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Carbon-Ionomer Nanocomposite Wetting Properties: The Role of Ionomer Composition and Surface Roughness
Sonal Mazumder,
Yanfang Fan,
Chris J. Cornelius
Issue:
Volume 4, Issue 2, March 2015
Pages:
69-76
Received:
10 January 2015
Accepted:
8 February 2015
Published:
16 February 2015
Abstract: Surface hydrophobicity changes of a series of nanocomposite films were evaluated as a function of roughness and ionomer concentration. Nanocomposite surfaces were created by coating a smooth silicon wafer and micro textured surfaces based on two types of 3M micro-replicated Brightness Enhancement Films (BEF). Multiple nanocomposite surfaces were evaluated as a function of Pt/C catalyst, a single walled carbon nanotube (SWCNT), and ionomer concentration varying between 7.5 to 27.3 wt% Nafion. An increase in hydrophobicity was observed for all nanocomposite surfaces as compared to bare substrates coated with ionomer. Bare substrates had observed water contact angles of 32.5o on silicon, 50.8o on BEF type Y, and 91.2o on BEF type P. Nanocomposites coated on BEF type P surfaces had the greatest increase in apparent contact angle starting from 101.5o on a surface coated with ionomer to 140.6o for an ionomer composite containing 100 wt% Pt/C followed by BEF type Y (78.4o - 135.4o) and Si (76.9o - 135.8o). Nanocomposite roughness increased with increasing ionomer concentration and was inversely related to the apparent contact angle of water. Nanocomposite wetting properties were strongly dependent upon ionomer concentration and micro scale roughness contributed to wetting behavior transitioning between Wenzel and Cassie modes.
Abstract: Surface hydrophobicity changes of a series of nanocomposite films were evaluated as a function of roughness and ionomer concentration. Nanocomposite surfaces were created by coating a smooth silicon wafer and micro textured surfaces based on two types of 3M micro-replicated Brightness Enhancement Films (BEF). Multiple nanocomposite surfaces were ev...
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The Life Predicting Calculations in Whole Process Realized by Calculable Materials Constants from short Crack to Long Crack Growth Process
Issue:
Volume 4, Issue 2, March 2015
Pages:
83-95
Received:
26 January 2015
Accepted:
14 February 2015
Published:
25 February 2015
Abstract: To use the theoretical approach, to adopt the simple stress-, or strain-parameter method, by means of the conventional material constants, to establish some new calculation models in whole crack growth process for elastic-plastic steels, which are the equations of the driving forces and the life predictions from micro to macro crack; To provide yet several crack growth-rate-linking-equations and life calculating expressions in whole process, for which are under different loading conditions in high cycle and low cycle fatigue. For key parameters A1, A2 and B2 have proposed some new concept, and to define their physical and geometrical meanings. For the transition crack size from crack forming stage to crack growth stage, provide concrete calculation processes and methods. Thereby to realized the lifetime predicting calculations in whole process based on traditional calculable material parameters. The purpose is to try to make the modern fatigue-fracture discipline depended on tests become gradually calculable subjects as the traditional material mechanics. So that will be having practical significances for saving testing manpower and funds, for promoting applying and development relevant disciplines.
Abstract: To use the theoretical approach, to adopt the simple stress-, or strain-parameter method, by means of the conventional material constants, to establish some new calculation models in whole crack growth process for elastic-plastic steels, which are the equations of the driving forces and the life predictions from micro to macro crack; To provide yet...
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Ammonium Alunite and Basic Aluminum Sulfate: Effect of Precipitant Agent
Adrián Zamorategui Molina,
Julio del Ángel Soto,
Merced Martínez Rosales,
Rafael Romero Toledo
Issue:
Volume 4, Issue 2, March 2015
Pages:
96-100
Received:
7 February 2015
Accepted:
24 February 2015
Published:
9 March 2015
Abstract: Ammonium bisulfite as a precipitating agent was used to synthesize basic aluminum sulfate (BAS) by homogeneous precipitation. Aluminum sulfate in aqueous solution was used as the raw material. High concentration of the precipitant agent promotes the formation of ammonium alunite, which was confirmed by XRD, TG/DTG and FTIR analysis. The ammonium alunite has less sulfate ions and more water than the BAS, and so, the ammonium alunite heat treated up to 1200°C produces 28 weight percent of Al2O3. In comparison the BAS generates 48 weight percent of Al2O3 as a final product. Homogeneous precipitation promotes the formation of amorphous spherical particles of basic aluminum sulfate and lamellar crystalline particles of ammonium alunite which were observed by field emission microscopy (FEM).
Abstract: Ammonium bisulfite as a precipitating agent was used to synthesize basic aluminum sulfate (BAS) by homogeneous precipitation. Aluminum sulfate in aqueous solution was used as the raw material. High concentration of the precipitant agent promotes the formation of ammonium alunite, which was confirmed by XRD, TG/DTG and FTIR analysis. The ammonium al...
