Relevant bibliographies by topics / Silica

Academic literature on the topic 'Silica'

Author: Grafiati
Published: 4 June 2021
Last updated: 30 July 2024

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Journal articles on the topic "Silica"

1

RAMOS, Vanessa Machado Babinski, Maurício Gammertt RÖHNELT, and Rodrigo BRAMBILLA. "HDPE/SILICA COMPOSITES- PART I: PREPARATION AND CHARACTERIZATION OF METHYLSILANE AND OCTYLSILANE-MODIFIED SILICAS." Periódico Tchê Química 16, no. 32 (August 20, 2019): 263–78. http://dx.doi.org/10.52571/ptq.v16.n32.2019.281_periodico32_pgs_263_278.pdf.

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This paper reports the main results concerning the synthesis and characterization of methylsilane and octylsilane-modified silicas. The modification of the silicas with these groups aims to make the silica surface hydrophobic and thus compatible with high-density polyethylene (HDPE) in HDPE/silica composites. In the present work, two types of silica were organofunctionalized: a pyrogenic silica and a silica gel. The silicas were characterized by a series of complementary techniques with the objective of investigating the nature of the surface species and their textural and morphological characteristics. The SEM images showed that the modification of the silicas with organosilanes has been not resulted in changes on the morphology and on the size of silica particles. In relation to the texture properties, determined by N2 adsorption-desorption porosimetry, the silica modification resulted in a decrease of the specific area (SBET) and the mean pore volume, a behavior attributed to the partial coverage of the adsorption sites by the organosilane molecules. The TGA analysis showed that both the methylsilane groups and the octylsilane groups on the surface of silica and silica gel are thermally stable up to 200 ° C, which enables the organofunctionalized silicas in terms of thermal stability, for the process of preparing the composites by extrusion. The results of applying these organofunctionalized silicas in the development of HDPE/silica composites will be presented in a subsequent article, part II of this research.
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2

Dilma Purnama Ubit, Yusmaniar Yusmaniar, and Erdawati Erdawati. "Adsorbsi Pewarna Direct Black 38 Menggunakan Komposit Silika Mesopori Dari Abu Sekam Padi/Karbon Aktif Dari Tempurung Kelapa." JRSKT - Jurnal Riset Sains dan Kimia Terapan 8, no. 1 (October 9, 2019): 1–9. http://dx.doi.org/10.21009/jrskt.081.01.

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Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1. Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash Abstrak Pada penelitian ini adsorben komposit silika mesopori dan karbon aktif dibuat untuk mengadsorpsi zat warna direct black 38. Silika mesopori dibuat dari abu sekam padi dan karbon aktif dibuat dari tempurung kelapa. Silika direaksikan dengan NaOH menjadi larutan natrium silikat lalu direaksikan dengan PEG yang selanjutnya PEG diekstraksi secara solvotermal sehingga menghasilkan produk silika mesopori dengan luas permukaan dan pori yang lebih besar. Silika mesopori diproses menjadi komposit dengan karbon aktif yang telah diaktivasi sebelumnya dengan larutan ZnCl2. Kandungan dari komposit silika mesopori/karbon aktif ditunjukkan melalui hasil analisis SEM bahwa komposit hasil sintesis menunjukkan penyebaran karbon dan silika terlihat pada morfologi komposit. Hasil analisis EDX menunjukan komponen penyusun komposit yaitu 38,6% karbon; 46,8% oksigen dan 14,6% silika. Hasil penelitian menunjukan bahwa kondisi optimum yang diperlukan untuk adsorpsi direct black 38 dengan komposit silika mesopori/karbon aktif yaitu pH 2 dan waktu optimum 30 menit. Adsorpsi direct black 38 oleh komposit silika mesopori/karbon aktif mengikuti isoterm adsorpsi Langmuir. Oleh karena itu, adsorpsi yang terjadi membentuk lapisan monolayer dengan kapasitas adsorpsi 68,493 mg g-1 Kata kunci: abu sekam padi, adsorpsi, karbon aktif, komposit, PEG, silika mesopori Abstract In this research, mesopore silica/activated carbon composite adsorbent was formed for dye adsorption direct black 38. The mesopore silica was from rice husk ash and activated carbon was from coconut shell. This rice husk ash is processed into sodium silicate solution and the solution was hybrid with PEG. Then PEG was extracted with solvotermal method to produce a higher surface area of mesopore silica. The mesopore silica was processed into composite with activated carbon that has been activated by ZnCl2 solution. The mesopore silica/activated carbon composite was analysed by SEM and showed the distribution of carbon, silica and oxygen as composite morphology. The EDX analysis showed that the composite contains of 46.8% carbon; 3.6% oxygen and 14.6% silica. The results showed that the optimum condition required for the adsorption of direct black 38 dye with mesopore silica/activated carbon composite pH was 2 and the optimum contact time was 30 minutes. Adsorption of direct black 38 by mesopore silica/activated carbon composite followed Langmuir adsorption isotherm and formed a monolayer layer with adsorption capacity 68.493 mg g-1. Keywords: activated carbon, adsorption, composite, mesopore silica, PEG, rice husk ash
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3

Hamzah, Moh, Mahendra A., and Eryanti Kalembang. "Potensi Silika Kuarsa Lokal sebagai Filler Kompon Karet dalam Pembuatan Balon Peluncur Kapal." Majalah Ilmiah Pengkajian Industri 8, no. 3 (July 31, 2019): 115–20. http://dx.doi.org/10.29122/mipi.v8i3.3666.

