Judul: Studi Aplikasi Knapsack Sprayer, Knapsack Power Sprayer, dan Boom Sprayer di PT Laju Perdana Indah, Palembang, Sumatera Selatan
Abstrak: The purpose of the research was to determine effectiveness, herbiciding cost, and performance of weed control using knapsack sprayer (KS), knapsack power sprayer (KPS), and boom sprayer (BS) in dry land sugar cane area at Laju Perdana Indah Company, Palembang, South Sumatera. Three kind of sprayers were applied for herbiciding on March 2012. Knapsack sprayer and knapsack power sprayer were manually operated by operator, were as boom sprayer was mechanically operated by 75 hp (56 kW) tractor. Active substances were use for herbiciding are 2,4 D-amina, ametryn, paraquat, sticker, glyphosate, and diuron with dosage range of (0.5-2.5) litre/ha. Research showed that herbiciding effectiveness and efficiency using three kind of sprayers gave different results. KPS was more effective than KS because percentage killed weeds after herbiciding using KPS is 77.0%, however using KS is (53.6-59.5)%. Average operational speed when at herbiciding using KS, KPS, and BS were 0.56 m/sec, 0.59 m/sec, and 2.00 m/sec respectively, so that it gave big influence for effective field capacity were (0.10-0.11) ha/hour, 0.20 ha/hour, and 2.66 ha/hour respectively. Herbicide Solutions discharge using KS, KPS, and BS were (60.69-65.40) litre/hour, 85.30 litre/hour, and 1206.00 litre/hour respectively, so that it gave result for throwput capacity are (588.64-617.01) litre/ha, 418.94 litre/ha, and 453.87 litre/ha. Difference in kind of sprayers would gave different performance. Herbiciding inefficiency using KS and KPS were (47.2- 54.3)% and 4.7%, so that it dissipation (188.64-217.01) litre/ha and 18.94 litre/ha, therefore using BS was most economically because it could economize hebicide solutions consumption of 24.4% or 146.13 litre/ha. Herbiciding cost using KS, KPS, and BS were Rp (294,925.75-303,230.95)/ha, Rp 317,575.82/ha, Rp 127,712.46/ha respectively. Herbiciding time using KS, KPS, and BS were (9- 10.17) hour/ha, 4.91 hour/ha, and 0.38 hour/ha respectively. The herbiciding effectiveness on the field for KS was (82.6-82.8)% with killed weeds percentage was (53.6-59.5)% and KPS was 93.7% with killed weeds percentage was 77%. KPS was more effective in hebiciding than KS and BS was the most efficient sprayer for herbiciding in dry land sugar cane area.
Keyword: 

Judul: Performance of Motorized Carrying Sprayer for Weed Control at Various Concentrations of Herbicide Solutions and Liquid Pressure
Abstrak: Knapsack power sprayer memiliki keunggulan yaitu besar tekanan bisa diatur dengan mengubah bukaan throttle, sehingga dapat ditentukan besar tekanan cairan, ukuran butiran semprot (droplet) dan kerapatan droplet sesuai dengan konsentrasi larutan herbisida yang digunakan. Tujuan penelitian ini adalah untuk menentukan kinerja herbiciding gulma lahan kering pada berbagai konsentrasi larutan herbisida dan tekanan cairan menggunakan knapsack power sprayer. Hasil uji kinerja knapsack power sprayer di laboratorium untuk nosel kerucut diperoleh tekanan yang paling optimum dengan bukaan throttle 50% (P3) sebesar 25 kgf/cm2. Sedangkan 4 parameter utama pada bukaan throttle 50% (P3) antara lain diameter droplet, kerapatan droplet , lebar penyemprotan efektif dan debit penyemprotan masing-masing sebesar 221.67 µm; 275.64 droplet/cm2, 0.96 m, dan 6.27 liter/menit. Hasil kinerja pengendalian gulma di lapangan yang paling optimum dengan konsentrasi larutan herbisida 3,5% (C3) untuk nosel kerucut yaitu diperoleh efektivitas terbesar adalah 81.67% dengan kapasitas keluaran sebesar 46.01 liter/ha serta biaya larutan aplikasi herbisida sebesar Rp 8 695.97 per jam. Sedangkan hasil uji kinerja knapsack power sprayer di laboratorium untuk nosel kipas diperoleh tekanan yang paling optimum dengan bukaan throttle minimum (P1) sebesar 10 kgf/cm2. Sedangkan 4 parameter utama pada bukaan throttle minimum (P1) antara lain diameter droplet, kerapatan droplet, lebar penyemprotan efektif dan debit penyemprotan masing-masing sebesar 198,67 µm; 214.93 droplet/cm2, 1,12 m, dan 3,08 liter/menit. Hasil kinerja pengendalian gulma di lapangan yang paling optimum pada konsentrasi larutan herbisida 1,5% (C1) untuk nosel kipas yaitu diperoleh efektivitas terbesar 82.43%; dengan kapasitas keluaran sebesar 5.36 liter/ha serta biaya larutan aplikasi herbisida sebesar Rp 1 181.25 per jam., Knapsack power sprayer has the advantage that it can be adjusted by changing the throttle opening, so that the liquid pressure, droplet size and droplet density can be determined according to the concentration of the herbicide solution used. The purpose of this study was to determine the performance of dryland weed herbicides at various concentrations of herbicide solutions and liquid pressure using a knapsack power sprayer. The results of the knapsack power sprayer performance test in the laboratory for the cone nozzle obtained the most optimal pressure with a throttle opening of 50% (P3) of 25 kgf / cm2. Meanwhile, the 4 main parameters at the 50% throttle opening (P3) include droplet diameter, droplet density, effective spraying width and spraying discharge of 221.67 µm; 275.64 droplets / cm2, 0.96 m, and 6.27 liters / minute. The most optimal field control results with a concentration of 3.5% herbicide solution (C3) for the most effective cone nozzle is 81.67% with an output capacity of 46.01 liters / ha and the cost of herbicide application solution is IDR 8 695.97 per hour . While the results of the knapsack power sprayer performance test in the laboratory for the fan nozzle, the optimal pressure is obtained with a minimum throttle opening (P1) of 10 kgf / cm2. Meanwhile, the 4 main parameters for the minimum throttle opening (P1) are droplet diameter, droplet density, effective spraying width and spraying discharge of 198.67 µm respectively; 214.93 droplets / cm2, 1.12 m, and 3.08 liters / minute. The most optimal field control results were at a concentration
Keyword: weeds, knapsack power sprayer, herbicide solution concentration, pressure

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology