Hasil Pencarian  ::  Simpan CSV :: Kembali

"As part of alarger investigation on segmental retaining wall (SRW) concrete durability, databases of ASTM C 1262 freesing and thawing mass loss were compared with SRW material characteristics to assess the usefulness use these characteristics as indexes of frost durability. It was determined that the paste to total (air and compaction) voids ratio consistenly ranked among the most reliable parameters correlating with mass loss in the water. The national Concrete Masonry Association (NCMA) index also showed fair correlation to mass loss. The sapcing factor and saturation coefficient, which are common frost durability criteria for other types of porous materials, displayed low correlation with mass loss, and their applicability to SRW concretes is thus questionable. Threshold values of material characteristics above or below which mass loss was significant were determined and compared with standard specification limits. Finally, results for tests in 3% NaCl solution were briefly examined and shown to have greater variability compared to results for tests in water. Thus, the correlation between frosts resistance and material properties as determined from tests in water cannot be used to predict specimen performance in saline solution."

"Nickel slag which is a waste product of nickel mining in Soroako, Kabupaten Luwu Utara, and Province South Sulawesi deposited in allarge amount and is not used optimally. The use of Nickel slag for road construction by mining authority just as base materials. For that reason, this study is aimed to evaluate technically the use of Soraoako?s Nickel slag as coarse aggregate in wearing course asphaltic mixtures focused to evaluate asphaltic durability. The mixture used in this study is a No 11 of SNI gradation type. The nickel slag content is combined with coarse aggregate in variation of 0%, 25%, 50%, 75% and 100%. The optimum asphalt content is determined by varied asphalt content in range of 4.5% to 6.5% by 0, 5% increment. The mixture durability test is conducted according to standard Marshall immersion (24 hours immersed at temperature of 600 C) andmodified Marshall Immersion (immersed at temperature of600 C for 4, 7 and 14 days). Performance analysis of the mixture is expressed by Retained Strength Index (1KS), the First Durability Index (IDP) and the Second Durability Index (IDK). As the result, it was known that Nickel slag Streak can be used finely either combined by conventional coarse aggregate or as the coarse aggregate in asphaltic mixture. The mixture that content Nickel slag Soroako is more durable against water infiltration compared the mixture that content conventional course aggregate."

"Dalam dunia konstruksi, beton sebagai material utama pembentuk struktur, telah banyak ditemukan dalam pembuatan berbagai tipe konstruksi umum maupun khusus, seperti jalan raya, jembatan, gedung bertingkat, bendungan, konstruksi saluran air (canal linings), terowongan, dan lain-lain. Dikarenakan peruntukan beton sebagai bahan utama dalam kegiatan konstruksi, maka penggunaan beton sebagai bahan konstruksi harus didasari oleh sifat-sifat beton yang dapat mendukung kemudahan pelaksanaan dilapangan tanpa mereduksi kemampuan dan sifat beton itu sendiri. Perkembangan industri konstruksi yang terjadi di Indonesia dalam hal penyediaan dan penggunaan beton siap pakai menjadi salah satu kebutuhan mendasar dimana sifat-sifat mekanis maupun fisis beton merupakan hal utama yang sangat mendukung industri konstruksi ini. Dalam memenuhi kebutuhan akan berbagai sifat-sifat beton yang digunakan sesuai dengan peruntukkannya dalam dunia konstruksi, maka penggunaan bahan tambah (admixture) merupakan salah satu jawaban yang dapat mendukung industri beton ini. Salah satu produk bahan tambah yang akan digunakan dalam penelitian ini adalah senyawa trigliserida dengan nama produk yaitu Emtal 50WP. Emtal 50WP adalah admixture atau bahan tambahan pada campuran beton yang berfungsi utama sebagai bahan pelapis anti air dan bahan tambahan untuk menaikkan kekuatan beton. Secara garis besar penelitian ini bertujuan untuk mengetahui pengaruh bahan tambah ini dalam campuran beton terhadap sifat fisis dan mekanis beton. Pengujian sifat mekanis beton dibatasi hanya untuk pengujian kuat tekan, kuat lentur, kuat geser dan kuat tarik belah serta permeabilitas beton keras. Sedangkan untuk sifat fisis beton dilakukan pengujian workabilitas beton berupa konsistensi slump beton an waktu ikat beton (initial setting time). Berdasarkan penelitian ini diharapkan dapat diketahui kadar optimum dari bahan tambah trigliserida jenis Emtal 50WP yang diperlukan untuk mendapatkan kenaikan kekuatan beton yang optimum serta penurunan tingkat permeabilitas yang signifikan."

