bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutritional quality enrichment of rice straw using Pleurotus sajor-caju (Fr.) singer and micro-filamentous fungi
Authors: Begum Most Ferdousi , Alimon Abdul Razak
Published: February 2014

Solid state fermentation was carried out by Pleurotus sajor-caju, micro-filamentous fungi and culture filtrate of P. sajor-caju with different combinations to improve nutritional qualities of rice straw. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents of the fermented rice straw were significantly reduced in mixed culture with filamentous fungi and P. sajor-caju. The cellulose and hemicellulose contents also reduced in similar manner. P. sajor-caju showed strong lignolytic activity resulting cellulose/lignin ratio of 5:1 when rice straw and PKC were supplemented. The protein content increased from 5.86 - 11.12, 12.98 and 13.14%, respectively. The maximum and significant amount of soluble protein 11.84 mg/g and glucosamine 18.50 mg/g was recorded in mixed culture at 30% palm oil kernel cake (PKC) supplementation. The maximum reducing sugar of 18.76 mg/g and endoglucanase activity 11.54 U/ml was recorded in same treatment. The mineral contents K, P, Ca, Mg and Fe were significantly higher in fermented sample while Cu and Zn were non-significant. The antioxidant activity improved by 45% and significantly varied between fermented and unfermented samples. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18039 Bangladesh J. Bot. 42(2): 333-341, 2013 (December)
Response of intercrops and nutrient management on the performance of tobacco based intercropping system and assessment of system sustainability
Authors: Singh Anil Kumar , Singh KA , Bharati RC , Chandra Naresh
Published: February 2014

Intercropping of tobacco with garlic produced the highest total (2292 kg/ha) and first grade (1256 kg/ha) cured leaves of tobacco. In the recommended dose of respective intercrops 75% produced total and first grade cured tobacco leaves compared to 100 per cent of the recommended dose. Tobacco quality was also influenced with nutrient management. Puckering and maturity scores did not impaired up to 50 per cent application of nutrients to intercrops. Among the intercrops garlic gave the highest economic yield (1.18 t/ha) over three years on the basis of monetary gain. The highest net return (Rs 47,948 / ha) and cost benefit ratio (1:1.78) was achieved under tobacco + garlic intercropping system. Nutrient supplied at 75 percent of recommended dose provided net return (Rs 45551/ ha) and cost benefit ratio (1:1.81) equivalent to 100 per cent of recommended doses. Soil fertility was either maintained or improved due to intercropping intervention in comparison to cultivating tobacco sole. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18040 Bangladesh J. Bot. 42(2): 343-348, 2013 (December)
Influence of activator on meiosis of tomato (Lycopersicon esculentum Mill.)
Authors: Çali Ilkay Öztürk , Candan Reyza
Published: February 2014

The cytogenetic effects of activator Act-2 (based in compounds of addition hydro soluble of K-vitamin group a new and specific organic metabolic activator) on meiosis of tomato (Lycopersicon esculentum Mill.) were studied. The activator was applied to tomato plant grown in greenhouse at the dosage (150 cc/100 water) recommended by the manufacturing company and double the recommended dosage (300 cc/100 water) as well. It was observed that all dosages of the activator gave rise to some changes in cell shapes, chromosome structures, cell division patterns and cell sizes of tomato pollen. As a consequence of chromosomal anomalies sterile pollens were produced that affected yield negatively. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18045 Bangladesh J. Bot. 42(2): 361-365, 2013 (December)
Biochemical composition of Enicostemma littorale Blume extracts
Authors: Abirami P , Gomathinayagam M
Published: February 2014

Analysis of organic solvent extracts of Enicostemma littorale reveals the presence of total phenols, vitamin C and E and carbohydrates. The organic solvent extracts of E. littorale exhibited antibacterial activities. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18046 Bangladesh J. Bot. 42(2): 367-369, 2013 (December)
A Hybrid Artificial Reputation Model Involving Interaction Trust, Witness Information and the Trust Model to Calculate the Trust Value of Service Providers
Authors: Ransi Gurdeep , Kobti Ziad
Published: February 2014

Agent interaction in a community, such as the online buyer-seller scenario, is often uncertain, as when an agent comes in contact with other agents they initially know nothing about each other. Currently, many reputation models are developed that help service consumers select better service providers. Reputation models also help agents to make a decision on who they should trust and transact with in the future. These reputation models are either built on interaction trust that involves direct experience as a source of information or they are built upon witness information also known as word-of-mouth that involves the reports provided by others. Neither the interaction trust nor the witness information models alone succeed in such uncertain interactions. In this paper we propose a hybrid reputation model involving both interaction trust and witness information to address the shortcomings of existing reputation models when taken separately. A sample simulation is built to setup buyer-seller services and uncertain interactions. Experiments reveal that the hybrid approach leads to better selection of trustworthy agents where consumers select more reputable service providers, eventually helping consumers obtain more gains. Furthermore, the trust model developed is used in calculating trust values of service providers.
Loss of TRPV2 Homeostatic Control of Cell Proliferation Drives Tumor Progression
Authors: Liberati Sonia , Morelli Maria , Amantini Consuelo , Farfariello Valerio , Santoni Matteo , Conti Alessandro , Nabissi Massimo , Cascinu Stefano , Santoni Giorgio
Published: February 2014