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Secara praktis material karet untuk produk barang teknik memerlukan sejumlah bahan lain sebagai bahan tambahan yang mampu meningkatkan kemampuan proses, nilai karakteristik teknis dan memperpanjang waktu pakai. Bahan filler digunakan untuk meningkatkan karateristik teknis terkait dengan karakteristik karet. Salah satu filler yang sering diaplikasikan adalah silika, namun dalam bentuk teraktivasi. Beberapa penelitian menunjukan bahwa filler silika mampu mempengaruhi karakteristik seperti tensile strength, abrasion and tear resistance. Penggunaan filler silika pada balon peluncur kapal juga meningkatkan kinerja wet traction, dan wear resistance serta mengurangi dampak rolling resitance. Untuk mengaplikasikan silika kuarsa sebagai filler karet maka perlu mengaktivasi permukaan silika kuarsa antara lain dengan cara nanosizing atau memodifikasi permukaan silika melapisi dengan silane-69 atau PEG-4000. Saat ini produk silika lokal yang dihasilkan belum memenuhi spesifikasi silika berukuran sub mikron seperti yang dibutuhkan oleh pasar, umumnya produksi silika lokal berukuran ≥ 30 μm. Oleh karena itu utilisasi kapasitas produksi industri silika lokal belum maksimal, baru 50%. Dengan adanya sentuhan teknologi diharapkan dapat memaksimalkan potensi silika lokal.Kata kunci : Nanosilika, Balon peluncur kapal, Filler kompon karet, SilikaAbstractPractically rubber material for engineering goods requires a number of other ingredients as additives that can improve the ability of the process, the value of the technical characteristics and extend the lifetime. Filler material is used to improve the technical characteristics related to the characteristics of the rubber. One of the frequently applied filler is silica, but in the activated form. Several studies have shown that the silica filler capable of affecting characteristics such as tensile strength, abrasion and tear resistance. The use of silica filler on the balloon launcher ships also improves wet traction performance and wear resistance and reduce the impact of rolling resitance. To apply as a quartz silica filler rubber it is necessary to activate the surface of silica quartz, among others, by the way nanosizing or modify the silica surface with silane coat-69 or PEG- 4000. Currently local silica products produced not meet the specifications of sub- micron sized silica as required by the market, local silica production generally sized ≥ 30 lm. Therefore, industrial production capacity utilization is not maximized local silica, 50% new. With the touch technology is expected to maximize the potential of local silica.Keywords : Nanosilika, Balloon launcher boats, Rubber compound filler, Silica
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4

RAMOS, Vanessa Machado Babinski, Maurício Gammertt RÖHNELT, and Rodrigo BRAMBILLA. "HDPE/SILICA COMPOSITES-PART II: EFFECT OF SILICA PARTICLE SIZE AND SILICA MODIFICATION ON THE THERMAL AND MECHANICAL PROPERTIES." Periódico Tchê Química 16, no. 32 (August 20, 2019): 287–305. http://dx.doi.org/10.52571/ptq.v16.n32.2019.305_periodico32_pgs_287_305.pdf.

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In this work, the effect of silica particle size and organosilane type used in the silica organofunctionalization on the thermal and mechanical properties of high-density polyethylene (HDPE)/silica composites were evaluated. HDPE/silica composites were prepared by the extrusion method using two types of silica: fumed silica, with nanometric particle size and silica gel, micrometric, modified with organosilanes containing methyl or octyl functional groups. Silicas were added to the HDPE at 1% v/v concentration. The addition of the silicas to the HDPE did not influence the melt (Tm) and the crystallization (Tc) temperatures of the resulting composites but influenced its crystallinity. The mechanical property of Izod impact strength, the dynamicmechanical rheological test (DMTA) and the surface contact angle analysis showed improvements in relation to pure HDPE when used methyl-modified pyrogenic silica as filler. This result suggests that the surface modification of pyrogenic silica with methylsilane groups results in a stronger interaction of this silica with the HDPE matrix. This effect was not observed for micron-sized silica gel, where modification with organosilanes was not sufficient to guarantee interfacial interaction with the HDPE matrix.
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5

Hanum, Farrah Fadhillah, and Aster Rahayu. "Studi pemanfaatan dan metode pemisahan silika dari coal fly ash." Open Science and Technology 2, no. 1 (January 8, 2022): 26–32. http://dx.doi.org/10.33292/ost.vol2no1.2022.44.

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Penggunaan batubara sebagai sumber energi masih belum tergantikan hingga saat ini, sehingga kajian mengenai pemanfaatan abu batubara masih sangat perlu untuk dikembangkan. Abu batubara merupakan limbah hasil proses pembakaran batu bara yang komposisinya akan berbeda sesuai dengan jenis batubara yang digunakan dan proses pembakaran yang dilakukan. Salah satu komposisi penyusun utama dari abu batubara ini adalah silika. Silika memiliki potensi untuk dimanfaatkan dalam berbagai tujuan seperti untuk pengolahan limbah, untuk bahan aditif dalam pertanian, hingga sebagai nanosilika. Paper ini berisi informasi mengenai pemanfaatan silika dari abu batubara yang sudah ada serta metode yang efektif untuk mendapatkan silika dari limbah abu batu bara ini. Dari pembahasan diketahui bahwa studi pemanfaatan silika saat ini umumnya berfokus ke arah sintesis zeolite. Penelitian pemanfaatan silika sebagai nanosilika baru mulai dikembangkan baru-baru ini. Sementara itu, pemanfaatan silika tidak terlepas dari metode ekstraksi silika dari coal fly ash tersebut. Dari pembahasan diketahui NaOH masih menjadi pilihan utama dalam proses leaching silika. Studi ini diharapkan dapat memberikan informasi bagi kemajuan riset dalam rangkapengolahan dan pemanfaatan limbah. The use of coal as an energy source has not been replaced until now, subsequently the studies on the utilization of coal fly ash still need to be developed. Coal fly ash is waste from the coal combustion process whose composition will differ according to the type of coal used and the combustion process carried out. One of the main constituents of coal ash is silica. Silica has the potential to be used in various purposes such as for waste treatment, for additives in agriculture, to nanosilica. This paper contains information on the utilization of silica from existing coal fly ash and an effective method for obtaining silica from the coal fly ash. Based on the discussion, it is known that the current study of the use of silica generally focuses on the synthesis of zeolite. The research on the use of silica as nanosilica has only recently been developed. Meanwhile, the role of silica is related to the method of extracting silica from the coal fly ash. It is known that NaOH is the main leaching solution in the case of silica leaching process. This study is expected to provide information for research progress in the context of processing and utilizing waste.
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Chiao, May. "In silica in silico." Nature Physics 5, no. 10 (October 2009): 709. http://dx.doi.org/10.1038/nphys1407.

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7

Hartanto, Djoko, Yusmaniar Yusmaniar, and Erdawati Erdawati. "Ekstraksi Karbon Aktif Bebas Silika dari Arang Sekam Padi untuk Adsorpsi Zat Warna Methyl Orange." JRSKT - Jurnal Riset Sains dan Kimia Terapan 9, no. 1 (June 30, 2023): 1–10. http://dx.doi.org/10.21009/jrskt.091.01.

