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Effects of Carrier Gas Flow-Rate and Oxygen Admixture Ratio on Particle Properties in Ar-O2 Plasma
M. Rafiqul Alam,
Feroza Begum,
Quazi Delwar Hossain,
M. Mofazzal Hossain
Issue:
Volume 3, Issue 2, March 2014
Pages:
14-19
Received:
25 December 2013
Published:
30 January 2014
DOI:
10.11648/j.ijmsa.20140302.11
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Abstract: Taking into account the strong plasma-particle interactions and particle loading effects, a plasma-particle interactive flow model for argon-oxygen plasma has been developed. We can predict the particle temperature, velocity, trajectory and plasma temperature isotherm by solving the model numerically during the in-flight thermal treatment of granulated micro-particles under local thermal equilibrium (LTE) conditions. It is found that the carrier gas flow-rate strongly affects the particle temperature, the admixture ratio of argon to oxygen and the plasma temperature isotherm.
Abstract: Taking into account the strong plasma-particle interactions and particle loading effects, a plasma-particle interactive flow model for argon-oxygen plasma has been developed. We can predict the particle temperature, velocity, trajectory and plasma temperature isotherm by solving the model numerically during the in-flight thermal treatment of granul...
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Steady-State Electron Transport within InAlN Bulk Ternary Nitride, using the Monte Carlo Method
Nadia Bachir,
Abdelkader Hamdoune,
Nasr Eddine Chabane Sari
Issue:
Volume 3, Issue 2, March 2014
Pages:
20-24
Received:
20 December 2013
Published:
20 February 2014
DOI:
10.11648/j.ijmsa.20140302.12
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Abstract: Al-bearing III-nitride semiconductor materials are essential for the development of high-frequency and high-power electronic devices and optoelectronic devices operating in the ultraviolet spectral region, because of their wide band gap and unique electronic characteristics. The InAlN alloy is attracting much attention, due to its lattice matching capability to GaN substrates or buffer layers and its variable band gap energy which can be changed from 1.9 to 6.2 eV [1]; it can potentially be used for the fabrication of advanced electronic and optoelectronic devices. AlGaN is being replaced by InAlN which is more advantageous and possesses quite remarkable properties. Unlike AlGaN which, for example, in its use in HEMT structures is in high stress, InAlN can be used in its unstressed state. Thus, the generation of defects introduced by the constraints is greatly reduced. This has the advantages of limiting the electrical performance degradation associated with the presence of such defects and improving the reliability of the material. In this work, the ternary compound InxAl1-xN in the stationary mode is studied, using the Monte Carlo simulation method. The steady-state electron drift velocity is investigated for different mole fractions of indium in the alloy, for various temperatures. The same calculation is performed at 300K for AlGaN and InGaN alloys, in order to compare them.
Abstract: Al-bearing III-nitride semiconductor materials are essential for the development of high-frequency and high-power electronic devices and optoelectronic devices operating in the ultraviolet spectral region, because of their wide band gap and unique electronic characteristics. The InAlN alloy is attracting much attention, due to its lattice matching ...
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Preparation of PVA/Corn Starch Blend Films and Studying the Influence of Gamma Irradiation on Mechanical Properties
Shafik S. Shafik,
Kawakib J. Majeed,
Mohanad I. Kamil
Issue:
Volume 3, Issue 2, March 2014
Pages:
25-28
Received:
27 December 2013
Published:
20 February 2014
DOI:
10.11648/j.ijmsa.20140302.13
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Abstract: In this paper, polyvinyl alcohol (PVA) /Corn Starch (CS) blend films were prepared using the solution casting method by changing the blending ratio of starch/PVA. The effects of gamma irradiation and soil burial on the biodegradability of the tested films were investigated by the mechanical properties (tensile strength and elongation to break %) and the determination of weight loss. Nevertheless, the results from the tensile strength and elongation at break tests showed that as the CS content increased, the strength decreased. After irradiation, the tensile strength and elongation to break of the films were improved the blends due to the crosslinking caused by the chemical reactions between starch macromolecules under the action of ionizing radiation. Finally, It was noticed that the weight loss increases with increasing of CS content.
