-
Effect of Phase Transition Temperature of Bati0.9Sn0.1o3 on the Operating Mode of Ferroelectricrandom Access Memories (FeRAM)
M. Ourrad,
A. Merad,
T. Benouaz
Issue:
Volume 2, Issue 3, May 2013
Pages:
78-82
Received:
28 March 2013
Published:
2 May 2013
Abstract: The outstanding dielectric, ferroelectric and piezoelectric properties of BaTiO3 make it the desirable primary material for a variety of applications such as nonvolatile memories (RAM). At the Curie’s temperature the dielectric prop-erties of BaTiO3 undergo phase transition. The Landau-Devonshire’s phenomenological theory has been investigated in this paper to present the relation between the temperature and the electric induction. The effect of the variation of electric induction versus temperature of BaTi0.9Sn0.1O3 investigated in the fabrication of nonvolatile ferroelectric random access memories (FeRAM) which may lead us to discover a strange phenomenon called «determinist chaos », now the FeRAM lose its reliability.
Abstract: The outstanding dielectric, ferroelectric and piezoelectric properties of BaTiO3 make it the desirable primary material for a variety of applications such as nonvolatile memories (RAM). At the Curie’s temperature the dielectric prop-erties of BaTiO3 undergo phase transition. The Landau-Devonshire’s phenomenological theory has been investigated in t...
Show More
-
A Practical Electrode for Microwave Plasma Processes
Hiromichi Toyota,
Shinfuku Nomura,
Shinobu Mukasa
Issue:
Volume 2, Issue 3, May 2013
Pages:
83-88
Received:
10 April 2013
Published:
2 May 2013
Abstract: In-liquid plasma chemical vapor deposition (CVD) method is useful for high speed production of high quality diamond films. The method is simple and secure comparing usual CVD methods. In this paper, new electrodes for in-liquid plasma CVD by receiving microwaves are developed and introduced. This paper examines the fabrication of electrodes that enable the generation of plasma by effectively receiving microwaves. The fabricated electrodes are used to generate plasma in a waste liquid and the performance of the electrode is evaluated by the speed at which gases are created by decomposing the liquid. By using experiments in decomposing n-dodecane using in-liquid plasma and through detailed investigation into the length of the electrode used, it is confirmed that the half wavelength is optimal for the generation of plasma. The fabri-cated electrodes are used to test the formation of diamond film by plasma CVD in the microwave oven. Diamond film is successfully created inside microwave oven by using the vapor from a mixture of methanol and ethanol.
Abstract: In-liquid plasma chemical vapor deposition (CVD) method is useful for high speed production of high quality diamond films. The method is simple and secure comparing usual CVD methods. In this paper, new electrodes for in-liquid plasma CVD by receiving microwaves are developed and introduced. This paper examines the fabrication of electrodes that en...
Show More
-
Effect of Li2CO3 Addition on the Sintering Behavior and Physical Properties of PZT-PZN-Pmnn Ceramics
Le Dai Vuong,
Phan Dinh Gio
Issue:
Volume 2, Issue 3, May 2013
Pages:
89-93
Received:
13 May 2013
Published:
10 June 2013
Abstract: The 0.8Pb(Zr0.48Ti0.52)]O3–0.125Pb(Zn1/3Nb2/3)O3–0.075Pb(Mn1/3Nb2/3)O3 + x wt% Li2CO3 ceramics (PZT-PZN-PMnN), where x = 0 1.0, has been prepared by two-stage calcinations method. The Li2CO3 addition significantly improved the sinterability of the ceramics, resulting in a reduction of sintering temperature from 1150 0C to 930 0C. The effect of the Li2CO3 addition on the sintering behavior and physical properties of ceramic samples have been investigated. Experimental results showed that all samples have pure perovskite phase with tetragonal structure, the c/a ratio increases with increasing of Li2CO3 content. At x = 0.7, electrical properties of ceramics are best: the density () of 7.86 g/cm3, the electromechanical coupling factor, kp = 0.64 and kt = 0.51, the dielectric constant, ε = 1320, the dielectric loss (tan) of 0.005, the mechanical quality factor (Qm) of 1150, the piezoelectric constant (d31) of 145 pC/N, and the remanent polarization (Pr) of 30.5 C/cm2, which makes it as a promising material for high power piezoelectric devices.