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Abstrak Ekstrak karbon aktif bebas silika disintesis dari arang sekam padi berhasil diperoleh melalui perbandingan mol karbon:NaOH sebesar 1:3. Hasil karakterisasi SEM pada karbon aktif menunjukkan morfologi materialnya berbentuk butiran dan hasil karakterisasi EDX menunjukkan komposisimya terdiri dari 93.29% karbon; 6.71% oksigen dan 0% silika. Hasil karakterisasi FTIR karbon aktif bebas silika menunjukkan tidak adanya puncak silika pada bilangan gelombang 1100 cm-1. Berdasarkan hasil karakterisasi SAA, karbon aktif bebas silika memiliki luas permukaan sebesar 6.0018 m2g-1 yang tergolong jenis mikropori. Proses adsorpsi dari karbon aktif bebas silika dalam penyerapan zat warna methyl orange optimum pada massa adsorben sebanyak 200 mg dan maksimum pada massa adsorben 250 mg. Kata kunci: adsorpsi, karbon aktif bebas silika, methyl orange. Abstract The extraction of activated carbon free silica from rice husk with 1:3 mole ratio of carbon : sodium hydroxide has been successfully performed. The SEM result on activated carbon show the morphology of the material is granular and the EDX result showed the composition consisted of 93.29% carbon, 6.71% oxygen, 0% silica. The result of characterization FTIR not showing silica any peak of silica in wavelength 1100 cm-1. Based of characterization of SAA, indicates the material of activated carbon free silica has a surface area of 6.0018 m2/g, has a microporous type. The adsorption process on methyl orange pigment optimum at 200 mg and maximum at 250 mg. Keywords: adsorption, activated carbon free silica, methyl orange.
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Fairus, Sirin, H. Haryono, Mas H. Sugita, and Agus Sudrajat. "Proses pembuatan waterglass dari pasir silika dengan pelebur natrium hidroksida." Jurnal Teknik Kimia Indonesia 8, no. 2 (October 2, 2018): 56. http://dx.doi.org/10.5614/jtki.2009.8.2.4.

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Waterglass from silica sand production process with buster sodium hydroxideWaterglass may be prepared by the fusion process of silica sand using alkali. Waterglass component, which mainly contains SiO2 and Na2O, have various applications depending on their composition. Waterglass is usually used in the soap and detergent, paper, textile, and ceramic industries, in the cleaning of metals, the manufacture of silica gel, and others. This research was done to study the effect of silica sand particle size and the quantity of NaOH as fluxing agent on the yield and SiO2 content of waterglass produced by the alkali fusion process in a furnace. Silica sand particle size was varied at 35/40 and 50/60 mesh. The quantity of NaOH fluxing agent was varied at 1:1, 1.5:1, 2.4:1, 3.2:1, and 4:1 g/g to mass of the silica sand. Other fusion process variables, namely temperature, time, and silica sand quantity, were held constant at 500oC, 2 hours, and 10 gram, respectively. Research results indicated that decreasing silica sand particle size resulted in the increasing SiO2 and Na2O content. Increasing NaOH fluxing agent quantity increases the Na2O content of the waterglass. In this research, the highest SiO2 content of the waterglass of 34.6 %-mass SiO2, was obtained at an NaOH content of 2.4:1 g/g to mass of the silica sand, and silica sand particle size of 50/60 mesh.Keywords: silica sand, NaOH fluxing agent, particle size, waterglass AbstrakWaterglass dapat dibuat melalui proses peleburan pasir silika dengan alkali. Kandungan dalam waterglass, terutama berupa SiO2 dan Na2O mempunyai berbagai kegunaan tergantung pada komposisinya masing-masing. Biasanya waterglass digunakan pada industri sabun atau deterjen, kertas, tekstil, keramik, digunakan untuk pembersihan logam, pembuatan silika gel, dan lain sebagainya. Penelitian ini bertujuan untuk mempelajari pengaruh ukuran partikel pasir silika dan jumlah NaOH sebagai pelebur terhadap perolehan waterglass dan kadar SiO2 pada pembuatan waterglass dengan proses peleburan alkali di dalam furnace. Variabel berupa ukuran partikel pasir silika dipelajari pada ukuran 35/40 dan 50/60 mesh. Sedangkan banyaknya pelebur NaOH divariasikan sebanyak 1:1, 1,5:1, 2,4:1, 3,2:1, dan 4:1 g/g terhadap pasir silika. Kondisi peleburan lainnya berupa temperatur, waktu dan jumlah pasir silika, dilakukan pada nilai konstan, secara berturutan pada 500°C, 2 jam, dan 10 gram. Hasil penelitian menunjukkan bahwa pada penggunaan pasir silika dengan ukuran partikel yang makin kecil diperoleh waterglass dengan kadar SiO2 dan Na2O yang makin besar. Dan dengan makin banyaknya penggunaan pelebur NaOH, diperoleh kadar Na2O dalam waterglass juga makin tinggi. Pada penelitian ini waterglass dengan kadar SiO2 tertinggi diperoleh pada penggunaan pelebur NaOH sebanyak 2,4:1 g/g terhadap pasir silika dan ukuran pasir silika sebesar 50/60 mesh, yaitu sebesar 34,6 %-b SiO2.Kata kunci: pasir silika, pelebur NaOH, ukuran partikel, waterglass.
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Rahayu, Aster, Maryudi Maryudi, Joni Aldilla Fajri, Lee Wah Lim, and Nuraini Nuraini. "Synthesis of Silica-PEG By Physically Coating With PEG 4000 For Absorption of Ion Nitrate." Elkawnie 8, no. 2 (December 31, 2022): 250. http://dx.doi.org/10.22373/ekw.v8i2.14680.

