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"Glass production is thought to date to ~2500 BC and had found numerous uses by the height of the Roman Empire. Yet the modern view of glass-based chemical apparatus (beakers, flasks, stills, etc.) was quite limited due to a lack of glass durability under rapid temperature changes and chemical attack. This “brief” gives an overview of the history and chemistry of glass technology from its origins in antiquity to its dramatic expansion in the 13th century, concluding with its impact on society in general, particularly its effect on chemical practices."

"Komposit serat kaca yang diperkuat dengan bahan polimer Glasss Fibre Reinforced Polymer GFRP memiliki kekurangan yaitu kurang tahan terhadap api. Penggunaan clay dapat meningkatkan sifat tahan api terhadap GFRP. Akan tetapi, diperlukan pencampuran yang baik agar clay dapat terdispersi dengan baik. Penelitian ini bertujuan untuk mengetahui pengaruh clay dan kondisi pencampuran terhadap sifat anti bakar, kuat impak, dan modulus lengkung komposit GFRP/clay. Polimer Unsaturated polyester UP , serat kaca, dan 3-Aminopropyltriethoxysilane masing-masing digunakan sebagai matriks, penguat, dan compatibilizer untuk membuat komposit. Unsaturated polyester-clay-silane dicampur menggunakan magnetic stirrer dengan variasi kecepatan dan waktu pencampuran. Komposit unsaturated polyester-serat kaca-clay-silane difabrikasi menggunakan metode vacuum bagging. Variasi clay yang digunakan adalah 1 wt. , 2wt. , dan 3 wt.. Variasi kecepatan rotasi dan waktu pencampuran masing-masing 100,150, 200 rpm dan 60, 90, dan 120 menit. Komposit UP ndash; serat kaca digunakan sebagai bahan pembanding.Hasil penelitian menunjukkan bahwa komposit dengan kandungan clay 1wt tidak terbakar dengan nilai laju bakar sebesar 0 mm/min. Tidak terdapat perubahan variabel yang signifikan pada kuat impak dengan mekanisme berbeda seperti shear dan difusi yang bekerja bersamaan saat mendispersikan clay. Nilai modulus lengkung optimum dimiliki oleh komposit dengan komposisi clay 1 wt _200 rpm_60 menit sebesar 10 0.4 GPa , yang mengalami kenaikan 20 dibandingkan dengan UP ndash; serat kaca.

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Glass fibre reinforced polymer GFRP composites have a weakness in fire resistant property. The addition of clay can improve the fire resistant property of GFRP. However, a good mixing is needed to disperse the clay. This research aims to observe the effect of clay and mixing conditions on fire resistance, impact strength, and flexural modulus of GFRP clay composites. Unsaturated polyester UP , glass fiber and 3 Aminopropyltriethoxysilane respectively were used as a matrix, a reinforcement and a compatibilizer respectively to build the composites. Unsaturated polyester clay silane were mixed using a magnetic stirrer with a variation of rotation speed and mixing duration. The composites were fabricated using a vacuum bagging method. The composition of clay was varied from 1, 2, and 3 wt. The rotation speed and mixing time were varied at 100, 150, 200 rpm and 60, 90, and 120 minutes, respectively. UP glass fiber was used as a comparison material.

The results showed that composites with 1 wt clay content was not burned with the buring rate value of 0 mm min. There were no significant effects of variables on impact strength in between the boundaries that attributed to different mechanisms such as shear and diffusion that worked together to disperse the clay. The optimum flexural modulus was found in the 1 wt clay 200 rpm 60 minute composites with a value of 10 0.4 GPa in which 20 higher compared to the UP glass fibre composites."

"Penelitian ini bertujuan untuk mengetahui pengaruh lama perendaman dalam berbagai pH saliva buatan terhadap kekerasan permukaan material restoratif glass hybrid (EQUIA® FORTE Glass Hybrid Restorative System, GC Corporation, Japan). Jumlah spesimen 90 buah terbagi dalam sembilan kelompok perlakuan yaitu perendaman dalam saliva buatan dengan pH 4,5; 5,5; dan 7 dengan waktu perendaman masing-masing 1 jam, 24 jam, dan 72 jam pada suhu 37oC. Uji kekerasan permukaan menggunakan Knoop Microhardness Tester (Shimadzu HMV-G Micro Hardness Tester, Japan) dengan beban 50 gram selama 15 detik sebanyak 5 indentasi pada tiap spesimen. Hasil data dianalisis statistik dengan One-way ANOVA (p<0,05). Hasil penelitian menunjukkan terdapat perbedaan bermakna pada setiap kelompok perlakuan yaitu nilai kekerasan pada perendaman dengan larutan saliva buatan pH 4,5 dan lama perendaman 1 jam, 24 jam, dan 72 jam berturut-turut adalah sebesar 69,48 0,57 KHN, 54,76 0,23 KHN, dan 42,90 0,41 KHN. Sementara itu, nilai kekerasan dengan saliva buatan pH 5,5 dan lama perendaman 1 jam, 24 jam, dan 72 jam berturut-turut adalah sebesar 75,34 0,32 KHN, 57,45 0,47 KHN, dan 45,84 0,27 KHN. Dengan larutan saliva buatan pH 7 dan lama perendaman 1 jam, 24 jam, dan 72 jam didapatkan nilai kekerasan berturut-turut adalah 82,89 0,68 KHN, 62,49 0,37 KHN, dan 49,84 0,14 KHN. Disimpulkan bahwa dengan menurunnya pH saliva buatan dan semakin lamanya perendaman dapat menurunkan nilai kekerasan permukaan material restoratif glass hybrid.

