Studies on Engineering Properties of Red Seaweed (Kappaphycus spp.)
Cherryflor R. Balingasa1 and Arnold R. Elepano2
Tensile strength, density, porosity, specific heat, thermal conductivity and thermal diffusivity of red seaweed (Kappaphycus spp.) were determined within a moisture range of 46.8% to 975.3% dry basis (31.9% to 90.7% wet basis).
Tensile strength was based on the ratio of breaking load and linear density; density was measured using the relationship between mass and volume of the seaweed; specific heat was determined by using a calorimeter with toluene as a heat transfer medium; thermal conductivity was obtained using a modified Fitch set-up; and thermal diffusivity was computed from the experimentally determined values of thermal conductivity, specific heat and density.
Tensile strength of seaweeds increased from 2.61 to 37.3 x 10-4 N/tex with decreasing moisture content. Bulk density was found to vary between 88.5 to 383.9 kg/m3. Specific heat and thermal conductivity values obtained increased from 1.38 to 3.99 kJ/kg-C and 0.221 to 0.304 W/m-C, respectively with increasing moisture. Thermal diffusivity ranged from 1.98 to 18.1 x 10-7 m2/s.
Regression equations showing the relationships of moisture content with the engineering properties of red seaweed were presented. Results of the study can be used in the design of process equipment such as dryers and moisture meters.
Keywords: thermo-physical properties, red seaweed, tensile strength, density, porosity, specific heat, thermal conductivity, thermal diffusivity
1Instructor, Institute of Engineering and Technology, Camarines Sur State Agricultural College, Camarines Sur, Philippines and 2Associate Professor, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Banos, Philippines.