495 research outputs found

    Isolated Magnetic Dipole MIMO Antenna with Linear Port Configuration for Wireless Applications

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    This paper is presenting preliminary research to design Isolated Magnetic Dipole MIMO Antenna for wireless application. Isolated Magnetic Dipole (IMD) structure is one of the unique geometries that offers compact and low damaging electrical current at the ground surface. However, less attention in discussing design the MIMO antenna using IMD structure. The two elements MIMO antenna using IMD with linear port configuration has constructed at 2.4 GHz. Then simulated and analyzed to validate the feasibility of the IMD-MIMO antenna. The simulation and analysis cover S-Parameters, radiation, Gain, Correlation coefficient, and diversity gain. In addition, simple Semi-circle structure etched on the ground layer to improve the isolation of MIMO antenna. From the simulation results, the IMD-MIMO antenna has better results and highly recommended for designing compact MIMO antenna

    Analysis of Circular Patch Antenna of 2-3GHz for Electromagnetic Applications

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    This paper present analysis of bandwidth of circular patch antenna for electromagnetic (EM) applications at frequency 2-3GHz for reflection coefficient less than -10 dB. The final dimension of the proposed antenna is 48mmx30mm (LsxWs) for its FR4 substrate with thickness of 1.6mm, circular patch of radius 12.5mm and a feedline with 25mmx3mm (LpxWp). Thickness of circular patch and feedline both at 0.035mm.The proposed antenna is wideband of 24.50%, highest gain of 3.292 dB and in Omni-directional radiation pattern. Circular patch antenna is chosen because of its better directivity, easiness in fabricating process and in analyzing its structure to provide a best wideband. In EMR, it preserves Omni-directional radiation characteristic because of it equally well in process of receiving signal. Ultimately, the operating frequency range is determined and the design is analyze to be used for EM application. The performance of the designed antenna was analyzed in terms of return loss provided its stable Omni-directional radiation pattern and gain

    Increasing T-method accuracy through application of robust M-estimatior

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    Mahalanobis Taguchi System is an analytical tool involving classification, clustering as well as prediction techniques. T-Method which is part of it is a multivariate analysis technique designed mainly for prediction and optimization purposes. The good things about T-Method is that prediction is always possible even with limited sample size. In applying T-Method, the analyst is advised to clearly understand the trend and states of the data population since this method is good in dealing with limited sample size data but for higher samples or extremely high samples data it might have more things to ponder. T-Method is not being mentioned robust to the effect of outliers within it, so dealing with high sample data will put the prediction accuracy at risk. By incorporating outliers in overall data analysis, it may contribute to a non-normality state beside the entire classical methods breakdown. Considering the risk towards lower prediction accuracy, it is important to consider the risk of lower accuracy for the individual estimates so that the overall prediction accuracy will be increased. Dealing with that intention, there exist several robust parameters estimates such as M-estimator, that able to give good results even with the data contain or may not contain outliers in it. Generalized inverse regression estimator (GIR) also been used in this research as well as Ordinary Lease Square Method (OLS) as part of comparison study. Embedding these methods into T-Method individual estimates conditionally helps in enhancing the accuracy of the T-Method while analyzing the robustness of T-method itself. However, from the 3 main case studies been used within this analysis, it shows that T-Method contributed to a better and acceptable performance with error percentages range 2.5% ~ 22.8% between all cases compared to other methods. M-estimator is proved to be sensitive with data consist of leverage point in x-axis as well as data with limited sample size. Referring to these 3 case studies only, it can be concluded that robust M-estimator is not feasible to be applied into T-Method as of now. Further enhance analysis is needed to encounter issues such as Airfoil noise case study data which T -method contributed to highest error% prediction. Hence further analysis need to be done for better result review

    Optimization of Pb(II) removal using Magnetic y-Fe2O3/KCC-1 Synthesized from Palm Oil Fuel Ash

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    The pollution of lead, Pb(II) in water bodies has severely threatened the environment and human health due to its toxicity. Thus, removing Pb(II) from water bodies is an imperative task. In this study, the removal of Pb(II) using magnetic y-Fe2O3/KCC-1 synthesized from Palm Oil Fuel Ash (POFA) was explored. The characterization analysis confirmed a successful preparation of y-Fe2O3/KCC-1 with BET surface area and pore volume of 401 m2g-1 and 0.90 cm3g-1, respectively. The optimization by response surface methodology (RSM) with independent variables of initial Pb(II) concentration

