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ARPN Journal of Engineering and
Applied Sciences October 2006 | Vol.1 No.3 |
Title: |
Performance analysis of solar driven heat engine with internal
irreversibilities under maximum power and power density condition |
Author (s): |
A.
Biswas, K. M. Pandey and R. Deb |
Abstract: |
Thermodynamic
optimizations based on the maximum power and maximum power density
criteria have been performed for a solar-driven heat engine with
internal irreversibilities. In the analysis, it is assumed that the heat
transfer from the hot reservoir is to be in the radiation mode and the
heat transfer to the cold reservoir is to be in the convection mode. The
power and power density functions have been derived, and maximization of
these functions has been performed for various design and operating
parameters. The obtained results for the maximum power and power density
conditions have been compared. |
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Title: |
Primitive variable approach to calculate
separation point in laminar boundary layer along a flat plate |
Author (s): |
Md. Tanvir Rahman
Faisal and A. K. M. S. Islam |
Abstract: |
Primitive variable
approach has been used to model the Navier Stokes Equation. This is the
method by which one can see what is going on in boundary layer. In the
present work that primitive variable approach is considered to calculate
incompressible, steady state laminar boundary layer along a flat plate
with different flow conditions. This approach uses implicit finite
difference method which consists of replacing the partial derivatives
with respect to flow direction by finite differences. As a result the
partial differential equations are approximated by ordinary differential
equations. This method is capable of solving any flow problem for which
the boundary layer equations remain valid. This implicit finite
difference scheme is advantageous comparing to explicit finite
difference scheme because the results are unconditionally stable
regardless the step size. In the present work, the method is used to
compute accurately the separation points of flow. |
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Title: |
Combined free and
forced convection inside a two-dimensional multiple ventilated
rectangular enclosure |
Author (s): |
Sumon Saha, Goutam
Saha, Mohammad Ali and Md. Quamrul Islam |
Abstract: |
Combined free
convection and forced convection from a flush-mounted uniform heat
source on the bottom of a horizontal rectangular enclosure with side
openings is studied numerically. The inlet opening allows an externally
induced air stream at the ambient temperature to flow through the cavity
and exits from another two openings placed top of the both side walls.
Two-dimensional forms of Navier-Stokes equations are solved by using
control volume based finite element technique. Three typical values of
the Reynolds numbers, based on the enclosure height, are chosen as Re =
50, 100 and 200, and steady, laminar results are obtained in the range
of Richardson number as 0 ≤ Ri ≤ 10 and a fixed Prandtl number of 0.71.
The parametric studies for a wide range of governing parameters show
consistent performance of the present numerical approach to obtain as
stream functions and temperature profiles. Heat transfer rates at the
heated walls are presented in terms of average Nusselt numbers. The
computational results indicate that the heat transfer coefficient is
strongly affected by Reynolds number and Richardson number. An empirical
correlation is developed by using Nusselt number, Reynolds number and
Richardson number. |
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Title: |
Stochastic modeling
of monthly rainfall at Kota region |
Author (s): |
S. R.
Bhakar, Raj Vir Singh, Neeraj Chhajed and Anil Kumar Bansal |
Abstract: |
A study on stochastic
modeling for rainfall was undertaken using 35 years (1987–2003) data of
Kota region. The performed statistical tests indicated that the series
of the monthly rainfall data was trend free. The periodic component of
monthly rainfall could be represented by third harmonic expression. The
stochastic components of the monthly rainfall followed first order
Markov model. Validation of generated monthly rainfall series was done
by comparison of generated and measured series. The correlation
coefficient between generated and measured rainfall series was found to
be 0.9961. The correlation was tested by t-test and found to be highly
significant at 1 per cent level. The regression equation is very near to
1:1 line. Therefore, developed model could be used for future prediction
of monthly rainfall. |
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Title: |
Study and simulation
of competitive sorption of 2,4-d and phenol on waste tyre rubber
granules |
Author (s): |
Md.
Jahir Bin Alam, R. K. Chowdhuary, M. M. Hasan, A. Huda and S. Sobhan |
Abstract: |
Batch study for
sorption of 2,4-D and phenol on waste tyre rubber granules (WTRG) were
carried out for checking feasibility of rubber granules as adsorbent.
After 100 minutes of reaction time, it was evident that the kinetics
profiles gradually became horizontal indicating the final equilibrium.
The removal of 2,4-D and phenol beyond 120 was very low. The removal was
83.2% and 87% in 2hr at 0.75mg/l and 0.4mg/l, respectively for 2,4-D.
