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VOLUME 14CODEN : IEMSEW |
NUMBER 4 |
AUGUST 2007 ISSN : 0971-4588 |
Engineering
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Experimental
investigation on the influence of reinforcement and precipitation hardening
parameters of AA 6061-SiCp composites |
277 |
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[IPC Code: C22C 47/00] |
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Elastic-plastic
stress analysis of a thermoplastic composite disc under parabolic temperature
distribution |
282 |
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[IPC Code: C08B] |
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Current
differencing transconductance amplifier-based
current-mode four-phase quadrature oscillator |
289 |
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[IPC Code: H03L] |
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Evaluation
of creep coefficient on concrete-filled steel tubular columns |
295 |
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[IPC Code: E04C 3/30] |
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Materials Science |
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Corrosion
susceptibilities of Al-Cu/TiC MMCs fabricated by conventional hot pressing |
303 |
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[IPC Code: C22F, C22C 47/00] |
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Synthesis
of nanosized AlN powder using novel nitridation route |
309 |
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[IPC Code: C01F 7/00] |
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Study of
optical constants in CdxZn1-xS vacuum evaporated thin
films |
313 |
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[IPC Code: H01C 17/075] |
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Low-frequency
dielectric response and chain dynamics study of poly(vinyl
pyrrolidone)-poly(ethylene glycol) coexisting two-phase polymeric blends |
317 |
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[IPC Code C08L 39/04] |
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Predicting
heats of detonation of explosives via specified detonation products and
elemental composition |
324 |
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[IPC Code: C06B] |
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________________ |
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IPC: International Patent
Classification |
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Int. Cl.8: International Classification
8th edition, 2006 |
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Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 277-281
Experimental investigation on the influence of reinforcement and precipitation hardening parameters of AA 6061-SiCp composites
K Mahadevan, K Raghukandan, B C Pai & U T
The presence of discrete reinforcement particles in the matrix of the discontinuously reinforced metal matrix composites considerably alters the matrix microstructure and hence the precipitation hardening kinetics. Therefore, precipitation hardening schedule of aluminium alloys are not applicable to aluminium matrix based discontinuously reinforced composites. In the present work, an attempt has been made to systematically study the effects of reinforcement percentage and precipitation hardening parameters on the behaviour of AA 6061-SiCp composites. The result reveals that AA 6061-SiCp composites demand longer solutionizing time (3 h) compared to unreinforced AA 6061 alloy (1 h). Moreover, successively during artificial aging, the time required to attain peak aging condition is shorter and almost same for AA 6061-SiCp composites irrespective of percentage of reinforcement.
IPC Code: C22C47/00
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 282-288
Elastic-plastic stress analysis of a thermoplastic composite disc under parabolic temperature distribution
Faruk Sen, Yeliz Pekbey, Onur Sayman
In this study, an elastic-plastic thermal stress analysis was
carried out on a steel fiber reinforced thermoplastic composite disc under a
parabolic temperature distribution. The thermal elastic and elastic-plastic
solutions were obtained both analytically and numerically. Therefore, FORTRAN
and ANSYS programs were used to calculate of thermal stresses for comparison.
Tsai-Hill theory was used as a yield criterion during the solution. Thermal
stresses occurred in the disc for the parabolic temperature distribution due to
the different thermal expansions in radial and tangential directions. The
magnitudes of the radial stress components were obtained to be small in
comparison with the tangential stress components. Additionally, the tangential
stress component was found to be compressive and the highest around the inner
surface. According to obtained results these two solutions to be in good
agreement. The intensities of the residual stress component of the tangential stress
and plastic flow were the highest at the inner surface.
IPC Code: C08B, G01L1/00
Indian
Journal of Engineering & Materials Sciences
Vol. 14, August 2007, pp. 289-294
Current differencing transconductance amplifier-based
current-mode four-phase quadrature oscillator
Worapong Tangsrirat
A realization of a current-controlled current-mode four-phase quadrature oscillator based on current differencing transconductance amplifiers (CDTAs) is proposed. The proposed oscillator circuit employs only three CDTAs and two grounded capacitors, which can provide four high output impedance sinusoidal current outputs with four-phase difference. The oscillation condition and oscillation frequency can be controlled electronically and independently by the transconductance gain of the CDTA. PSPICE simulation and experimental results with the commercially available ICs are given to confirm the operation of the proposed oscillator.
