approximately 180 nm. The EDX analysis also confirmed the stoichiometry of Ba0.5Sr0.5Co0.8Fe0.2O3-δ. Possible formation mechanism of BSCF nanorods inside the AAO template is also discussed in this paper.
The Suitability of Rice Straw Ash as a Precursor for Synthesizing β-Wollastonite
Authors: Shamsudin Roslinda , Ismail Hamisah , Hamid Muhammad Azmi Abdul
Published: March 2016

In this study, β-wollastonite is produced from a reaction between silica (SiO2) and calcium oxide (CaO) with the SiO2/Cao ratio of 55:45. Rice straw ash is chosen as the source for SiO2 instead of rice husk ash because the straw can yield up to 85% of silica even though this percentage is lower than those silica yielded from rice husk ash. It is found that period of autoclaving and sintering play an important role in producing the wollastonite. As shown in the XRD results, a single phase β-wollastonite is obtained after 8 h of autoclaving and 3 h of sintering at 950 °C. The produced β-wollastonite phase also shows a good crystallinity but needs longer sintering time compared with wollastonite produced using rice husk ash. DTA graph shows a chemical reaction between silica and calcium oxide started to occur at 788.3°C. IR spectroscopic analysis data confirm that the IR peaks at 681, 894 and 931 cm-1 are due to the β-Wollastonite phase. Form the results obtained, it can be concluded that rice straw ash is comparable to rice husk ash as a precursor in producing β-Wollastonite material.
Electrical Conductivity and Hall Effect Study of Organic Solar Cell Using Downy Rose Myrtle Berries as Natural Dye: A Heat Treatment
Authors: Nor Laily Abdul Rashid , Salleh Hasiah , Nik Aziz N.A. , Dagang Ahmad Nazri , Mohd Ghazali Salmah
Published: March 2016

This work focused on the electrical and Hall Effect of Organic Solar cell (OSC). In this work, Indium Tin oxide (ITO) glass as substrate was heated at 50 °C to 200 °C. The polymer used was Poly (3-Dodecylthiophene) (P3DT) thin film and Downy Rose Myrtle berries (RhodomyrtusTomentosa(Ait.) Hassk.) as dye. The P3DT were deposited on the ITO substrate using electrochemistry method at room temperature. While, the dye of Downy Rose Myrtle berries was deposited by layered using spin coating method. The electrical conductivity of ITO deposited thin film was explored by four point probes (FPP) under dark and under light radiation (range of 10 Wm-2 to 200Wm-2). From FPP study, the electrical conductivity was increased by the increment of light intensity and temperature of substrate. Lastly, the samples were examined using Hall Effect measurement to obtain the type of sample, Hall mobility, and highest charge carrier in the sample of OSC. The results show that the sample is suitable for further solar cell application.
Visible Luminescence of Nanoporous Silicon Using Alternating Current Photo-Assisted Electrochemical Etching for Potential MSM Photodetector
Authors: Mahmood Ainorkhilah , Hassan Zainuriah , Ahmed Naser Mahmoud , Shahiri Ellis , Abd Rahim Alhan Farhanah , Abdullah Mohamad Syarizal
Published: March 2016

The formation of nanocrystalline porous silicon (PS) was successfully prepared under a novel alternating current (sine-wave a.c. (50 Hz)) photo-assisted electrochemical (ACPEC) etching condition of an n-type (100) silicon (Si) substrate under the illumination of an incandescent white light. As grown Si and PS through conventional direct current(DC) anodization were also included for comparison. The ACPEC formed porous Silicon (PS) with excellent structural and surface morphological characteristic. According to the field emission scanning electron microscope (FESEM) micrographs, the nanoporous structures exhibited pores with uniform circular structure with estimated sizes, ranging between 20.5 nm and 30.5 nm. The atomic force microscopy (AFM) revealed an increase in the surface roughness induced by porosification. As compared to the as-grown Si, PS by AC method exhibited a substantial visible photoluminescence (PL) intensity enhancement with blue-shift associated with the quantum confinement effect of the nanostructure Si. Thermally treated nickel (Ni) finger contact was deposited on the PS to form MSM photodetector. Ni/PS MSM photodetector showed lower dark and higher photocurrent compared to the as grown Si device.
Dielectric Properties of Li-Zr Modified NiO at High Frequency
Authors: Ping C.T. , Salim Syarifah Aishah Syed , Mohamed Julie Juliewatty , Ahmad Zainal Arifin
Published: March 2016

Li+ and Zr2+ codoped NiO ceramics was successfully prepared from the mixture of commercial Li2CO3, ZrO2 and NiO using solid state reaction. The mixture of varies Li+ concentration (x = 0.01, 0.02, 0.03, 0.05 and 0.1), Zr2+ (y = 0.02) and NiO were ball milled for 24 hours. The samples were calcined at 1000oC for 2 hours, pressed into pellet shape at 250 MPa and sintered at 1280°C for 10 hours. The sintered pellets were subjected to XRD, SEM, density testing and Impedance analyzer. XRD result shows the single phase formation of LixNi1-x-0.02Zr0.02O. The grain becomes larger with the increament of Li+ mole %. The dielectric constant of LixNi1-x-0.02Zr0.02 decrease with the increasing frequency. The NiO codoped with Li+ and Zr2+ can be use excellently at high frequencies.Keywords: NiO doped Li+ and Zr2+, dielectric constant, high frequency