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Abstract: All production activities will eventually produce waste, especially liquid waste. The nitrate ion (NO3-) is one of the substances in liquid waste that can have a significant impact on water systems and human health. Several methods can be used to treat the nitrate contained in the water, such as adsorption, phytoremediation, and wetland treatment. One of its methods was adsorption. The silica was modified with polymer due to its huge carbon chain. This research was focused on optimizing the ability of silica-based materials using PEG by physically coating them since PEG has a long carbon chain that could be transformed into a helix. In this research, the adsorbent will be prepared from modified silica gel with PEG 4000 by physical coating. Several parameters will be observed, including the effect of coating time, silica-PEG ratio, and PEG concentration. The capacity of silica-PEG to absorb NO3- is being studied. The characterization of functional group content in silica-PEG was carried out by Fourier Transform Infrared (FTIR). The study results show that the coating time was 10 minutes with the ratio of silica to PEG of 1:5, and the concentration of PEG used was 15%, indicating the optimum performance of silica-PEG when used as an absorbent, which achieved 84.44 % nitrate removal. An increase in the absorption capacity of silica-PEG demonstrates the ability of silica-PEG as a porous material. It was compared to silica gel without the PEG coating process, which was 9.09% to 84.44%.Abstrak: Semua kegiatan produksi pada akhirnya akan menghasilkan limbah, terutama limbah cair. Limbah cair biasanya akan bermuara di sungai dan berakhir di laut. Salah satu zat dalam limbah cair adalah ion nitrat (NO3-) yang mana dalam jumlah banyak dapat mengganggu sistem perairan dan kesehatan. Beberapa metode dapat digunakan untuk mengolah nitrat yang terkandung dalam air, seperti adsorpsi. Salah satunya dimodifikasi dengan polimer karena memiliki rantai karbon yang besar. Penelitian ini dikonsentrasikan untuk menyelidiki optimalisasi kemampuan silika dengan PEG dengan pelapisan fisik karena PEG memiliki rantai karbon panjang yang dapat bertransformasi menjadi heliks. Dalam penelitian ini, adsorben akan dibuat dari silika gel termodifikasi dengan PEG 4000 dengan pelapisan fisik. Beberapa parameter yang akan diamati antara lain pengaruh waktu pelapisan, rasio silika-PEG, konsentrasi PEG, dan temperatur pelapisan. Kinerja silika-PEG untuk menyerap NO3- diselidiki. Karakterisasi kandungan gugus fungsi pada silika-PEG dilakukan dengan Fourier Transform InfraRed (FTIR). Hasil penelitian menunjukkan bahwa waktu pelapisan adalah 10 menit dengan perbandingan silika dan PEG 1:5, dan konsentrasi PEG yang digunakan adalah 15%, menunjukkan kinerja silika-PEG yang optimum bila digunakan sebagai penyerap NO3-. Kemampuan silika-PEG sebagai bahan berpori dibuktikan dengan peningkatan kapasitas penyerapan silika-PEG dibandingkan silika gel tanpa proses pelapisan PEG.
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Fathurrahman, Muhammad, Usep Suhendar, Ani Iryani, Diana Widiastuti, Sherin Nurhafidza Ahmad, and Esya Juniar. "Sintesis dan Karakterisasi Komposit Eugenol-Silika Gel dari Abu Tongkol Jagung serta Analisis Antibakteri dan Daya Serap terhadap Air." ALCHEMY Jurnal Penelitian Kimia 18, no. 1 (February 2, 2022): 10. http://dx.doi.org/10.20961/alchemy.18.1.47161.10-18.

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<p dir="ltr">Tongkol jagung mempunyai kandungan silika yang cukup tinggi, yaitu 67,41% dari total abunya yang memungkinkan untuk dimanfaatkan untuk pembuatan komposit eugenol-silika gel. Penelitian ini bertujuan mempelajari pembuatan komposit eugenol-silika gel dengan bahan dasar abu tongkol jagung menggunakan metode sol gel, diikuti dengan analisis daya serap air dan aktivitas antibakteri terhadap <em>E. coli</em> dan <em>S. aureus</em>. Komposit eugenol-silika gel ini dikarakterisasi menggunakan <em>Fourier Transform Infrared</em> (FTIR), <em>X-ray Diffraction</em> (XRD), <em>Scanning Electron Microscope</em> (SEM) dan <em>Thermogravimetric Analysis</em> (TGA). Hasil karakterisasi dengan FTIR menunjukkan bahwa sintesis komposit eugenol-silika gel berhasil dilakukan. Analisis menggunakan XRD menunjukkan bahwa komposit eugenol-silika gel memiliki bentuk amorf. Karakteristik mikrostruktur menggunakan SEM menunjukkan permukaan yang tidak merata dan terdapat gumpalan (<em>cluster</em>) yang menandakan adanya bentuk butiran-butiran yang beragam berbentuk bulat atau globular pada permukaan komposit eugenol-silika gel. Analisis termogravimetri yang dilakukan sampai suhu 600 °C menunjukkan total prosentase pengurangan massa komposit eugenol silika-gel sebesar 13,10%. Daya serap air komposit eugenol-silika gel memiliki nilai persentase yang lebih tinggi dibandingkan dengan silika gel <em>food grade</em>. Akan tetapi, komposit eugenol-silika gel tidak memiliki aktivitas antibakteri terhadap <em>E. coli</em> dan <em>S. aureus</em>.</p><div><p dir="ltr"><strong>Synthesis and Characterization of Eugenol-Silica Gel Composite from Corn Cob Ash and Analysis of Antibacterial and Water Absorption. </strong>Corn cobs have high silica content, specifically 67.41% of the total ash, possibly used for eugenol-silica gel composite manufacture. This study aims to synthesize eugenol-silica gel composite with corn cob ash as the base material by sol gel method, followed by analyzing water absorption and antibacterial activity against <em>E. coli</em> and <em>S. aureus</em>.<strong> </strong>The method used is the sol-gel method. This eugenol-silica gel composite was characterized using Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Thermogravimetric Analysis (TGA). The characterization results by FTIR showed that the synthesis of the eugenol-silica gel composite was successfully carried out. Analysis using XRD showed that the eugenol-silica gel composite had an amorphous form. Microstructural characteristics using SEM showed an uneven surface and clusters indicating the presence of various globular or spherical shapes on the surface of the eugenol-silica gel composite. Thermogravimetric analysis carried out until a temperature of 600 °C showed the total percentage reduction in mass of the eugenol silica-gel composite was 13.10%. The water absorption of eugenol-silica gel composite has a higher percentage value than food-grade silica gel. However, eugenol-silica gel composite has no antibacterial activity against <em>E. coli</em> and <em>S. aureus. </em></p></div>
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Dissertations / Theses on the topic "Silica"

1

Chiaranussati, Preeyanuj. "NMR studies of silicas and platinum/ silica catalysts." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319580.