Herein we evaluate the involvement of the TRPV2 channel, belonging to the Transient Receptor Potential Vanilloid channel family (TRPVs), in development and progression of different tumor types. In normal cells, the activation of TRPV2 channels by growth factors, hormones, and endocannabinoids induces a translocation of the receptor from the endosomal compartment to the plasma membrane, which results in abrogation of cell proliferation and induction of cell death. Consequently, loss or inactivation of TRPV2 signaling (e.g., glioblastomas), induces unchecked proliferation, resistance to apoptotic signals and increased resistance to CD95-induced apoptotic cell death. On the other hand, in prostate cancer cells, Ca2+-dependent activation of TRPV2 induced by lysophospholipids increases the invasion of tumor cells. In addition, the progression of prostate cancer to the castration-resistant phenotype is characterized by de novo TRPV2 expression, with higher TRPV2 transcript levels in patients with metastatic cancer. Finally, TRPV2 functional expression in tumor cells can also depend on the presence of alternative splice variants of TRPV2 mRNA that act as dominant-negative mutant of wild-type TRPV2 channels, by inhibiting its trafficking and translocation to the plasma membrane. In conclusion, as TRP channels are altered in human cancers, and their blockage impair tumor progression, they appear to be a very promising targets for early diagnosis and chemotherapy.
Entropy and Its Correlations with Other Related Quantities
Authors: Wu Jing , Guo Zengyuan
Published: February 2014

In order to find more correlations between entropy and other related quantities, an analogical analysis is conducted between thermal science and other branches of physics. Potential energy in various forms is the product of a conserved extensive quantity (for example, mass or electric charge) and an intensive quantity which is its potential (for example, gravitational potential or electrical voltage), while energy in specific form is a dissipative quantity during irreversible transfer process (for example mechanical or electrical energy will be dissipated as thermal energy). However, it has been shown that heat or thermal energy, like mass or electric charge, is conserved during heat transfer processes. When a heat transfer process is for object heating or cooling, the potential of internal energy U is the temperature T and its potential “energy” is UT/2 (called entransy and it is the simplified expression of thermomass potential energy); when a heat transfer process is for heat-work conversion, the potential of internal energy U is (1 − T0/T), and the available potential energy of a system in reversible heat interaction with the environment is U − U0 − T0(S − S0), then T0/T and T0(S − S0) are the unavailable potential and the unavailable potential energy of a system respectively. Hence, entropy is related to the unavailable potential energy per unit environmental temperature for heat-work conversion during reversible heat interaction between the system and its environment. Entropy transfer, like other forms of potential energy transfer, is the product of the heat and its potential, the reciprocal of temperature, although it is in form of the quotient of the heat and the temperature. Thus, the physical essence of entropy transfer is the unavailable potential energy transfer per unit environmental temperature. Entropy is a non-conserved, extensive, state quantity of a system, and entropy generation in an irreversible heat transfer process is proportional to the destruction of available potential energy.
Impact of Hot-Water Extraction on Acetone-Water Oxygen Delignification of Paulownia Spp. and Lignin Recovery
Authors: Gong Chen , Bujanovic Biljana
Published: February 2014

A hardwood-based biorefinery process starting with hot-water extraction (HWE) is recommended in order to remove most of the hemicelluloses/xylans before further processing. HWE may be followed by delignification in acetone/water in the presence of oxygen (AWO) for the production of cellulose and lignin. In this study, the HWE-AWO sequence was evaluated for its effectiveness at removing lignin from the fast-growing species Paulownia tomentosa (PT) and Paulownia elongata (PE), in comparison with the reference species, sugar maple (Acer saccharum, SM). HWE might lead to a remarkable increase in lignin accessibility, and as a result, a greater AWO delignification degree was observed for extracted PT, PE, and SM than for unextracted ones. Organosolv lignin was recovered from the spent liquor of AWO delignification of PT with/without prior HWE and characterized to evaluate the benefits of HWE on the lignin structure and purity. The lignin recovered from the spent liquor of HWE-AWO sequence is of higher purity and lighter color than that recovered from the AWO spent liquor. These properties along with low sulfur content are desirable for lignin high-value applications.
Optimized Production of Vanillin from Green Vanilla Pods by Enzyme-Assisted Extraction Combined with Pre-Freezing and Thawing
Authors: Zhang Yanjun , Mo Limei , Chen Feng , Lu Minquan , Dong Wenjiang , Wang Qinghuang , Xu Fei , Gu Fenglin
Published: February 2014

Production of vanillin from natural green vanilla pods was carried out by enzyme-assisted extraction combined with pre-freezing and thawing. In the first step the green vanilla pods were pre-frozen and then thawed to destroy cellular compartmentation. In the second step pectinase from Aspergillus niger was used to hydrolyze the pectin between the glucovanillin substrate and β-glucosidase. Four main variables, including enzyme amount, reaction temperature, time and pH, which were of significance for the vanillin content were studied and a central composite design (CCD) based on the results of a single-factor tests was used. Response surface methodology based on CCD was employed to optimize the combination of enzyme amount, reaction temperature, time, and pH for maximum vanillin production. This resulted in the optimal condition in regards of the enzyme amount, reaction temperature, time, and pH at 84.2 mg, 49.5 °C, 7.1 h, and 4.2, respectively. Under the optimal condition, the experimental yield of vanillin was 4.63% ± 0.11% (dwb), which was in good agreement with the value predicted by the model. Compared to the traditional curing process (1.98%) and viscozyme extract (2.36%), the optimized method for the vanillin production significantly increased the yield by 133.85% and 96%, respectively.
Evaluation of InSAR and TomoSAR for Monitoring Deformations Caused by Mining in a Mountainous Area with High Resolution Satellite-Based SAR
Authors: Liu Donglie , Shao Yunfeng , Liu Zhenguo , Riedel Björn , Sowter Andrew , Niemeier Wolfgang , Bian Zhengfu
Published: February 2014

