Sebelas Maret University

About: Sebelas Maret University is a education organization based out in Surakarta, Indonesia. It is known for research contribution in the topics: Population & Public health. The organization has 10901 authors who have published 10832 publications receiving 33057 citations. The organization is also known as: Universitas Negeri Surakarta & Universitas Sebelas Maret.

Performance ‘S’ Type Savonius Wind Turbine with Variation of Fin Addition on Blade

Abstract: Wind power has been receiving attention as the new energy resource in addressing the ecological problems of burning fossil fuels. Savonius wind rotor is a vertical axis wind turbines (VAWT) which has relatively simple structure and low operating speed. These characteristics make it suitable for areas with low average wind speed as in Indonesia. To identify the performance of Savonius rotor in generating electrical energy, this research experimentally studied the effect of fin addition for the 'S' shape of Savonius VAWT. The fin is added to fill the space in the blade in directing the wind flow. This rotor has two turbine blades, a rotor diameter of 1.1 m and rotor height of 1.4 m, used pulley transmission system with 1:4.2 multiplication ratio, and used a generator type PMG 200 W. The research was conducted during dry season by measuring the wind speed in the afternoon. The average wind speed in the area is 2.3 m/s with the maximum of 4.5 m/s. It was found that additional fin significantly increase the ability of Savonius rotor VAWT to generate electrical energy shown by increasing of electrical power. The highest power generated is 13.40 Watt at a wind speed of 4.5 m/s by adding 1 (one) fin in the blade. It increased by 22.71% from the rotor blade with no additional fin. However, increasing number of fins in the blade was not linearly increase the electrical power generated. The wind rotor blade with 4 additional fins is indicated has the lowest performance, generating only 10.80 Watt electrical power, accounted lower than the one generated by no fin-rotor blade. By knowing the effect of the rotor shape, the rotor dimension, the addition of fin, transmission, and generator used, it is possible to determine alternative geometry design in increasing the electrical power generated by Savonius wind turbine.

Simulation of Jatropha curcas shell in gasifier for synthesis gas and hydrogen production

Abstract: This paper examines a simulation of Jatropha curcas shell within an entrained flow gasifier to predict the composition of gaseous product. Since there is no available data of Jatropha shell experiment, we validated the model using other biomass: rice husk and sawdust. The validation results showed that the model agreed with the experimental data of rice husk and sawdust. Furthermore, the same model is applied for Jatropha curcas properties data. From this simulation, we obtained that carbon monoxide (CO) and hydrogen (H2) increased when reactor temperature was raised. Meanwhile, carbon dioxide (CO2) and methane (CH4) decreased. Since the simulation is not validated directly with Jatropha shell experimental data, error may come because of this situation. Therefore, we applied the Mean Error Approach (MEA) and produced a range of gas products through Jatropha shell in a simulation. The MEA data shows that methane (CH4) has the highest mean errors with both sawdust and rice husk, at values of 0.8776 and 0.6115, respectively. Carbon monoxide (CO) on the other hand, has the lowest error. When we then apply this MEA to Jatropha shell simulation result, it shows that the range of carbon dioxide (CO2) produced by Jatropha shell gasification has a composition ranging from 40.54 to 52.32% at a temperature of 1000 °C. The composition ranges of hydrogen (H2), carbon dioxide (CO2), and methane (CH4) gases are 27.07–35.91%, 5.43–28.29%, and 0.49–9.96%, respectively.

Biomass, Chlorophyll and Nitrogen Content of Leaves of Two Chili Pepper Varieties (Capsicum Annum) in Different Fertilization Treatments

Abstract: Abstrak. Suharja, Sutarno. 2009. Biomassa, kandungan klorofil dan nitrogen daun dua varietas cabai (Capsicum annum) pada berbagai perlakuan pemupukan. Nusantara Bioscience 1: 9-16. Penelitian ini bertujuan untuk mengetahui pengaruh berbagai perlakuan pemupukan terhadap biomassa, kandungan klorofil dan nitrogen daun dari dua varietas cabai, Sakti (cabai besar) dan Fantastic (cabai keriting). Penelitian dilakukan di Desa Gatak, Kecamatan Karangnongko, Kabupaten Klaten, Jawa Tengah pada September 2006 sampai Maret 2007. Penelitian menggunakan rancangan blok lengkap dengan dua faktorial yaitu varietas cabai dan perlakuan pemupukan. Perlakuan pemupukan meliputi tanpa pupuk (kontrol) (P1); pupuk kandang 2 kg/tanaman (P2), pupuk kandang (1 kg/tanaman) + pupuk kimia (ZA, SP-36, KCl = 2: 1: 1) + NPK (P3); dan pupuk kandang (1 kg/tanaman) + pupuk kimia (SP-36: KCl = 1:1) + pupuk organik cair (P4). Kadar klorofil diukur merujuk Harborne (1987), sedangkan kadar nitrogen daun diukur dengan metode Kjeldahl. Data dianalisis menggunakan Analisis Varians dilanjutkan DMRT. Hasil penelitian menunjukkan pada cabai Fantastic, perlakuan berbagai macam pemupukan berpengaruh terhadap biomassa dan klorofil a, namun tidak berpengaruh terhadap kandungan klorofil b, total klorofil dan nitrogen daun. Pada cabai Sakti perlakuan pemupukan berpengaruh terhadap bobot segar tanaman, kandungan klorofil a dan total klorofil, namun tidak berpengaruh terhadap bobot kering, bobot buah segar, kandungan klorofil b dan nitrogen daun. Oleh kerena itu direkomendasikan untuk menggunakan formulasi pupuk kandang + pupuk kimia (SP-36: KCl = 1: 1) + pupuk organik cair dalam budidaya cabai. Kata kunci: biomasa, klorofil, nitrogen daun, cabai, Capsicum annum, pemupukan.

Mengangkat Budaya dan Kearifan Lokal dalam Sistem Konservasi Tanah dan Air

Abstract: Kualitas lingkungan hidup saat ini sebagian besar mengancam kelangsungan perikehidupan manusia dan makhluk hidup lainnya, sehingga perlu dilakukan perlindungan dan pengelolaan lingkungan yang tangguh dan konsisten oleh semua pemangku kepentingan. Berbagai asas dipergunakan dalam perlindungan dan pengelolaan lingkungan hidup. Salah satu asas tersebut adalah budaya dan kearifan lokal. Kearifan lokal adalah nilai-nilai luhur yang berlaku dalam tata kehidupan masyarakat untuk antara lain melindungi dan mengelola lingkungan hidup secara lestari. Kegiatan perlindungan dan pengelolaan lingkungan hidup harus memperhatikan nilai-nilai luhur yang berlaku dalam tata kehidupan masyarakat. Salah satu permasalahan yang menjadi perhatian saat ini adalah krisis air yang diakibatkan berkurangnya sumber air dan menurun-nya kualitas tanah dan air yang mengancam ketersediaan air di Indonesia. Berbagai upaya telah dilakukan dalam rangka konservasi tanah dan air baik oleh pemerintah maupun pemerhati lingkungan. Pengelolaan sumber daya air dan tanah bukan hanya tanggung jawab pemerintah yang dituangkan dalam berbagai kebijakan tertulis, namun juga tanggung jawab masyarakat setempat yang nampak dalam pengetahuan dan pengalaman masyarakat dalam aktivitas menjalankan berbagai aktivitas pengelolaan air dan tanah. Sinergi yang baik antara pemerintah, pemerhati lingkungan, serta budaya dan kearifan lokal yang telah lama berkembang dan dipertahankan di masyarakat diharapkan dapat menjadi strategi konservasi tanah dan air yang efektif.