Kabiru Saidu Musa and Bilyaminu Bako

Abstract: This study estimated both long-run and short-run impact of internet usage and energy consumption on economic growth in the case of Nigerian economy between 1996-2014 and applied vector error correction model to analyze the data on internet usage, energy consumption and economic growth. The breakpoint unit root test indicated that all the three series were concluded to be I(1) and cointegrated as shown by Johansen and Juselius test for cointegration. The long-run result from vector error correction model revealed that internet usage and energy consumption have significant positive impact on economic growth whereas CO₂ emissions exerts significant negative impact on economic growth. However, the result also indicated that in the short-run energy consumption has a significant positive impact and this is an indication that energy consumption matters a lot in the relationship, while CO₂ emissions has significant negative impact on economic growth and slow adjustment speed estimated at 20.8 percent annually. The Granger causality result indicated that there are unidirectional causalities flowing from internet usage to economic growth, CO₂ emissions to economic growth, CO₂ emissions to internet usage and economic growth to energy consumption. The empirical findings of this paper would serve as a beneficial tool for the same economies to offer proper ICT, energy consumption and economic growth-related policy decisions.

Keywords: Internet usage, energy consumption, economic growth, Breakpoint unit root test, Johansen and Juselius cointegration test, Vector error correction model.

Malek Hassanpour

Abstract: In Iran, the quantity of produced beet reached up to 9 million tons/year, and about 40 ethanol production plants have currently participated in the processing operation. The waste materials procured and created a relevant resource and feedstock for lots of demands. The basic knowledge needs to be promoted in parallel with the nation's development and civilization. The updating available knowledge in the alcohol generation from beet molasses bio-degradation was the objective of the present review. The data and information gathered by the current review were a collection of new techniques reported in scientific databases. The present review comprised the description of ethanol generation of beet molasses from project level to new and novel technologies developed. The exploitation of new technologies is recommended to culminate the efficiency and productivity of manufacturing products in individual or integrated configurations. Reviewing the alternative technologies paves the way for decision-makers to figure out the relevant technology in this regard. Also, the introduced technologies attract decision maker's ideas in decision-making theory and assign multi-criteria decision-making models to select and prioritize the best alternatives regarding the criteria of technologies. The aggregation of industry information in the framework of project identification regarding new technologies applicable in the way of economic prosperity can be mentioned as a great achievement and conclusion of the current review.

Keywords: Alcohol generation, bio-degradation, beet molasses, industries.

Bunkun Chhun, Sébastien Bonnet* and Shabbir H. Gheewala

Abstract: As a developing country, Cambodia is promoting hydropower as a renewable energy source to increase electricity production, minimize the cost of electricity and enhance energy security. However, potential adverse impacts from hydropower still remain to be assessed. The objectives of this study consisted in evaluating the environmental impacts of the Kamchay hydropower plant, the first large scale dam in Cambodia, using life cycle assessment and identifying mitigation options for the sustainable development of hydropower in the country. The greenhouse gas emissions from the Kamchay hydropower plant amount to 141 kg CO2_-eq./MWh and are the major contributor to the impacts on human health and ecosystem damage. These emissions were identified to be mainly from the construction and operation & maintenance phases. The rest of the emissions and resources consumption had a marginal significance compared to greenhouse gas emissions. These findings point out to the necessity of focusing on the construction and operation phases to mitigate greenhouse gas emissions and in doing so improve the environmental performance of large-scale dams with reservoir.

Keywords: Cambodia, Hydropower, Life cycle assessment (LCA), Reservoir, Renewable energy.

Papon Srisanong, Pornlada Daorattanachai and Navadol Laosiripojana*

Abstract: This work is focusing on producing synthetic ester based biolubricant from cheap and non-edible source, i.e., palm fatty acid distillate (PFAD), as a substrate. Biolubricant was synthesized by esterification reaction with polyhydric alcohol, i.e., trimethylolpropane (TMP), in order to produce polyol ester (triester) which has more thermal stability than monoester and diester. With concerns of using high corrosive Brønsted acid as a homogeneous catalyst, the novelty of this study is the use of methane sulfonic acid (MSA) in the transformation of PFAD to TMP-based triester as a biolubricant. This research studied and optimized the effect of production variables including temperature, time, catalyst loading and molar ratio by applying the response surface methodology (RSM) based on central composite design (CCD) of experiment. The reaction condition of 160 ℃, 6 h, catalyst loading 1.5% by weight of PFAD and 3:1.5 PFAD:TMP molar ratio with a percentage conversion of 99.65% and 32.26% oleic triester yield was selected as a center point for optimization. The optimized condition obtained from the statistical software was 160.7 ℃, 4 h, catalyst loading of 1% by weight of PFAD and 3:1.99 with oleic triester yield 38.17%. Finally, the lubrication properties of the product were compared with other works. In this study, it was found that the viscosity index, pour point, oxidation induction time, and wear scar diameter (WSD) of synthetic biolubricant were 126, 12 ℃, 130 ℃ for 12 min, and 0.62 mm, respectively.

Keywords: Synthetic lubricant; Palm fatty acid; Esterification; Methane sulfonic acid.