Claim Missing Document
Check
Articles

Found 6 Documents
Search

Geochemical and Thermodinamic Modeling of Segara Anak Lake and the 2009 Eruption of Rinjani Volcano, Lombok, Indonesia Solikhin, Akhmad; Kunrat, S. I.; Bernard, A.; Barbier, B.; Campion, R.
Indonesian Journal on Geoscience Vol 5, No 4 (2010)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (969.974 KB) | DOI: 10.17014/ijog.v5i4.106

Abstract

DOI: 10.17014/ijog.v5i4.106Rinjani is the second highest volcano in Indonesia with an elevation of 3726 m above sea level. The steep and highest cone of Rinjani consists mainly of loose pyroclastic ejecta and contains a crater with a few solfataras. The West of this cone is Segara Anak caldera. The western side of the caldera is occupied by a 230 m deep lake, covering an area of 11 km² and its volume was (before the 2009 eruption) estimated 1.02 km3. This is probably the largest hot volcanic lake in the world.The lake water is neutral (pH: 7-8) and its chemistry dominated by chlorides and sulfates with a relatively high TDS (Total Dissolved Solids: 2640 mg/l). This unusual TDS as well as the lake surface temperatures (20 - 22°C) well above ambient temperatures (14 - 15°C) for this altitude, reflect a strong input of hydrothermal fluids. Numerous hot springs are located along the shore at the foot of Barujari volcanic cone. Bathymetric profiles show also several areas with columns of gas bubbles escaping from the lake floor indicating a significant discharge of CO gas into the lake. The mass and energy balance model of Rinjani Crater Lake produce total heat lost value on the average of 1700 MW. Most of the heating periods of the lake occurred when the heat released by the surface of the lake to the atmosphere was lower than the heat supplied from the hydrothermal system. Peaks of heat losses correspond to period of strong winds. Crater lake monitoring can provide a basic information about deep magmatic activity and surface processes that occur in the volcano. The monitoring also contributes to predict the next eruption in order to improve mitigation of volcanic eruption. Precursory signals of the May 2009 eruption can be seen from significant changes in the temperature and chemistry of some of the hot springs, the increase of Fe concentrations in spring #54, chemical plume of low pH and dissolved oxygen, acidification of Segara Anak Lake, and increasing of lake surface temperatures. The new lava flow from May - August 2009 eruption covers an area of 650,000 m2. The shoreline was significantly modified by the entry of lava into Segara Anak Lake. The area of the lake is reduced by 460,000 m2.
PENGEMBANGAN MODEL PEMBELAJARAN SISTEM PEREDARAN DARAH BERSUPLEMEN ARTIKEL Solikhin, Akhmad; Prasetyo, Andreas Priyono Budi
Journal of Biology Education Vol 4 No 2 (2015)
Publisher : Journal of Biology Education