Interferometric Synthetic Aperture Radar (InSAR) and Differential Interferometric Synthetic Aperture Radar (DInSAR) have shown numerous applications for subsidence monitoring. In the past 10 years, the Persistent Scatterer InSAR (PSI) and Small BAseline Subset (SBAS) approaches were developed to overcome the problem of decorrelation and atmospheric effects, which are common in interferograms. However, DInSAR or PSI applications in rural areas, especially in mountainous regions, can be extremely challenging. In this study we have employed a combined technique, i.e., SBAS-DInSAR, to a mountainous area that is severely affected by mining activities. In addition, L-band (ALOS) and C-band (ENVISAT) data sets, 21 TerraSAR-X images provided by German Aerospace Center (DLR) with a high resolution have been used. In order to evaluate the ability of TerraSAR-X for mining monitoring, we present a case study of TerraSAR-X SAR images for Subsidence Hazard Boundary (SHB) extraction. The resulting data analysis gives an initial evaluation of InSAR applications within a mountainous region where fast movements and big phase gradients are common. Moreover, the experiment of four-dimension (4-D) Tomography SAR (TomoSAR) for structure monitoring inside the mining area indicates a potential near all-wave monitoring, which is an extension of conventional InSAR.
Characterization of Antimicrobial Resistance Patterns and Detection of Virulence Genes in Campylobacter Isolates in Italy
Authors: Di Giannatale Elisabetta , Di Serafino Gabriella , Zilli Katiuscia , Alessiani Alessandra , Sacchini Lorena , Garofolo Giuliano , Aprea Giuseppe , Marotta Francesca
Published: February 2014

Campylobacter has developed resistance to several antimicrobial agents over the years, including macrolides, quinolones and fluoroquinolones, becoming a significant public health hazard. A total of 145 strains derived from raw milk, chicken faeces, chicken carcasses, cattle faeces and human faeces collected from various Italian regions, were screened for antimicrobial susceptibility, molecular characterization (SmaI pulsed-field gel electrophoresis) and detection of virulence genes (sequencing and DNA microarray analysis). The prevalence of C. jejuni and C. coli was 62.75% and 37.24% respectively. Antimicrobial susceptibility revealed a high level of resistance for ciprofloxacin (62.76%), tetracycline (55.86%) and nalidixic acid (55.17%). Genotyping of Campylobacter isolates using PFGE revealed a total of 86 unique SmaI patterns. Virulence gene profiles were determined using a new microbial diagnostic microarray composed of 70-mer oligonucleotide probes targeting genes implicated in Campylobacter pathogenicity. Correspondence between PFGE and microarray clusters was observed. Comparisons of PFGE and virulence profiles reflected the high genetic diversity of the strains examined, leading us to speculate different degrees of pathogenicity inside Campylobacter populations.
Double Fault Detection of Cone-Shaped Redundant IMUs Using Wavelet Transformation and EPSA
Authors: Lee Wonhee , Park Chan
Published: February 2014

A model-free hybrid fault diagnosis technique is proposed to improve the performance of single and double fault detection and isolation. This is a model-free hybrid method which combines the extended parity space approach (EPSA) with a multi-resolution signal decomposition by using a discrete wavelet transform (DWT). Conventional EPSA can detect and isolate single and double faults. The performance of fault detection and isolation is influenced by the relative size of noise and fault. In this paper; the DWT helps to cancel the high frequency sensor noise. The proposed technique can improve low fault detection and isolation probability by utilizing the EPSA with DWT. To verify the effectiveness of the proposed fault detection method Monte Carlo numerical simulations are performed for a redundant inertial measurement unit (RIMU).
A Smart Exhibition Platform of Power Measurement Vehicle based on the GIS and GPS Techniques
Authors: Tang Chao , Xie Jufang , Hu Dong , Li Jiao
Published: February 2014

A kind of embedded, GIS and GPS centered, smart exhibition platform of power system engineering vehicle were developed in this paper. The system was composed by three parts, which is the vehicle terminal, the server software platform and the monitoring center. The Windows NT Server, Oracle software and VB.NET were used as the developing tools. Together with the GIS and GPS technologies, the N-tier Architecture and the reusable component technology were used to display the real time information of engineering vehicle. The trial operation in the Chongqing Power Electrical Corp. indicated that, with the special structure, the application program development has no connection with the software platform, the heterogeneous database interaction is very convenient, and the system is open, safety and efficient. This smart exhibition system enhanced the dispatching management on the power measurement engineering vehicle, improved the reaction ability on the sudden accident of power equipment and power measurement equipment, and played an important role in the safety maintenance of power grid as well as the loss decrease caused by the measurement errors of power measurement equipment.
Henri IV dévoilé. Le corps dé-voué du souverain ou la royauté sans sacrifice
Authors: Lignereux Yann
Published: February 2014

