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Characterization of Cost Effective PbTiO3 Nanofibres by Electrospinning Technique
Zin Min Tun,
Zin Min Myat,
Than Than Win,
Yin Maung Maung
Issue:
Volume 6, Issue 1, January 2017
Pages:
1-5
Received:
21 August 2016
Accepted:
19 September 2016
Published:
12 December 2016
Abstract: This research aims to synthesize and characterize the PbTiO3 nanofibres by electrospinning technique. PbTiO3 nanofibre was fabricated onto Al-substrate by home-made electrospinning setup. The spinning or running time was set to 20 min. After spinning, subsequent annealing in oxygen and atmospheric ambient was performed at 600°C for 1 h and followed to form the PbTiO3 nanofibres. Surface morphology and fibres quality of PbTiO3 nanofibres were examined by Field Emission Scanning Electron Microscopy (FESEM). From FESEM image, the fibre diameter was measured to be (150-180 nm) with different collector distances. The experimental data resulted from this research showed that the home-made device compiled and growth chemistry was technically simple and easily adaptable.
Abstract: This research aims to synthesize and characterize the PbTiO3 nanofibres by electrospinning technique. PbTiO3 nanofibre was fabricated onto Al-substrate by home-made electrospinning setup. The spinning or running time was set to 20 min. After spinning, subsequent annealing in oxygen and atmospheric ambient was performed at 600°C for 1 h and followed...
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Ideal Distribution of Polycrystalline Phosphor Particles for Application to Phosphor Screens in CRT
Issue:
Volume 6, Issue 1, January 2017
Pages:
6-17
Received:
7 October 2016
Accepted:
5 December 2016
Published:
17 December 2016
Abstract: Our daily activity is supported with information stored in tiny tips in computers that are invisible by the naked eyes. The stored information of PC and TV broadcasting images displays on lighted phosphor screens. Comfortable images on the phosphor screens for the naked eyes should be equivalent with the daytime scenery under slightly overcastting sky {10 25 visible photons (m2, s) -1} that the eyes have adjusted for 5 million years. We have developed the CRTs that display the required images on the phosphor screen as the consequence of the statistical study on the sizes of the phosphor particles. Phosphor screens in CRT are constructed with the polycrystalline phosphor particles in the size at around 5 x 10-6 m. The phosphor powder in 1 gram contains 3 x 1020 particles that should distribute with a log-normal distribution. Then, we have significantly increased the luminance to 100 ft-L (equivalent to 330 lumens m-2) from 7 ft-L by the change in the operation conditions of the phosphor particles after the measurements of the VD and CD curves of CL. The sharp and stable images on the lighted phosphor screen in CRTs are only obtained with the phosphor particles that have the clean surface chemically and physically.
Abstract: Our daily activity is supported with information stored in tiny tips in computers that are invisible by the naked eyes. The stored information of PC and TV broadcasting images displays on lighted phosphor screens. Comfortable images on the phosphor screens for the naked eyes should be equivalent with the daytime scenery under slightly overcastting ...
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Low Cycle Fatigue Behaviour of Nitrided Layer of 42CrMo4 Steel
Mohamed Ali Terres,
Rafik Bechouel,
Salem Ben Mohamed
Issue:
Volume 6, Issue 1, January 2017
Pages:
18-27
Received:
12 August 2016
Accepted:
25 August 2016
Published:
4 January 2017
Abstract: Steel 42CrMo4, used in the manufacturing of transmission systems (gears), poses problems in service under specific cyclic stress conditions of the operating mode of its bodies. The treatment of ion nitriding during 20 hours with 520°C applied to 42CrMo4 steel in an untreated state (quenched and tempered) led to the formation of a compound layer (mixture of nitrides ' and carbonitrides with irregular thickness evaluated at 5µm and a diffusion layer of depth equal to 295µm). In the diffusion layer, the presence of inserted nitrogen leads to the increase in hardness (3 times that of basic material) and to the creation of a compressive residual stress field (-400MPa). This superficial hardening does not modify the tensile mechanical characteristics of 42CrMo4 steel but renders it more sensitive to overload in fatigue. As a result, a 0.7% total deformation imposed corresponding to a loading level of 850MPa, constitutes the limit of gain in fatigue obtained by the ion nitriding considered.
