Glycerol steam reforming with low steam/glycerol ratio in a two-zone fluidized bed reactor

The production of hydrogen from glycerol steam reforming has been studied in several reactors. In conventional reactors the catalyst is deactivated by coke: in fixed bed reactors plugging was observed if a low steam/glycerol ratio was employed, while in fluidized bed reactors it was possible to operate for a longer time-on-stream. The use of a two-zone fluidized bed reactor is studied in this work, as a method to counteract the problem of catalyst deactivation by coke. The glycerol reforming takes place in the upper part of this reactor while the catalyst is simultaneously regenerated in the lower part, where a stream of a regenerating gas is introduced. It has been found that CO2, O2 or H2O can act as regenerating gas in a two-zone-fluidized bed reactor, allowing steady state operation at a water:glycerol molar ratio as low as 1.25. The effect of the operating conditions has been studied and the yield to the main products was compared with the calculated values assuming thermodynamic equilibrium

Environmentally friendly and regioselective C3-alkylation of indoles with alcohols through a hydrogen autotransfer strategy

The direct alkylation of indoles using KOH and alcohols, as initial source of the electrophile, under solvent-free conditions is a safe and environmentally benign strategy for selective modification of these structures at the C3-position, without using hazardous and difficult to handle bromide or iodide derivatives or toxic and expensive transition metal catalysts. The protocol shows a broad scope, including halogenated indoles and secondary alcohols.This work was supported by the current Spanish Ministerio de Economía y Competitividad (Consolider Ingenio 2010 CSD2007-00006, CTQ2011-24151) and the Generalitat Valenciana (G.V.; PROMETEO 2009/03, FEDER). R.C. thanks to G.V. for a fellowship through the PROMETEO program

Analisis Biaya, Pendapatan dan R/c USAhatani Jagung (Zea Mays L.) (suatu Kasus di Desa Margaharja Kecamatan Sukadana Kabupaten Ciamis)

Tujuan penelitian ini untuk mengetahui 1) Besarnya biaya, 2) Besarnya pendapatan, 3) Besarnya R/C USAhatani jagung per hektar per satu kali musim tanam di Desa Margaharja Kecamatan Sukadana Kabupaten Ciamis.Metode penelitian yang digunakan adalah survey dengan responden 43 orang petani jagung dari populasi 840 orang petani di Desa Margaharja Kecamatan Sukadana Kabupaten Ciamis, dengan menggunakan teknik penarikan sampel acak kelompok (cluster random sampling), analisis data dilakukan secara deskriptif. Berdasarkan hasil penelitian menunjukan: 1) Usahatani jagung di Desa Margaharja per hektar per satu kali musim tanam biaya produksi yang dikeluarkan (biaya tetap dan biaya variabel) adalah sebesar Rp. 8.161.721,09, 2) Pendapatan petani per hektar per satu kali musim tanam sebesar Rp. 11.557.187,90 dari penerimaan yang diperoleh sebesar Rp. 19.718.907,99 yaitu produk sebanyak 6.572,97 kilogram dengan harga produk Rp. 3.000 perkilogram, 3) Besarnya R/C yang diperoleh petani adalah sebesar 2,42 artinya apabila biaya yang dikeluarkan sebesar Rp. 1,00 maka diperoleh penerimaan sebesar Rp. 2,42. Dengan demikian maka USAhatani jagung yang dilaksanakan para petani di Desa Margaharja Kecamatan Sukadana Kabupaten Ciamis menguntungkan

Uniaxial die compaction of food powders

This paper presents a study of uniaxial die compaction of food powders for typical food powders such as maize powder and maize grits as well as a universal binder known as microcrystalline cellulose or Avicel. This method of compaction is widely applied in the industry as it can investigate the compressibility and compactability characteristics of powders prior to handling, storage, packaging, and transportation. In the current context, a cylindrical uniaxial die of 20 mm was used to compress the powders into compact. Pressures ranging of 30 and 160 MPa were applied to the uniaxial die using a universal testing machine. It was found that Avicel powder showed the highest compactability characteristic, ability to form bonding easily. Whereas, compactability of both the coarse maize and fine maize were quite similar, which may be due to the similar chemical composition. The data were then validated using an established compression equation. The asymptotic residual modulus value reduced as the ability of the food powders to form plastic junctions - assuming that they existed - increased. For the tensile strength test, Avicel compact showed the greatest tensile strength, many times that of fine maize and coarse maize compacts. However, between the fine maize and coarse maize, fine maize had higher tensile strength which may be due to its smaller particle size, as well as the fact that the contact area may be increased, and consequently may form a more coherent compact. The results indicate that this simple approach can be used to understand the compressibility and compactability characteristics of food powders which are essential for engineering and technology application

Catalyzed addition of acid chlorides to alkynes by unmodified nano-powder magnetite: synthesis of chlorovinyl ketones, furans, and related cyclopentenone derivatives

