Research on groundwater aquifer investigation in Banua Buha Asri 1 housing Buha Village by using resistivity geoelectric method goals to create a 2-dimensional model map of subsurface groundwater distribution. The uneven distribution of ground water causes problems for the community to fullfil their daily needs, because almost all human activities in their daily needs intersect with water. The presence of ground water stored in aquifers can be identified using geophysical exploration. The dipole-dipole configuration of geoelectric method is suitable as a method for identifying groundwater aquifers. Measured data processed by using Res2Dinv software. Exploration produced a 2-dimensional map of subsurface resistivity cross-sectional models. Potential groundwater aquifer (resistivity ? = 24 Om) surface with a depth of = 8 m on line 1 and = 12 m on line 2. Deep ground water was identified at a depth of =20 m on both lines.

A research aimed to study the adsorption of methylene blue on hydroxyapatite obtained from red snapper fish bones (Lutjanus sp.) was performed. The bones were calcined in a furnace at 600, 800, and 1000 oC and ground to pass a 100 mesh sieve. The materials were used in the adsorption experiment and the data obtained were analyzed using Langmuir, Freundlich, and Dubinin-Raduskevich adsorption isotherm models. The results showed that the higher the calcination temperature, the lower the capacity of the adsorbent to adsorb methylene blue. Calculated adsorption energy which was in a range of 0.84-1.14 kJ mol-1 indicated that the dye was adsorbed physically on the adsorbent and the adsorption could be well described by Freundlich adsorption isotherm model.

Odd harmonious graphs are graphs that have odd harmonious labeling properties. The purpose of this study is to get a new class of graphs which are odd harmonious graphs. The research method used consists of several stages, namely construction of definitions, formulation of labeling functions and proof of theorems. The results of this study is to get a graph construction will be given, namely the flower quadrilateral graphs FDQ(m) with m=1 and the flower variation of quadrilateral graphs FDQ(m) with m=1, which are the development of double quadrilateral graphs DQ and variation double quadrilateral graphs VDQ. It has further been proven that FDQ(m) and FVDQ(m) are odd harmonious graphs.