Judul: Sintesis dan Karakterisasi Octacalcium phosphate berbasis Cangkang Kerang Darah (Anadara granosa Linn.) dengan Variasi Molaritas dan Suhu Sintering.
Abstrak: Octacalcium phosphate (OCP) adalah biomaterial pengganti tulang dan gigi yang memiliki sifat biodegradable dan biocompatible yang tinggi. Sintesis OCP menggunakan cangkang kerang darah sebagai sumber kalsium dan H3PO4 sebagai sumber fosfat. Cangkang kerang hasil kalsinasi pada suhu 900 C selama 8 jam adalah murni CaO .Hasil uji AAS diperoleh kandungan Ca sebesar 66.41%. OCP disintesis dengan meneteskan larutan H3PO4 kedalam suspense CaO dengan variasi molaritas dan suhu sintering. Variasi molaritas Ca/P yang digunakan adalah [0.6]/[0.45], [1.2]/[0.9], dan [2.4]/[1.8] sedangkan varisi suhu sintering adalah 700 C, 800 C, 900 C, dan 1000 C. Identifikasi senyawa yang dihasilkan dianalisis menggunakan x-ray diffraction dan fourier transform infrared. Hasil pola difraksi sinar-X dan spektra FTIR menunjukan bahwa OCP terbanyak terbentuk pada molaritas Ca/P [2.4]/[1.8] dengan suhu sintering 900 C.
Keyword: fourier transform infrared, octacalcium phosphate, x-ray diffraction

Judul: Sintesis dan Karakterisasi Hidroksiapatit Berpori dari Cangkang Kerang Darah (Anadara granosa Linn.) dengan Porogen Lilin Lebah
Abstrak: Calcium phosphate compound is ceramic material that is used as good biomaterial for bones because of its bioactive and good biocompatibility which the composition is same as pure bone. The most stable calcium phosphate compound is hydroxyapatite (HAp) (Ca10(PO4)6OH2). But HAp has low dissolving level, thus porous HAp was made. HAp was synthesized by sol gel methods with main calcium material was provided by Cockle (A. granosa ) and as the porous agent was used beeswax dissolved by ethanol 96%. This research was done by 5 difference concentrations of beeswax, i.e. 10%, 20%, 30%, 40%, and 50%. Synthesis result was analyzed with X-ray diffractometer, scanning electron microscopy, and Fourier transform infrared. The result from X-ray diffractometer analysis showed the best porous HAp in this research used 30% beeswax as porous agent. Scanning microscopy electron analysis result showed big porous formed by using 50% beeswax with average macro porous size was about 1,74 μm and average micro porous size was about 0,245 μm . Calcium phosphate compound was sintered on the temperature 900o C for 5 hours.
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Judul: Dynamics Model for Rural and Urban Economic Growth
Abstrak: Lewis theory of structural change has focused on mechanisms that allow countries to transform their domestic economic structure to a more modern economy. The proposed model deals with the mechanism of interaction between rural and urban Economic. This model is concerned with the process of labor transfer from rural to urban areas. This study aims to model the dynamics of economic growth in rural and urban areas, including determining the equilibrium solution and to carry out simulation of the model. The simulation results show that the transfer of labor from rural to urban areas will increase the rate of change of capital so that structural changes can be realized. In addition, increased propensity to save in rural areas will also accelerate structural change
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