Abstract:Increased energy efficiency is one of the most effective ways to achieve climate change mitigation. This study aims to evaluate the energy efficiency of seventeen countries. The evaluation is based on an integrated method that combines the super slack-based (super SBM) model and the Malmquist productivity index (MPI) to investigate the energy efficiency of seventeen countries during the period of 2010-2015. The results in this study are that the United States, Columbia, Japan, China, and Saudi Arabia perform the best in energy efficiency, whereas Brazil, Russia, Indonesia, and India perform the worst during the entire sample period. The energy efficiency of these countries arrived mainly from technological improvement. The study provides suggestions for the seventeen countries' government to control the energy consumption and contribute to environmental protection.

Balancing economic development with environmental protection has become a critical concern worldwide. However, along with the highly competitively global marketplace, economic factors are known to directly affect an enterprise's development and its future business. Therefore, selecting the right partner for sustainable collaboration that will lead to improved business performance and reduce carbon dioxide (CO 2 ) emissions is a significant problem for many enterprises. In addition, investigating the economic impact of companies that are charged to protect the environment is becoming increasingly problematic. Thus, the purpose of this paper is to evaluate the comparative efficiencies of 16 Green Logistics Providers (GLPs) in the USA from 2012 to 2015, and the projected four-year period of 2016-2019, by means of an integrated approach that combines the grey forecasting model GM (1,1) and Data Envelopment Analysis (DEA). The results show that there are two GLPs, Knight Transportation and the Union Pacific Corporation, that possess a higher efficiency level and are achieving positive technical change. However, this study also determined that Hyster-Yale Materials Handling and CSX Corporation did not reach an acceptable efficiency score; therefore, they should improve technical efficiency to mitigate environmental concerns. This completely integrative methodology has the potential to provide the best decision-making strategies for finding suitable collaborative partners who are able to meet the sustainability requirements in most economic and environmental areas.

No abstract

This study presents the design and construction of the Dual Axis Solar Tracking System to ensure maximum energy gain. The solar tracking system will automatically follow the sun's position to maximize the intensity of the light emitted from the sun. When the light intensity decreases, the system automatically changes its direction to get the maximum light intensity. Light Dependent Resistor (LDR) is used to track the coordinates of the sun. The two servo motors that receive signals from the central processing unit will turn the solar panel to the appropriate location for optimum performance. The energy results obtained by the dualaxis solar system are compared with single and fixed solar systems. This research provides optimal solar energy usage.