Judul: Water Balance Analysis of the Dawak River in Meeting the Water Needs of Oil Palm Plantations in Toba District, West Borneo
Abstrak: Air merupakan sumber daya alam yang menjadi kebutuhan paling penting bagi semua mahluk hidup. Pertambahan luas area perkebunan kelapa sawit dapat menimbulkan dampak terhadap kondisi lingkungan, di antaranya adalah berkurangnya jumlah ketersediaan air pada suatu kawasan. Penelitian ini bertujuan untuk menghitung neraca air dan potensi Sungai Dawak dalam memenuhi kebutuhan air irigasi bagi perkebunan kelapa sawit yang berada di catchment area Sungai Dawak. Analisis neraca air dilakukan dengan metode FJ Mock. Dari hasil analisis debit Sungai Dawak rata-rata 1,10 m3/bulan dan kebutuhan air irigasi tanaman kelapa sawit rata-rata 0,52 m3/bulan. Berarti terjadi surplus air sepanjang tahun, dengan surplus terbesar terjadi pada bulan November sebesar 1,16 m3/detik atau sekitar 3.009.439 m3/bulan dan surplus terkecil terjadi pada bulan September sebesar 0,01/ m3/detik atau sekitar 33.394 m3/bulan. Tidak terjadi kondisi defisit di sepanjang tahunnya, sehingga potensi air Sungai Dawak dapat memenuhi kebutuhan air perkebunan kelapa sawit., Water is a natural resource that is the most important need for all living things. The increase in the area of oil palm plantations can have an impact on environmental conditions, including the reduction in the amount of water available in an area. This study aims to calculate the water balance and the potential of the Dawak River in meeting irrigation water needs for oil palm plantations located in the catchment area of the Dawak River. Water balance analysis was carried out using the FJ Mock method. The analysis result showed that the average discharge of Dawak River 1.10 m3/month and the irrigation water demand for oil palm plantations was 0.52 m3/month. It meaned that there was a water surplus throughout the year, with the largest surplus occurring in November of 1.16 m3/s or around 3,009,439 m3/month and the smallest surplus occurred in September of 0.01 m3/s or around 33,394 m3/month. There is no deficit condition throughout the year, so the water potential of the Dawak River can meet the water needs of oil palm plantations.
Keyword: evapotranspiration, F J Mock, oil palm, rainfall, river discharge

Judul: Analysis of Water Requirement for Pine Plants in the  WNS Wonoasri Forest, Wonogiri Regency
Abstrak: Kabupaten Wonogiri merupakan wilayah yang sering mengalami masalah kekeringan. Hal tersebut mengakibatkan pemenuhan kebutuhan air tanaman dapat terganggu. Siklus hidrologi salah satunya dipengaruhi oleh evapotranspirasi, yaitu proses kehilangan air dari tanah dan tumbuhan. Sehingga mekanisme pemberian air yang sesuai perlu dilakukan untuk memenuhi kebutuhan air tanaman. Penelitian mengenai ketersediaan air untuk pemenuhan kebutuhan air tanaman masih jarang dilakukan di Kabupaten Wonogiri. Oleh karena itu, penelitian mengenai kebutuhan air tanaman pinus yang ada di Kabupaten Wonogiri perlu dilakukan. Penelitian ini bertujuan untuk menganalisis kebutuhan air tanaman pinus menggunakan aplikasi CropWat 8.0 yang dipengaruhi oleh laju dekomposisi serasah tanaman pinus tersebut. Penelitian ini dilakukan menggunakan metode Penman-Mounteith melalui aplikasi CropWat 8.0. Hasil penelitian menunjukkan bahwa kebutuhan air tanaman pinus mengalami fluktuasi yang signifikan setiap bulannya. Secara umum kebutuhan air tersebut dapat dipenuhi atau mengalami surplus pada bulan Januari hingga Juni, yaitu sebesar 135,17 mm hingga 200 mm. Sementara pada bulan Juli hingga Desember mengalami defisit karena telah mencapai batas titik layu permanen, yaitu sebesar 100 mm. Hal tersebut juga didukung oleh laju dekomposisi serasah yang besar sehingga evapotranspirasi cenderung lebih tinggi., The Wonogiri Regency is regularly plagued by drought. As a result, the fulfillment of plant water requirements may be endangered. Evapotranspiration, the process of losing air from soil and plants, influences one of the hydrological cycles. As a result, an adequate air supply mechanism must be established to meet the plant's water requirements. Water availability research to satisfy plant water requirements is still rare in Wonogiri Regency. As a result, research into the requirements of pine plants in Wonogiri Regency is required. This research aims to analyze the water requirements of pine plants using the CropWat 8.0 which is influenced by the rate of decomposition of pine plant litter. This study, conducted with the CropWat 8.0, employed the Penman-Mounteith approach. The water requirements of pine plants dramatically grow month after month. In general, water requirements can be surplus from January to June, namely 135.17 mm to 200 mm. Meanwhile, from July to December, there was deficit because it had reached the permanent lay point limit, which was 100 mm. This is also supported by the large litter decomposition rate so evapotranspiration tends to be higher.
Keyword: Cropwat, deficit, drought, evapotranspiration, water surplus

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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