Study of fuel insolubles: Formation conditions and characterization of copper compounds

The solids formed in the systems containing copper in different oxidation states, in the presence and absence of hexanoic acid and dodecanethiol, together and separately, at room temperature, were studied. The experiments were performed in a mineral oil matrix, free of sulfur compounds and metals; a diesel oil matrix; and the reagents alone, without any matrix. The deposits formed were analyzed by elemental analysis (EA), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and total copper by inductively coupled plasma-optical emission spectrometry (ICP-OES), for their identification and determination of the probable structures. In samples containing both hexanoic acid and dodecanethiol, when there is copper(I), anhydrous copper(II) hexanoate is preferentially formed, but in samples of copper(II), copper(II) mercaptate is formed first. In samples of metallic copper in mineral oil matrix, no deposit formations occur. In all cases in which deposits were formed, they were the same as in diesel oil matrix.     

Promising nature-based nitrogen-doped porous carbon nanomaterial derived from borassus flabellifer male inflorescence as superior metal-free electrocatalyst for oxygen reduction reaction

In this present study, novel hierarchical nitrogen-doped porous carbon for use as a metal-free oxygen reduction reaction (ORR) electrocatalyst is derived from borassus flabellifer male inflorescences by calcining at 1000 °C in an inert atmosphere using metal hydroxides as activating agent and melamine as nitrogen doping agent. The BET surface areas of the lithium-ion (Li-ion), potassium-ion (K-ion) and calcium-ion (Ca-ion) activated carbon are observed to be 824.02, 810.88 and 602.88 m² g^-1 respectively. Another interesting fact is that the total surface energy calculated by wicking method (73.2 mJ/m²), is found to be higher for Li-ion activated carbons. Among the prepared nitrogen-doped porous carbon, Li-ion activated system, showed an outstanding performance in ORR reaction in alkaline medium, thanks to its high surface area and notable surface activity. An incontrovertible of note that ORR half-wave potential of Li-ion activated nitrogen-doped carbon (0.90 V) is relatively higher in comparison to the commercial 20 wt % Pt/C catalyst (0.86 V). Inspite of overwhelming performance, the ORR reaction followed the preferred 4- electron transfer mechanism involving in the direct reduction pathway in all activated carbons. The ORR performance is also noticeably better and comparable to the best results in the literature based on biomass derived carbon catalysts.     

Study on LiI and KI with low melting temperature for electrolyte replenishment in molten carbonate fuel cells

Molten carbonate fuel cells (MCFCs) are regarded as the closest fuel cell to commercialization due to their high capacity and energy efficiency. However, they are operated at a high temperature (620 °C or higher), where liquid electrolyte loss occurs during operation; hence, their lifetime is limited. For the long-term operation of MCFCs, it is essential to develop a novel method to replenish the electrolyte during operation. However, it is very difficult to directly inject the electrolyte, (Li_0.62K_0.38)₂CO₃, into each unit cell of the stack unless it is supplemented through liquid or gas phase at low temperature. It was verified whether LiI and KI, which have low melting points and high vapor pressures, could replenish the lost electrolyte in MCFCs. In this study, the LiI and KI injected into the unit cell in liquid phase showed a similar tendency to the Li/K carbonate electrolyte. This is because LiI and KI react with the CO₂/O₂ gases supplied to the cathode during MCFC operation to form Li/K carbonate electrolytes.     

Photoreforming driven by indium hydroxide/oxide nano-objects

In(OH)₃/In₂O₃ nano-objects (plates and tubes) were prepared under controlled mild reaction conditions by simple basic thermal hydrolysis of 1-(2-methoxy-ethyl)-3-methyl imidazolium tetrachloro-indate (BMIOMe·InCl₄) ionic liquid (IL). As the reaction temperature increased from 10 °C to 80 °C, there was not only an increase in concentration of In₂O₃ but the growth of nano-tubes (NTs) also increased. At 10 °C, 30 °C, 50 °C, and 80 °C, 25.2 ± 7 nm sized nanoplates (NPls), small nanotubes (26.6 ± 6 nm in length and 8 ± 2 nm in width), NTs with a length of 25.9 ± 6 nm, and larger nanotubes (49.2 ± 18 nm) were obtained, respectively. The surface concentration of In(OH)₃ decreased with the augmentation of the reaction temperature (from 100% at 10 °C to 5.1% at 80 °C). The nano-objects displayed a band gap of 5.4 eV, which is in the range expected for photo-catalytic activity to generate hydrogen from alcoholic solutions. Remarkably, In(OH)₃/In₂O₃ catalyst prepared at 30 °C revealed 3.72 μmol h⁻¹ of rate of hydrogen with apparent quantum yield of 16.3%, yielding a total H₂ productivity of 57.6 μmol (5.76 mmol/g) after 32 h. This is the most active semiconductor photocatalysts reported so far of bare indium-based. The presence of In₂O₃ inside the nano-tubes is also important for the photacatalytic activity of the In(OH)₃ based semiconductor. The presence of the IL layer not only acts as a template to control the structure of the nano-objects, but its presence also induces H₂ generation.     

Investigation of appropriateness of coated steel piston for aluminium alloy piston for small engines

ABSTRACT

Materials substitution is an imperative research area. The aim of this research is cost reduction, improved performance on its physical, chemical or mechanical properties like improved strength, reduced weight or in terms of performances. The objective of this paper is to investigate the possibilities to use the steel piston in place of the aluminium alloy piston for small engine applications like portable generator. Aluminium alloy piston, uncoated steel piston, nickel-coated steel piston and hard chrome-coated steel piston are considered. Steel pistons plated had standard thickness and were physically experimented. The thermal analysis like thermal deformation, total and directional heat flux analysis were carried out in ANSYS software. For the outperformed piston, the CFD analyses on contoured particles were carried out with help of ANSYS Fluent software. The CFD analysis on contoured particles includes the static pressure, velocity as well as directional velocity components and path line of contoured particles.     

Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness, abrasion resistance and thermal properties compared to the alone CB filled rubber vulcanizates.     

Experimental studies on flow and heat transfer characteristics of secondary refrigerant-based CNT nanofluids for cooling applications

ABSTRACT

The aim of the research work is to explore the convective heat transfer coefficient characteristics of propanol-based nanofluids for cooling applications. The stable suspension of the nanofluid with volume fractions of 0.15 and 0.3 is prepared and characterised. The measurement on the density shows that there is only a negligible increase in the density of the nanofluid and the specific heat of the nanofluid increases with the volumetric concentration of nanofluids. Furthermore, there is an enhancement in the convective heat transfer coefficient of 70% for the nanofluid containing 0.3% of CNT.

Abbreviations: CNT: carbon nanotubes; IPA: isopropyl alcohol; MWCNT: multi-walled carbon nanotubes; SDBS: sodium dodecyl benzene sulphate