The possibility of optimization of morphological features of multiwall carbon nanotubes (MWCNTs) using the statistical design of experiments (DoE) is investigated. In this study, MWCNTs were synthesized using a catalytic chemical vapour deposition (CCVD) method in a horizontal reactor using acetylene as the carbon source. The effects of six synthesis parameters (synthesis time, synthesis temperature, catalyst mass, reduction time, acetylene flow rate and hydrogen flow rate) on the average diameter and mean rectilinear length (MRL) of carbon nanotubes were examined using fractional-factorial design (FFD) coupled with response surface methodology (RSM). Using a 2III6–3 FFD, the main effects of reaction temperature, hydrogen flow rate and chemical reduction time were concluded to be the key factors influencing the diameter and MRL of MWCNTs; then Box–Behnken design (BBD) was exploited to create a response surface from the main factors. The total number of required runs is 26: 8 runs are for FFD parameter screening, 17 runs are for the response surface obtained by the BBD, and the final run is used to confirm the predicted results.

No abstract

The possibility of diameter optimization of ZnO nanowires by using statistical design of experiment (DoE) is investigated. In this study, nanowires were synthesized using a vapor–liquid–solid (VLS) growth method in a horizontal reactor. The effects of six synthesis parameters (synthesis time, synthesis temperature, thickness of gold layer, distance between ZnO holder and substrate, mass of ZnO and Ar flow rate) on the average diameter of a ZnO nanowire were examined using the fractional factorial design (FFD) coupled with response surface methodology (RSM). Using a 2III6−3 FFD, the main effects of the thickness of the gold layer, synthesis temperature and synthesis time were concluded to be the key factors influencing the diameter. Then Box–Behnken design (BBD) was exploited to create a response surface from the main factors. The total number of required runs for the DoE process is 25, 8 runs for FFD parameter screening and 17 runs for the response surface obtained by BBD. Three extra runs are done to confirm the predicted results.

No abstract

In recent years, authorities in Iran have introduced supporting policies for renewable energy resources but there is no comprehensive and updated survey from this perspective. This work aims to give a comprehensive survey on the country's background from energy outlook and its prominent policies for renewable energy resources. Due to the high CO 2 emissions alongside with the high solar energy harvesting potential in Iran, We have presented a clear simulation on 20 kW and 1 MW grid-connected photovoltaic (PV) power plants using RETScreen software to determine the environmental and economic aspects based on the net greenhouse gases (GHG) emissions reduction, the annual electricity exported to the grid, the cumulative cash flows, and the payback period for the initial investment. According to this simulation, the annual GHG emissions reduction and the annual electricity exported to the grid for 20 kW and 1 MW PV power plants are 22.06 tCO 2 , 1103 tCO 2 , 39 MWh, and 1953 MWh, respectively. From the economic outlook, based on the new feed-in tariff for power plants and the supposed initial costs, the payback period for the initial investments are between 3 and 4, and 5 years for 20 kW and 1 MW PV power plants, respectively.

No abstract

No abstract

No abstract