Md. Ashiqur Rahman | Searcharxiv

arXiv2024

Fabrication of zinc oxide/graphene-carbon nanotubes nanocomposite with enhanced dye degradation ability

A comparative study between zinc oxide graphene-carbon nanotubes nanocomposite and ZnO nanoparticles was carried out to investigate their abilities in the degradation of Rhodamine B dye. We utilized the Modified Hummer method to prepare the graphene oxide nanosheet. Moreover, graphene-carbon nanotubes had been synthesized from GO and multi-walled carbon nanotubes with a hydroxyl group. The hydrothermal method was employed to fabricate the zinc oxide graphene-carbon nanotubes nanocomposite from ZnO nanoparticles and graphene-carbon nanotubes. During the characterization by X-ray Diffraction (XRD), all the significant peaks of ZnO and zinc oxide graphene-carbon nanotubes nanocomposite were found in the same phase angle. In addition, the final nanocomposite was also characterized by Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray Spectroscopy (EDS). Finally, from the dye degradation test, it was apparent that zinc oxide graphene-carbon nanotubes nanocomposite showed superior dye removal ability compared to the ZnO nanoparticles.

cond-mat.mes-hall↗

arXiv2023

A Computational Approach to Evaluate the Effect of Shelter Construction Material and Fuel Load on the Fire Spread Behavior in Rohingya Refugee Camp

Numerous fires break out, especially from January to March every year, destroying thousands of shelters in the Rohingya Refugee Camps. In this study, a computational approach has been taken to analyze the fire dynamic behavior of informal settlements (ISs) in Rohingya Refugee Camps. The design parameters for the mathematical model are determined based on a comprehensive survey carried out in Rohingya Refugee Camps in Cox's Bazar, Bangladesh. This survey is conducted on three camps having distinctive fuel features, i.e., Kutupalong Registered Camp (KRC), Camp 5, and Camp 4 Extension (Ex), in order to accumulate data on the type, density, arrangement of fuel, etc. Using the dataset of almost 500 shelters having 42 fuel characteristics features, simplified small scale representation of each camp under fire had been modelled in Fire Dynamic Simulator (FDS). It is found that Camp 5 is more vulnerable to fire hazard than Camp 4 Ex and KRC because of the dense fuel arrangement, bamboo structure and negligible separation distance between ISs. KRC's brick exterior acts as a fire barrier, and thereby despite having the largest internal fuel load of all three camps, prevents further spreading of fire from the ignited enclosure. It is also found that type of building material and separation distance are crucial for fire spread and increasing fuel load density causes the ceiling temperature to rise higher and the flashover point to approach faster. The findings of our study can be helpful for informed decision making of fire safety measures in the Rohingya Refugee Camps.

physics.flu-dyn↗