Academic Research Publishing Agency Press
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
by Sara Taati, Nader Hakimipour, Mohammad Sadegh Alipour, Reza Saberi4 & Ayoub Faramarzi
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.

Source: International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015

2. OPTIMIZATION OF SAND WASHING WASTE AS POZZOLANIC MATERIAL

by Taheni KALLEL, Basma SAMET, Rakia S’HABOU & Abderrazek KALLEL

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.

Source: International Journal of Research and Reviews in Applied Sciences 
April 2015-- Vol. 23 Issue 1 -- 2015

3. CHEMICAL AND ELECTROCHEMICAL INVESTIGATIONS OF COFFEE HUSK AS GREEN CORROSION INHIBITOR FOR ALUMINUM IN HYDROCHLORIC ACID SOLUTIONS
by A.S.Fouda,H.S.Gadow & K.Shalabi
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.

Source: International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015

4. ANALYSIS OF COPPER LOSSES DUE TO UNBALANCED LOAD IN A TRANSFORMER

by Okakwu K. Ignatius, Abagun K. Saadu & Oluwasogo S. Emmanuel

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.

Source: International Journal of Research and Reviews in Applied Sciences 
April 2015-- Vol. 23 Issue 1 -- 2015

5. BALANCING OF THE FLEXIBLE ROTORS WITH ICA METHODS
by Nader Mohammadi & Arash Mohammadzadeh
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.

Source: International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015

6. ACID REMOVAL OF MINERALIZED INCRUSTATION IN PETROLEUM PRODUCTION PIPE
by Fernando B. Mainier, Alan Eduardo R. de Freitas, Anne Aparecida M. Figueiredo
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.

Source: International Journal of Research and Reviews in Applied Sciences
April 2015-- Vol. 23 Issue 1 -- 2015













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