L’absolutisme ne se définit pas seulement à travers des textes ou dans des pratiques et des gestes ; l’art supporte éloquemment la puissance d’affirmation de cette prétention royale à un pouvoir et à une autorité indépassables. L’étude proposée a donc pour but d’appréhender cette faculté d’expression non pas tant au travers de l’examen d’une architecture monumentale et spectaculaire ou par le biais de l’analyse d’une peinture éblouissante et remarquable mais depuis un petit objet, une statuette de bronze de Barthélemy Prieur, insolite et quasi invisible au regard de l’historiographie du règne d’Henri IV, à travers laquelle se joue, pourtant, la refondation de l’autorité monarchique après le régicide de 1589 dans sa prétention à un absolutisme établi bel et bien comme la vocation salvatrice et sacrée du Prince dans sa puissance d’affranchissement. C’est alors dans le paradoxal et silencieux dénuement du corps royal, loin de la « montre » emphatique d’un pouvoir souverain rempli de bruits et de fureurs, que sont établies pour la France des XVIIe et XVIIIe siècles les assises les plus solides de l’imaginaire absolutiste moderne.
Control Strategy of the Dual Motors Coupling Propulsion for Battery Electric Buses
Authors: Han Guang Wei , Zhang Cheng Ning , Zhang Shuo , Wu Xiao Hua
Published: February 2014

A novel drive system the Dual Motors Coupling Propulsion (DMCP) for battery electric buses was proposed, and its structure and working principle were introduced. For the power and comfort performance of the vehicle, the control method of the motors and the coordinated control strategy of the DMCP were developed. The co-simulation platform of AMESim and Simulink was established, based on which the dynamic model of the vehicle equipped the DMCP was built. The simulation results show that the DMCP runs smoothly in the Chinese typical city bus driving schedule. This indicates that the control strategy can manipulate the DMCP to drive the bus powerfully and smoothly. This has laid the foundation of the further research of the DMCP.
Microstructure Evolution of Nickel Aluminum Bronze Alloy during Compression at Elevated Temperatures
Authors: Thossatheppitak Borpit , Suranuntchai Surasak , Uthaisangsuk Viton , Manonukul Anchalee , Mungsuntisuk Pinai
Published: February 2014

In this work, effects of temperature and strain rate on microstructure development of a Nickel Aluminum Bronze (NAB) alloy during hot compression were investigated. The temperatures between 750°C and 900°C, strain rates between 0.1 s-1 and 10 s-1 and a deformation degree of 60% were considered. Microstructure analyses were performed for the samples after the compression using scanning electron microscopy technique. The results showed that microstructure of as-cast NAB alloy consisted of α, β' and κ phase. After homogenization β' phase transformed to the α and κ phase. Furthermore, different heating temperatures led to varying initial microstructures before forming and subsequent deformation, forming rates and cooling caused precipitation of various intermetallic phases. The α phase was found in the final microstructures of all forming conditions. At high forming temperatures, some intermetallic κ phases tended to dissolve and precipitated during cooling according to applied strain rate. However, at lower temperatures of 750-850°C, no significant effect of the strain rate on alteration of intermetallic κ phases.
Durability and Stability of LSCF Composite Cathode for Intermediate-Low Temperature of Solid Oxide Fuel Cell (IT-LT SOFC): Short Review
Authors: Agun Linda , Rahman Hamimah Abdul , Ahmad Sufizar , Muchtar Andanastuti
Published: February 2014

Solid oxide fuel cell (SOFC) is well known as power and heat generation device which converts chemical energy directly from fuel into electricity. SOFC operate at high temperature becomes obstacle for SOFC which reducing ionic conductivity material of current electrolyte, reduce lifetime of cell components, high fabrication cost, limited durability and performance issues. This introduce to environment pollution and decrease the SOFC lifetime. The fabrication of durability and stability composite cathode are comprised from mixing of perovskite La0.6Sr0.4CO0.2Fe0.8 (LSCF) powders with nanoscale ionically conducting ceramic electrolyte materials, SDC-carbonate (SDCc) was overcome this problems. Powder preparation and composite cathode fabrication must consider which as main factors in the development of durability and stability of LSCF-SDCc composite cathode. Powders must in nanoscale to enhance the conductivity and decrease the interfacial polarization resistance and the composite cathode should in nanoporous morphology for achieve high power density over than 500 h and remarkable durability. Calcination also plays in important role and its operations will effects to the SOFC durability and performance. The necessary to prolong the lifetime and increase the SOFC performance has lead to development of durability and stability of SOFC. This paper reviews the durability and stability of the composite cathode and focus on the challenges in material technology.
Enhanced Transport Critical Current Density of NiO Nano Particles Added YBCO Superconductors
Authors: Abd-Ghani Siti Nurdalila , Wye Hon Kah , Kong Ing , Abd-Shukor Roslan , Kong Wei
Published: February 2014

The effects of NiO nanoparticles addition in YBa2Cu3O7-δ (YBCO) superconductors had been investigated. YBCO superconductor powders were prepared by using high purity oxide powders via solid state reaction method. 0.01 0.05 wt.% of NiO nanoparticles were added into YBCO. The critical temperature (Tc) and transport critical current density (Jc) were determined by using four point probe method. The lattice parameters and morphology of the samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. Tc of YBCO increased from 84 K to 87 K with 0.02 wt.% of NiO nanoparticles addition. The addition on NiO nanoparticles have significantly enhanced transport critical current density of YBCO by acting as flux pinning centers. YBCO with 0.03 wt.% of NiO nanoparticles performed the highest Jcup to 1265 mA/cm2 among the NiO-added samples. However, excessive addition of NiO nanoparticles in YBCO caused degradation in Tc and Jc.
Cellulose Extraction from Hardwood Waste of Resak (Vatica spp.)
Authors: Zainul Abidin Nurul Aimi Mohd , Abdul Aziz Fauziah , Shahidan Radiman , Azraaie Noriean , Mamat Razali Nur Amira , Ibrahim Nur Ain
Published: February 2014