Abstract: Steel 42CrMo4, used in the manufacturing of transmission systems (gears), poses problems in service under specific cyclic stress conditions of the operating mode of its bodies. The treatment of ion nitriding during 20 hours with 520°C applied to 42CrMo4 steel in an untreated state (quenched and tempered) led to the formation of a compound layer (mi...
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Effect of Association Natural-Recycling Aggregates (Crushed Glass and Waste Tire) on Mechanical Properties of the Concrete
Mamery Adama Serifou,
Olivier Moro Boffoué,
Paul Sery Obre Jolissaint,
Clement Koffi Kouadio,
Edjikémé Emeruwa
Issue:
Volume 6, Issue 1, January 2017
Pages:
28-31
Received:
31 October 2016
Accepted:
11 November 2016
Published:
12 January 2017
Abstract: This study relates to the use of the industrial waste as substitute to the natural aggregates. It relates to two types of waste: Crushed glass and waste tires. These wastes were incorporated into concrete for a partial substitution of the aggregates in the proportions of 5%, 10%, 15%, 20%, 25% and 30% for the same matrix (mortar). The compressive strength and the mode of rupture are compared. The results show a decrease of compressive strength when the proportion of waste increases. Moreover, the compressive strength of concrete of used tire is lower than that of the concrete of crushed glass. Variation of the mode of rupture between these two types of concrete was also observed.
Abstract: This study relates to the use of the industrial waste as substitute to the natural aggregates. It relates to two types of waste: Crushed glass and waste tires. These wastes were incorporated into concrete for a partial substitution of the aggregates in the proportions of 5%, 10%, 15%, 20%, 25% and 30% for the same matrix (mortar). The compressive s...
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Investigation on Electrical Conductivity Enhancement of Water Based Maghemite (γ-Fe2O3) Nanofluids
Irwan Nurdin,
Satriananda
Issue:
Volume 6, Issue 1, January 2017
Pages:
32-36
Received:
22 October 2016
Accepted:
13 December 2016
Published:
14 January 2017
Abstract: The study of this research is to measure the electrical conductivity of maghemite nanofluids. Maghemite nanofluids were prepared by dissolving maghemite nanoparticles in water as base fluids. The investigation on electrical conductivity of maghemite nanofluids have been performed at different particle volume fractions and temperatures. The electrical conductivity was measured by a 4-cell conductivity electrode meter. The electrical conductivity of maghemite nanofluids was linearly increased as the particle volume fraction and temperature rises. The highest enhancement of electrical conductivity of maghemite nanofluids due to the particle volume fraction and temperature are 160.49% and 22.55%, respectively. This condition obtained at a particle volume fraction of 2.5% and temperature 60°C. Significant effect of particle volume fraction and temperature were considered.
Abstract: The study of this research is to measure the electrical conductivity of maghemite nanofluids. Maghemite nanofluids were prepared by dissolving maghemite nanoparticles in water as base fluids. The investigation on electrical conductivity of maghemite nanofluids have been performed at different particle volume fractions and temperatures. The electric...
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Studies on the Synthesis of Silica Powder from Rice Husk Ash as Reinforcement Filler in Rubber Tire Tread Part: Replacement of Commercial Precipitated Silica
Addis Lemessa Jembere,
Solomon Workneh Fanta
Issue:
Volume 6, Issue 1, January 2017
Pages:
37-44
Received:
30 November 2016
Accepted:
26 December 2016
Published:
18 January 2017
Abstract: Rice husks, which can be considered as an agricultural waste, are produced every year in South Gonder, Ethiopia. Precipitated silica is commonly used as reinforcing filler in rubber industry, in the present study an effort has been attempted to replace commercial silica commonly used in natural rubber industries with rice husk ash silica (RHAS). Silica was extracted from RHA by using alkaline extraction followed by acid precipitation. The synthesized RHAS was characterized by AAS, BET, DSC, FTIR, and XRD. RHAS was then used as reinforcing filler in natural rubber. The curing characteristics of natural rubber products filled with RHAS resulted a smaller scorch time which caused a premature vulcanization than the commercial silica filled rubber composite. Overall mechanical properties like hardness, young’s modulus, abrasion resistance of rubber products reinforced with RHAS was better than commercial silica filled rubber composite.
