We have investigated different nonidealities in Cu2ZnSnSe4-CdS-ZnO solar cells with 9.7% conversion efficiency, in order to determine what is limiting the efficiency of these devices. Several nonidealities could be observed. A barrier of about 300 meV is present for electron flow at the absorber-buffer heterojunction leading to a strong crossover behavior between dark and illuminated current-voltage curves. In addition, a barrier of about 130 meV is present at the Mo-absorber contact, which could be reduced to 15 meV by inclusion of a TiN interlayer. Admittance spectroscopy results on the

Recently, emerging vehicular applications are increasing the demand of vehicles which form significant burdens on network backhaul and represents a cause to the quality of experience (QoE) decay of the vehicular users. Proactive caching is a promising technique to mitigate the load on core networks by caching some of the expected data items. This work proposes a hierarchical proactive caching scheme which jointly considers caching in vehicles and roadside units (RSUs). Minimization of the vehicle communication latency is the main objective of our study. The optimization problem is formulated

Manufacturing systems evolution is afunction in multiple external and internal factors. With today's global awareness of environmental risks as well as the pressing needs to compete through efficiency, manufacturing systems are evolving into a new paradigm. This paper presents a system model for the new green manufacturing paradigm. The model captures various planning activities to migrate from a less green into a greener and more eco-efficient manufacturing. The various planning stages are accompanied by the required control metrics as well as various green tools in an open mixed architecture

Thermal insulators have a crucial role in reducing the operational building energy. They are commonly fabricated from petrochemical materials that mostly cause negative environmental impacts. This study aims to develop banana leaves-polystyrene composites (BL-PS) as a sustainable and low-cost thermal insulator. The BL powder was mixed with PS in different weight ratios (90:10, 80:20, 70:30, and 60:40). Thermal conductivity, electrical conductivity, SEM, XRD, FTIR, TGA, and DSC were carried out on BL and BL-PS composites that were prepared with 10 wt.% of PS powder (BL-PS1) and 30 wt.% of PS

Nano particles contribute as a partial substitute in the production of eco-friendly building materials. This research presents a quantitative assessment of the sustainability effect of partially replacing cement in the green concrete mix with two types of nano-waste particles. The assessment is achieved using two weighing criteria developed by a Sustainable Decision Support System (SDSS) model. This assesses the alternatives using scoring systems based on both the Life Cycle Assessment (LCA) technique and Multi-Criteria decision analysis method. Ten sustainable aspects comprising four

Much research has focused on the development of optimal strategies for rehabilitation and replacement of water and sewer infrastructures. Condition assessment is an integral component in any asset management program for assessing the asset physical condition. Determining the condition of buried infrastructure tends to be cumbersome, costly and error-prone. As such, decision makers must balance the value of obtained information through condition assessments with the cost of obtaining this information. Such decisions must balance between conflicting needs and need to consider the sought level of

Sensor Actor NETworks (SANET) represent a major component of ubiquitous service environments promising interesting solutions to a wide range of problems. Despite the obvious increase in the research activities proposing architectures and protocols for SANETs, we are still no where near the production of industrial-grade SANET software that can be relied upon for mission critical applications. The cost of programming, deploying and maintaining SANET environments is still highly prohibitive due to the lack of industrial tools capable of realizing adaptive SANET software in a cost effective way