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Penelitian ini bertujuan untuk mengembangkan model pembelajaran sistem peredaran darah bersuplemen artikel dan menguji pengaruhnya terhadap hasil belajar siswa. Pengembangan produk dilaksanakan di Jurusan Biologi FMIPA Universitas Negeri Semarang. Uji skala terbatas dilakukan di SMA Teuku Umar Semarang dan uji skala luas dilakukan di SMA Negeri 1 Semarang pada semester genap 2013/2014. Uji pengaruh model pembelajaran terhadap hasil belajar menggunakan only post test control group design. Sampel diambil menggunakan teknik convenience sampling, sedangkan kelas kontrol menggunakan kelas XI MIA 2 dan kelas eksperimen menggunakan kelas XI MIA 10. Data hasil belajar berupa skor post test. Hasil penelitian menunjukkan model pembelajaran memperoleh skor sangat layak; skor kelayakan perangkat pembelajaran adalah layak; dan skor keterlaksanaan model yaitu sedang. Uji-t menunjukkan perbedaan signifikan antara kelompok eksperimen dan kontrol (thitung > ttabel). Berdasarkan hasil pengembangan dan penelitian dapat disimpulkan bahwa model pembelajaran sistem peredaran darah bersuplemen artikel yang dikembangkan layak dan berpengaruh signifikan terhadap hasil belajar.  This study aimed to develop model of teaching on circulation system suplemented by article and  examine the effect of it on student learning achievement. The process of product development was conducted at Departement of Biologycal Science, Semarang State University. The trials of small-scale products was carried out in SMA Teuku Umar Semarang and the trials of large-scale products was carried out in SMA Negeri 1 Semarang at second semester 2013/2014. The testing effect model of teaching on learning achievement used only post test control group design. Sample was taken with convenience sampling technique, whereas control class used XI MIA 2 and eksperiment class used XI MIA 10. The data about learning achievement are form score of post test. The result showed that models of teaching get score of advisability are very feasible; score advisability of teaching device are feasible; and score sustainability of teaching model are middle. T-test showed that there are significant difference between eksperiment class with control class (thitung > ttabel). Based on the result of research and development, it could be concluded that model of teaching on circulation system suplemented by article developed feasible and have effect significant it on learning achievement.
Partial Purification, Characterization, and Application of Extracellular Aspartic Protease from Lactobacillus casei WSP in Producing the Bioactive Peptides with Antibacterial and Antioxidant Activity Solikhin, Akhmad; Mustopa, Apon Zaenal; Suharsono, Suharsono; Putranto, Wendry Setiyadi
ANNALES BOGORIENSES Vol 22, No 2 (2018): Annales Bogorienses
Publisher : Research Center for Biotechnology - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/ann.bogor.2018.v22.n2.47-56

Abstract

   Lactobacillus casei WSP-derived an aspartic protease was sequentially purified by using chromatography gel filtration sephadex G-50. It resulted in a 22.81-fold increase of specific activity (51.5 U/mg) with a final yield of 1.9%. The estimated molecular weight of the purified enzyme was 37 kDa and showed gelatinolytic activity in zymogram assay. The enzyme exhibited optimum activity at 40ºC and pH 6 with casein as the substrate. Enzyme activity was significantly inhibited by pepstatin A (0.5 mM and 1 mM), confirming that this enzyme is a group of aspartic proteases, while other inhibitors such as EDTA, PMSF and iodoacetic acid showed no inhibition effect on the activity of enzyme. The addition of metal ion to the enzyme decreased enzyme activity, indicating the proteolytic enzyme was metal ion- dependent. Denaturant such as DDT tended to increase caseinolytic activity. Furthermore, this enzyme was capable of generating the new peptides from skimmed milk with the size 8 kDa, 10 kDa and 15 kDa. These peptides have potential as antibacterial and antioxidant agents.
Functional properties of Saccharomyces kluyveri Y97-fermented solo black garlic SETIYONINGRUM, FITRI; PRIADI, GUNAWAN; HERLINA, NINA; SOLIKHIN, AKHMAD; LISANI, NURUL
Asian Journal of Agriculture Vol 2 No 02 (2018)
Publisher : Society for Indonesian Biodiversity & Universitas Mulawarman, Samarinda, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/asianjagric/g020203

Abstract

Setiyoningrum F, Pribadi G, Afiati F, Herlina N, Solikhin A, Lisani N. 2018. Functional properties of Saccharomyces kluyveri Y97-fermented solo black garlic. Asian J Agric 2: 48-51. Saccharomyces kluyveri Y97-fermented solo black garlic was made by fermentation of fresh solo garlic in medium containing S. kluyveri aging in 70C and relative humidity close to 60%. The fermentation period of fresh solo garlic in the medium was 0, 2, 4 dan 6 days. The black aging period was 0 (fresh garlic), 7, 14 dan 21 days. Antioxidant capacity, flavonoid content and total poliphenol were observed. S. kluyveri Y97-fermented solo black garlic had higher antioxidant capacity, flavonoid content and total polifenol compared to solo black garlic without fermentation. Fermentation of fresh solo garlic by S. kluyveri Y97 before aging process could increase solo black garlic’s functional properties.
Sistem Kontrol Dan Monitoring Berbasis IoT Pada Lampu Dan AC Di Laboratorium Komputer Politeknik Mitra Karya Mandiri Ibrahim, Anton Maulana; Solikhin, Akhmad
Jurnal Sistem Informasi, Teknologi Informatika dan Komputer Volume 13 No 2, Januari Tahun 2023
Publisher : Universitas Muhammadiyah Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24853/justit.13.2.87-91