Cellulose is one of the most important natural polymers. The aims of this study are to extract and characterize the properties cellulose from local hardwood waste, Resak (Vatica spp.). There are two main stages in the extraction of cellulose at atmospheric pressure. The initial stage is delignification and second stage is bleaching process. At the second stage, the cellulose substance are bleached in two different bleaching medium; a) sodium hydroxide (NaOH), b) acidified hydrogen peroxide (H2O2). Then, the cellulose properties of treated and untreated hardwood waste of Resak (Vatica spp.) were characterized via X-ray diffraction (XRD) and Field emission scanning electron microscope (FESEM).
Preparation and Characterization of Alpha Cellulose of Pineapple (Ananas comosus) Leaf Fibres (PALF)
Authors: Ibrahim Nur Ain , Azraaie Noriean , Zainul Abidin Nurul Aimi Mohd , Mamat Razali Nur Amira , Abdul Aziz Fauziah , Zakaria Sarani
Published: February 2014

The main component in natural fibre is cellulose (C6H10O5)n. Cellulose from agricultural by-product is abundant, low cost, eco-friendly, biodegradable, and renewable. This research work was prepared alpha cellulose from pineapple leaf fibre (PALF), which obtained from the leaves of pineapple plant, Ananas comosus belonged to the family Bromeliaceae. The treated and untreated samples were characterized using X-ray diffraction (XRD).
Structural and Optical Properties of Nickel (Ni)/indium Tin Oxide (ITO) Thin-Films Deposited by RF Magnetron Sputtering
Authors: Sobri M. , Abu Bakar Ahmad Shuhaimi , Mazwan M. , Hakim K.M. , Najwa S. , Ameera N. , Mamat Mohamad Hafiz , Musa M.Z. , Rusop Mohamad
Published: February 2014

Nickel (Ni)/ indium tin oxide (ITO) thin-films have been deposited on silicon (Si) and glass substrates using radio-frequency (RF) magnetron sputtering at 200°C temperature. ITO layer was deposited on top of Ni layer with various deposition parameter. The material and optical properties of the ITO samples with and without Ni seed layer were analyzed. X-ray diffraction studies shows that the films are crystalline with the typical ITO diffraction peaks of (222), (400) and (411). The FESEM and AFM images shows that the grains have uniform shapes and sizes. FESEM results reveal that the grain size along the sample surface decreases when the Ni seed layer is added. Both the samples shows higher transmittance of more than 95% in UV-vis spectrometer.
Electro-Optic Potential of Room and High Temperature Polymer Stabilised Blue Phase Liquid Crystal
Authors: Rahman Md. Asiqur , Yamana Itaru , Yeow Yeap Guan , Said Suhana Binti Mohd , Kimura Munehiro
Published: February 2014

In the field of liquid crystals, blue phases (BPs) are one of the most unique and interesting sub-phases. Blue-phase liquid crystal holds the potential to become next-generation display and photonics device because of its sub-millisecond gray-to-gray response time, alignment-layer-free process, optically isotropic dark state, and cell gap insensitivity. The BPLC is a highly chiral liquid crystal system possessing crystal like unit cell structure and exist over a small temperature range (0.5-2 °C) between isotropic and chiral nematic (N*) thermotropic phase. The narrow phase range has been an intrinsic problem for blue phase, and a useful strategy of widening the phase is by adding polymer to form a polymer stabilised blue phase liquid crystal. In this paper, we demonstrate polymer stabilization using two different cases: a room temperature mixture containing E8, PE-5CNF and CPP-3FF, and a high temperature mixture using a single molecule blue phase liquid crystal material, TCB5. Comparison of the polymer stabilization effects on these two cases will be discussed, in the perspective of their potential in electro-optic applications.
Optical Properties of Undoped and Dy3+-Doped Boro-Tellurite Glass
Authors: Ab Rasid Atiqah , Wagiran Husin , Hashim Suhairul , Hussin Rosli , Ibrahim Zuhairi
Published: February 2014

A series of undoped and Dy3+-doped boro-tellurite glasses were prepared, and their optical properties have been studied through XRD, absorption, optical band gap energy and photoluminescence. The XRD pattern has been used to confirm the amorphous nature of the prepared glass. The optical absorption spectra showed eight absorption bands which corresponded to 4I15/2, 4F9/2, 6F3/2, 6F5/2, 6F7/2, 6F9/2, 6F11/2 and 6H11/2 transitions from the ground state, 6H15/2. The optical band gap energy, Eopt for undoped glass was 3.08 eV and the Dy3+-doped glasses Eopt values varied from 3.16 3.24 eV. The emission spectra from photoluminescence spectroscopy showed two dominant emission peaks at 483 nm and 574 nm with an excitation wavelength of 325 nm (3.82 eV). Keywords: X-ray diffraction, boro-tellurite glass, photoluminescence, absorption spectrum, UV-Vis spectroscopy, energy band gap.
Influence of Er3+ Dopants on Optical Properties of Boro-Tellurite Glass
Authors: Mahraz Zahra Ashur Said , Sahar M.R. , Ghoshal Sib Krishna
Published: February 2014

