Judul: Analisis Kekuatan Tekuk Kolom Bambu Tali (Gigantochloa apus (J.A. & J.H. Schultez) Kurz) dengan Variasi Panjang dan Jumlah Batang Penyusun Kolom
Abstrak: Bambu tali berpotensi dijadikan sebagai kolom. Tekuk merupakan titik kritis penyebab kegagalan struktur kolom dalam menahan beban tekan. Penelitian ini bertujuan mengetahui kekuatan tekuk maksimum kolom bambu tali dengan variasi panjang dan jumlah batang penyusun. Bambu tali diperoleh dari pasar komersial di Jl. Raya Dramaga, Bogor, Jawa Barat. Bambu dipotong menjadi ukuran 1, 2, dan 3 m. Pengukuran dimensi berdasarkan BS ISO 19624:2018, sedangkan pengukuran geometri berdasarkan BS ISO 22157:2019. Pengujian sifat fisis meliputi kadar air, kerapatan, dan kerapatan linear, serta pengujian mekanis yaitu kekuatan tekuk kolom bambu tali. Uji lanjut Duncan digunakan untuk membandingkan hasil pengujian tekuk kolom bambu tali dengan variasi panjang dan jumlah batang penyusun kolom. Contoh kolom berukuran 1 m, 2 m, dan 3 m. Pengujian tekuk kolom 1 m mengunakan UTM SATEC-Baldwin berkapasitas 30 ton, sedangkan pengujian tekuk kolom 2 m dan 3m menggunakan alat uji tekan berkapasitas 100 ton. Pengujian tekuk kolom dilakukan dengan memberikan pembebanan secara vertikal pada kolom. Pengolahan data faktor tekuk menggunakan Formula Ylinen’s. Kolom bambu panjang memiliki angka kelangsingan tinggi dan menghasilkan nilai tekuk rendah, sehungga kolom mudah mengalami tekuk. Kolom bambu tali komposisi ganda dua, tiga, maupun empat memiliki nilai kekuatan tekuk lebih tinggi dibandingkan jumlah kekuatan tekuk masing-masing batang penyusunnya karena adanya kerjasama antar komponen penyusun. Peningkatan kekuatan akibat kerjasama antar komponen penyusun ini dapat dinyatakan sebagai repetitive member factor (komponen struktur berulang) yang masih perlu diperhitungkan., Bamboo tali has the potential to be used as a column. Buckling is a critical point that causes the failure of the column structure to withstand compressive loads. This study aims to determine the maximum buckling strength of the bamboo tali column with variations in length and number of comonents. The bamboo tali was obtained from commercial market on Jl. Raya Dramaga, Bogor, West Java. The bamboo is cut into 1, 2, and 3 meters. Dimensional measurements are based on BS ISO 19624:2018, while geometric measurements are based on BS ISO 22157:2019. Physical properties tests include moisture content, density, and linear density, as well as mechanical testing, namely the buckling strength of the bamboo tali column. Duncan's further test was used to compare the results of the buckling test of bamboo tali columns with variations in length and number of components making up the column. The column test speciments are 1 m, 2 m, and 3 m. The 1 m sized columns are tested using UTM SATEC-Baldwin 30 tons capacity, while the 2 m and 3 m sized column were tested using compressive testing machine 100 tons capacity. The column buckling test is carried out by applying vertical loading to the column. Buckling factor data processing using Ylinen's Formula. Long bamboo columns have a high slenderness rate and produce a low buckling value, so that the column is prone to buckling. The the buckling strength of bamboo multicolumns are higher than the sum of single colunms buckling strengths because of the cooperation between the column’s components. The strength improvement because of the column’s components cooperation can be determined as repetitive member factor which should be considered.