"Sekretom merupakan medium kultur sel punca (stem cells) yang berisikan molekul-molekul protein yang disekresikan oleh sel. Pengaplikasian sekretrom dalam dunia medis dapat menggantikan terapi sel punca karena jauh lebih aman dan memiliki fungsi penyembuhan yang hampir sama dengan terapi sel punca. Dalam suatu penyembuhan atau terapi menggunakan obat atau bahan aktif, faktor transfer obat menjadi salah satu parameter keberhasilan. Untuk mengoptimalkan transfer obat maka obat atau bahan aktif yang digunakan dapat dienkapsulasi dalam suatu vesikel, salah satunya adalah transfersom. Transfersom merupakan vesikel berbasis lipid yang tersusun atas fosfolipid dan surfaktan sebagai edge activator. Dengan menggunakan transfersom memungkinkan obat atau bahan aktif dihantarkan secara transdermal, tanpa melalui injeksi, operasi, maupun pemasangan implan. Pada penelitian ini, transfersom dibuat untuk enkapsulasi bovine serum albumin sebagai model protein sekretom. Bahan penyusun transfersom yang digunakan dalam penelitian ini adalah dipalmitoylphosphatidylcholine (DPPC) dan Tween 80 dengan perbandingan fosfolipid dengan surfaktan adalah 97,5:2,5 %w/w. Pada penelitian ini partikel transfersom dibentuk dengan melibatkan siklus freeze-thaw untuk mengetahui pengaruhnya terhadap karakteristik transfersom. Perlakuan siklus freeze-thaw tersebut terbukti dapat memengaruhi karakteristik transfersom. Dalam penelitian ini, siklus freeze-thaw dapat meningkatkan efisiensi enkapsulasi hingga 81,63 ± 0,004% dengan ukuran partikel sekitar 180,70 ± 0,87 nm. Selanjutnya, protein yang dilepaskan secara in-vitro selama 78 jam mencapai 52,80%, lebih banyak dibandingkan tanpa perlakuan freeze-thaw. Dengan demikian, perlakuan siklus freeze-thaw dapat digunakan untuk meningkatkan karakteristik partikel transfersom.

---

The secretome is a stem cell culture medium containing protein molecules that are secreted by the cells. In the medical field, secretome can substitute stem cell therapy because it is safer and almost has the same function as stem cell therapy. In a cure or therapy using drugs or active ingredients, the drug transfer factor is one of the parameters of success. To optimize drug transfer, the drugs or active compounds can be encapsulated into a vesicle, one of which is transfersome. Transfersome is a lipid based vesicle composed of phospholipid and surfactant as an edge activator. By using transfersome, drugs or active compounds can be transferred transdermally without any injection, operation, or implant placement. In this research, transfersome is made for encapsulating bovine serum albumin as a secretome protein model.  The building blocks for transfersomes used in this study were dipalmitoylphosphatidylcholine (DPPC) and Tween 80 with a 97.5:2.5 %w/w ratio of phospholipids to surfactants. In this research, transfersome is fabricated with involving the freeze-thaw cycles method to study its effect to transfersome characteristics. The freeze-thaw cycles that are involved in transfersome fabrication is proved affecting to transfersome characteristics. In this research, freeze-thaw cycles can increase particle encapsulation to 81.63 ± 0.004% with a particle size of 180.70 ± 0.87 nm. Furthermore, the protein released from transfersome particle for 78 hours reached 52.80%, more than without freeze-thaw cycles treatment. Hence, freeze-thaw cycles treatment can be used to improve transfersome particle characteristics."

"This volume contains the proceedings of the 8th International PhD Student Workshop on Service Life and Durability of Reinforced Concrete Structures that was held in Marne-la-Vallee, France, on September the 26th and 27th 2016.Topics discussed in the book are related to durability performance of reinforced concrete, service life modelling, prevention, protection and repair.Reinforced concrete structures may prove to be very durable, however, their gradual degradation over time impairing both serviceability and structural safety is still a matter of great practical concern in view of the large economic consequences for assessment, maintenance and repair. Corrosion of steel reinforcement is considered to be the most detrimental process responsible for structural deterioration.Many studies are in progress to develop a comprehensive engineering approach for assessment of the initiation and the propagation period of corrosion in both uncracked and cracked concrete. Modelling of chloride penetration and carbonation has attracted a great deal of attention in recent years, however, there is still much debate on several essential aspects such as the chloride threshold level. ASR, and acid, sulphate and frost attack and other mechanisms remain important areas of study. In addition, the interaction between different degradation mechanisms requires further understanding.The worskhop was organised under the auspices of RILEM EAC (Educational Activities Committee), with the aim to bring together young researchers in the field of durability of concrete."

"This book presents the work done by the RILEM Technical Committee 227-HPB (Physical properties and behaviour of High-Performance Concrete at high temperature). It contains the latest research results on the behaviour of high-performance concretes at high temperature.The book presents the state of the art of experimental data on High-Performance concretes and it collects and synthesizes useful data about concrete behaviour at high temperatures. The book is divided into independent chapters dealing with degradation reactions in concrete exposed to high temperatures; mass transport properties; thermal properties; and mechanical properties.The results presented especially target a group of users composed by universities and testing laboratories, building material companies and industries, material scientists and experts, building and infrastructure authorities, designers and civil engineers."

"This book presents the work done by the RILEM Technical Committee 227-HPB (Physical properties and behaviour of High-Performance Concrete at high temperature). It contains the latest research results on the modelling of concrete behaviour at high temperature. Some monographs on the subject have been published already but generally they do not cover the whole range of possibilities which are encountered in the literature as well as in practice. Moreover, there has been a rapidly increasing development of computational models during the last twenty years, which deserves attention. Therefore, it is the aim of this report to compile and present most of the tools that are proposed in the literature and are nowadays available for practice in some commercial computational packages.The book is divided in 3 main chapters dealing with:- engineering modelling- advanced modelling- constitutive parameters including hydral, thermal and mechanical parameters."