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Lorier, Troy Howard. "The dissolution kinetics of quartz and amorphous silica in natural waters : a baseline for silica reactivity." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/25757.

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Spaargaren, Susan Marianne Rosemary. "Radiation effects on silica based waveguides." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267942.

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Bashir, Muhammad Ahsan. "Impact of Physical Properties of Silica on the Reaction Kinetics of Silica Supported Metallocenes and Polyethylene Morphology." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1253/document.

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Les polyolefins représentent plus de la moitié de la production mondiale de plastiques et 80% de ces polymères sont produits avec des catalyseurs hétérogènes de type Phillips, Ziegler-Natta et métallocènes. En effet, un bon fonctionnement des unités du fait d'un faible encrassement du réacteur ou des autres équipements de l'unité, une activité stable, une bonne morphologie particulaire des polymères et un une densité apparente élevée sont obtenus en utilisant des catalyseurs hétérogènes. D'un autre côté l'hétérogénéisation d'un catalyseur s'accompagne d'une diminution de l'activité et d'un élargissement de la distribution de masses molaires qui est parfois non désiré car cela peut influencer l'aptitude à la transformation et les propriétés mécaniques des polyoléfines. Plusieurs explications ont été avancées dans la littérature afin d'expliquer l'effet de l'immobilisation d'un catalyseur ce qui inclut la résistance diffusionnelle au transport du (des) (co)- monomère(s) vers le site actif et la modification du comportement du catalyseur conduisant à plusieurs espèces actives. Néanmoins l'ensemble de ces explications est en connexion avec les propriétés physiques du support (tailles des particules, surface spécifique, volume poreux, diamètre des pores…) car ce dernier peut en effet impacter la nature des espèces actives ainsi que leur dispersion et la diffusion des monomères. Les catalyseurs métallocène sont considérés comme mono-site et tout changement dans la nature du site actif au cours de son immobilisation et toute résistance au transfert de matière peuvent être détectés par un élargissement de la distribution des masses molaires. Le présent travail a pour objet d'étudier les effets des propriétés physiques des catalyseurs métallocènes supportés sur silice concernant la cinétique de polymérisation et les caractéristiques des polymères produits. Pour cela le traitement thermique de la silice a été fixé à 600°C afin de contrôler son état de surface tandis que la quantité de catalyseur supporté a été gardée autant que possible constante. De plus les protocoles de polymérisation en phases suspension et gaz ont été fixés après avoir évalué différentes conditions de polymérisation et différents composés alkylaluminium. Cette étude systématique a permis d'attribuer les différences observées en termes de cinétique de réaction des catalyseurs métallocènes à la différence des paramètres physiques des silices utilisées comme support et par conséquent à la résistance diffusionnelle au transport du (des) (co)-monomère(s) au(x) site(s) actif(s) durant la polymérisation
Polyolefins account for more than half of the world’s plastic production and about 80% of these polyolefins are commercially produced with heterogeneous olefin polymerization catalysts such as Phillips, Ziegler-Natta and metallocenes. Trouble-free plant operation due to low fouling of the reactor or other plant equipment, relatively stable catalytic activity, good polymer morphology and high polymer bulk densities can be achieved by employing heterogeneous olefin polymerization catalysts. On the other hand, heterogenization of the olefin polymerization catalysts lead to drastic reduction in their activities and broadening of the polymer molar mass distribution which is undesirable in some cases because it can influence the processability and mechanical properties of the polyolefin grade. Various explanations have been proposed in the open literature to explain these effects of catalyst immobilization which mainly include existence of diffusion resistance to (co)-monomer(s) transport at the active sites during polymerization and the change of the active site(s) behavior due to immobilization leading to multiple site types on the final supported catalyst. Nevertheless, both of these explanations have a connection with the physical properties (e.g., particle size, surface area, pore volume, pore diameter etc.) of the support because the support can impact the nature of the final active species formed on it, dispersion of the active species throughout the support particles and, last but not the least, the intraparticle diffusion of (co)-monomer(s) during polymerization. Metallocenes are considered as single-site catalysts and any changes in the nature of the active site(s) upon their immobilization on a support or during the course of polymerization due to mass transfer resistance can be detected from the broadening of polyolefin molar mass distribution. Therefore, the present work is an attempt to study the effects of physical properties of silica supported metallocenes on their ethylene polymerization kinetics as well as on the morphology of the produced polyethylene. For this purpose, the surface chemistry of the used commercial silica supports was fixed by dehyroxylating all of them at 600 °C, whereas, the final metal loadings of the supported catalysts were nearly kept constant by preparing them under identical conditions. Furthermore, slurry and gas phase polymerization protocols along with the used aluminum alkyl scavenger (which can also induce chemical effects on the catalytic behavior of supported metallocenes) were also fixed by testing different polymerization protocols and scavengers. Such systematic study has allowed us to attribute the observed differences in the reaction kinetics of the supported metallocenes, explicitly, to the differences in the physical parameters of the silica supports and, consequently, to the existence of diffusion resistance to (co) monomer(s) transport at the active site(s) during the course of polymerization
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Durham, Simon J. P. "Carbothermal reduction of silica to silicon nitride powder." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74221.

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The processing conditions for carbothermal reduction of silica to silicon nitride was found to be sensitive to several key processing parameters: namely the intimacy of mixing of carbon and silica, the temperature, the specific high surface area of carbon, the nitrogen gas purity and the action of the nitrogen gas passing through the reactants.
Sol-gel processing was found to provide superior mixing conditions over dry mixing, which allowed for complete conversion to silicon nitride at optimum carbon:silica ratios of 7:1. The ideal reaction temperature was found to be in the range of 1500$ sp circ$C to 1550$ sp circ$C. Suppression of silicon oxynitride and silicon carbide was achieved by ensuring that: (a) the nitrogen gas was gettered of oxygen, and (b) that the gas passed through the reactants. Thermodynamic modelling of the Si-O-N-C system showed that ordinarily the equilibrium conditions for the formation of silicon nitride are very delicate. Slight deviations away from equilibrium leads to the formation of non-equilibrium species such as silicon carbide caused by the build-up of carbon monoxide. Reaction conditions such as allowing nitrogen gas to pass through the reactants beneficially moves the reaction equilibrium well away from the silicon carbide and silicon oxynitride stability regions.
The particle size of silicon nitride produced from carbon and silica precursors was of the order of 2-3 $ mu$m and could only be reduced to sub-micron range by seeding with ultra-fine silicon nitride. It was shown that the mechanism of nucleation and growth of unseeded reactants was first nucleation on the carbon by the reaction between carbon, SiO gas and nitrogen (gas-solid reaction), and then growth of the particles by the gas phase reaction (CO, SiO, N$ sb2$).
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Pacheco, e. Silva Viviane. "Compositos elastomericos de fibras curtas de silica/silicona." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250485.

