In the present work freezing and melting characteristics of water seeded with chemically functionalized graphene nano-platelets in a vertical cylindrical capsule was experimentally studied. The volume percentage of functionalized graphene nano-platelets was varied from 0.1% to 0.5% with an interval of 0.1%. The stability of the synthesised samples were carried out by zeta potential distribution. The thermal conductivity of the nanocomposite samples were experimentally measured using transient hot wire method. A maximum enhancement of ~24% in the thermal conductivity was observed for the 0.5% volume percentage in the liquid state while a ~53% enhancement in the solid state. Freezing and melting behaviour of water dispersed with graphene nanoplatelets were carried out using a cylindrical stainless steel capsule in a constant temperature bath. The bath temperatures considered for studying freezing characteristics were considered to be −6 °C and −10 °C, while to study the melting characteristics the bath temperature was set as 31 °C and 36 °C. The freezing and melting time decreased for all the test conditions when the volume percentage of GnP increased. The freezing rate was enhanced by ~ 43% and ~32% for the bath temperatures of −6 °C and −10 °C respectively at 0.5 vol % of graphene loading. The melting rate was enhanced by ~42% and ~63% for the bath temperature of 31 °C and 36 °C respectively at 0.5 vol % of graphene loading.

Nickel foam substrates are frequently utilised for renewable energy applications as porous 3D-substrates. Preparation of these substrates usually includes an acid washing step, however the degree to which this step affects the final electrochemical performance after spray coating a catalyst ink is unreported. Herein, we report the effect of acid washing through physicochemical and electrochemical characterisation. The electrochemical performance was determined by repeated measurements of catalyst-coated nickel foam substrates both with and without the initial step of acid washing. Acid washing increased current density by 17.9% for the acid treated, MoS2-coated nickel foam electrode. This increment was affiliated with an electrochemically active surface area which increased by 87.1%, where Tafel analysis indicated that the acid treated, MoS2-coated electrodes facilitates the initial water dissociation step of the hydrogen evolution reaction with greater ease. Similar effects were also discovered for acid treated PtIr(1:3)/C-coated nickel foam substrates, albeit with less pronounced effects. Stability was also improved where the degradation rate was reduced by 18.9% for the acid treated, MoS2-coated electrodes. This proves the utility of acid washing nickel foam electrodes.

The impact of long-term soil and crop management practices on soil biological and chemical properties in oilseed brassica-based production systems were deliberated for holistic soil health improvement in the present study. Different tillage, crop residue re-cycling and cropping systems were studied for 5-years in 0-15 and 15-30 cm soil profiles. No-till permanent beds with crop residue (PB+R) noticeably improved soil organic carbon (SOC), microbial biomass carbon (MBC), enzymes [dehydrogenase (DHA) and alkaline phosphatase (AlP)], nitrogen fractions (available, nitrate and total), and available phosphorus and potassium content in both the soil layers compared to conventional tillage without crop residues. Though, the plow soil layer (0-15 cm) showed higher concentration of soil carbon, enzymes, N fractions and available P than in the sub soil (15-30 cm). The dynamic soil biological and chemical properties were also varied with the crop stage, and recorded higher MBC at 30 days, SOC and enzymatic activities at 60 days, and N fractions and available P and K at harvest of mustard crop. Green gram-mustard rotation showed higher values of biological and chemical parameters. Thus, the legume-based mustard crop rotation following no-till permanent beds and residue re-cycling found holistic in improving soil health, and nutrient cycling.