Abstract: In this paper, polyvinyl alcohol (PVA) /Corn Starch (CS) blend films were prepared using the solution casting method by changing the blending ratio of starch/PVA. The effects of gamma irradiation and soil burial on the biodegradability of the tested films were investigated by the mechanical properties (tensile strength and elongation to break %) an...
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Sputter Rate Distribution and Compositional Variations in Films Sputtered from Elemental and Multi-Element Targets at Different Pressures
Erik Särhammar,
Erik Strandberg,
Nicolas Martin,
Tomas Nyberg
Issue:
Volume 3, Issue 2, March 2014
Pages:
29-36
Received:
12 February 2014
Published:
28 February 2014
DOI:
10.11648/j.ijmsa.20140302.14
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Abstract: We report on the quantitative dependence of the deposition rate during magnetron sputtering as a function of the atomic mass, processing pressure and substrate location relative to the target. Targets made of four different materials (C, Al, Ti and Ta), ranging from very light to rather heavy atomic masses, were investigated theoretically initially to determine the deposition rate distribution of the sputtered atoms. In the second part, targets made of different combinations of these materials (Ta/C, Ta/Al, Ta/Ti and Ti/Al) were sputtered to investigate the compositional variations of deposited films. The different targets were sputtered at both low (0.27 Pa) and high (2.7 Pa) pressures, and both the deposition rates and compositions were determined at four different locations in the chamber. Further, Monte Carlo simulations were performed for the sputtered atoms in a simplified model of the vacuum chamber. Simulation and experiments are in adequate agreement and show a significant influence of the processing pressure on the deposition rate in various locations of the chamber. This effect is different for different target compositions and may sometimes result in very large compositional variations in films sputtered from segmented multi-element or alloy targets. Transport phenomena of the sputtered particles are also discussed based on a ballistic or diffusion-like process, depending on the sputtering pressure, mass and size of the sputtered atom as well as location in the deposition chamber. Since the materials studied range from light to heavy and the processing pressures cover the values where sputtering normally takes place, the results in this work can be extrapolated to predict the deposition profiles and compositional gradients for arbitrary material combinations and processing pressures.
Abstract: We report on the quantitative dependence of the deposition rate during magnetron sputtering as a function of the atomic mass, processing pressure and substrate location relative to the target. Targets made of four different materials (C, Al, Ti and Ta), ranging from very light to rather heavy atomic masses, were investigated theoretically initially...
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Isolation and Physicochemical Characterization of Tigernut (Cyperus esculentus) Starch as a Potential Industrial Biomaterial
Adama Kenneth K.,
Afolayan Michael O.,
Oberafo Anthony A.,
Thomas Sunday
Issue:
Volume 3, Issue 2, March 2014
Pages:
37-41
Received:
11 February 2014
Published:
10 March 2014
DOI:
10.11648/j.ijmsa.20140302.15
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Abstract: Tigernut (Cyperus esculentus) seeds were examined for its starch composition and applicability as biomaterial in hybrid composite materials development. The physicochemical properties of the starch extracted were then compared with standard industrial maize starch. The starch was isolated using 1% w/v sodium metabisulphite solution and the obtained starch was found to be a brilliant white, crystalline, non- hygroscopic powder with yield of about 21%. The starch percentage solubility at 90°C was 2.36 with a swelling power of 13.7 and gelatinization temperature of 66°C. It had a browning temperature of 257.0 – 268.2°C, charring temperature of 281.4 – 291.6°C, water absorption capacity of 71%, pH of 5.6, foam and emulsion capacities of 2.8% and 8.17% respectively. The proximate analysis (%) was found to be: fat – 2.3, ash – 0.24, protein – 0.18, moisture – 8.67 and carbohydrates – 88.61. XRD scan (a gonio (2Θ) scan) of the starch sample at 10°C – 100°C 2Θ angle established the organic nature of the starch. Analysis of the starch sample by XRD gave amylose to be 28% and amylopectin to be 72%. The α-amylose of the starch had an orthorhombic crystal system with a high purity rate. The spectral revealed peak positions at 2Θ positions of 11.3189°, 14.9662°, 17.0105°, 17.8645°, 22.8843°, 26.4595° and 30.2574° corresponding to a Full Width at Half Maximum (FWHM) (2Θ) of 0.6593°, 0.5274°, 0.5274°, 0.3296°, 0.7252°, 0.6593° and 0.7911° respectively. The XRD analysis confirmed the starch to be of high purity and quality with a score of 83% on the ICDD database. Applicability in composite materials studies showed a high level of compatibility as binder/filler materials within the matrix and fiber materials employed. Generally, the values obtained from the characterization of tigernut starch showed that it has high potential for industrial applications especially but not limited to use as biomaterials in composites, food, textile and pharmaceutical industries.
