On the wake of a Darrieus turbine

The theory and experimental measurements on the aerodynamic decay of a wake from high performance vertical axis wind turbine are discussed. In the initial experimental study, the wake downstream of a model Darrieus rotor, 28 cm diameter and a height of 45.5 cm, was measured in a Boundary Layer Wind Tunnel. The wind turbine was run at the design tip speed ratio of 5.5. It was found that the wake decayed at a slower rate with distance downstream of the turbine, than a wake from a screen with similar troposkein shape and drag force characteristics as the Darrieus rotor. The initial wind tunnel results indicated that the vertical axis wind turbines should be spaced at least forty diameters apart to avoid mutual power depreciation greater than ten per cent

Base-catalyzed reactions of environmentally relevant N-chloro-piperidines. A quantum-chemical study

Electronic structure methods have been applied to calculate the gas and aqueous phase reaction energies for base-induced rearrangements of N-chloropiperidine, N-chloro-3-(hydroxymethyl)piperidine, and N-chloro-4-4-fluorophenyl)-3-(hydroxymethyl)piperidine. These derivatives have been selected as representative models for studying the chemical fate of environmentally relevant chloramines. The performance of different computational methods (MP2, MP4, QCISD, B3LYP and B2PLYP) for calculating the thermochemistry of rearrangement reactions was assessed. The latter method produces energies similar to those obtained at G3B3(+) level, which themselves have been tested against experimental results. Experimental energy barriers and enthalpies for ring inversion, nitrogen inversion and dehydrochlorination reactions in -chloropiperidine have been accurately reproduced when solvent effects have been included. It was also found that the combined use of continuum solvation models (e.g. CPCM) and explicit consideration of a single water molecule is sufficient to properly describe the water-assisted rearrangement of N-chlorinated compounds in basic media. In the case of N-chloro-4-(4-fluorophenyl)-3-(hydroxymethyl)piperidine, which represents the chlorinated metabolite of the antidepressant paroxetine, several different reactions (intramolecular addition, substitution, and elimination reactions) have been investigated. Transition state structures for these processes have been located together with minimum energy structures of conceivable products. Imine 4A is predicted to be the most stable reaction product, closely followed by imine 4B and oxazinane 8, while formation of isoxazolidine 7 is much less favourable. Calculated reaction barriers in aqueous solution are quite similar for all four processes, the lowest barrier being predicted for the formation of imine 4A

Bioactive secondary metabolites from the endophytic fungus Chaetomium sp. isolated from Salvia officinalis growing in Morocco

This study reports the chemical investigation and cytotoxic activity of the secondary metabolites produced by the endophytic fungus Chaetomium sp. isolated from Salvia officinalis growing in Morocco. This plant was collected from the Beni-Mellal Mountain in Morocco and belongs to the Lamiaceae family and is named in Morocco 'Salmia'. The endophytic fungus Chaetomium sp. was isolated from the tissues of the stem of this plant. The fungal strain was identified by PCR. The crude organic extract of the fungal strain was proven to be active when tested for cytotoxicity against L5178Y mouse lymphoma cells. Chemical investigation of the secondary metabolites showed that cochliodinol is the main component beside isocochliodinol. The structures of the isolated compounds were determined on the basis of NMR analysis (1H, 13C, COSY and HMBC) as well as by mass spectrometry using ESI (Electron Spray Ionisation) as source

Base Solution

Definition of the Smarandache function S(n): S(n) = the smallest positive integer such that S(n)! is divisible by n

Characterization of Asphalt Treated Base Course Material

INE/AUTC 11.0

PENGARUH PENAMBAHAN GLENIUM ACE 8590 TERHADAP SIFAT MEKANIK BETON RINGAN DENGAN AGREGAT KASAR BATU APUNG

Beton dapat dikategorikan beton ringan apabila memiliki berat jenis di bawah 1850 kg/m3. Salah satu cara membuat beton ringan dengan merubah komposisi dan jenis material penyusun beton itu sendiri, seperti batu apung sebagai pengganti agregat kasar. Secara umum beton ringan memiliki kekurangan dalam hal kuat tekan. Salah satu alternative mengatasi hal tersebut dengan menambahkan Glenium ACE 8590. Beton ringan dapat dikategorikan beton ringan struktural apabila memiliki nilai kuat tekan melebihi 17 MPa. Penelitian ini untuk mengetahui pengaruh penambahan Glenium ACE 8590 sebesar 0%, 0.5%, 1%, dan 1,5% terhadap mutu beton ringan. Pengujian yang dilakukan adalah berat jenis, kuat tekan, modulus elastisitas, dan kuat lentur beton ringan dengan penambahan Glenium ACE 8590. Bentuk benda uji yang akan digunakan untuk pengujian kuat tekan dan modulus elastisitas adalah berupa silinder, dengan diameter 15 cm dan tinggi 30 cm. sedangkan untuk pengujian kuat lentur menggunakan balok dengan ukuran 10 cm x 10 cm x 50 cm. Pengujian kuat tekan dilakukan pada umur 7 hari, 14 hari, dan 28 hari. Sedangkan pengujian modulus elastisitas dan juga kuat lentur dilakukan pada umur 28 hari. Berdasarkan penelitian yang telah dilakukan, diperoleh nilai kuat tekan rata-rata pada umur 7 hari BGR 0%, BGR0,5%, BGR1%, dan BGR 1,5% berturut-turut adalah 6,11 MPa, 6,54 MPa, 7,41 MPa, dan 8,76 MPa. Dan pada nilai kuat tekan rata-rata pada umur 14 hari BGR 0%, BGR0,5%, BGR1%, dan BGR 1,5% berturut-turut adalah 7,79 MPa, 8,72 MPa, 9,45 MPa, dan 10,02 MPa. Sedangkan pada nilai kuat tekan rata-rata pada umur 28 hari BGR 0%, BGR0,5%, BGR1%, dan BGR 1,5% berturut-turut adalah 8,36 MPa, 8,80 MPa, 9,59 MPa, dan 11,37 MPa. Kuat tekan beton ringan maksimum terjadi pada penggunaan Glenium ACE 8590 sebesar 1,5%. Pada pengujian modulus elastisitas rata-rata pada umur 28 hari BGR 0%, BGR0,5%, BGR1%, dan BGR 1,5% berturut-turut adalah 14579,37 MPa, 15929,33 MPa, 17539,32 MPa, dan 19214,46 MPa. Nilai modulus elastisitas tertinggi terjadi pada penambahan Glenium ACE 8590 sebesar 1,5%. Sedangkan untuk pengujian kuat lentur rata-rata pada umur 28 hari BGR 0%, BGR0,5%, BGR1%, dan BGR 1,5% berturut-turut adalah 2,17 MPa, 3,62 MPa, 4,11 MPa, dan 5,71 MPa. Kuat lentur paling tinggi terjadi pada penambahan Glenium ACE 8590 sebesar 1,5%. Setiap variasi memiliki berat jenis dibawah 1850 k0g/m3

Knowledge Base Version Reintegration

Given two versions of a knowledge base (KB), independently modified, we investigated the problem of incorporating changes made to one KB version into the other. We have implemented a system that will perform such a reintegration, autonomously, using predetermined user preferences. This effort has lead to a greater insight into the version reintegration problem and has highlighted those areas where user intervention would be the most beneficial in a semi-autonomous system