The removal was 53.2% and 58.7% in 2hr at 0.75 mg/l and 0.4mg/l,
respectively for phenol. It is clear from the analysis that Freundlich
model fitted well with the experimental data and predicted amount of
absorbed well in bi-solute. |
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Title: |
Effect of high
pressure coolant on chip, roundness deviation and tool wear in drilling
AISI-4340 steel |
Author (s): |
N. R.
Dhar, M. H. Rashid and A.T. Siddiqui |
Abstract: |
Hole making had long
been recognized as the most prominent machining process, requiring
specialized techniques to achieve optimum cutting condition. Drilling
can be described as a process where a multi-point tool is used to remove
unwanted materials to produce a desired hole. It broadly covers those
methods used for producing cylindrical holes in the work piece. However,
high production machining and drilling with high cutting velocity, feed
and depth of cut is inherently associated with generation of large
amount of heat and high cutting temperature. Such high cutting
temperature not only reduces dimensional accuracy and tool life but also
impairs the surface integrity of the product. In this case,
high-pressure coolant (HPC) is very effective to reduce temperature.
When temperature is increased a large amount of tool wear appears at the
drill bit. In this situation, high temperature either affects roundness
of the hole or chip shape and color of chip. HPC is applied in the same
direction as the drill bit. HPC has reduced temperature as well as
improving roundness and also provide lubrication in the tool tip and
surface interface. |
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Title: |
Possible
use of fly ash generated from Barapukeria Power Plant for sustainability |
Author (s): |
Md.
Jahir Bin Alam, A. S. M. A. Awal, M. J. B. Alam, A. Hasan, B. K. Banik,
S. Islam and M. M. Hasan |
Abstract: |
Fly ash is extensively
used in concrete as an admixture in order to reduce cost of cement. For
sustainability in production of cement in Bangladesh, feasibility of fly
ash generated from Barapukoria Power Plant was tested. This was used as
an admixture with Shah Special cement in different proportion in order
to reduce cost of cement and environmental pollution such as green house
effect, problem of fly ash as solid waste. Laboratory test for different
parameters such as compressive strength, workability of such mixtures
were performed. The results show almost no sacrifice for the strength of
cement due to mixture of fly ash with a proportion of 10%. The results
show that curing of the even plain concrete in chloride environment is
not desirable right from the time of demoulding. |
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Title: |
Frequency analysis of consecutive days maximum rainfall at Banswara,
Rajasthan, India |
Author (s): |
S. R.
Bhakar, Anil Kumar Bansal, Neeraj Chhajed and R. C. Purohit |
Abstract: |
Annual one day maximum
rainfall and two to five days consecutive days maximum rainfall
corresponding to return period varying from 2 to 100 years are used by
design engineers and hydrologists for the economic planning, design of
small and medium hydrologic structures and determination of drainage
coefficient for agricultural fields. A maximum of 154.31mm in 1 day,
250.88mm in 2 days, 270.15mm in 3 days, 284.18mm in 4 days and 295.54mm
in 5 days is expected to occur at Udaipur, Rajasthan every 2 years. For
a recurrence interval of 100 years, the maximum rainfall expected in 1
day, 2, 3, 4 and 5 days is 773.6mm, 849.34mm, 874.19mm, 931.78mm and
957.89mm, respectively. The magnitudes of 1 day as well as 2 to 5
consecutive days annual maximum rainfall corresponding to 2 to 100 years
return period were estimated using Gamma function. Various probability
distributions and Transformations can be applied to estimate one day and
two to five consecutive days annual maximum rainfall of various return
periods. Three commonly used probability distributions (viz: Normal, Log
Normal and Gamma distribution) were tested by comparing the Chi-square
value. Gamma distribution was found to be best fit for the region. |
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Title: |
Socio-cultural evaluation of sanitation hygiene in Sylhet city of
Bangladesh |
Author (s): |
M.
Ahmed, M. A. Hoque, M. S. K. A. Sarkar, M. A. I. Chowdhury, A. Begum |
Abstract: |
Sylhet, the
northeastern divisional city of Bangladesh is a hilly area, where many
ethnic minorities live. Their socio- cultural life is a little different
from other people. The city is the main tea-producing and natural gas
exploration region of Bangladesh. As a result of these extremely
labor-intensive economic activities, a large number of low income
workers live in and around the city, many of them are from ethnic
minorities. The sanitation condition of low income areas is remarkably
poor. Economic status, socio- cultural condition and topography of the
region are the main reasons for this condition. This year long research
work was undertaken to assess the existing sanitation condition of some
low income areas of Sylhet city, find out the factors, responsible for
the condition, monitor the behavioral changes of the dwellers, as well
as health-hygiene improvement after taking some measures for improving
the sanitary condition. |
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