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Due to its potential application in luminescence technologies, the complete understanding on pressure dependence of ruby is especially important. Up to recently, the theoretical prediction on the structural properties of ruby under pressure has been made involving the empirical parameters. Therefore, here we performed a non-empirical study on the pressure dependence of ruby bond length. Due to the Cr3+ substitution and the applied external pressure, the local structure of α-Al2O3: Cr3+ was changed. We estimated this effect by performing the first-principles band-structure calculations using Cambridge Serial Total Energy Package (CASTEP) method and compared with the Shannon’s crystal radii method. The two different bond lengths; Cr-1st nearest neighbour oxygen (d 1) and Cr-2nd nearest neighbour oxygen (d 2) were investigated in detail. The results show that under 0-110 GPa the d 1 and d 2 decreased ca. 0.172 and 0.145 Å, respectively. These results were slightly smaller than the d 1 and d 2 decreases in the case of pure α-Al2O3 crystal, they were observed to be ca. 0.167 Å for d 1 and 0.177 Å for d 2. In the other words, the d 1-d 2 differences were larger at the higher pressure, ca. 0.052-0.080 Å for 0-110 GPa.

Tahu adalah makanan yang sangat populer di masyarakat. Tahu bersifat mudah rusak (busuk), pada kondisi biasa (suhu kamar) daya tahannya rata-rata 1-2 hari saja. Setelah lebih dari batas tersebut rasanya menjadi asam lalu berangsur-angsur busuk, sehingga tidak layak dikonsumsi lagi. Oleh karena itu, produsen tahu sering menambahkan zat pengawet berbahaya seperti formalin untuk memperpanjang masa simpan tahu. Bawang putih dan daun pandan merupakan alternatif pengawet alami yang diharapkan bisa memperpanjang masa simpan tahu dan mem-buat rasa tahu tetap disukai masyarakat. Tujuan penelitian ini untuk mengetahui perbedaan masa simpan dan citarasa tahu yang direndam dalam campuran larutan 2,5 % bawang putih dan 2,5 % daun pandan dengan tahu yang direndam dalam air mineral. Jenis penelitian adalah kuasi eksperimen dengan desain penelitian post-test only with control group. Obyek penelitian adalah 1.440 buah tahu putih berukuran 2 cm x 2 cm x 2,5 cm untuk 16 kali ulangan. Masa simpan di-ketahui dengan metoda ESS berdasarkan uji organoleptik, sementara tingkat kesukaan berda-sarkan citarasa diketahui dari lima orang panelis yang mengamati setiap 12 jam sekali. Karena  dengan uji Shapiro-Wilk diketahui bahwa data terdistribusi tidak normal, maka analisis statistik yang digunakan adalah Mann-Whitney yang menghasilkan nilai-p < 0,001; yang dapat disim-pulkan bahwa masa simpan dan citarasa tahu yang direndam dalam campuran larutan 2,5 % bawang putih dan 2,5 % daun pandan berbeda dengan tahu yang direndam dalam air mineral. Lama waktu simpan tahu eksperimen 23,3 jam lebih lama dan citarasanya lebih disukai diban-dingkan dengan tahu kontrol.

In the era of globalization, social media plays a great role in influencing students’ development. This influence tends to be a negative impact in which they easily imitate some negative actions such as doing student brawls, using and selling drugs, committing criminal acts, etc. These negative attitudes need to be handled and anticipated. One that can be proposed to overcome this problem is through the character education program. This program can be inserted into the Civics subject at school in which the Civics teachers play the main role as the leader of this character education. This type of research is descriptive qualitative. This research was conducted at SMA Negeri 12 Semarang. The results of the study show that the efforts of Civics teachers in shaping the character of students at SMA Negeri 12 Semarang are making learning devices in which there are character values, through active learning, in learning activities character values are inserted, Civics teachers become models and make themselves examples. for students as teachers of character. Some of them are such as emphasizing approaches to students through good communication with students, through independent assignments outside school hours by observing problems that are developing in the community so that students have concern for the surrounding environment and become critical in solving a problem. In addition, Civics teachers emphasize discipline to students.