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Abstract. This paper presents the corresponding compressive strength of RPC with variable pressure combined with heating rate, heating duration, and starting time of heating. The treatments applied were 8 MPa static pressure on fresh RPC prims and heat curing at 240 °C in an oven. The compressive strength test was conducted at 7-d and 28-d. The images of RPC morphology were captured on the surface of a fractured specimen using Scanning Electron Microscopy in Secondary Electron detector mode to describe pore filing mechanism after treatments. The results show that a heating rate at 50 °C/hr resulted in the highest compressive strength about 40 % more than those at 10 or 100 °C/hr. A heating duration of 48 hours led to the maximum compressive strength. Heat curing applied 2 days after casting resulted in the maximum compressive. Heat curing had a signicant effect on the compresssive strength due to the acceleration of both reactions (hydration and pozzolanic) and the degree of transformation from tobermorite to xonotlite. It is concluded that the optimum condition of treatments is both pressure and heat curing at 2-day after casting with a rate of 50 °C/hr for 48 hours.

Jagung merupakan komoditas pertanian terpenting setelah padi. Produktivitas jagung perlu senantiasa ditingkatkan dalam rangka swasembada jagung nasional. Jagung selain sebagai pangan juga digunakan untuk pakan (hewan), dan bahan baku industri. Salah satu hal yang dapat digunakan untuk memperbaiki produktivitas jagung yaitu dengan melakukan pencegahan terhadap serangan hama dan penyakit. Untuk itu perlu dibuat sistem untuk menyimpan pengetahuan tersebut. Pada artikel ini dibahas tentang klasifikasi hama dan penyakit pada tanaman jagung menggunakan Naive Bayes Classifier. Data yang digunakan berasal dari Dinas Pertanian Kabupaten Bangkalan. Data terdiri dari 15 hama dan penyakit serta 46 gejala. Ujicoba sistem dilakukan dengan simulasi melalui pengamatan terhadap 15 citra tanaman jagung. Hasil dari pengamatan secara langsung selanjutnya menjadi entri data untuk diolah menggunakan metode Naive Bayes. Untuk keperluan validasi hasil mining dari sistem dibandingkan dengan pendapat pakar. Uji validasi dari pakar menunjukkan prosentase kesesuaian hingga 73,33%.

An earthquake seismicity parameter study has been conducted in the southern part of the Sumatra Subduction Zone (SSZ) for the period of 1919 to 2019 with a hypocentre depth of 120 km and magnitude of ≥4Mw. The researched area is divided into three segments, Bengkulu, Lampung, and Sunda segments, respectively. This study aims to evaluate the seismicity parameters in the form of a-value, b-value, fractal dimension, and probabilities of earthquake recurrence period. Frequency-magnitude correlation statistical approach introduced by Gutenberg-Richter was used to calculate the seismicity parameters based on catalogue data obtained from USGS. An a-value variation of 5.11±1.84 to 5.85±2.46 obtained indicates the most dominant seismic intensity. b-value of 0.69±0,.17 to 0.83±0.35 correlates with high-stress levels, the level of spatial heterogeneity on the SFZ, and the probabilities of bigger earthquakes in the future. The calculation of fractal dimension of 1.4±0.33 to 1.7±0.71 indicates an earthquake distribution pattern was caused by a single fracture zone along the southern part of SSZ. The fracture zone is located on the left and right sides of the southern part of SSZ, which may not have been connected. In addition, the calculation result of earthquake recurrence period with magnitude ≥6.5Mw indicates that there will be an 5 -6 earthquake event in the Bengkulu segment, 2 -3 event in the Lampung segment, and 1 -2 event in the Sunda segment, while the probabilities of an earthquake with magnitude ≥7.5Mw along the southern part of SSZ is 1 -2 times.