A Review of Parameters and Mechanisms in Spray Cooling

Miniaturisation in avionics, electronics, and medical appliances has led to demands for rapid heat dissipation techniques. The spray cooling technique has gained importance recently due to its advantage over other cooling methods. Parameters affecting heat transfer mechanisms during spray cooling are contemplated. This review presents different heat transfer parameters and their effect on spray cooling by analysis from past studies. Heat transfer surface modifications and different coolant variations to enhance heat transfer effectiveness are also reviewed. Apart from high heat flux having more applications, low heat flux studies have also grabbed the researchers to find solutions with a temperature range lower than 250˚C. Therefore, the upcoming spray cooling technology will have broad applications that will contribute to the maximum efficiency of the heat removal rate

An Experimental Investigation on the Strength and Durability Aspects of Bacterial Concrete with Fly Ash

This paper presents the results of an experimental investigation carried out to evaluate the influence of Bacillus sphaericus bacteria on the compressive strength, split tensile strength, flexural strength, shear strength, water absorption and chloride permeability of concrete made without and with fly ash. Cement was replaced with two percentages (10 and 20) with fly ash by weight. Three different cell concentration (0, 103,105,107 cells/ml) of bacteria were used in making the concrete mixes. Tests were performed at the age of 28 days. Test results indicated that inclusion of B. sphaericus in fly ash concrete enhanced the compressive strength reduced the water absorption and chloride permeability of fly ash concrete. Maximum increase in compressive strength 15.47% was observed with 105cells/ml of bacteria. This improvement in strength was due to deposition on the bacteria cell surfaces within the pores. The present work highlights the influence of bacteria on the properties of concrete made with supplementing cementing material such as like fly ash. Usage of bacteria like B. sphaericus improves strength and durability and strength of fly ash concrete through self-healing effect. Keywords: Bacterial concrete, Bacillus sphaericus, compressive strength, water absorption, chloride penetratio