An experimental analysis of a stepped solar box cooker (SSBC) improved using energetic SiO2/TiO2 nanoparticles. They were used in different ratios between 5% to 25% as a coating on a bar plate to enhance thermal performance. The SSBC was assessed experimentally to obtain a costeffective solution and the best performance for the bar plate temperature, enabling increased cooking activities performance. The furious SiO2/TiO2 nanoparticles were coated over a bar plate, which allows them to absorb more solar radiation and increase the system of inner moist air temperature. The SiO2/TiO2 nanolayers used as 15% improved overall thermal efficiency by 31.42% of the system. The bar plate performances coated with SiO2/TiO2 nanolayers and used in SSBC were compared to other doping nanoparticles percentage for their solar thermal characteristics. The SiO2/TiO2 nanolayers coated by the SSBC is enabled to increase the performance by about 31.77%, 37.69%, 49.21%, 36.99%, and 34.66% when was used 5%, 10%, 2 15%, 20%, and 25%, respectively and compared to that of single nanolayers (SiO2, TiO2) of convention cooker.

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The lightweight titanium alloys possess good resistance to corrosion and temperature. They are used in turbine engines and aircraft structures. The strength of weld joint is dependent on thermal history in the weld zone and the weld bead geometry. The quality of weld can be improved by specifying the optimal welding parameters. Trial-and-error experimental methods are time-consuming and expensive. This paper deals with Computational Fluid Dynamics (CFD) models to carry out three-dimensional thermo-fluid analysis. Buoyancy and Marnangoni stress are incorporated. Temperature dependent properties of Ti-6Al-4V alloy and the process conditions are specified for generating the weld bead profile. The CFD model is validated initially through comparison of existing test data. Further studies are made by conducting tests on the pulsating laser welding of Ti-6Al-4V alloy. The effects of welding speed, pulse width and pulse frequency on the weld bead geometry are examined. This study confirms the adequacy of modeling and simulations of weld bead geometry with test results.

<abstract> <p>Day by day laser welding (LW) is gaining industrial importance. Good quality of weld joints can be realized through this process. Because this process yields low distortion and small weld bead. Aerospace, nuclear, automotive, and biomedical industries are opting for the lightweight and corrosion resistance titanium alloys. This paper deals with the generation of optimal weld bead profiles in the conduction mode laser beam welding (LBW) of thin Ti–6Al–4V alloy sheets. Laser beam diameter, power and welding speed are the 3 LBW parameters, whereas, bead width, depth of penetration, heat affected zone and maximum temperature are the performance indicators (PIs). 3 levels are set for each LBW parameter. Taguchi's L₉ OA (orthogonal array) is selected to minimize the numerical simulations. ANSYS Fluent V16.0 with Vc++ code is used to develop a generic model. %Contribution of each process variable on the PIs is assessed performing ANOVA analysis. The range of PIs is assessed adopting the modified Taguchi approach. A set of optimal LBW parameters are identified considering a multi-objective optimization technique. For these optimal LBW parameters weld bead width is minimum, and the depth of penetration is maximum. Empirical relations for PIs are developed and validated with simulations. Utilizing the Taguchi's design of experiments, empirical relations are developed for the performance indicators in laser beam welding (LBW) simulations performing few trial runs and identified the optimal LBW process parameters.</p> </abstract>

Lightweight aggregate concrete is developed by substituting normal weight aggregate either fully or partially based on strength and density required. Expanded polystyrene (EPS) bead is a type of low density material, which also has good energy-absorbing characteristics and can be used as light weight aggregate in concrete. In the present study, Structural lightweight aggregate concrete (SLWAC) was produced by fully replacing normal weight aggregate with combinations of EPS beads to Cinder by the ratio 20:80, 40:60, 60:40, 80:20 respectively. And GGBS was used as supplementary cementitious material. The resulting concrete had strength variation between 29.5 to 11.6 MPa, and the density variation of 2192 to 1701 kg/m3. Considering strength and density criteria 40:60 ratios was observed as the optimal mix. The Compressive strength acquired by concrete was inversely proportional to the volume of EPS beads. Effect of fibers on mechanical properties such as flexural strength, compressive strength, and split-tensile strength was studied on the optimal mix by using polypropylene fibers, it was observed that an 8.78% increase in flexural strength at 1% fibers, 16.5% increase in Compressive strength at 0.5% fibers, and 35.4% increase in split-tensile strength at 1% fibers. Along with this, durability tests such as water absorption and permeability tests were performed, the performance of this concrete in water absorption test is well within the limits but in permeability, it underperformed which confirms that as the EPS ratio in the concrete increased, the absorption and depth of penetration values increased considerably. Microscopic observations were also made to study the interface amongst the cement paste and aggregates. It was revealed that GGBS did not influence significantly on the bonding with EPS beads.