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International Journal of Research and Reviews in Applied Sciences
ISSN: 2076-734X, EISSN: 2076-7366
Volume 23, Issue 1(April, 2015)
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1. |
ANALYSIS OF CONDITIONAL ASYMMETRIC VOLATILITY OF REAL GDP AND MAIN ECONOMIC SECTORS GROWTH RATES IN IRAN |
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by Sara Taati, Nader Hakimipour, Mohammad Sadegh Alipour, Reza Saberi4 & Ayoub Faramarzi |
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Abstract |
GDP
growth is one of the basic and effective factors of economic growth of country and
it is directly so-called economic growth, so we must pay a lot attention to its
volatilities. Most empirical studies of economic growth exclude these volatilities
and the dimension of conditional volatility shocks.
In
this paper we search for evidence of conditional volatility in quarterly real GDP
of Iran. Furthermore, in order to investigate the basic reasons of these volatilities,
we also examined four main economic sectors including agricultural, industrial and
mining, oil and service sectors. The widely accepted exponential GARCH model of
Nelson is employed to record the possible existence and asymmetric conditional volatility
in real GDP and main sectors. The data set are in constant prices and quarterly
observation from 1367 Q1 to 1391Q3.
The
government needs to use these volatilities to implement stabilizing policies which
are the new method for analyzing of GDP and help for understanding the existing
disturbances and growth rates. In this paper we capture the real GDP volatilities
and its main determinants, afterwards it proves that the necessity of well-advised
government intervention.
As
a result of this paper, it is calculated the equation for growth rate variance and
persistence and asymmetry are gotten. Also, the negative shocks of GDP have more
effects on future values of GDP than positive ones by equal values. Moreover, the
results show that oil shocks are the most important reasons of real GDP volatilities.
Consequently, for removing the variations, strategic action of government and diminishing
the effectiveness of oil are needed. The results can be used for growth and development to achieve an economy with a stable and increasing growth.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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2. |
OPTIMIZATION OF SAND WASHING WASTE AS POZZOLANIC MATERIAL |
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by Taheni KALLEL, Basma SAMET, Rakia S’HABOU & Abderrazek KALLEL
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Abstract |
Waste of sand washing collected from the region of Sfax in Tunisia is studied as
artificial pozzolan in mortars. The chemical, physical and mineralogical properties
of crude and calcined materials are well detailed for understanding its behavior.
The pozzolanic activity of the calcined waste product was tested and its fineness
was optimized by using the strength activity index test.
The aim of this study is to investigate and optimize the properties of the blended
cement and its paste and mortars in which calcined waste is employed as a pozzolan.
In order to check the effect of
three variables,
(calcination temperature: X1, calcination time: X2 and % of calcined waste in the
blended cement: X3) on the compressive strength of
blended cement mortar at 28 and 90 days, a Box–Behnken design is set up.
The compressive strength is governed especially by the calcination duration and
the percentage of the calcined waste in the blended cement. Finally, a blended cement
composition has been formulated and optimized. The optimized blended cement contains
30% of calcined waste, heated for 3 hours at a temperature of 650°C.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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3. |
CHEMICAL AND ELECTROCHEMICAL INVESTIGATIONS OF COFFEE HUSK AS GREEN CORROSION INHIBITOR FOR ALUMINUM IN HYDROCHLORIC ACID SOLUTIONS |
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by A.S.Fouda,H.S.Gadow & K.Shalabi |
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Abstract |
The inhibition action of coffee husk extract
towards the corrosion of aluminum in 0.5 M HCl solution was studied at temperatures
25 and 450C by weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency
modulation (EFM) methods. Surface morphology was tested using
energy dispersive X-ray (EDX) and scanning
electron microscopy (SEM). The results showed that the inhibition efficiency increased with
increasing
concentration of extracts. Polarization data showed that this extract
acts as mixed type inhibitor. Adsorption of extract on aluminum surface was found
to obey Langmuir and Temkin isotherms. The thermodynamic parameters were calculated
and discussed.
