Pembuatan Biokompatibel Suture Anchor Berbasis 3D Printing Filament dari Nano Hidroksiapatit Berbahan Dasar Cangkang Keong Sawah

Suture anchor is used to attach soft tissues to the bone. One of the materials that can be used for making suture anchors is hydroxyapatite [Ca10(PO4)6(OH)2]. Hydroxyapatite (HAp)  has similarities with the properties of bone minerals, so it has the potential to be used as a material for making biocompatible suture anchors. However, HAp is brittle and has poor strength, so HAp is usually combined with polymers such as composites to overcome the limitations of its mechanical properties. One of the polymers that can be used is Polycaprolactone (PCL). In this study, HAp was synthesized from rice field snail shells, due to its high calcium contents.  Further, the combination of HAp and PCL in the manufacture of 3D printing filaments such as suture anchors was obtained. The variables used in this study were the mixing ratio of HAp:PCL in making filaments with a mixing ratio of 0.5:9.5; 1:9 ; 2:8. The results of various variables shows that the tensile strength most optimal composite in 7,3 % when mixing HAp:PCl is 0.5:9,5

Optimasi Panas Pada Unit SO2 Conversion Di Pabrik Asam Sulfat Dengan Metode Pinch Technology Menggunakan Aspen Energy Analyzer

Pada proses produksi asam sulfat terdapat 5 tahapan proses dan salah satu tahapannya adalah proses SO2 conversion. Proses ini terjadi dalam keadaan eksotermik karena aliran yang keluar dari reaktor nantinya akan menghasilkan panas setelah mengalami reaksi. Oleh karena itu, diperlukan upaya untuk menjaga suhu pada temperatur yang optimal. Optimasi panas merupakan salah satu upaya yang dapat dilakukan. Metode yang dapat digunakan adalah pinch technology, yaitu dengan cara mengintegrasikan aliran panas dan aliran dingin. Tujuan dari analisa optimasi ini adalah untuk mengetahui cara memaksimalkan penggunaan energi panas yang dihasilkan dari keadaan eksotermik pada proses SO2 conversion serta mengetahui pengaruh metode pinch technology pada jaringan heat exchanger dalam megoptimalkan panas pada proses SO2 conversion. Tahapan yang dilakukan adalah mengidentifikasi aliran proses, kemudian mengolah data termodinamika aliran untuk menentukan nilai pinch dari diagram cascade. Kemudian, data termodinamika diolah dengan menggunakan software aspen energy analyzer V.10 untuk mendapatkan grid diagram pada kondisi existing, lalu menentukan solusi yang mencakup hasil dari retrofit design menurut dengan kondisi data termodinamika pada kondisi existing. Pengevaluasian yang telah dilakukan didapatkan bahwa kondisi existing terdapat cross pinch. Oleh karena itu, didapatkan suhu pinch hot dan cold sebesar 115 oC dan 105oC. Selain itu, hasil analisa yang telah dilakukan yaitu jumlah unit Heat Exchanger yang dapat digunakan untuk kondisi existing dan retrofit design adalah 5 unit, dengan 7 unit shell pada kondisi existing dan 11 unit shell pada kondisi retrofit design, area kondisi existing dan retrofit design sebesar 6383 m2 dan 3272 m2 , nilai capital cost untuk kondisi existing sebesar 2493 x 106 sedangkan untuk retrofit design sebesar 8794 x 105 , dan total cost untuk kondisi existing sebesar 0.2085, sedangkan untuk retrofit design sebesar 0.1469. ==================================================================================================================================== In the sulfuric acid production process, there are 5 stages of the process and one of the stages is the SO2 conversion process. This process occurs in an exothermic state because the flow leaving the reactor will produce heat after experiencing the reaction. Because of that, efforts are needed to maintain the temperature at an optimal temperature. Heat optimization is one effort that can be applied. The method that can be used is pinch technology, by integrating hot flow and cold flow. The purpose of this optimization analysis is to find out how to maximize the use of heat energy resulting from exothermic conditions in the SO2 conversion process and to know the effect of the pinch technology method on heat exchanger networks in optimizing heat in the SO2 conversion process. The steps taken are the process of identifying the flow, then processing the thermodynamic data of the flow to determine the pinch value of the cascade diagram. After that, the thermodynamic data is processed using the Aspen energy analyzer V.10 software to obtain a grid diagram for the existing conditions, then determine a solution that includes the results of the retrofit design according to the thermodynamic data conditions for the existing conditions. The evaluation that has been carried out found that the existing condition has a cross pinch. Therefore, the pinch hot and cold temperatures are 115 oC and 105oC. In addition, the results of the analysis that has been carried out are the number of Heat Exchanger units that can be used for existing conditions and retrofit design is 5 units, with 7 shell units in existing conditions and 11 shell units in retrofit design conditions, the existing condition area and retrofit design are 6383 m2 and 3272 m2 , the value of capital cost for existing conditions is 2493 x 106 while for retrofit design is 8794 x 105, and the total cost for existing conditions is 0.2085. while the retrofit design is 0.1469