Abstract: The 0.8Pb(Zr0.48Ti0.52)]O3–0.125Pb(Zn1/3Nb2/3)O3–0.075Pb(Mn1/3Nb2/3)O3 + x wt% Li2CO3 ceramics (PZT-PZN-PMnN), where x = 0 1.0, has been prepared by two-stage calcinations method. The Li2CO3 addition significantly improved the sinterability of the ceramics, resulting in a reduction of sintering temperature from 1150 0C to 930 0C. The effect of th...
Show More
-
Relationship between Graphite Flake Sizes and the Mechanical Properties of Grey Iron
Adeleke Victor Adedayo,
A. V.
Issue:
Volume 2, Issue 3, May 2013
Pages:
94-98
Received:
17 May 2013
Published:
10 June 2013
Abstract: Cast Irons are important engineering materials which possess a wide range of attractive properties. Their properties are significantly dependent on the microstructure of the cast, cast iron components. A way of controlling the microstructure of cast iron is through the control of cooling rates during solidification. To control cooling rate, the heat storage capacity of the mould is important. This paper presents the report of a study on the characteristic effects of graphite flake sizes on some mechanical properties of grey cast iron. Six mould materials with heat storage capacities ranging from 1.52 kJ.m-2.K-1.s-1/2 to 2.16 kJ.m-2.K-1.s-1/2 were prepared and used to cast some grey cast iron samples whose microstructures were observed by optical microscopy. Mechanical properties of the grey iron were evaluated. The results show that the properties increased with the heat storage capacity of the mould. Also, the microstructures show a dependence on heat storage capacity of the mould.
Abstract: Cast Irons are important engineering materials which possess a wide range of attractive properties. Their properties are significantly dependent on the microstructure of the cast, cast iron components. A way of controlling the microstructure of cast iron is through the control of cooling rates during solidification. To control cooling rate, the hea...
Show More
-
Determination of the Contact Angles of Kaolin Intercalates of Oleochemicals Derived from Rubber Seed (HeveaBrasiliensis) and Tea Seed (CameliaSinensis) Oils by the Capillary Rise Method
Chinedum Ogonna Mgbemena,
Chika Edith Mgbemena,
Rugmini Sukumar,
A. R. R. Menon
Issue:
Volume 2, Issue 3, May 2013
Pages:
99-103
Received:
21 May 2013
Published:
10 June 2013
Abstract: Pristine kaolin was organically modified by employing derivatives of oleochemicals namely rubber seed oil (SRSO) and tea seed oil (STSO). Intercalation was attained by the entrance of hydrazine hydrate as co-intercalate. Characterization of the pristine kaolin and modified kaolin was done using powder X-ray diffraction which revealed increase in the interlayer basal spacing d-001 for the SRSO-modified and STSO-modified kaolins, confirming intercalation process. The FTIR studies further revealed that the fatty acid salts of rubber seed oil and tea seed oil were effectively intercalatedin the kaolinite layers as per the bands at 1564 cm-1and 1553 cm-1for SRSO-modified and STSO-modified kaolins respectively. The contact angle measurement using capillary rise method was performed to confirm that the pristine kaolin with initial contact angle value of ~45° was effectively modified and ‘wetted’ from hydrophilic state to hydrophobic state of ~90° for the SRSO-modified and STSO-modified kaolin.The determination of the contact angles of the kaolin was performed to confirm intercalation of the modified kaolin with the oleochemical derivatives.
Abstract: Pristine kaolin was organically modified by employing derivatives of oleochemicals namely rubber seed oil (SRSO) and tea seed oil (STSO). Intercalation was attained by the entrance of hydrazine hydrate as co-intercalate. Characterization of the pristine kaolin and modified kaolin was done using powder X-ray diffraction which revealed increase in th...
Show More
-
Adaptive Finite Element Modeling of Fatigue Crack Propagation
Issue:
Volume 2, Issue 3, May 2013
Pages:
104-108
Received:
24 May 2013
Published:
10 June 2013
Abstract: An adaptive finite element interactive program has been developed for fatigue crack propagation simulation under constant amplitude loading condition. The purpose of this model is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. As part of a linear elastic fracture mechanics analysis, the determination of the stress intensity factor distribution is a crucial point. The fatigue crack direction and the corresponding stress-intensity factors are estimated at each small crack increment by employing the J-integral technique. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors under linear elastic fracture mechanics assumption. The stress intensity factors range history has to be recorded along the small crack increments. Upon completion of the stress intensity factors range history recording, fatigue crack propagation life of the examined specimen is predicted. Verification of the predicted fatigue life is validated with relevant experimental data and numerical results obtained by other researchers. The comparisons show that this model is capable of demonstrating the fatigue life prediction results as well as the fatigue crack path satisfactorily.
