Browsing by Author "Katiyar, Nirmal Kumar"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Open Access Large-scale manufacturing route to metamaterial coatings using thermal spray techniques and their response to solar radiation(Springer, 2021-07-04) Faisal, Nadimul Haque; Sellami, Nazmi; Venturi, Federico; Hussain, Tanvir; Mallick, Tapas; Muhammad-Sukki, Firdaus; Bishop, Alex; Upadhyaya, Hari; Katiyar, Nirmal Kumar; Goel, SauravMetamaterials, an artificial periodic two- or three-dimensional configuration can change propagation characteristics of electromagnetic waves (i.e., reflection, transmission, absorption). The current challenges in the field of metamaterial coatings are their manufacturing in large scale and large length scale. There is a clear need to enhance process technologies and scalability of these. Thermal spraying is a method used to deposit small to large scale coatings where the sprayed layer is typically formed by successive impact of fully or partially molten particles of a material exposed to various process conditions. This work aims to investigate the feasibility to manufacture large scale metamaterial coatings using the thermal spray technique and examine their response to solar radiation. Two types of coatings namely, Cr2O3 and TiO2 were deposited onto various substrates (e.g., steel, aluminium, glass, indium tin oxide (ITO) coated glass) with a fine wire mesh (143 µm and 1 mm aperture sizes) as the masking sheet to manipulate the surface pattern using suspension high-velocity oxy-fuel thermal spraying (S-HVOF) and atmospheric plasma-sprayed (APS) methods, respectively. Post deposition, their responses subjected to electromagnetic wave (between 250 nm to 2500 nm or Ultraviolet (UV)-Visible (Vis)-Infrared (IR) region) were characterised. The additional microstructural characterisation was performed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), three-dimensional profilometry and optical spectroscopy. It is demonstrated that through novel application of thermal spray techniques, large scale manufacturing of metamaterial coating is possible, and such material can affect the electromagnetic wave propagation. Comparison between Cr2O3 and TiO2 coatings on aluminium substrates showed reduced three orders of reduced reflectance for Cr2O3 coatings (for 1 mm aperture size) throughout the spectrum. It was concluded that for a similar bandgap, Cr2O3 coatings on aluminium substrate will yield improved optical performance than TiO2 coating, and hence more useful to fabricate opto-electronic devices.Item Open Access Potential pathway for recycling of the paper mill sludge compost for brick making(Elsevier, 2021-01-30) Goel, Gaurav; Vasić, Milica Vidak; Katiyar, Nirmal Kumar; Kirthika, S. K.; Pezo, Milada; Dinakar, P.This study's focus was to develop a potential pathway for recycling of the paper mill sludge compost (PMSC) in brick making. Composting reduces the paper mill sludge (PMS) moisture content considerably and shredding becomes easier. The addition of PMSC leads to an increase of porosities in bricks and makes them lighter, besides delivering energy to the firing process from burning organics. Lighter construction materials help minimize construction outlay by reducing labour and transportation costs and lesser expense on foundation construction. The variability in the experimental data and the brick properties were investigated for two types of soils, typical in the brick industry of India (alluvial and laterite soil), blended with PMSC in five mix ratios (0%, 5%, 10%, 15% and 20%). The samples of oven-dried bricks were fired at two different temperatures (850 and 900 ˚C) in an electrically operated muffle furnace representing typical conditions of a brick kiln. Various properties of bricks were analyzed which included linear shrinkage, bulk density, water absorption and compressive strength. Conclusions were drawn based on these properties. It was found that the addition of PMSC to the alluvial and laterite soil by up to 10% weight yield mechanical properties of fired bricks compliant with the relevant Indian and ASTM codes. Toxicity characteristic leaching procedure (TCLP) tests showed that PMSC incorporated fired bricks are safe to use in regular applications as non-load-bearing and infill walls. This study is timely in light of the European Green Deal putting focus on circular economy. Besides, it fulfils the objective of UN sustainable development goals (SDG).