Abstract: Tigernut (Cyperus esculentus) seeds were examined for its starch composition and applicability as biomaterial in hybrid composite materials development. The physicochemical properties of the starch extracted were then compared with standard industrial maize starch. The starch was isolated using 1% w/v sodium metabisulphite solution and the obtained...
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Physico - Chemical and Mineralogical Characterization of a Moroccan Bentonite (Azzouzet) and Determination of its Nature and its Chemical Structure
Azzeddine Er-ramly,
Abdelali Ider
Issue:
Volume 3, Issue 2, March 2014
Pages:
42-48
Received:
17 January 2014
Published:
20 March 2014
DOI:
10.11648/j.ijmsa.20140302.16
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Abstract: This study concerns the results of Physicochemical and mineralogical characterization of a Moroccan bentonite (bentonite Azzouzet) and determination of its nature and its chemical structure. Several techniques were used; in particular X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential thermal and gravimetric analyses (DTA-TGA) and finally infrared Fourier transform (FTIR) and X-ray fluorescence (XRF). The bentonite fine fraction (< 2 µm in size), was characterized by BET method for specific surface area, and a cation- exchange capacity.The X-ray diffraction analysis supplemented by gravimetric analysis showed that Azzouzet bentonite is primarily (smectite) (49 wt %) with the presence of feldspar (34 wt %), Quartz (5 wt %), magnetite (7 wt %) and amorphous iron oxide (3 wt %). It has a cation- exchange capacity of 73,3 meq/100g and a specific surface area by using surface area analyser and N2 gaz was used as adsorbate under atmosphere of 31 m²/g.the structural formula calculated for bentonite has shown that the montmorillonite has a high charge density. SEM-EDX, X-ray, chemical analysis and Infrared spectroscopy demonstrated that this montmorillonite contains iron Fe3 + in the octahedral sheet. The origin of the charge sheets is tetraedral (Si4) (Al2.12 Mg0.15), with the montmorillonite character of the bentonite (15%) is present (less than 50% octahedral charge) with a phase rich in iron.
Abstract: This study concerns the results of Physicochemical and mineralogical characterization of a Moroccan bentonite (bentonite Azzouzet) and determination of its nature and its chemical structure. Several techniques were used; in particular X-ray diffraction (XRD), scanning electron microscopy coupled with EDX microanalysis (SEM-EDX), differential therma...
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Phase Transformations and Thermodynamics of Binary Systems Fe2О3 - V2O5 and Fe2О3 - MnO at High Temperatures
Rossitza Paunova,
Radost Alexandrova,
Maksim Marinov
Issue:
Volume 3, Issue 2, March 2014
Pages:
49-57
Received:
13 February 2014
Published:
20 March 2014
DOI:
10.11648/j.ijmsa.20140302.17
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Abstract: The phase transformations and thermodynamics of the binary systems of Fe2O3-MnO2 as well as Fe2O3-V2O5 have been investigated. Pure oxides, waste vanadium catalyst (containing 4.12% V2O5) and manganese carbonate ore concentrate containing 44.56% MnO have been used for preparation of the mixtures. The purpose of these investigations was to study phase transformations, some thermodynamic characteristics of waste products, containing Fe-Mn-V-Si-O and further producing real Fe-Mn-V alloys from this products. Two methods have been used to study these systems. Four mixtures were prepared for the investigation: mix 1 - pure oxides - V2O5, Fe2O3, SiO2; mix 2 - waste vanadium catalyst, Fe2O3; mix 3 - pure oxides - MnO2, Fe2O3, SiO2; mix 4 - manganese concentrate, Fe2O3. Phase transformations have been defined by DTA and X-ray analysis up to 1473K. The formation of new phases FeV2O4 and MnFe2O4 (Jacobsite) in the samples can be formed up to this temperature only if in the initial materials there is waste vanadium catalyst and manganese concentrate. In the temperature range 853K – 953K solid solution between Fe2О3 and Мn2О3 is formed (for pure oxides – mix3) and then it decomposes peritectically at 1203K. The oxygen potential, respectively Gibbs energy in the temperature range 1073К – 1173К has been calculated using EMF method with reference electrode Ni/NiO. Gibbs energy values for mix 1 and mix 2 are very close compared to the theoretical indications calculated for Fe2O3. Gibbs energy for mix 3 is in compliance with the data of manganese oxide.