Keyword: angka kelangsingan, kolom, multikolom, tali, tekuk, slenderness ratio, column, multicolumns, tali, buckling

Judul: Buckling Properties of Hitam Bamboo (Gigantochloa atroviolaceae) with Variations in The Number of Bamboo Culumns
Abstrak: Bambu merupakan salah satu material konstruksi yang tersebar melimpah di daerah tropis. Bambu hitam (Gigantochloa atroviolacea) memiliki buluh berwarna kehitaman dan telah banyak dibudidayakan di Indonesia. Tujuan dari penelitian ini adalah untuk mendeskripsikan bentuk geometri, sifat fisis, dan kapasitas tekan bambu, selanjutnya menganalisis pengaruh jumlah komponen penyusun multikolom bambu terhadap kapasitas tekan kolom. Contoh uji buluh bambu dipotong dengan ukuran 1 meter, 2 meter, dan 3 meter masing-masing ukuran berjumlah 30 sampel. Sampel diikat menggunakan tali ijuk berjarak 40 cm antar ikatan dengan variasi 2, 3, dan 4 komponen kolom bambu. Pengikatan kolom bambu menggunakan simpul pangkal. Pengujian tekuk menggunakan Universal Testing Machine (UTM) SATEC-Baldwin kapasitas 30 ton dan alat mesin uji tekuk kolom bambu ukuran penuh kapasitas 100 ton. Berdasarkan uji ancova jumlah komponen bambu dan kapasitas tekan dugaan berpengaruh nyata terhadap kapasitas tekan bambu. Semakin banyak jumlah komponen bambu yang menyusun sebuah kolom, kapasitas tekan kolom tersebut juga semakin besar. Sedangkan ukuran bambu secara statistik tidak berpengaruh nyata terhadap kapasitas tekan bambu karena berautokorelasi dengan kapasitas tekan dugaan. Kapasitas tekan dugaan merupakan jumlah kapasitas tekan setiap batang bambu yang menyusun sebuah kolom. Pada contoh uji dengan panjang 1 m dan 2 m nilai kapasitas tekan kolom yang tersusun oleh beberapa batang bambu lebih rendah dibandingkan nilai estimasinya. Nilai estimasi kapasitas kolom menahan tekuk merupakan jumlah nilai kapasitas tekan setiap batang bambu penyusunnya yang telah direduksi dengan faktor tekuk. Pada penelitian ini diameter bambu hitam cukup besar, sehingga pada contoh uji 1 m dan 2 m peristiwa tekuk tidak terjadi. Kolom berukuran 1 m dan 2 m tidak termasuk kolom langsing tetapi masih berada dalam wilayah kolom berukuran sedang, sehingga jumlah komponen penyusun kolom tidak meningkatkan nilai faktor reduksi tekuk secara signifikan. Contoh uji 3 meter sudah mengalami tekuk akibat beban tekan. Hal ini ditunjukkan oleh nilai kapasitas tekan dugaan (Fcr estimate) yang lebih rendah daripada nilai empirisnya (Fcr empiris)., Bamboo is a construction material that abundancely spread in tropical regions. Hitam bamboos (Gigantochloa atroviolacea) have black-colored culm and they have been cultivated in Indonesia. The purpose of this study is to describe the shape of the geometry, the physical properties, and the compressive capacity of bamboo, then to analyze the effect on the number constituent components bamboo multicolumn to the compressive capacity of columns. Bamboo culm specimens were cut to the size of 1 m, 2 m, and 3 m length. The number of specimens of each length are 30, thus the total specimens are 90. The bamboo culms are tied using rope fibers at 40 cm interval to build a multicolumn. Each multiculm are made from 2, 3, or 4 pieces of bamboo culms. The clove hitch methods are applied to tie the components to become a multiculms. Compression test are conducted to 1 m and 2 m specimens using a Universal Testing Machine (UTM) SATEC-Baldwin 30 tons capacity, while the 3 m specimens are tested using UTM 100 tons capacity. Based on the ancova test, the number of bamboo components and the estimated compressive capacity significantly affect the empiric compressive capacity of bamboo multicolumn. Increasing the number of
Keyword: angka kelangsingan, bambu hitam, kapasitas tekan, multi kolom, tekuk, buckling, compressive capacity, hitam bamboo, multiculumn, slenderness ratio

Judul: Pemurnian dan karakterisasi protein inhibitor RNA helikase virus hepatitis C
Abstrak: Hepatitis C virus (HCV) infection is the second most common chronic viral infection in the world with global prevalence. This infection is contribution to chronic hepatitis and liver cirrhosis, often leading to hepatocellular carcinoma. There is no effective drug and vaccine available against HCV. The current standard treatment, a combination of pegylated interferon-α with ribavirin, is limited by its suboptimal response rate in a significant patient population, side effects, and affordability. Therefore, development of effective drug is needed. One approach to find out the candidate of antiviral drug is to discover the inhibitor of enzyme that essential for virus replication, such as RNA helicase. Streptomyces chartreusis 5-095 produce the inhibitor of HCV RNA helicase. The aim of this study was to purify the protein inhibitor which has inhibition activity against ATPase activity of RNA helicase HCV from S. chartreusis 5-095. The supernatant of culture S. chartreusis 5-095 exhibited high inhibiton activity against ATPase activity of RNA helicase HCV (approximately 72%) at 10 days of incubation. The extracellular protein inhibitor was partially purified by procedures of precipitation with ammonium sulfate to 65% saturation and gel filtration (Sephadex G50) using methanol water solution (4:6) as an eluen. The purity of protein inhibitor was monitored by SDS PAGE. The protein inhibitor showed a relative molecular mass were estimated to be 14 kDa and increased the purity 23,08 fold than those of the crude protein. The specific activity and IC50 after purification were 13,1338 U/mg and 0,0767 mg/mL, respectively. The activity of purified protein inhibitor showed its stability over pH range from 5-8 and optimum at pH 7,4. The inhibition activity showed its stability up to 70% at temperature 100 oC. The purified protein inhibitor relatively stable its activity at storage in the range of -20 oC to room temperature for 35 days.
Keyword: