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Abstrak :
Pembengkakan pada tanah liat adalah salah satu masalah yang sering dijumpai dalam reservoir gas lapisan batubara. Aktivitas ini dapat mengakibatkan beberapa kesalahan seperti kegagalan pompa, penghentian produksi dan penurunan permeabilitas lapisan batubara. Pengendapan Mg(OH)2 dalam struktur tanah liat telah di evaluasi dengan menggunakan bentonite clay sebagai model tanah liat dalam penelitian. Efek konsentrasi dari MgCl2.6H2O dan NaOH dalam membentuk pengendapan pada tanah liat yang dapat membengkak, telah di pelajari dan dijelaskan dalam skripsi ini. Kesimpulan menunjukan adanya penurunan indeks pembengkakan ketika konsentrasi MgCl2.6H2O ditambahkan dari 2wt% to 10wt%. Namun, terjadi penurunan yang signifikan pada angka indeks pembengkakan ketika konsentrasi diantara 4wt% dan 6wt%. Demikian, penelitian lebih lanjut dilakukan untuk mengetahui karateristik tanah liat dengan melihat konsentrasi MgCl2.6H2O, yaitu 4.5wt%, 5wt% and 5.5wt%. Indeks pembengkakan menunjukan hasil yang serupa dengan penelitian sebelumnya, sesuai dengan perhitungan ketidakpastian. Penelitian lain telah dilakukan, dengan memvariasikan konsentrasi NaOH dan menetapkan konsentrasi garam Magnesium pada 6wt%. Hasil ini menunjukan penurunan angka indeks pembengkakan ketika konsentrasi NaOH ditambahkan. Namun, angka indeks pembengkakan menjadi lebih tinggi ketika jumlah MgCl2.6H2O digunakan lebih banyak daripada konsentrasi NaOH. Fenomena ini dapat terjadi dikarenakan jumlah OH- yang digunakan lebih sedikit yang bisa berinteraksi dengan ion Mg2+. Sedangkan ion natrium dilarutkan karena lebih banyak ion khlorida dalam larutan yang digunakan. ......Clay swelling is one of the biggest issue in coal seam gas reservoir. This leads to several problems like pump failure, production shutdown and reduction in permeability. In this report, precipitation of Mg(OH)2 on clay structure has been evaluated by utilising bentonite as model clay. The effect of MgCl2.6H2O and NaOH concentrations on the precipitation and swelling index have been studied and reported in this work. The conclusion showed a gradually decreased in swelling index when increasing MgCl2.6H2O concentration from 2wt% to 10wt%. However, there was a significant decreased of swelling index value when the concentration is between 4wt% and 6wt%. Thus, advance experiment was done to identify this behaviour by performing 4.5wt%, 5wt% and 5.5wt% Mg salt (MgCl2.6H2O) concentration. The swelling indexes indicated similar behaviour to previous experiment, based on uncertainty measurement. Another experiment with varying NaOH concentration while maintaining concentration of 6wt% Mg salt was also undertaken. These results showed decreasing behaviour in swelling index as the amount of NaOH concentration was increased. However, higher swelling index was achieved when amount of MgCl2.6H2O was higher than NaOH concentration. This might occur due to less amount of OH- to be coordinated by Mg2+, while sodium ions were dissolved since more chlorite ion presence in the solution.

Abstrak :
For centuries humankind has wondered at the instability of earth material, especially clays; one day they are dry and hard, and the next wet and soft. The result are usually excessive deflections and diffrential movements resulting in damage to foundation systems structural elements and architectural features. Foundation materials that exhibit volume change from change in soil moisture are referred to as expansive or swelling clay soils. Expansive soils many parts of the United States a significant hazard to foundations for light buildings. Swelling clays derived from residual soils can exert uplift pressures of as much as 5.500 psf to 15,000 psf. In the United States alone the damage caused by the shrinking and swelling soils amounts to about 9 billion dollars per year, which is greater than the combined damages from natural disasters such as floods, hurricanes, earthquakes and tornados.South Sumatra local Government is planning to build a new International and Modem Trading Port including Industrial and Ware Housing Estate at Tanjung Api-Api area. Most of soils around Tanjung Api-Api area are expansive soils, so the objective of this study to analize and obtain suitable foundation on unsaturated expansive soil, that can be implemented in Tanjung Api-Api area. From the result ofOedometer test, it can be concleded that the swelling potential value is about 15 percent, and the soil uplift pressure is about 2,0000 psf.

