Judul: . Analysis of Prefabricated Vertical Drain Depth in The Reclamation of Belawan Port, Medan City
Abstrak: Proyek Reklamasi Pelabuhan Belawan Paket II dilakukan untuk membangun lapangan penumpukan kontainer atau peti kemas. Fungsi tersebut didukung dengan kestabilan tanah di lokasi pelabuhan. Dari hasil uji SPT, tanah di lokasi pelabuhan tergolong tanah lunak dengan kedalaman 41 m sehingga perlu dilakukan perbaikan pada tanah tersebut agar stabil. Salah satu metode yang dapat digunakan untuk mengatasi masalah tersebut adalah metode Preloading dan Prefabricated Vertical Drain (PVD). Salah satu yang memperngaruhi efektifitas metode ini adalah kedalaman PVD. Penelitian ini bertujuan untuk mengetahui pengaruh dari pemasangan berbagai kedalaman PVD di lokasi seluas 174000 m2 Ha ini. Kedalaman PVD yang diteliti adalah 0%, 25%, 50%, 75% dan 100% dari kedalaman tanah lunak. Data yang dibutuhkan adalah rata-rata index properties tanah yang didapatkan dari uji laboratorium dengan sampel tanah dari 9 titik bor. Dari hasil perhitungan didapatkan potensi pemampatan tanah di lokasi adalah 2,4 m. Tanpa PVD, dibutuhkan waktu selama 50670 hari agar mencapai konsolidasi 90%. Sementara dengan menggunakan PVD diperlukan waktu tercepat 69 hari dengan PVD kedalaman 100% tanah lunak. Selain itu, semakin dalam PVD maka sisa pemampatan dalam 10 tahun semakin kecil. Dari variasi kedalaman Pemasangan PVD didapatkan termahal yaitu Rp14, 938 miliar dengan lama instalasi 111 hari., Belawan Port Reclamation Project II was carried out to build a container yard. This function is supported by soil stability at the port location. From the results of the SPT test, the soil at the port location is classified as soft soil with a depth of 41 m so it is necessary to make improvements to the soil so that it is stable. One method that can be used to overcome this problem is the Preloading and Prefabricated Vertical Drain (PVD) method. One that affects the effectiveness of this method is the depth of the PVD.This study aims to determine the effect of installing various depths of PVD in this 174000 m2 project site. The PVD depths studied were 0, 25, 50, 75, and 100% of the soft soil depth. The data needed is the average index of soil properties obtained from laboratory tests with soil samples from 9 drill points. This study shows that the potential for land subsidence at the location is 2.4 m. Without PVD, it would take 50670 days to reach 90% consolidation. While using PVD, it takes 69 days with a PVD depth of 100% soft soil. In addition, the deeper the PVD, the smaller the remaining compression in 10 years. The most expensive cost is 14,938 billion IDR with an installation time of 111 days from the variation in depth of PVD installation.
Keyword: Pemampatan, perbaikan tanah, PVD, SPT, tanah lunak

Judul: Evaluation of Ready-Mix Concrete Waste Settling Pond in Batching Plants
Abstrak: Air cucian dari batching plant dan mixer truck menghasilkan limbah cair beton sebanyak 7,5 m3 yang mengandung sedimen rata-rata sebesar 1,5 m3/hari. Limbah tersebut dialirkan dan diendapkan pada kolam pengendapan (settling pond). Kolam pengendapan (settling pond) untuk limbah beton ready-mix pada site Sedayu belum berfungsi secara maksimal karena limbah tidak terendap sempurna dan mengalir langsung ke sungai serta frekuensi pengerukan kolam sampai 8 kali dalam satu bulan. Penelitian bertujuan untuk menganalisis kapasitas kolam pengendapan yang sesuai serta frekuensi pengerukan kolam. Tahapan penelitian meliputi analisis curah hujan rencana dengan metode Gumbel, debit limpasan, dan waktu pengerukan. Curah hujan rencana untuk periode ulang hujan 2 tahun diperoleh sebesar 103,88 mm dan rata-rata intensitas hujan 9,4 mm/jam. Berdasarkan hasil analisis diketahui bahwa kapasitas kolam yang ada sebesar 67,2 m3, lebih kecil daripada standar kapasitas minimal yang berlaku. Site Sedayu membutuhkan kolam pengendapan berkapasitas 75,74 m3, dengan panjang 14 m, lebar 4 m, dan kedalaman 1,4 m. Kolam pengendapan direkomendasikan untuk dikeruk secara berkala, setiap 25 hari., Waste water from the batching plant and mixer truck produced concrete liquid waste 7.5 m3/day which contained sediment of 1.5 m3/day. The waste was flowed and deposited in the settling pond. The settling pond for ready-mix concrete waste at the Sedayu site has not functioned optimally because the waste was not completely settled and flowed directly into the river and the frequency of dredging is up to 8 times/month. The research aimed to analyse the capacity of a suitable settling pond and the frequency of pond dredging. The stages of the research included planned rainfall analysis using the Gumbel method, runoff discharge, and dredging time analysis. The planned rainfall for the 2 years rainfall returned period was 103.88 mm and the average rainfall intensity was 9.4 mm/hour. The analysis result showed that the existing settling pond capacity was 67.2 m3. This capacity is smaller than the standard of settling pond minimum capacity. The Sedayu site needed a settling pond with a capacity of 75.74 m3, with 14 m in length, 4 m in width, and 1.4 m in depth. The settling ponds is recommended to dredge periodically, every 25 days.
Keyword: rainfall, dredging, capacity

Judul: Mitochondrial DNA Gene Organization and Phylogenetic Relationship of Naja siamensis
Abstrak: Naja siamensis is one of Asiatic cobra in the Family of Elapidae, known as a cryptic snake. It has many morphological variations that lead to misidentification. Misidentification can cause the wrong concept in developing antivenom types due to high snakebite cases occur in Thailand. Thus, an accurate species identification using a molecular approach is crucially required. Mitochondrial DNA has been used widely in snake molecular studies. These studies were aimed to determine the arrangement of the N. siamensis partial mitochondrial genes using reptile-oriented primers and to reveal the phylogenetic relationship among other species of Asian cobra. DNA extraction was carried out based on the standard DNA salting-out protocol and was conducted by bioinformatics analysis using BLASTn and MEGA 6 software. Gene annotation was performed against N. kaouthia complete genome. A total of 3121 bp of N. siamensis mtDNA genes were sequenced consisting of partial of six regions: 16S rRNA, ND1, tRNA-Ile, CRII region, tRNA-Leu, tRNA-Gln, and COI genes. The mtDNA gene organization of N. siamensis was predicted to has a similar pattern with the common Elapidae mtDNA gene organization. This study showed that there is a monophyletic form in Naja genus and N. kaouthia is the closest species with N. siamensis based on partial 16S rRNA and ND1 gene.
Keyword: 16S rRNA, Elapidae, ND1, phylogenetic relationship