Inexpensive and commercially available nano-powder magnetite is an excellent catalyst for the addition of acid chlorides to internal and terminal alkynes, yielding the corresponding chlorovinyl ketones in good yields. The process has been applied to the synthesis of 5-chloro-4-arylcyclopent-2-enones, 3-aryl-1H-cyclopenta[a]naphthalen-1-ones, and (E)-3-alkylidene-2,3-dihydro-1H-cyclopenta[a]naphthalen-1-ones, just by changing the nature of the starting acid chloride or the alkyne. All tested processes elapse with an acceptable or excellent regio- and stereo-selectivity. Moreover, the use of the iridium impregnated on magnetite catalyst permits the integration of the chloroacylation process with a second dehydrochlorination–annulation process to yield, in one-pot, 1-aryl-2,4-dialkylfurans in good yields, independently of the nature of the starting reagents, and including the heteroaromatic ones.This work was supported by the current Spanish Ministerio de Economía y Competitividad (Consolider Ingenio 2010 CSD2007-00006 and CTQ2011-24151) and the Generalitat Valenciana (G.V.; PROMETEO 2009/03, FEDER). R.C. thanks to G.V. for a fellowship through the PROMETEO program

Peningkatan Hasil Belajar Siswa pada Pembelajaran IPA Menggunakan Metode Diskusi Kelas IV Sekolah Dasar

The purpose of this study is to determine the ability of the teacher in planning and implementing the discussion method learning science and how much the students\u27 improvement learning outcomes in learning by using the method of discussion . The method used is descriptive. It is collaborative research. The study is conducted in fourth grade of SDN 02 Sanggau , the object of study is the teacher and students of fourth grade of SDN 02 Sanggau. Data collection techniques are direct observation and measurement. The data are collected through observation sheets and students\u27 test sheet. The results of the study: (1) The ability of teacher increased from 2 in cycle I to 3.95 in cycle II. It increased 1.95. (2) The ability of teacher to implement the learning increased from 2.2 in cycle I to 3.96 in cycle II, It increased 1.76 (3) The student learning outcomes 54.78 in cycle I change to 87.82 in cycle II. It increased 33.04. (4) Thus, students have increased a good learning outcome

Stairs detection with odometry-aided traversal from a wearable RGB-D camera

Stairs are one of the most common structures present in human-made scenarios, but also one of the most dangerous for those with vision problems. In this work we propose a complete method to detect, locate and parametrise stairs with a wearable RGB-D camera. Our algorithm uses the depth data to determine if the horizontal planes in the scene are valid steps of a staircase judging their dimensions and relative positions. As a result we obtain a scaled model of the staircase with the spatial location and orientation with respect to the subject. The visual odometry is also estimated to continuously recover the current position and orientation of the user while moving. This enhances the system giving the ability to come back to previously detected features and providing location awareness of the user during the climb. Simultaneously, the detection of the staircase during the traversal is used to correct the drift of the visual odometry. A comparison of results of the stair detection with other state-of-the-art algorithms was performed using public dataset. Additional experiments have also been carried out, recording our own natural scenes with a chest-mounted RGB-D camera in indoor scenarios. The algorithm is robust enough to work in real-time and even under partial occlusions of the stair

Influence of the sampling device on somatic cell count variation in cow milk samples (by official recording)

The objective of this study was to investigate the variability in cow's milk somatic cell counts (SCC) depending on the type of milk meter used by dairy farms for official milk recording The study was performed in 2011 and 2012 in the major cattle area of Spain. In total, 137,846 lactations of Holstein-Friesian cows were analysed at 1,912 farms. A generalised least squares regression model was used for data analysis. The model showed that the milk meter had a substantial effect on the SCC for individual milk samples obtained for official milk recording. The results suggested an overestimation of the SCC in milk samples from farms that had electronic devices in comparison with farms that used portable devices and underestimation when volumetric meters are used. A weak positive correlation was observed between the SCC and the percentage of fat in individual milk samples. The results underline the importance of considering this variable when using SCC data from milk recording in the dairy herd improvement program or in quality milk programs.Peer reviewe

An instability criterion for nonlinear standing waves on nonzero backgrounds

A nonlinear Schr\"odinger equation with repulsive (defocusing) nonlinearity is considered. As an example, a system with a spatially varying coefficient of the nonlinear term is studied. The nonlinearity is chosen to be repelling except on a finite interval. Localized standing wave solutions on a non-zero background, e.g., dark solitons trapped by the inhomogeneity, are identified and studied. A novel instability criterion for such states is established through a topological argument. This allows instability to be determined quickly in many cases by considering simple geometric properties of the standing waves as viewed in the composite phase plane. Numerical calculations accompany the analytical results.Comment: 20 pages, 11 figure