    Receptor-mediated delivery of engineered nucleases for genome modification

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    Engineered nucleases, which incise the genome at predetermined sites, have a number of laboratory and clinical applications. There is, however, a need for better methods for controlled intracellular delivery of nucleases. Here, we demonstrate a method for ligand-mediated delivery of zinc finger nucleases (ZFN) proteins using transferrin receptor-mediated endocytosis. Uptake is rapid and efficient in established mammalian cell lines and in primary cells, including mouse and human hematopoietic stem-progenitor cell populations. In contrast to cDNA expression, ZFN protein levels decline rapidly following internalization, affording better temporal control of nuclease activity. We show that transferrin-mediated ZFN uptake leads to site-specific in situ cleavage of the target locus. Additionally, despite the much shorter duration of ZFN activity, the efficiency of gene correction approaches that seen with cDNA-mediated expression. The approach is flexible and general, with the potential for extension to other targeting ligands and nuclease architectures

    Nanoscale magnetic structure and properties of solution-derived self-assembled La0.7Sr0.3MnO3 islands

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    The following article appeared in Journal of Applied Physics 111.2 (2012): 024307 and may be found at http://scitation.aip.org/content/aip/journal/jap/111/2/10.1063/1.3677985Strain-induced self-assembled La0.7Sr0.3MnO 3 nanoislands of lateral size 50-150 nm and height 10-40 nm have been grown on yttria-stabilized zirconia (001)-substrates from ultradiluted chemical solutions based on metal propionates. The nanoislands grow highly relaxed withstanding the epitaxial relation (001)LSMO[110]//(001) Ysz[010] and show bulk-like average magnetic properties in terms of Curie temperature and saturation magnetization. The interplay of the magnetocrystalline and shape anisotropy within the nanoisland ensemble results in an in-plane magnetic anisotropy with a magnetocrystalline constant K 1(150K) = -(5±1) kJ/m3 and in-plane easy axis along the [110] -La0.7Sr0.3MnO3 direction as measured, for the first time, through ferromagnetic resonance experiments. Magnetic force microscopy studies reveal the correlation between nanoisland size and its magnetic domain structure in agreement with micromagnetic simulations. In particular, we have established the required geometric conditions for single domain, multidomain, and vortex configurations.We acknowledge the financial support from MEC (MAT2008-01022, Consolider NANOSELECT and FPU), Comunidad Autónoma de Madrid (CAM S2009/MAT-1467), Generalitat de Catalunya (Catalan Pla de Recerca 2009-SGR- 770 and XaRMAE), and EU (NESPA). R. D. Zysler and C. A. Ramos acknowledge support from PIP-1333(2007) CONICET and PICT 829 (2006) and PICT 832(2006) ANPCyT of Argentina. Serveis Científic-Tècnics from Universitat de Barcelona and Servei de Micròscopia from Universitat Auto`noma de Barcelona are acknowledged for TEM facilities

    Ergogenic, anti-diabetic and antioxidant attributes of selected Malaysian herbs: characterisation of flavonoids and correlation of functional activities

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    In the present work, aqueous ethanolic (60% ethanol) extracts from selected Malaysian herbs including Murraya koenigii L. Spreng, Lawsonia inermis L., Cosmos caudatus Kunth, Piper betle L., and P. sarmentosum Roxb. were evaluated for their ergogenic, anti-diabetic and antioxidant potentials. Results showed that the analysed herbs had ergogenic property and were able to activate 5'AMP-activated protein kinase (AMPK) in a concentration dependant manner. The highest AMPK activation was exhibited by M. koenigii extract which showed no significant (p > 0.05) difference with green tea (positive control). For anti-diabetic potential, the highest α-glucosidase inhibition was exhibited by M. koenigii extract with IC50 of 43.35 ± 7.5 μg/mL, which was higher than acarbose (positive control). The determinations of free radical scavenging activity and total phenolics content (TPC) indicated that the analysed herbs had good antioxidant activity. However, C. caudatus extract showed superior antioxidant activity with IC50 against free radical and TPC of 21.12 ± 3.20 μg/mL and 221.61 ± 7.49 mg GAE/g, respectively. RP-HPLC analysis established the presence of flavonoids in the herbs wherein L. inermis contained the highest flavonoid (catechin, epicatechin, naringin and rutin) content (668.87 mg/kg of extract). Correlations between the analyses were conducted, and revealed incoherent trends. Overall, M. koenigii was noted to be the most potent herb for enhancement of AMPK activity and α-glucosidase inhibition but exhibited moderate antioxidant activity. These results revealed that the selected herbs could be potential sources of natural ergogenic and anti-diabetic/antioxidant agents due to their rich profile of phenolics. Further analysis in vivo should be carried out to further elucidate the mechanism of actions of these herbs as ergogenic aids and anti-diabetic/antioxidant agents