The effect of the rare earth ion concentration on the physical and spectroscopic properties of Er3+-doped boro-tellurite glass is studied. Glasses with compositions 30B2O3+10ZnO+(60-x)TeO2+xEr2O3 (where x=0, 0.5, 1, 1.5 and 2mol%) are prepared by melt-quenching method. The structural analyses are made through XRD, FTIR and UV-VIS-IR absorption spectroscopy. IR-spectra reveal five absorption bands in the region of 450-1500 cm-1 for different B-O and Te-O vibrational groups. The UV-VIS-IR spectra exhibits seven absorption bands corresponding to the transitions from 4I15/2 ground state to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 2H11/2, 4F7/2 and 4F3/2 excited states. The bonding parameters are determined from the optical absorption spectra and are found to be covalent in nature. The optical band gap energy values corresponding to the direct and indirect allowed transitions decreases while the Urbach energy and cut-off wavelengths increases by the introduction of Er3+ ions. Keywords: Er3+ ions, melt-quenching, boro-tellurite glass, optical band gap
The Effect of Annealing Temperatures on the Dielectric Constant of PVDF/MgO Nanocomposites Thin Films
Authors: Arshad Adillah Nurashikin , Mohd Dahan Rozana , Mohd Wahid Mohamad Hafiz , Sarip Muhamad Naiman , Mahmood Mohamad Rusop
Published: February 2014

Poly(vinylidene flouride)/nano-magnesium oxide (PVDF/MgO) nanocomposites with MgO loading percentage of (7% wt. %) were annealed with various annealing temperatures ranging from 70°C to 170°C with rapid removal from the oven. From dielectric constant, the samples annealed at temperature of 70°C showed an improvement in the dielectric constant from 21 to 23 at frequency 103 Hz for UN and AN70 respectively. However, as the temperatures were increased, the dielectric constant of PVDF/MgO (7%) was found to decrease. XRD showed the presence of β-phase for PVDF/MgO(7%) sample annealed at 70°C in comparison to unannealed sample, hence PVDF/MgO(7%) film is suitable to be used for low frequency capacitor application.
Structural and Optical Properties of Nickel-Doped and Undoped Zinc Oxide Thin Films Deposited by Sol-Gel Method
Authors: Basri Siti Hajar , Mohd Sarjidan Mohd Arif , Majid Wan Haliza A.
Published: February 2014

ZnO thin films with and without Ni-doping were successfully deposited by sol-gel method with zinc acetate dihydrate as inorganic precursor, and nickel (II) acetate tetrahydrate as dopant. The solutions were prepared by dissolving zinc acetate and nickel (II) acetate in ethanol and diethanolamine (DEA) as its chelating agent. Thin films were fabricated by using spin-coating method on glass substrates. ZnO films were obtained by pre-heating and post-heating at 300 °C for 10 minutes and 500 °C for 1 h respectively. The films were analyzed by X-ray diffraction (XRD), UV-Vis transmittance and photoluminescence (PL). All samples exhibit high transparency in visible. Ni dopant does not alter so much ZnO structure, which due to the ion substitution between Ni and Zn. However, the Ni tends to create a dopant energy interlayer in ZnO energy band gap which cause significant change in PL intensity.
Luminescence Enhancement of Samarium-Doped Tellurite Glass Containing Silver Nanoparticles
Authors: Fauzia Abdullah Nur Alia , Sahar Md Rahim , Hamzah Khaidzir , Ghoshal Sib Krishna
Published: February 2014

Samarium-doped tellurite glass embedded with silver nanoparticles are synthesized by melt quenching technique and optically characterized. The effect of silver nanoparticles on the luminescent properties of the samarium-doped sodium tellurite glass is investigated. Upon pumping with 406 nm radiation, it is found that there are four distinctive emission bands centered at 562 nm, 599 nm, 645 nm and 705 nm. In the presence of silver nanoparticles in the glass substrates, we observe significant enhancement in the intensity of these emission bands. The enhancement tends to increase with the increasing of silver nanoparticles concentration. The mechanism of luminescence enhancement is discussed in terms of localized surface plasmon resonance.
Structural, Thermal and Magnetic Analysis of Co2FeO4 Spinel Oxide Synthesized by Co-Precipitation Process
Authors: Reddy Pradeep , Raja Yesu , Ashok M.
Published: February 2014

Co2FeO4 spinel oxide nano powder was synthesized by co-precipitation process. Samples were annealed at different temperatures of 500, 800 and 900o C and the phase purity were also analyzed. As-prepared sample has two spinel phases and on annealing at 900 οC single phase compound formed. The crystallite size of as-prepared is found to be 11.9 nm. The crystallite size increased with increase in annealing temperature to a maximum of 17.4 nm for 900 °C. Samples were subjected to necessary characterization for finding thermal, magnetic and optical band gap.
Spectroscopic Studies of Er3+-Yb3+ Codoped Multicomposition Tellurite Oxide Glass
Authors: Baki Sharudin Omar , Tan L.S. , Kan C.S. , Kamari Halimah Mohamed , Noor A.S.M. , Mahdi Mohd Adzir
Published: February 2014

Multicomposition of Er3+-Yb3+ codoped tellurite oxide, TeO2-ZnO-PbO-TiO2-Na2O glass has been investigated. Detailed spectroscopic study of the Judd-Ofelt analysis has been performed from the measured absorption spectrum in order to obtain the intensity parameters Ωt (t=2, 4, 6). The calculated Ωt values were then utilized in the determination of transition probabilities, radiative lifetimes and branching ratios of the Er3+ transitions between the J(upper)-J(lower) manifolds. Both visible upconversion and near-infrared spectra were characterized under the 980 nm laser diode excitation at room temperature.
Investigation of Phase, Purity, Morphology and Particle Size of Zn(1-x)CuxO Materials via X-Ray Diffraction (XRD) and Microscopic Techniques
Authors: Kasim Muhd Firdaus , Kamarulzaman Norlida , Kamil Suraya Ahmad
Published: February 2014