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Orientador: Inez Valeria Pagotto Yoshida
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-04T13:38:50Z (GMT). No. of bitstreams: 1 PachecoeSilva_Viviane_M.pdf: 4530394 bytes, checksum: 571677ec4e372aa12989ee8eada906a1 (MD5) Previous issue date: 2005
Mestrado
Quimica Inorganica
Mestre em Química
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7

Martinez, Nelson Yohan Reidy Richard F. "Wettability of silicon, silicon dioxide, and organosilicate glass." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/ark:/67531/metadc12161.

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Savchyn, Oleksandr. "Silicon-sensitized erbium excitation in silicon-rich silica for integrated photonics." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4642.

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It is widely accepted that the continued increase of processor performance requires at least partial replacement of electronic interconnects with their photonic counterparts. The implementation of optical interconnects requires the realization of a silicon-based light source, which is challenging task due to the low emission efficiency of silicon. One of the main approaches to address this challenge is the use of doping of silicon based matrices with optical centers, including erbium ions. Erbium ions incorporated in various hosts assume the trivalent state (Er[super]3+) and demonstrate a transition at 1.54 micrometer], coinciding with optical transmission windows in both silicon and silica. Due to the low absorption cross-section and discrete energy levels of the Er[super]3+ ion, indirect excitation is necessary. In late 90s it was demonstrated that the incorporation of excess silicon in erbium-doped silica results in strong erbium sensitization, leading to an increase of the effective absorption cross-section by orders of magnitude. The sensitization was considered to occur via silicon nanocrystals that formed at high annealing temperatures. While a large increase of the absorption cross-section was demonstrated, the incorporation of Si nanocrystals was found to result in a low concentration of excited erbium, as well as silicon related free-carrier absorption. The focus of this dissertation is the investigation of the nature of the sensitization mechanism of erbium in silicon-rich silica. The results presented in the dissertation demonstrate that erbium in silicon-rich silica is predominantly excited by silicon-excess-related luminescence centers, as opposed to the commonly considered silicon nanocrystals. This is a remarkable conclusion that changes the view on the exact origin of erbium sensitization, and that resolves several technical challenges that exist for nanocrystal-based sensitization.; The work shows that in order to sensitize erbium ions in silicon-rich silica there is no need for the presence of silicon nanocrystals, and consequently lower fabrication temperatures can be used. More importantly, the results strongly suggest that higher gain values can be acquired in samples annealed at lower temperature (without silicon nanocrystals) as compared to samples annealed at high temperatures (with silicon nanocrystals). In addition, the maximum gain is predicted to be relatively independent of excitation wavelength, significantly relaxing the requirements on the pump source. Based on the experimental results it is predicted that relatively stable performance of erbium-doped silicon-rich silica is possible up to typical processor operating temperatures of ~ 80 - 90[degrees]C making it a viable material for on-chip devices. The results suggest that low temperature annealed erbium-doped silicon-rich silica is a preferable material for on-chip photonic devices as compared with its high temperature annealed counterpart.; The work shows that the density of indirectly excited erbium ions is significantly larger in samples without silicon nanocrystals (annealed at T[less than]1000[degrees]C) as opposed to samples with silicon nanocrystals (annealed at T[greater than]1000[degrees]C). The density of indirectly excited erbium ions, defining the maximum achievable gain, was demonstrated to be approximately excitation wavelength independent, while the effective erbium absorption cross-section was shown to significantly depend on the excitation wavelength. The excitation mechanism of erbium by luminescence centers was shown to be fast (less than] 30 ns) and capable of erbium sensitization to different energy levels. This multilevel nature of erbium excitation was demonstrated to result in two different mechanisms of the excitation of the first excited state of erbium: fast (less than]30 ns) direct excitation by the luminescence centers, and slow (greater than]2.3 microseconds]) excitation due to the relaxation of erbium ions excited into higher energy levels to the first excited state. Based on photoluminescence studies conducted in the temperature range 15-300K it was shown that the relaxation efficiency of erbium from the second excited state to the first excited state (responsible for the slow excitation mechanism) is temperature independent and approaches unity. The relative stability of the optical properties demonstrated in the temperature range 20-200[degrees]C, implies that relatively stable optical gain can be achieved under realistic on-chip operating conditions. The optimum Si excess concentration corresponding to the highest density of sensitized Er[super]3+ ions is shown to be relatively insensitive to the presence of Si nanocrystals and is ~ 14.5 at.% and ~ 11.5 at.% for samples without and with Si nanocrystals respectively. The presented results and conclusions have significant implications for silicon photonics and the industrial application of Er-doped SiO[sub]2. The work shows that in order to sensitize erbium ions in silicon-rich silica there is no need for the presence of silicon nanocrystals, and consequently lower fabrication temperatures can be used. More importantly, the results strongly suggest that higher gain values can be acquired in samples annealed at lower temperature (without silicon nanocrystals) as compared to samples annealed at high temperatures (with silicon nanocrystals). In addition, the maximum gain is predicted to be relatively independent of excitation wavelength, significantly relaxing the requirements on the pump source. Based on the experimental results it is predicted that relatively stable performance of erbium-doped silicon rich silica is possible up to typical processor operating temperatures of ~ 80 - 90[degrees]C making it a viable material for on-chip devices. The results suggest that low temperature annealed erbium doped silicon-rich silica is a preferable material for on-chip photonic devices as compared with its high temperature annealed counterpart.
ID: 029094291; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references.
Ph.D.
Doctorate
Optics and Photonics
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9

Ahmad, Nazwin. "Production of high purity silica from Malaysian silica sand." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427764.