Abstract: An adaptive finite element interactive program has been developed for fatigue crack propagation simulation under constant amplitude loading condition. The purpose of this model is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. As part of a linear ...
Show More
-
Analysis of Thermal Ageing Effect (Hold Time - Crystallinity Rate - Mechanical Property) on High Density Polyethylene (HDPE)
Rabah Ferhoum,
Meziane Aberkane,
Mohand Ould ouali,
Kamel Hachour
Issue:
Volume 2, Issue 3, May 2013
Pages:
109-114
Received:
1 June 2013
Published:
20 June 2013
Abstract: This work is devoted to the experimental study of thermal ageing effect on the large deformation stress–strain behaviour of PE100, tensions tests are conducted on this material samples submitted to a temperature of 90°C during different hold times. It is found that thermal ageing causes an increase of all properties measured, including crystallinity, melting temperature, Young Modulus, yield stress and stress at break. We show, by different investigation techniques like X-rays diffraction, Transform Infrared Spectroscopy (FTIR), that increase of mechanical properties is not due to a chemical change but is due to an increase of the crystallinity rate commonly designated by the post-crystallization phenomena. DSC and DMA experiments show secondary crystallization, homogenization of primary crystals and decrease of the amorphous phase mobility.
Abstract: This work is devoted to the experimental study of thermal ageing effect on the large deformation stress–strain behaviour of PE100, tensions tests are conducted on this material samples submitted to a temperature of 90°C during different hold times. It is found that thermal ageing causes an increase of all properties measured, including crystallinit...
Show More
-
The Improvement of Stainless Steel Properties after Pulse Plasma Processing
Anuar Zhukeshov,
Asylgul Gabdullina,
Assem Amrenova,
Svetlana Pak,
Jangaly Moldabekov,
Marjan Mukhamedryskyzy
Issue:
Volume 2, Issue 3, May 2013
Pages:
115-119
Received:
5 March 2013
Published:
20 June 2013
Abstract: The results of researches of stainless steel samples surface properties after interaction by pulsed plasma streams are presented. The modification carried out on CPU-30 pulsed plasma accelerator, operated on “continuously filling” mode, by single and multiple times. The structure of material was researched by SEM and XRD methods. The evolution of the grain dimension, in depending on the basic processing parameters is investigated. The physical properties of modified material were significant chance after multiple impacts. The role of new phases and crystal size influence on process are discussed.
Abstract: The results of researches of stainless steel samples surface properties after interaction by pulsed plasma streams are presented. The modification carried out on CPU-30 pulsed plasma accelerator, operated on “continuously filling” mode, by single and multiple times. The structure of material was researched by SEM and XRD methods. The evolution of t...
Show More
-
Exploring Voltage Output Using a Dye-Sensitized Solar Cell
E. O. Osafile,
O. D. Ojuh
Issue:
Volume 2, Issue 3, May 2013
Pages:
120-123
Received:
5 January 2013
Published:
30 June 2013
Abstract: A dye-sensitized solar cell consisting of two conducting glass electrodes in a sandwich arrangement was developed in the laboratory. Both electrodes were coated with tin dioxide after which the non conductive electrode was again coated with titanium dioxide. The titanium dioxide is designed to serve as an absorbent for the dye. The technology adopted in this paper is that the dye molecules absorb light, and produce excited electrons which in turn generate current in the output terminals of the cell. The dye regains its lost electron with the aid of the iodide electrolyte present in the cell. This work was done using the following light sources: fluorescent and overhead projector light. The voltages measured from each light source were separately documented. This paper shows that the solar cell exposed to the overhead projector light produced a voltage of between 1.3v and 1.5v while the voltage produced from the solar cell exposed to the fluorescent light was rather low. Cells made from raspberries, blackberries, spinach leaves, and grape fruit dyes were independently experimented on, and results showed that only cells made from the berries yielded reasonable quantity of electrons. This is because they have the right chemical composition and the energy band required to bond with the titanium dioxide which enables the release of electrons when light falls on them. The dye sensitized solar cell is very attractive because the materials needed are not only available but also cheap. In this laboratory work, efficiency evaluation yielded about 14.3% for the blackberry dye-sensitized solar cell.
Abstract: A dye-sensitized solar cell consisting of two conducting glass electrodes in a sandwich arrangement was developed in the laboratory. Both electrodes were coated with tin dioxide after which the non conductive electrode was again coated with titanium dioxide. The titanium dioxide is designed to serve as an absorbent for the dye. The technology adopt...
Show More