Substitution of cations in metal oxides result in differences of materials characteristics. Substitution resulting in isostructural materials is not easy. In this work, Cu has been used as the substitution element for Zn in Zinc oxide. The Zn(1-x)CuxO (x=0.01, 0.02, 0.03, 0.04, 0.05) materials were prepared via a simple soft chemistry method without using any chelating agents. Results showed that some of the samples are pure but the heavily doped samples contain a very small amount of CuO as an impurity. XRD and microscopy results agree with each other.
Crystallographic Parameter and Optical Absorption Measurement of CuInSe2 Thin Films for Solar Cells
Authors: Al-Bassam A.A.I. , Elani U.A.
Published: February 2014

Thin films CuInSe2 (CIS) cells have been fabricated by the electro chemical method. Some of the physical properties such as lattice parameter, crystal structure and grain size of CuInSe2 (CIS) films with different Cu/In ratios ( 0.50-1.1) were determined using X-ray diffractornetry. The surface morphology with different Cu/In ratios was studied using a scanning electron microscope. The SEM studies on these films showed that the grain size increases the Cu/In ratios increases from 0.49 to 1.1. The variation of the band gap with different Cu/In ratio was determined from optical absorption measurements. The results showed that the band gap decreases as the Cu/In ratio increases over the considered range of composition. Key words: Thin films, Lattice Parameter , Optical Absorption, grain size
Luminescence from Silicon and Germanium Nanowires: A Phenomenological Model
Authors: Ghoshal Sib Krishna , Sahar M.R. , Arifin Ramli , Rohani M. Supar , Hamzah Khaidzirh
Published: February 2014

The room temperature luminescence intensity as a function of the size and the voltage of silicon (Si) and germanium (Ge) nanowires (NWs) having 5 to 30 atoms per wire with diameter ranging from 1.2 nm to 3.5 nm are investigated. The effects of exciton energy states, localized surface states and the quantum confinement are integrated in our phenomenological model to derive an analytical expression for the photoluminescence (PL) and electroluminescence (EL) intensity. By controlling a set of fitting parameters in the model, one can tune the EL and PL peak and intensity. Our results show that both quantum confinement and surface passivation in addition to exciton effects determine the optical and electronic properties of Si and Ge NWs. We observed that the EL and PL intensities occurs at the same energy, however the EL intensity has sharp Gaussian sub peaks and red shifted compared to the PL intensity.
Preparation of Photoelectrochemical Cell of ITO/Cu2O/PVC-LiClO4/Graphite Using Cu2O Films as an Active Layer
Authors: Halin Dewi Suriyani Che , Haroon Haiza , Talib Ibrahim Abu , Daud Abdul Razak , Hamid Muhammad Azmi Abd
Published: February 2014

Cuprous oxide (Cu2O) thin films were successfully grown on indium tin oxide (ITO) coated glass by sol-gel spin coating using diethanolamine (DEA) as a solubility agent. The films were annealed at 350 °C in 5% H2 + 95% N2 atmosphere. The films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Based on the SEM micrograph of the as obtained film, the film shows better coverage with the four sided pyramidal shape grain size of 108 nm. The prepared Cu2O thin film was used as an active electrode for photoelectrochemical cell of ITO/Cu2O/PVC-LiClO4/graphite. The photovoltaic cell was tested using current-voltage characteristic under light illumination of 100 mW/cm2.
The Effect of V/III Ratio on the Crystal Structure of Gallium Arsenide Nanowires
Authors: Muhammad R. , Wahab Y. , Ibrahim Zuhairi , Othaman Zulkafli , Sakrani S. , Ahamad Rahmalan
Published: February 2014

Gallium arsenide (GaAs) nanowires were grown vertically on GaAs (111)B substrate by gold particle-assisted using metal-organic chemical vapour deposition. Transmission electron microscopy and X-Ray diffraction analysis were carried out to investigate the effects of V/III ratio and nanowire diameter on structural properties and crystallinity changes. Results show that GaAs nanowires grow preferably in the wurtzite crystal structure than zinc blende structure with increasing V/III ratio. Additionally, XRD studies have revealed that wurtzite nanowires show prominent peaks especially at (222) orientation. The optimum V/III ratio was found to be 166 with less defect structure, uniform diameter and peak prominence. The nanowires with high quality are needed in solar cells technology for energy trapping with maximum capacity.Keywords : Nanowire; crystal structure; Gallium arsenide; Vapor Liquid Solid
Morphology and Optical Studies of (1-x)ZnAl2O4 – xSiO2 Thin Films Prepared by Sol-Gel Method
Authors: Zulfakar Mohd Syafiq , Abdullah Huda , Wan Jalal Wan Nasarudin , Shaari Sahbudin , Zalita Zainuddin
Published: February 2014

The effect of morphological structures and optical band gap of (1-x)ZnAl2O4xSiO2 samples with compositions of x = 0.00, 0.05, 0.10 and 0.15 were prepared by sol-gel method. Spin coating technique was used to deposited the (1-x)ZnAl2O4xSiO2 as a thin film and to investigate the structural and optical band gap. The produced thin film samples were annealed at 450 °C for 1h. Field emission scanning electron microscope (FESEM) was used to investigate the surface morphology of the samples. The average particle size for (1-x)ZnAl2O4xSiO2 is about 331.23 nm. The particle size are tend to increase as the composition of SiO2 increased. XRD analysis shows the formation of cubic structure phase and dominant peak has been observed with Miller Indices (311) plane. The average crystallite size, D was calculated with average size about 8 13 nm. The optical band gap was calculated for (1-x)ZnAl2O4xSiO2 samples and it was found within range of 3.34 to 3.94 eV.
Effects of Nano-Sized NiF2 Addition in Bi1.4Pb0.6Sr2Ca2Cu3O10+δ Superconductor
Authors: Hafiz Muhammad , Abd-Shukor Roslan
Published: February 2014