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Yoshida, Hisao. "Studies on Photocatalysis by Silica and Silica - Based Materials." Kyoto University, 1998. http://hdl.handle.net/2433/157038.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・論文博士
博士(工学)
乙第9830号
論工博第3320号
新制||工||1114(附属図書館)
UT51-98-G429
(主査)教授 吉田 鄕弘, 教授 川﨑 昌博, 教授 横尾 俊信
学位規則第4条第2項該当
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Books on the topic "Silica"

1

1924-, Bergna Horacio E., and Roberts William O. 1936-, eds. Colloidal silica: Fundamentals and applications. Boca Raton, FL: Taylor and Francis, 2005.

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Great Britain. Health and Safety Executive., ed. Silica. Sudbury: HSE Books, 1999.

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United States. Branch of Industrial Minerals., ed. Crystalline silica primer. [Washington, D.C.?]: U.S. Dept. of the Interior, U.S. Bureau of Mines, 1992.

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De La Rocha, Christina, and Daniel J. Conley. Silica Stories. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54054-2.

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Society for Mining, Metallurgy, and Exploration (U.S.), ed. Crystalline silica. Littleton, CO: Society for Mining, Metallurgy, and Exploration, 1998.

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Sachithanadam, Mahesh, and Sunil Chandrakant Joshi. Silica Aerogel Composites. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0440-7.

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Geitgey, Ronald P. Silica in Oregon. Portland, Or: State of Oregon, Dept. of Geology and Mineral Industries, 1990.

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Watson, D. M. Silica in Manitoba. Winnipeg: Manitoba Energy and Mines, Geological Services, 1985.

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1935-, Papirer Eugène, ed. Adsorption on silica surfaces. New York: Marcek Dekker, 2000.

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Innocenzi, Plinio. Mesoporous Ordered Silica Films. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-89536-5.

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Book chapters on the topic "Silica"

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Srivastava, Yash, and Amit Basu Sarbadhikari. "Silica, Silicate." In Encyclopedia of Lunar Science, 1–8. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-05546-6_215-1.

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Srivastava, Yash, and Amit Basu Sarbadhikari. "Silica, Silicate." In Encyclopedia of Lunar Science, 1096–103. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-319-14541-9_215.

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Heaney, Peter J. "Chapter 1. STRUCTURE AND CHEMISTRY OF THE LOW-PRESSURE SILICA POLYMORPHS." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 1–40. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-006.

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Hemley, Russell J., Charles T. Prewitt, and Kathleen J. Kingma. "Chapter 2. HIGH-PRESSURE BEHAVIOR OF SILICA." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 41–82. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-007.

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Palmer, David C. "Chapter 3. STUFFED DERIVATIVES OF THE SILICA POLYMORPHS." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 83–122. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-008.

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Kronenberg, Andreas K. "Chapter 4. HYDROGEN SPECIATION AND CHEMICAL WEAKENING OF QUARTZ." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 123–76. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-009.

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Wenk, H. R. "Chapter 5. PREFERRED ORIENTATION PATTERNS IN DEFORMED QUARTZITES." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 177–208. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-010.

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Graetsch, Heribert. "Chapter 6. STRUCTURAL CHARACTERISTICS OF OPALINE AND MICROCRYSTALLINE SILICA MINERALS." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 209–32. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-011.

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Knauth, L. Paul. "Chapter 7. PETROGENESIS OF CHERT." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 233–58. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-012.

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Dove, P. M., and J. D. Rlmstidt. "Chapter 8. SILICA-WATER INTERACTIONS." In Silica, edited by Peter J. Heaney, Charles T. Prewitt, and Gerald V. Gibbs, 259–308. Berlin, Boston: De Gruyter, 1994. http://dx.doi.org/10.1515/9781501509698-013.

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Conference papers on the topic "Silica"

1

Essid, M., M. Verhaegen, L. B. Allard, J. L. Brebner, and J. Albert. "Ion Implantation Induced Photosensitivity in Silica and Ge-Doped Silica." In Photosensitivity and Quadratic Nonlinearity in Glass Waveguides. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/pqn.1995.sub.16.

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Photosensitivity can be induced in silica1 and Ge-doped silica2 by high energy ion implantation. The optical absorption induced in the ultraviolet region by the implantation can be substantially reduced by exposure to excimer laser light resulting in a polarisation dependent3 change in the refractive index at longer wavelengths. This refractive index change can be related to the variation in the absorption by Kramers-Kronig analysis4,5. We describe here, the result of a series of experiments undertaken to determine the effects of ion implantation on the photosensitivity of silica and Ge-doped silica planar waveguide structures.
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Schmidt, C., A. Chipouline, T. Kasebier, G. K. Chowdhury, E. B. Kley, A. Tunnermann, L. Deych, and T. Pertsch. "Nonlinear effects in silica and hybrid silica/silicon disc micro resonators." In 2009 IEEE/LEOS Winter Topicals Meeting Series (WTM 2009). IEEE, 2009. http://dx.doi.org/10.1109/leoswt.2009.4771686.

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Schmidt, C., A. Chipouline, T. Kasebier, E. B. Kley, A. Tunnermann, L. Deych, and T. Pertsch. "Nonlinear optical response of silica and hyybrid silica/silicon disc micro resonators." In 11th European Quantum Electronics Conference (CLEO/EQEC). IEEE, 2009. http://dx.doi.org/10.1109/cleoe-eqec.2009.5194616.

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De La Rue, Richard M. "Sensitive silicon and silica based photonics." In LEOS 2009 -22nd Annuall Meeting of the IEEE Lasers and Electro-Optics Society (LEO). IEEE, 2009. http://dx.doi.org/10.1109/leos.2009.5343469.

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Wessely, F., D. Braeuhaus, G. Scheich, and N. Nielsen. "HBQ100 – A Novel Silicon-Silica Composite." In MS&T17. MS&T17, 2017. http://dx.doi.org/10.7449/2017/mst_2017_932_936.

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Wessely, F., D. Braeuhaus, G. Scheich, and N. Nielsen. "HBQ100 – A Novel Silicon-Silica Composite." In MS&T17. MS&T17, 2017. http://dx.doi.org/10.7449/2017mst/2017/mst_2017_932_936.

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Chaudhuri, Subhasis, Justin R. Sparks, Rongrui He, and John V. Badding. "Hollow core silicon-silica Bragg fiber." In CLEO: Science and Innovations. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/cleo_si.2015.stu1n.5.