Abstract: The phase transformations and thermodynamics of the binary systems of Fe2O3-MnO2 as well as Fe2O3-V2O5 have been investigated. Pure oxides, waste vanadium catalyst (containing 4.12% V2O5) and manganese carbonate ore concentrate containing 44.56% MnO have been used for preparation of the mixtures. The purpose of these investigations was to study ...
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From Transient to Permanent Phenomena during GMAW of a Thin-Walled Marine Aluminium Alloy
Stavros K. Chionopoulos,
Dimitris I. Pantelis
Issue:
Volume 3, Issue 2, March 2014
Pages:
58-69
Received:
4 March 2014
Published:
30 March 2014
DOI:
10.11648/j.ijmsa.20140302.18
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Abstract: In this study, an experimental investigation of thin-walled GMA welded plates of AA5083-H116 has been carried out. The aim of this investigation is to study the effects of the GMAW process on the transient thermal and mechanical phenomena of the welded elements. Thick (4mm) plates of dimensions 700x300 mm2 were welded using a robotic arm. Measurements of the thermal strains and distortions were performed from the start of the procedure to the end of the cooling cycle together with measurements of the welding thermal cycles in specific positions. After the welding the weld-induced residual stresses field was revealed using the blind-hole-drilling technique while a metallographic examination in different cross sections in the weld area was carried out. The scope of this article is to provide results of combined transient thermal and mechanical phenomena with regards to microstructure of aluminum welded plates.
Abstract: In this study, an experimental investigation of thin-walled GMA welded plates of AA5083-H116 has been carried out. The aim of this investigation is to study the effects of the GMAW process on the transient thermal and mechanical phenomena of the welded elements. Thick (4mm) plates of dimensions 700x300 mm2 were welded using a robotic arm. Measureme...
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The Success of the Backward Integration Policy in the Nigerian Cement Sector
Issue:
Volume 3, Issue 2, March 2014
Pages:
70-78
Received:
1 March 2014
Accepted:
8 April 2014
Published:
10 April 2014
DOI:
10.11648/j.ijmsa.20140302.19
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Abstract: The consumption of cement in Nigeria has increased to 18.5 million metric tonnes per annum (MMTPA) due to rapid urbanization and industrialization. Despite the huge demand for cement in Nigeria, domestic production was unable to meet the demand; hence the country relied on importation of cement to meet domestic construction needs. In 2002, the government adopted and implemented the backward integration policy (BIP), which requires cement import licenses be allocated only to importers who show proof of building factories for local cement manufacturing in Nigeria. Incentives under the policy include waiver of VAT and custom duty for importation of cement production equipment. The aim of this paper is to access the effect of the policy on the cement sector in Nigeria ten years after implementation. Following the implementation of the BIP, all the moribund existing government owned cement plants were privatized, while the private sector installed additional production and bagging capacities. Results showed that before BIP, Nigeria had an installed capacity of 4.03 MMTPA, but producing only 2 MMTPA. But 10 years after the implementation of the BIP, the country now produces 28 MMTPA with a total installed production capacity of 45 MMTPA and bagging capacity of 27.7 MMTPA, while additional 14 cement production plants of various capacities are under construction. Now that Nigeria has become self-sufficient in cement production, with domestic production exceeding the country’s need, additional policies that would address the new challenges of the cement sector particularly cement glut is required.
Abstract: The consumption of cement in Nigeria has increased to 18.5 million metric tonnes per annum (MMTPA) due to rapid urbanization and industrialization. Despite the huge demand for cement in Nigeria, domestic production was unable to meet the demand; hence the country relied on importation of cement to meet domestic construction needs. In 2002, the gove...
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