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Effect of Dip Time on the Structural and Optical Properties of Chemically Deposited CdSe Thin Films
R. A. Chikwenze,
P. A. Nwofe,
P. E. Agbo,
S. N. Nwankwo,
J. E. Ekpe,
F. U. Nweke
Issue:
Volume 4, Issue 2, March 2015
Pages:
101-106
Received:
3 February 2015
Accepted:
24 February 2015
Published:
17 March 2015
Abstract: In this study, the effect of dip time on the structural and optical properties of cadmium selenide (CdSe) thin films grown by the chemical bath deposition method is reported. The films were grown with varying dip time in the range of 4 h to 12h, and the other deposition variables (substrate temperature, source to substrate distance, pH, and concentration) were kept constant. X-ray diffractometry (XRD) and optical spectroscopy were used to characterise the layers. The results show that the crystallite size and the film thickness increased with an increase in the dip time up to a “critical value” and then decreased otherwise for the latter. The increase in the crystallite size was more pronounced at the lower dip time (< 8 h), and then exhibited a marginal increase for dip time > 8 h. The energy band gap was found to be direct with an optimum value of 1.2 eV obtained for films grown at a dip time of 8 h.
Abstract: In this study, the effect of dip time on the structural and optical properties of cadmium selenide (CdSe) thin films grown by the chemical bath deposition method is reported. The films were grown with varying dip time in the range of 4 h to 12h, and the other deposition variables (substrate temperature, source to substrate distance, pH, and concent...
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Design of Long Persistent White Phosphorescence in a Composite Phosphor Via Energy Transfer Mechanism
Hom Nath Luitel,
Rumi Chand,
Toshio Torikai,
Mitsunori Yada,
Takanori Watari
Issue:
Volume 4, Issue 2, March 2015
Pages:
107-114
Received:
19 February 2015
Accepted:
4 March 2015
Published:
21 March 2015
Abstract: A high quality composite phosphor powder of warm to cool white emission and long afterglow phosphorescence was reported by the process of energy transfer in a composite phosphor. The composite phosphor particles include at least two types of phosphor particles viz. a blue white persistent component and yellow fluorescent component. The blue white extremely long persistent component transfers its afterglow to the yellow fluorescent component in the composite phosphor followed by the color mixing process to generate the white afterglow. The composite phosphor is designed in such a way that the excitation spectrum of the fluorescent component was overlapped as much with the afterglow emission of the persistent component. The composite phosphor emission spectrum can be well tuned from warm to cool white depending on the proportions of the composite phosphors and energy transfer extent. Phosphor includes powders, ceramics and resin composites.
Abstract: A high quality composite phosphor powder of warm to cool white emission and long afterglow phosphorescence was reported by the process of energy transfer in a composite phosphor. The composite phosphor particles include at least two types of phosphor particles viz. a blue white persistent component and yellow fluorescent component. The blue white e...
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Design of Bentonite Acid Modified Electrodes in Cyanide Biosensors
Catherina Bijang,
Abd. Wahid Wahab,
Maming,
Ahyar Ahmad,
Paulina Taba
Issue:
Volume 4, Issue 2, March 2015
Pages:
115-119
Received:
11 February 2015
Accepted:
13 March 2015
Published:
24 March 2015
Abstract: A research has been done on the influence of sulfuric acid activation on the performance ofbentonite as a cyanide biosensor. The concentration of sulfuric acid used was 0.5; 1; 1.5and 2 M. Activation with 2 M sulfuric acid resulted in an increase in surface area and basal spacing. The membrane biosensor made from 2M acid activated bentonite had better performance than the untreated bentonite membrane biosensor. A study on theeffect of membrane thickness on theperformance of the cyanide biosensor has also been conducted. The resultshowed that the performance of membrane which 5 mg/mL of thickness did not differ significantly.
Abstract: A research has been done on the influence of sulfuric acid activation on the performance ofbentonite as a cyanide biosensor. The concentration of sulfuric acid used was 0.5; 1; 1.5and 2 M. Activation with 2 M sulfuric acid resulted in an increase in surface area and basal spacing. The membrane biosensor made from 2M acid activated bentonite had bet...
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Studies on the Mixed Ligand Complexes of Co(II), Ni(II) and Cu(II) with Phthalimide and Heterocyclic Amines
Md. Kudrat-E-Zahan,
Md. Masuqul Haque,
Lokonuzzaman Ahmmed,
M. Sher Ali,
Md. Saidul Islam
Issue:
Volume 4, Issue 2, March 2015
Pages:
120-123
Received:
18 March 2015
Accepted:
24 March 2015
Published:
9 April 2015
Abstract: This paper describes the synthesis and characterization of mixed ligand complexes of Co(II), Ni(II) and Cu(II) with, Phthalimide and heterocyclic amines. The Elemental analysis, IR, UV-vis and 1H-NMR spectral analysis, colours, molar conductances and magnetic properties suggested that the complexes have formulation as [M(Ph-imide)2(L)2~4], Where, M = Co(II), Ni(II) and Cu(II); Ph-imide = Phthalimide; L=Quinoline, Iso-quinoline, 2-Picoline and Pyridine. The prepared complexes of Co (II) and Ni (II) were octahedral and Cu (II) was square planar.
