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Abstract. Stinging Nettle (Urtica dioica L., latin) is a wild plant that grows in Indonesia, Asia, and Europe. Nettle in Bali, Indonesia is called as Lateng, Jelatang. Nettle plant has a very strong fiber and high fixed carbon. Nettle plants are covered with fine hairs, especially in the leaves and stems. When it is touched, it will release chemicals, sting and trigger inflammation that causes redness, itching, bumps and irritation to the skin. Nettle plants grow in the wild, regarded as a weed in the agricultural industry, easy to grow and snatch food from the parent plant. The main objective of this paper is to review of the potential nettle fibers and then explain about the potential of local nettle plant in Indonesia. Nettle is a plant group at the end of bast. Its plant fibers taken from the bark, as reinforcement in composite materials. Nettle fibers have three main advantages such as strong, lightweight and low environmental impact.

Teknologi gasifikasi tipe downdraft adalah salah satu teknologi untuk mengkonversikan bahan bakar padat atau biomassa padat secara thermokimia dengan temperatur 6000-7000 C menjadi bahan bakar gas mampu bakar dengan kebutuhan udara 20 – 40% Stoikiometri dimana suplai udara masuk dari atas menuju dasar reaktor dan proses gasifikasi terjadi di dasar reaktor.  Sampah kota atau ( Municipal Solid Westes) adalah bahan buangan yang terdiri dari bahan organik dan anorganik yang mempunyai nilai kalor sehingga dapat digunakan sebagai bahan bakar. Penelitian ini bertujuan untuk mengetahui performansi dari gasifier tipe dwondraft dengan variasi perlakuan awal bahan bakar kering, pellet, dan briket. Perbedaan perlakuan bahan bakar akan menghasilkan nilai kalor dan karakteristik bahan bakar yang berbeda sehingga nantinya akan didapatkan bahan bakar yang paling efektif. Hasil penelitian menunjukan bahwa efisiensi tertinggi didapatkan pada variasi perlakuan awal bahan bakar sampah kota yang di briketkan yaitu sebesar 61,32% dan FCR tertinggi terjadi pada bahan bakar pellet yaitu 4,61 kg/jam. Gasification type Downdraft technology is one technology to convert thermochemical solid or biomass fuels with temperatures of 6000-7000 C into combustible gas fuels with air requirements of 20 - 40% Stoichiometry where the supply of air enters from above to the reactor base and gasification process occurs at the bottom of the reactor. Municipal solid waste is a waste material consisting of organic and inorganic materials that has a heating value, so that it can be used as fuel of gasification. This study aims to determine the performance of the dwondraft gasifier with variations in the pretreatment of dry MSW, pellets and briquettes. Differences in fuel treatment will produce different heating values ??and fuel characteristics so that the most effective fuel will be found later. The results showed that the highest efficiency was found in the variation of initial treatment municipal solid waste briquettes which was 61,32%, and the highest FCR occurs in pellet fuel which is 4.61 kg / hour.

Coconut leaf is one of the most potential biomass to be converted into bio-oil through pyrolysis process and the availability in Indonesia is abundance. The mechanism of decomposition of coconut leaf into bio-oil productions requires further research because of the complexity of pyrolysis and differences in biomass composition. Therefore, the design, optimization and modeling of pyrolysis processes is strongly influenced by biomass characteristics. The purpose of this study was to find the characteristic differences in pyrolysis behavior of the three main parts of coconut leaf based on its constituent parts; leaflets, midrib and whole leaf. Moisture is removed by drying the sample in an electric oven at 110°C for 24 hours. Characteristics were tested using Cellulose Analysis, Ultimate Analysis, and Heat Value, whereas pyrolysis behavior used Thermogravimetric Analyzer (TGA). The results show that leaflets, midrib and whole leaf exhibit different pyrolysis behavior. In terms of considering flow process of separation, the whole leaf becomes an option as a fuel for further pyrolysis processes. The maximum temperature that as a reference in the pyrolysis process of coconut leaves is 500°C with temperature rate of 20°C/min and the process lasts as long for 130 minutes.

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The advantages of the fibrous nature of stinging nettles compared with other natural fibers are their strength and light weight. Stinging nettles thrive in Indonesia, Asia. Nettle fiber is used as a substitute for synthetic fibers to reinforce composite materials. The objective of this research was to study the relationship between the hardness and thermal conductivity of polymer composites reinforced with nettle fiber. Epoxy composites were reinforced with nettle fiber using fiber weight fractions of 10%, 15%, and 20%. Fibers were treated with 5% NaOH for 2 hours, had a length of 5 mm, and were in a random orientation. Composites were produced using the hand lay-up method. The results show that the composite hardness were 81.6, 84.4, and 86.6 Shore D, and the thermal conductivities were 0.129, 0.138, and 0.162 kcal/ms ºC. The relationship between control factors and performance output was determined by nonlinear regression analysis.

Rapid volatile matter evolution from high-volatile fuels such as wastes and biomass is one of problems associated with fluidized bed incinerators and gasifiers. When volatile matter evolves rapidly in the vicinity of the fuel feed point, the mixing of volatile matter with reactant gas is poor, and therefore, unreacted volatile matter is expected to be released from the reactor. In the present work, reduction of the volatile matter evolution rate was attempted by employing porous solids as bed materials instead of nonporous sand. The effect of bed material on the onset of devolatilization was measured by use of a bench-scale bubbling fluidized bed reactor. Volatile matter capture by the porous solids (capacitance effect) and the heat transfer rate within the bed, both of which affect volatile matter evolution rate, were also measured. Four types of porous solids, both with and without capacitance effect, were employed as the bed material. By employing porous solids without capacitance effect, the contributions of reduced heat transfer rate and capacitance effect to the delay of volatile matter evolution can be evaluated separately. For porous bed materials with a moderate capacitance effect (volatile matter capture of up to 20 %), the delay of the onset of devolatilization, which was measured by detecting the flame combustion of the volatile matter, was explained by the lower heat transfer between the fuel and bed. However, for a porous particle with high capacitance effect (volatile matter capture of 30 %), the capacitance effect also affected the delay of the onset of the flame combustion.

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