Abstract

Laboratorium Komputer selain digunakan untuk kegiatan praktikum juga dipakai untuk eksperimen riset ilmiah, komponen-komponen yang ada pada laboratorium komputer perlu pemeliharaan dan kontrol sabaik mungkin termasuk keberadaan lampu penerang ruangan dan AC untuk menjaga suhu ruang tetap sejuk dan nyaman ketika digunakan. Penelitian bertujuan membangun sistem kontrol dan monitoring lampu dan AC di laboratorium Komputer Politeknik Mitra Karya Mandiri sehingga pemantauan lampu dan AC dapat dilakukan secara realtime. Metode pengembangan sistem menggukan model prototype, pada metode ini pengguna dan pengembang berkomunikasi selama proses pembuatan sistem sehingga hasilnya dapat sesuai kebutuhan. Sistem Kontrol dan Monitoring berbasis IoT ini memungkinkan pengecekan Lampu dan AC secara realtime. Perangkat yang digunakan adalah ESP8266 sebagai pengolah data sehingga sistem dapat ditampilkan pada website. Modul relay digunakan untuk mengontrol aliran listrik. Software yang digunakan Arduino Integrated Development Enviroment, Firebase dan Visual Studio Code. Penelitian menghasilkan Sistem Kontrol dan Monitoring Lampu dan AC  berbasis IoT Laboratorium yang dapat dilakukan secara realtime.
Optimasi Kurva HVSR, Kemiringan Lereng dan Informasi Geologi untuk Pemetaan Vs30 dan Kerentanan Seismik Wilayah Likupang Cipta, Athanasius; Afif, Haunan; Pradipto, M Arifin J.; Solikhin, Akhmad; Omang, Amalfi
Jurnal Lingkungan dan Bencana Geologi Vol 14, No 1 (2023)
Publisher : Badan Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34126/jlbg.v14i1.463

Abstract

Teknik Nakamura adalah salahsatu pendekatan paling populer untumenghitung kerentanan seismik. Namun tentu saja ada keterbatasan dalam penerapan teknik ini, yang seringkali diabaikan oleh peneliti pemula. Teknik Nakamura disusun dengan asumsi kecepatan gelombang geser pada batuan dasar = 600 m/s sehingga harus ada pemilahan frekuensi alamiah pada rentang tertentu agar teknik ini menghasilkan estimasi kerentanan seismik yang andal. Selanjutnya, informasi geologi dan kelerangan sangat diperlukan dalam penentuan lokasi titik ukur mikrotremor. Pemilihan titik ukur mikrotremor yang tepat memungkinkan dilakukannya pembuatan formula regresi antara kerentanan seismik dengan parameter geologi dan kemiringan lereng. Penerapan teknik Nakamura dengan terhadap data HVSR dengan distribusi spasial yang mempertimbangkan informasi geologi dan kelerengan menghasilkan peta kerentanan seismik yang berdayaguna. Kata kunci: Teknik Nakamura, HVSR, kemiringan lereng, kerentanan seismik ABSTRACTOwing to its simplicity, Nakamura Technique is one of the most popular approach for estimating seismic vulnerability index. However, this technique contains some limitations in which undergraduate students and early career researchers frequently disobey. The technique was composed by assuming shear-wave velocity on bedrock equals to 600 m/s. Consequently, only natural frequencies in a certain range match well with the technnique. Furthermore, information regarding geological condition and slope should be highly considered in designing of acquisition sites of microvibration. The right choice of microtremor sites allows us to create regression formula relates seismic vulnerability index with geologic parameters and slope. Applying Nakamura technique to a set of well spatially distributed HVSR data resulting in a robust seismic vulnerability map. Key words : Nakamura Technique,HVSR, slope, seismic vulnerability