Abstract: Rice husks, which can be considered as an agricultural waste, are produced every year in South Gonder, Ethiopia. Precipitated silica is commonly used as reinforcing filler in rubber industry, in the present study an effort has been attempted to replace commercial silica commonly used in natural rubber industries with rice husk ash silica (RHAS). Si...
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Theoretical Study of the Spectral Response in Near Infrared of III-V Photodetectors Based on Al, Ga, In, and Sb: The Window Layer Effect
Mamadou Dia,
Babacar Mbow,
EL Hadji Mamadou Keita,
Abdoul Aziz Correa,
Mamadou Lamine Sow
Issue:
Volume 6, Issue 1, January 2017
Pages:
45-53
Received:
8 December 2016
Accepted:
20 December 2016
Published:
18 January 2017
Abstract: The spectral responses are particularly important for the design of photodetectors operating in the wavelength range between 0,78μm to 2,6μm. To elaborate each device; we purpose a theoretical model to calculate the internal quantum efficiency. The theoretical curves of the internal quantum efficiency are obtained, by simulation to define the geometrical and photoelectric parameters, of the photodetectors devices. The modelling of the various devices allows us to analyze the situation at surface and in volume of each model. The results and the theoretical models, of the heterostructures based on Ga1-xInxSb, Ga1-yAlySb grown on GaSb substrate, with window layer are shown after simulation of the internal quantum efficiency and sensitivity of each model. Analysis of these results allowed us to appreciate which of these models is more efficient and to identify the photoelectric parameters to improve for better internal quantum efficiency. We found that the presence of the window layer significantly reduces the losses by recombination thereby improving the photodetector performance.
Abstract: The spectral responses are particularly important for the design of photodetectors operating in the wavelength range between 0,78μm to 2,6μm. To elaborate each device; we purpose a theoretical model to calculate the internal quantum efficiency. The theoretical curves of the internal quantum efficiency are obtained, by simulation to define the geome...
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Effect of Vanadium Doping on Microstructure and Dielectric Behavior of CaCu3Ti4O12 Ceramics
Séka Simplice Kouassi,
Jean-Pierre Sagou Sagou,
Cécile Autret-Lambert,
Sonia Didry,
Anoop Nautiyal,
Marc Lethiecq
Issue:
Volume 6, Issue 1, January 2017
Pages:
54-64
Received:
16 December 2016
Accepted:
27 December 2016
Published:
21 January 2017
Abstract: In this work, effect of vanadium doping of CaCu3Ti4O12 (CCTO) on microstructure and complex dielectric constant over wide frequency (100 Hz-1 MHz) and temperature (0°C – 160°C) ranges has been studied. The vanadium doping of CCTO system results in an increase of grain size, the grains being surrounded by melted-like grain boundaries. Real parts of dielectric constant of all samples are similar at low frequency (<1 kHz). In doped samples, above 1 kHz, a relaxation appears which is evidenced by a drop of real part of permittivity and a peak of its imaginary part. This relaxation phenomenon is very significant at relatively low doping rates and then decreases again as vanadium content increases. AC conductivity behavior of vanadium-doped CCTO can be divided in three regions depending on conduction processes. The calculated activation energies were close to 0.46 eV.
Abstract: In this work, effect of vanadium doping of CaCu3Ti4O12 (CCTO) on microstructure and complex dielectric constant over wide frequency (100 Hz-1 MHz) and temperature (0°C – 160°C) ranges has been studied. The vanadium doping of CCTO system results in an increase of grain size, the grains being surrounded by melted-like grain boundaries. Real parts of ...
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