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Helm, John B., and Herbert A. Miska. "Specifying Fused Silica for Large Optics." In Optical Fabrication and Testing. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oft.1985.wbb1.

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While there are currently four suppliers of Fused Silica to the U.S. market, this paper deals with material produced by the Corning Glass Works because that is what the authors are familiar with. Fused Silica is a synthetic, amorphous glass manufactured by a flame hydrolysis process. It differs from more conventional optical glasses in that it consists of nearly 100% pure silicon dioxide and therefore features exceptional transmittance in the ultraviolet as well as a very low coefficient of thermal expansion. While conventional optical glasses are manufactured by melting batches of the correct mineral constituents, fused silica is made by a chemical process in which silicon tetrachloride, natural gas and oxygen are combined in a burner and droplets of pure SiO2 are caused to precipitate.
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Li, Deyu, Min Yue, Arun Majumdar, Rong Fan, Yiying Wu, and Peidong Yang. "Design and Fabrication of Silica Nanotube Arrays and Nanofluidic Devices." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43982.

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Silica nanotube arrays have been fabricated from vertical silicon nanowire templates prepared by Vapor-Liquid-Solid (VLS) epitaxial growth. The silicon nonowire arrays are uniformly oxidized by a dry oxidation process in a tube furnace heated to 1000 °C and filled with pure O2, which gives SiO2 sheaths with continuous silicon wire cores inside. A dry etch process with XeF2 as etchant removes the silicon cores, thus silica nanotube arrays are obtained. The resulting silica nanotubes are more than 10 μm long with an inner diameter range from 10 to 200 nm. A nonofluidic device has been fabricated based on individual silica nanotubes. The nanotube is drop-casted onto a silica substrate from a solution and after the solution is dried out, a 200 nm thick chrome layer is sputter deposited. A 3 μm wide Cr gate structure is patterned across the silica nanotube. Photoresist is patterned to define the hydrophilic (silica) and hydrophobic (photoresist) regions. The hydrophilic regions form a reservoir at each side of the nanotube, thus giving us a nanofluidic device. Ion current flow through the nanotube has been measured in 1 M KCl solution and the measured current matches the theoretical estimation reasonably well.
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Schmidt, C., A. Chipouline, T. Käsebier, E. B. Kley, A. Tünnermann, L. Deych, and T. Pertsch. "Thermal and Free Electron Nonlinearities in Silica and Hybrid Silica/Silicon Disc Micro Resonators." In Frontiers in Optics. Washington, D.C.: OSA, 2009. http://dx.doi.org/10.1364/fio.2009.fthc6.

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Reports on the topic "Silica"

1

Owens, L., T. M. Tillotson, and L. M. Hair. Characterization of vanadium/silica and copper/silica aerogel catalysts. Office of Scientific and Technical Information (OSTI), September 1995. http://dx.doi.org/10.2172/212472.

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Burroughs, Jedadiah, Jason Weiss, and John Haddock. Influence of high volumes of silica fume on the rheological behavior of oil well cement pastes. Engineer Research and Development Center (U.S.), July 2021. http://dx.doi.org/10.21079/11681/41288.

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Specialized classes of concrete, such as ultra-high-performance concrete, use volumes of silica fume in concrete that are higher than those in conventional concrete, resulting in increased water demand and mixing difficulty. This study considered the effects of eight different silica fumes in three dosages (10%, 20%, 30%) with three w/b (0.20, 0.30, 0.45) on rheological behavior as characterized by the Herschel-Bulkley model. Results indicated that the specific source of silica fume used, in addition to dosage and w/b, had a significant effect on the rheological behavior. As such, all silica fumes cannot be treated as equivalent or be directly substituted one for another without modification of the mixture proportion. The rheology of cement pastes is significantly affected by the physical properties of silica fume more so than any chemical effects.
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Venedicto, Melissa, and Cheng-Yu Lai. Facilitated Release of Doxorubicin from Biodegradable Mesoporous Silica Nanoparticles. Florida International University, October 2021. http://dx.doi.org/10.25148/mmeurs.009774.

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Cervical cancer is one of the most common causes of cancer death for women in the United States. The current treatment with chemotherapy drugs has significant side effects and may cause harm to healthy cells rather than cancer cells. In order to combat the potential side effects, nanoparticles composed of mesoporous silica were created to house the chemotherapy drug doxorubicin (DOX). The silica network contains the drug, and a pH study was conducted to determine the conditions for the nanoparticle to disperse the drug. The introduction of disulfide bonds within the nanoparticle created a framework to efficiently release 97% of DOX in acidic environments and 40% release in neutral environments. The denotation of acidic versus neutral environments was important as cancer cells are typically acidic. The chemistry was proved with the incubation of the loaded nanoparticle into HeLa cells for a cytotoxicity report and confocal imaging. The use of the framework for the anticancer drug was shown to be effective for the killing of cancerous cells.
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4

Daniels, Robert H., Esther Li, Oscar Abilez, Chengpei Xu, and Christopher Zarins. Silica Nanofiber Combat Hemostat (SINCH). Fort Belvoir, VA: Defense Technical Information Center, October 2008. http://dx.doi.org/10.21236/ada487916.

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Collings, R. K., and P. R. A. Andrews. Summary report no. 4: silica. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1989. http://dx.doi.org/10.4095/307287.

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Duffy, C. J. Kinetics of silica-phase transitions. Office of Scientific and Technical Information (OSTI), July 1993. http://dx.doi.org/10.2172/138671.

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7

Struble, Leslie J. Alkali-silica reaction in concrete. Gaithersburg, MD: National Bureau of Standards, 1985. http://dx.doi.org/10.6028/nbs.ir.85-3116.

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Abramoff, Bennet, and Lisa C. Klein. Elastic Properties of Silica Xerogels. Fort Belvoir, VA: Defense Technical Information Center, January 1990. http://dx.doi.org/10.21236/ada216528.

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9

Adelstein, N., and V. Lordi. Comparison of Atomic and Electronic Structures of Silica and Sodium Silicate Glasses. Office of Scientific and Technical Information (OSTI), October 2014. http://dx.doi.org/10.2172/1178383.

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Brown, K. L., D. H. Freeston, Z. O. Dimas, and A. Slatter. Pressure Drops Due to Silica Scaling. Office of Scientific and Technical Information (OSTI), January 1995. http://dx.doi.org/10.2172/895947.

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