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This study aims to determine the effect of immersion time in various pH of artificial saliva on the surface hardness of glass hybrid restorative materials (EQUIA® FORTE Glass Hybrid Restorative System, GC Corporation, Japan). There were 90 specimens (diameter 6mm, thickness 3mm), and the specimens were divided into nine groups immersed in artificial saliva with pH 4,5; 5,5; and 7 for 1 hour, 24 hours, and 72 hours at 37oC respectively. The surface hardness of each specimens were tested using Knoop Microhardness Tester (Shimadzu HMV-G Micro Hardness Tester, Japan) with 50 grams load for 15 seconds, with 5 indentations on each specimens. The statistical analysis using One-way ANOVA (p<0,05) showed that there were significant differences between each groups.

The result showed that the hardness number of the groups immersed in artificial saliva pH 4,5 for 1 hour, 24 hours, and 72 hours respectively are 69,48 0,57 KHN, 54,76 0,23 KHN, and 42,90 0,41 KHN. Meanwhile, the hardness number of the groups immersed in artificial saliva pH 5,5 for 1 hour, 24 hours, and 72 hours respectively are 75,34 0,32 KHN, 57,45 0,47 KHN, and 45,84 0,27 KHN. With artificial saliva of pH 7 for 1 hour, 24 hours, and 72 hours, the hardness number are 82,89 0,68 KHN, 62,49 0,37 KHN, and 49,84 0,14 KHN. It can be concluded that the lower pH value of artificial saliva and prolonged immersion time can reduce the surface hardness value of glass hybrid restorative materials."

"This book provides readers with an interest in medical ceramics with the ability to start making their own glasses and glass ceramics, together with an understanding of the various factors that control the final properties of these medical and dental materials. In addition, the authors describe various industrial problems with current, clinically-used medical glass ceramics and discuss appropriate scientific solutions."

"Komposit sandwich merupakan komposit struktur yang diproduksi menjadi panel atau balok ringan yang memiliki sifat kekakuan dan kekuatan yang tinggi. Penelitian ini bertujuan untuk membandingkan sifat mekanik dan morfologi komposit sandwich kulit polyester berpenguat woven roving E glass dan inti honeycomb polypropylene yang difabrikasikan dengan teknik VARI dan adhesif cold-press. Pengujian mekanik yang dilakukan pada penelitian ini adalah uji lentur, uji tarik, dan uji tekan. Pengamatan morfologi pada sebelum dan sesudah pengujian dilakukan dengan menggunakan kamera. Hasil penelitian ini menunjukkan bahwa fabrikasi adhesif cold-press memiliki nilai kekuatan lentur, tarik, dan tekan yang lebih unggul dibandingkan dengan metode VARI yaitu masing-masing sebesar (24,93 ± 0,21) MPa, (0,52 ± 0,02) MPa, dan (1,95 ± 0,05) MPa. Setelah uji lentur, tarik, dan tekan, sampel mengalami kerusakan pada bagian inti.

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Sandwich composites are structural composites that are manufactured into lightweight panels or beams with high stiffness and strength properties. This study aimed to compare the mechanical properties and morphological of polyester skin sandwich reinforced with woven roving E-glass reinforced polyester as skins and a polypropylene honeycomb core fabricated by the VARI and cold-press adhesive techniques. The mechanical tests which were flexural, tensile, and compressive tests were conducted. Morphological observations before and after testing were carried out using a camera. The results of this study indicated that the cold-press adhesive fabrication had superior flexural, tensile, and compressive strength values compared to the ones of VARI method, namely (24,93 ± 0,21) MPa, (0,52 ± 0,02) MPa, and (1,95 ± 0,05) MPa respectively. After bending, tensile, and compressive tests, all samples were failed in the core."