IPC Code: H03L
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 295-302
Evaluation of creep coefficient on concrete-filled steel tubular columns
Mustafa Hilmi Acar
This paper presents the evaluation of creep coefficient on concrete-filled steel tubular (CFST) sustained loaded columns. A test of the long-term behaviour of CFST columns has been carried out. Shrinkage and creep of CFST columns are measured. A comparison of results calculated using three prediction models proposed by CEB-FIP, BAZANT-PANULA, and ACI have shown a good agreement with test results. The study also showed that the shrinkage effect of the concrete core in CFST columns is negligible. The creep coefficient measured and calculated by those recommanded CEB-FIP, BAZANT-PANULA, and ACI during 200 days were in agreement for CFST columns.The creep coefficient ultimate calculated for CFST columns has been found 2. At the beginning of test, the percentage of load taken by steel section was 38% and at the end of test, it was 56%. This is a stress transfer from the concrete section to the steel section due to the creep. This creep coefficient ultimate evaluated is proposed for long-term behaviour calculation of CFST columns. In order to take the effect of creep into account, applied sustained load must be multiplied by the value of (1+fultimated)
IPC Code: E04C3/30
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 303-308
Corrosion susceptibilities of Al-Cu/TiC MMCs fabricated by conventional
hot pressing
Mehmet Gavgali, Burak Dikici & Fevzi Bedir
The effect of TiC particle volume fraction on the electrochemical
behaviours of metal matrix composites (MMCs), which is Al-Cu based reinforced
with TiCp has been investigated in both aerated and deaerated 1.0
IPC Code: C22F, C22C 47/00
Indian Journal of Engineering
& Materials Sciences
Vol. 14, August 2007,
pp. 309-312
Synthesis of nanosized AlN powder using novel nitridation route
Anjan Sil & Pankaj Kumar Verma
Nanonsized AlN powders were prepared by nitridation of coarse aluminium powder in flowing N2 and NH3 gases, using NH4Cl and KCl as additives. XRD analysis indicated that the pure phase of AlN powder could be obtained by nitridation at 1000˚C for 4 h with NH3 gas. The average particle size of the AlN powder estimated from the XRD pattern is about 29 nm. FE-SEM micrograph revealed the spherical morphology of the powder particles whose sizes are in the range of 26-43 nm.
IPC Code: C01F 7/00
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 313-116
Study of optical constants in CdxZn1-xS
vacuum evaporated thin films
Pawan Kumar, Aravind Kumar, P. N. Dixit & T. P. Sharma
Thin films of II-VI group semiconductors have been deposited by the vacuum evaporation technique onto highly cleaned glass substrates under the vacuum of the order of 10-5 torr. The optical properties of these thin films have been determined from transmission spectra by using Manifcier’s envelope method. These films posed, in general good transparency (T > 50%), exhibiting an interference pattern. The wavelength dependence of optical constant (refractive index and extinction coefficient) of these films have been reported.
IPC Code: H01C 17/075
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 317-323
Low-frequency dielectric response and chain dynamics study of poly(vinyl pyrrolidone)–poly(ethylene glycol) coexisting two-phase polymeric blends
R J Sengwa & Sonu Sankhla
The dielectric
response of various concentration poly(vinyl pyrrolidone)-poly(ethylene glycol)
(PVP–PEG) blends with change in polymer chain-length and their different volume
mixtures over the entire concentration range were investigated in the frequency
range 20 Hz-1 MHz at 25°C. The
complex dielectric constant e*(w), complex electric modulus M*(w), complex impedance Z*(w), and a.c. conductivity
data were used for the confirmation of the electrode polarization effect, ionic
conduction and the micro-Brownian motion of the PVP chain (m-process) in the PVP–PEG blends. All the blends show the
dielectric dispersion corresponding to the PVP segmental motion in the upper
experimental frequency range whereas in the lower frequency side of the spectra
has dielectric dispersion is due to ionic conduction and electrode
polarization. The different volume mixtures of some of the different
chain-length PVP–PEG blends also shows the polymer chain-length and
concentration dependence m-process.
All the blends show the
IP Code: C08L39/04
Indian
Journal of Engineering & Materials Sciences
Vol.
14, August 2007, pp. 324-330
Predicting
heats of detonation of explosives via specified detonation products and
elemental composition
M H Keshavarz
Heats of detonation of CaHbNcOd explosives are predicted using H2O-CO2 arbitrary1 as detonation products as well as ratios of oxygen to carbon (RO/C) and hydrogen to oxygen (RH/O). The methodology at first assumes that the heat of detonation of explosive compound can be approximated as the difference between heats of formation of the assumed detonation products and that of the explosive, divided by the formula weight of the explosive; then may be corrected by RO/C and RH/O. For the calculations in which only H2O-CO2 arbitrary were used, predicted heats of detonation for 27 non-aromatic and 31 aromatic energetic compounds have a root mean square (rms) deviation from experiment of 1.21 and 2.08 kJ/g, respectively. The corrected heats of detonation using RO/C and RH/O for both non-aromatic and aromatic energetic compounds have a rms deviation of 0.49 kJ/g from experiment, which show good agreement with respect to measured values. The new method is also applied to four new explosives, i.e., CL-20, FOX-7, ONC and NTO, which gives comparable results as compared to measured values.
IPC Code: C06B