Abstrak :
Tanah ekspansif dapat mengembang ke segala arah, baik arah vertikal maupun lateral. Pada arah lateral, tanah ekspansif menimbulkan tekanan pengembangan lateral atau lateral swelling pressure (LSP) yang mengakibatkan kerusakan berupa deformasi pada struktur. Aktivitas pengembangan tersebut dapat terjadi akibat adanya perubahan kadar air. Penelitian ini bertujuan untuk menganalisis pergeseran tiang pancang pada galian tanah ekspansif menggunakan aplikasi berbasis metode elemen hingga MIDAS GTS NX dengan studi kasus pergeseran tiang pancang jenis spun pile di Gresik, Jawa Timur. Pemodelan tiang pancang dilakukan dengan memodelkan material tiang yang bersifat elastis-plastis menggunakan mohr-coulomb serta bersifat elastis. Analisis dilakukan untuk mencari besar tekanan tanah ekspansif yang terjadi di lokasi penelitian dengan back analysis dan untuk mengetahui pengaruh kedalaman galian, kadar air awal, muka air tanah, serta beban alat berat terhadap pergeseran lateral tiang pancang. Hasil back analysis menunjukkan bahwa tiang akan mengalami pergeseran lateral sesuai dengan kondisi di lapangan ketika terdapat tekanan pengembangan lateral tanah ekspansif sebesar 527 KPa pada model elastis dan 478 KPa pada model elastis-plastis. Pada analisis pengaruh, pergeseran lateral tiang pancang akan semakin meningkat seiring dengan semakin dalamnya galian, semakin kecilnya kadar air awal, tidak tergenangnya galian oleh MAT, dan adanya alat berat di sisi galian ......Expansive soil can swell in any direction, both vertically and laterally. In the lateral direction, expansive soils cause lateral swelling pressure (LSP) which results in deformations of the structure. The swelling can occur due to changes in moisture content. This study aims to analyze the displacement of piles in expansive soil excavations using a finite element method-based application MIDAS GTS NX with a case study of spun pile displacement in Gresik, East Java. Piles are modeled with elastic-plastic material behavior using mohr-coulomb and elastic material behavior. The analysis was conducted to find the pressure of expansive soil that may occurs in the study site with back analysis and to determine the effect of excavation depth, initial water content, groundwater level, and heavy equipment load on pile lateral displacement. The results of the back analysis show that the piles will be displaced laterally in accordance with the actual conditions when there is a lateral swelling pressure of 527 KPa in the elastic model and 478 KPa in the elastic-plastic model. In the effect of environmental conditions and construction stage analysis, the lateral displacement of the piles will increase with the deeper the excavation, the smaller the initial water content, the non-inundation of the excavation by MAT, and the addition of heavy equipment on the side of the excavation.

Abstrak :
Hidrogel homopolimer poliakrilamida dan poli(N-metilol akrilamida) serta hidrogel IPN poliakrilamida-poli(N-metilol akrilamida) disintesis dengan menggunakan metode polimerisasi radikal bebas. Pada proses sintesis dilakukan variasi konsentrasi pengikat silang N,N'-metilen bis akrilamida (MBA) pada jaringan polimernya untuk mengetahui pengaruhnya terhadap swelling. Variasi konsentrasi pengikat silang menyebabkan perubahan matriks hidrogel sehingga rasio swelling akan berbeda. Proses polimerisasi berhasil, ditandai dengan hilangnya puncak C=C dan C-H sp² alkena pada FTIR. Uji swelling dilakukan pada suhu ruang dan variasi pH 3, 5, 7, 9, dan 12 selama 24 jam perendaman.  Hasil swelling hidrogel IPN ditemukan lebih tinggi dibandingkan hidrogel homopolimer dikarenakan keberadaan jaringan kedua. Swelling variasi pH pada hidrogel PNMA dan IPN mempunyai swelling tertinggi pada pH 5. Hidrogel dengan konsentrasi pengikat silang 1% untuk PAAm dan IPN PAAm serta konsentrasi pengikat silang 2% untuk PNMA dan IPN PNMA memiliki swelling tertinggi.

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Homopolymer hydrogel polyacrylamide and poly(N-methylol acrylamide) also IPN hydrogel polyacrylamide-poly(N-methylol acrylamide) were synthesized using the free radical polymerization method. In the synthesis process, variations of concentration N, N'-methylene bis acrylamide (MBA) crosslinkers were used on the polymer network to determine their effect on swelling behaviour. Variations of crosslinker concentration  caused changes in the hydrogel structure and thus the swelling ratio will be different. The polymerization process conducted successfully, which was marked by the loss of the C = C and C-H sp2 alkene peaks at FTIR. Swelling test were carried out at room temperature and pH 3, 5, 7, 9, and 12. The IPN hydrogel swelling ratio was found to be higher than homopolymer hydrogel due to the presence of the second network. The highest swelling behaviour in different pH for PNMA and IPN hydrogels was found at pH 5. Hydrogels with a crosslinking concentration of 1% for PAAm, IPN PAAm and 2% for PNMA, IPN PNMA had the highest swelling.

Abstrak :
Bioplastik sebagai alternatif plastik konvensional dapat disintesis dengan berbahan dasar poli(vinil alkohol) (PVA) dan bahan alami di alam yaitu pati dari tepung tapioka. Bioplastik disintesis melalui metode ikat silang (crosslinking) dengan ditambahkan asam maleat dimana terjadi reaksi esterifikasi Fischer yang bertujuan untuk mengurangi mobilitas dari struktur dan dapat meningkatkan kekuatan mekanis dari polimer plastik yang disintesis. Plastik tersebut lalu ditambahkan dengan filler selulosa yang termodifikasi dengan asam palmitat yang berguna untuk menurunkan tingkat asupan air dan meningkatkan kekuatan daripada lapisan campuran PVA/Pati sehingga menghasilkan produk bioplastik biodegradable yang memiliki sifat ketahanan tarik yang tinggi dan memiliki tingkat swelling yang rendah. Plastik tersebut lalu dikarakterisasi dan diuji tingkat kekuatan tarik, kelarutan dan kemampuan swelling. ......Bioplastics as an alternative to conventional plastic can be synthesized from poly(vinyl alcohol) (PVA) and natural ingredients in nature such as starch especially from tapioca flour. Bioplastic was synthesized through a crosslinking method by adding maleic acid where a Fischer esterification reaction occurs which aims to reduce the mobility of the structure and can increase the mechanical strength of plastic. The plastic was then added with cellulose which was modified with palmitic acid which is useful to reduce the level of water intake and increase the strength of the PVA/starch mixture layer to produce bio-based plastic products that are biodegradable but can also can have high tensile resistance features, be resistant to water and have a low level of swelling. The plastic was then characterized and tested the level of tensile strength, solubility and swelling ability.