Abstract: This paper describes the synthesis and characterization of mixed ligand complexes of Co(II), Ni(II) and Cu(II) with, Phthalimide and heterocyclic amines. The Elemental analysis, IR, UV-vis and 1H-NMR spectral analysis, colours, molar conductances and magnetic properties suggested that the complexes have formulation as [M(Ph-imide)2(L)2~4], Where, M...
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The Hydrated and Hydrolyzed States of Exchangeable Cations in the Montmorillonite and Their Quantitative Assessment
Issue:
Volume 4, Issue 2, March 2015
Pages:
124-129
Received:
18 March 2015
Accepted:
31 March 2015
Published:
9 April 2015
Abstract: In the paper is submitted opinion according to which, a part of the hydrated exchangeable cations in the montmorillonite is hydrolyzed. A new experimental method has been proposed, which allows to estimate the hydrated/hydrolyzed state of these cations. The method consists in the use of thermal analysis data of mineral, and is particularly effective in the study of homoionic forms of montmorillonite. The mathematical formulas have been proposed for processing the obtained experimental data.
Abstract: In the paper is submitted opinion according to which, a part of the hydrated exchangeable cations in the montmorillonite is hydrolyzed. A new experimental method has been proposed, which allows to estimate the hydrated/hydrolyzed state of these cations. The method consists in the use of thermal analysis data of mineral, and is particularly effectiv...
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Influence of Nanosize Silica Particles on the Rheological Behaviour of Lyotropic Cubic Phase of Glucopone (APG) Surfactant
Mohamed A. Siddig,
Abubaker A. Siddig,
Lal S. Jan,
Abdelrahman A. Elbadawi,
Shahidan Radiman
Issue:
Volume 4, Issue 2, March 2015
Pages:
130-137
Received:
21 March 2015
Accepted:
6 April 2015
Published:
17 April 2015
Abstract: The effect of nanosize silica particle on the stability, structures and rheological behaviours of cubic liquid crystalline phases of Glucopone/water/heptane system were investigated. Small-angle X-ray scattering (SAXS) and polarizing microscope were used for phase identification and structure characterization. SAXS scattering profile was characteristic to cubic phase before and after the addition of silica particles. The cubic samples showed several diffraction peaks and can be assigned to the Ia3d space group. The area per surfactant molecule was found to increase as the silica concentrations was increased. Moreover, the rheological study on the cubic phase with different silica concentration was performed. The frequency-dependent storage and loss modulus were found to be characteristic of the cubic phase in the linear viscoelastic region. The cubic samples behave as solid-like material with storage modulus G’~ 0.7106 Pa typical of cubic lyotropic materials. The elasticity of cubic samples was found to increase with silica concentration. The increase in the elasticity was ascribed to the network and the formation of smaller structure as indicated by SAXS measurements. As temperature was further increased a decreased in the elasticity was observed confirming the structural change as indicated by the change in slopes of G’ and G”. The cubic samples exhibited shear thinning behaviours, with the dynamic viscosity being affected by the silica particles concentrations and the effect of silica particles on the rheological behaviours was quite noticeable as the concentration increased. The results showed strong correlation between rheology and microstructural changes in the dispersion of nanoparticle silica in the cubic phase system.
Abstract: The effect of nanosize silica particle on the stability, structures and rheological behaviours of cubic liquid crystalline phases of Glucopone/water/heptane system were investigated. Small-angle X-ray scattering (SAXS) and polarizing microscope were used for phase identification and structure characterization. SAXS scattering profile was characteri...
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Effect of pH on the Optical Properties of Cadmium Sulphide (CdS) Thin Film Deposited Using Chemical Bath Method
Rita Anionye Daniel-Umeri
Issue:
Volume 4, Issue 2, March 2015
Pages:
138-142
Received:
21 March 2015
Accepted:
9 April 2015
Published:
18 April 2015
Abstract: Cadmium Sulphide (CdS) thin films have been deposited on glass substrates at room temperature by using Chemical bath deposition method. The bath composition included cadmium chloride hemidihydrate [CdCl2.2½H2O], thiourea [SC (NH2)2] and Ammonia (NH3) solution. The effects of the pH value on the optical properties of the films have been investigated. The as-deposited films have been characterized by the UV-VIS Spectrophotometer. The spectrum showed that absorbance was high in the UV and low in the VIS-NIR region. The optimum percentage transmittance and reflectance are 84.7% and 20.3% respectively within the same region. The band gap values of the films range from 2.4 to 2.6 eV. The optical properties of the films within the UV- VIS-NIR regions indicate that the films can find application in solar thermal technology, particularly in antireflection coating.
Abstract: Cadmium Sulphide (CdS) thin films have been deposited on glass substrates at room temperature by using Chemical bath deposition method. The bath composition included cadmium chloride hemidihydrate [CdCl2.2½H2O], thiourea [SC (NH2)2] and Ammonia (NH3) solution. The effects of the pH value on the optical properties of the films have been investigated...
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