    Direct observation of a highly spin-polarized organic spinterface at room temperature

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    Organic semiconductors constitute promising candidates toward large-scale electronic circuits that are entirely spintronics-driven. Toward this goal, tunneling magnetoresistance values above 300% at low temperature suggested the presence of highly spin-polarized device interfaces. However, such spinterfaces have not been observed directly, let alone at room temperature. Thanks to experiments and theory on the model spinterface between phthalocyanine molecules and a Co single crystal surface, we clearly evidence a highly efficient spinterface. Spin-polarised direct and inverse photoemission experiments reveal a high degree of spin polarisation at room temperature at this interface. We measured a magnetic moment on the molecule’s nitrogen p orbitals, which substantiates an ab-initio theoretical description of highly spin-polarised charge conduction across the interface due to differing spinterface formation mechanisms in each spin channel. We propose, through this example, a recipe to engineer simple organic-inorganic interfaces with remarkable spintronic properties that can endure well above room temperature

    Conversion of cellulose to short chain polyols over metal loaded on KCC-1 catalyst

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    The production of short chain polyols from cellulose over metal (Ce, Ni or Ru) loaded on fibrous mesoporous silica KCC-1 catalysts was studied at temperature range of 150-240 °C. The KCC-1 was prepared by microwave assisted hydrothermal method. Then it was modified with Ce, Ni or Ru by incipient wetness impregnation method. The KCC-1, Ce/KCC-1, Ni/KCC-1 and Ru/KCC-1 were characterized with XRD, FESEM, FTIR and nitrogen-phy-sisorption analyzer. The XRD analysis showed that the introduction of metals did not change much of the XRD pattern for KCC-1. The FESEM and EDX results showed the presence of Ce, Ni and Ru metals on the uniform spherical shape of fibrous silica particle. The surface area of KCC-1, Ce/KCC-1, Ni/KCC-1 and Ru/KCC-1 was 393.81, 371.56, 314.22 and 351.97 m2/g, respectively. At 220 °C, 5 bars of nitrogen, and 2 h of reaction, the con-version of cellulose reached 95 % over Ce/KCC-1 with the product distribution of 3-buten-1-ol (S=63.30%), diiso-propyl ether (S=2.86%) and cyclopropane carboxylic acid (S=33.70%). While, bare KCC-1, Ni/KCC-1 and Ru/KCC-1 showed less activity than that of Ce/KCC-1. The high activity of Ce/KCC-1 may be due to the presence of Ce metal and fibrous silica which provided large surface area and average pore diameter

    The modification of PVDF membrane via crosslinking with chitosan and glutaraldehyde as the crosslinking agent

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    Poly(vinylidene fluoride) (PVDF) has outstanding properties such as high thermal stability, resistance to acid solvents and good mechanical strength. Due to its properties, PVDF is widely used as a membrane matrix. However, PVDF membrane is hydrophobic properties, so as for specific applications, the surface of membrane needs to be modified to become hydrophilic. This research aims to modify PVDF membrane surface with chitosan and glutaraldehyde as a crosslinker agent. The FTIR spectra showed that the modified membrane has a peak at 1655 cm-1, indicating the imine group (–N=C)- that was formed due to the crosslink between amine group from chitosan and aldehyde group from glutaraldehyde. Results showed that the contact angle of the modified membrane decreases to 77.22° indicated that the membrane hydrophilic properties ( 90°). The results of porosity, Ɛ (%) for unmodified PVDF membrane was 55.39%, while the modified PVDF membrane has a porosity of 81.99%. Similarly, by modifying the PVDF membrane, pure water flux increased from 0.9867 L/m2h to 1.1253 L/m2h. The enhancement of porosity and pure water flux for the modified PVDF membrane was due to the improved surface hydrophilicity of PVDF membrane
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