The inhibition efficiencies obtained from all techniques employed
are in good agreement with each other.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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4. |
ANALYSIS OF COPPER LOSSES DUE TO UNBALANCED LOAD IN A TRANSFORMER |
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by Okakwu K. Ignatius, Abagun K. Saadu & Oluwasogo S. Emmanuel
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Abstract |
This
work investigates how distribution network ohmic
losses can vary significantly with varying load unbalance. The analysis of distribution
system losses is presented that considers balanced and unbalanced loads and their
effect on the copper losses of a typical power distribution transformer. Load readings
taken from all the public and private 11/0.415-kV transformers fed from the New
Idumagbo Injection substation, 2X 15MVA, 33/11-kV were from EKO Electricity Distribution
Company, Marina, Lagos. The result
showed that the total transformer copper losses calculated for both balanced and
unbalanced load for Adeniji Adele feeder is 3379701 units and 3490724 units respectively
for the period (June 2012 and May 2013) under review. For Tokunboh feeder, 1660620
units and 1743982 units were obtained for both balanced and unbalanced loads respectively.
Furthermore, the result also showed that the total transformer losses in Dolphin
feeder amounted to 321555 units and 321993.8 units for both balanced and unbalanced
load respectively. Comparison was made between the transformer copper losses calculated
from the existing unbalanced load condition and the losses that would have resulted
if the loads on the transformer were equally distributed between the phases. The
result of these comparison shows that high levels of load unbalance produces greater
losses in the distribution transformers when compared to balanced load. Therefore,
copper losses of transformer vary considerably with the degree of load unbalance,
hence reduction in the capacity of the transformer.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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5. |
BALANCING OF THE FLEXIBLE ROTORS WITH ICA METHODS |
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by Nader Mohammadi & Arash Mohammadzadeh |
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Abstract |
Increased running
speeds and the requirement for rotating machinery to operate within specified levels
of vibration mean that the control of machinery vibration is essential in today’s
industry. In this work, the flexible rotor balancing problem based on the influence
coefficient method and holospectrum technique is formulated as a minimax optimization
problem. This formulation can solve the minimax high-speed rotating machinery’s
balancing problem under practical balancing constraints effectively while ensuring
the balancing machinery runs up safely. Imperialist Competitive Algorithm (ICA)
method is employed to solve the minimax balancing problem. An experimental and a
real world balancing example are given to demonstrate the effect of this formulation.
The performance of ICA is compared with that of other established approaches; some conclusions are derived.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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6. |
ACID REMOVAL OF MINERALIZED INCRUSTATION IN PETROLEUM PRODUCTION PIPE |
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by Fernando B. Mainier, Alan Eduardo R. de Freitas, Anne Aparecida M. Figueiredo |
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Abstract |
Hard, rough and
compact scale, adherent to the metal surface, with a thickness of 5-7 mm, composed
mainly of calcium carbonate (CaCO3) and silica (SiO2), occurred
within the production pipe, discontinues oil, for two years, and reduced the run-off
area by about 22 %. To return to the initial operating conditions an acid removal
operation was carried out with a mixture of hydrochloric acid (HCl) and hydrofluoric
acid (HF). For internal protection of the carbon steel pipe a corrosion inhibitor
was added. In the evaluation of the laboratory tests a chemical process of acid
dissolution of the incrustation and gravimetric testing were used to determine the
anti-corrosion protection of a commercial corrosion inhibitor based on propargyl
alcohol (2-propyn-1-ol). Two acidic solutions were tested for the dissolution of
scale. Solution A: 10% (by mass) of HCl and 1% (by mass) of HF; Solution B: 15%
(by mass) of HCl and 3% (by mass) of HF. The temperatures for the tests were fixed
at 25, 40 and 50 °C. The results of the laboratory tests showed that the acidic
solutions tested reacted fully with the scale and increasing the temperature favoured
reducing the test time. The propargyl alcohol-based inhibitor represented excellent
efficiency, exceeding 96 % mass loss.
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Source: |
International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015 |
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