The effects of NiF2 addition on the superconducting and transport properties of Bi1.4Pb0.6Sr2Ca2Cu3O10+δ (Bi-2223) were studied. Bi-2223 superconductor samples were prepared via conventional nitrate coprecipitation method, and 0.01 wt% - 0.05 wt% of NiF2 nanoparticles with average size of 20 nm were added into the samples. The critical temperature (Tc) of each sample was measured by using the four-point probe method. Furthermore, phase formation and the microstructure of the samples were identified using x-ray diffraction method (XRD) and scanning electron microscope (SEM) respectively. The optimum Tc was observed for the sample with 0.04 wt% addition of NiF2. Results of electrical transport measurement are presented.
Preparation of Activated Carbon Monolith Electrodes from Sugarcane Bagasse by Physical and Physical-Chemical Activation Process for Supercapacitor Application
Authors: Taer Erman , Iwantono Iwantono , Manik Saidul Tua , Taslim R. , Dahlan D. , Deraman M.
Published: February 2014

Binderless activated carbon monoliths (ACMs) for supercapacitor electrodes were prepared from sugarcane bagasse by two different methods of physical and combination of physical-chemical activation process. The CO2 gas was used as physical activation agent and 0.3 M KOH was chosen as chemical activation agent. The ACMs were tested as electrodes in two-electrode systems of the coin tape cell supercapacitor that consists of stainless steel as current collectors and 1 M H2SO4 as an electrolyte. The improving of resistive, capacitive and energy properties of combination of physical-chemical ACMs electrodes were shown by an impedance spectroscopy, a cyclic voltammetry and a galvanostatic charge-discharge method. The improving of resistive, capacitive and energy properties as high as 1 to 0.6 Ω, 146 to 178 F g-1, 3.83 to 4.72 W h kg-1, respectively. The X-ray diffraction analysis and field emission scanning electron microscope were performed to characterize the crystallite and morphology characteristics. The results showed that the combination of physical-chemical activation process have given a good improving in performance of the bagasse based ACMs electrodes in supercapacitor application.
Epoxidised Natural Rubber Based Polymer Electrolyte Systems for Electrochemical Device Applications
Authors: Idris Razali , Bujang Noor Hidaya
Published: February 2014

Epoxidized Natural Rubber (ENR50), lithium imide salt, [LiN(SO2CF3)2] with and without solvent were prepared by solvent casting technique. Non solvated polymer electrolyte showed modest ionic conductivity at ambient temperature. To further enhance ionic conductivity a mixed solvent of ethylene carbonate/propylene carbonate was added into the system. Thermal characterization showed that single transition glass temperature (Tg) for all systems and amorphous phase is dominant. DSC traces of non solvated samples have shown Tg values increased whereas addition of mixed EC/PC solvent into the electrolyte system reduced their values respectively. Impedance measurements for the solvated epoxidized natural rubber (ENR) based electrolyte systems have shown optimal ionic conductivity 10-4 S cm-1 whereas 10-6 S cm-1 for a non solvated one. ENR electrolyte systems showed similar temperature dependence, which suggests that the conductivity is thermally activated.
Determination of Sintering Activity of Sodium-Potassium Feldspar
Authors: Sokolař Radomír , Vodová Lucie
Published: February 2014

The aim of the article is to describe the sintering activity of industrially milled sodium potassium feldspar to determine of optimal firing temperature during fast firing typical for e.g. production of dry pressed ceramic tiles. The change of porosity, flexural strength, firing shrinkage and mineralogical composition in dependence on the firing temperature (1120 1210 °C) were determined on the test samples made from dry granulate prepared from the pure feldspar. Tested alkali sodium potassium feldspar is characterized by low sintering temperature (1190 °C) during fast firing (heating rate 10 °C/min). During the sintering process, feldspar gradually disappears in phases first of all potassium feldspar (microcline), sodium feldspar (albite) we can find in the fired body at firing temperature 1180 °C.
Pozzolanic Aktivity Increase of Recycled Glass
Authors: Dvořák Karel , Dobrovolný Petr , Gazdič Dominik
Published: February 2014

This work deals with oportunity of recycled glass utilization as pozzolanic aktive substance. It analyzes pozzolanic dependency on reached specigic surface and method of grinding in various types of mills. This way arisen admixture is researched in mineralogical and technical aspekt.
To the Problems of Determination of Dynamic Elasticity Modules of Calcium Silicate Bricks by Means of Resonance Method
Authors: Brožovský Jiří , Dufka Ámos
Published: February 2014

Modulus of elasticity of building materials can be determined in a static way (loading in a press) or by means of non-destructive test methods (ultrasonic pulse method and resonance method); the parameter is most frequently determined for concrete and both methods of determining elasticity modulus are codified in Standards. Elasticity characteristics of calcium silicate bricks were determined by means of resonance test method. Because the shape of calcium silicate bricks (a block with oblong foot) is different from the shape of test specimens for concrete (usually blocks with square foot), expected frequencies for verification of accuracy of measurement by resonance method were determined. Moisture content of calcium silicate bricks (water absorbing capacity is up to 12-14%) has influence on the value of resonance frequency. Difference between dynamic Young's modulus of elasticity from fundamental longitudinal and transverse resonant frequency is on average 2.8%.