An experiment was conducted to obtain information on the estimation of the reduction of yield of bidi tobacco due to different degrees of infestation by leaf eating caterpillar, Prodenia litura F. It was found that the reduction in yield was to an extent of 23.4, 44.2 and 50.4 per cent when the plants were infested with 2, 4 and 8 larvae per plant respectively, which gave a financial loss of Rs. 489.60 to Rs. 1,053.45 per hectare at Rs. 1.50 per kg., the average price of tobacco during the years under experiment.

The power generation industry is facing challenges from ever-tightening environmental constraints, increased competition and deregulation of the markets. Modelling and simulation of novel power generation cycles is vital in proposing technically and economically feasible solutions which are environmentally friendly. The development of a Virtual Plant Demonstration Model (VPDM) in the UK is addressing the challenges by providing a distributed simulation environment in which heterogeneous component models can securely be run remotely at partner sites using the Internet. The VPDM programme is comprised of UK companies and academia, and is receiving support from the DTI Carbon Abatement Technologies Programme. This paper presents the creation of the VPDM framework and uses a steam turbine component model to demonstrate the key features of the VPDM.

Cross linked polyimides containing a s-triazine ring have been synthesized via the Diels-Alder intermolecular polymerization of 2,4,6-tris(2-furanyl methyl imino)-1,3,5-triazine with various bis(maleimide) compounds, followed by the aromatization of the corresponding Diels-Alder products. All the poly(imino-s-triazine imide)s were characterized by elemental analysis, FT-IR spectral studies and thermogravimetry. Glass fibre reinforced composites were prepared via an in-situ Diels-Alder intermolecular reaction between 2,4,6-tris(2-furanyl methyl imino)-1,3,5-triazine and various bis(maleimide) compounds without evolution of by-products. The resulting composites were characterized by mechanical properties.

The present study deals with turbulent flow over a long train of fixed two-dimensional dunes, identical in size and shape. A detailed study was carried out by PIV over a range of flow depths in a fully developed region. The present study confirmed the global features of flow past a fixed dune noticed in previous studies, i.e. the size and shape of the reverse flow, the mean velocity and turbulence profiles across the separated and attached flows. The turbulence and shear stress profiles reveal the presence of larger values along the line extending from crest to crest. At stations ahead of the dune crest, the presence of a peak in the streamwise turbulence profiles around y/h = 2 indicates the sustenance of turbulence generated in the separation zone of the previous zone which will be carried over to the next dune.

A series of oligomeric acid azo dyes has been prepared by coupling various aromatic diazonium salts to 1,5-dihydroxy-naphthalene formaldehyde (1,5-DHNF) oligomer. They were evaluated in terms of their softning point, yield, colour, solubility, IR and UV-Vis spectra. Structure property relationships are discussed and dyeing on wool, silk and nylon-6,6 were assessed. Dyeing on wool, silk and nylon-6,6 resulted in yellow, orange and brown to red colorations having excellent light fastness and washing fastness.

A series of new monomers for polyimide (PI) formation were prepared by the condensation reaction of 4-alkoxy-2,6-dichloro-s-triazine (I) with 2-furanmethylamine. The resulting 2,6-bis(2-furanylmethyl imino)-4-alkoxy-s-triazines (II) were obtained in 60-70% yield and were characterized by elemental analysis, IR, and NMR spectroscopy Preliminary experimental study of the Diels-Alder (DA) intermolecular polymerization of such bis-furan derivatives (II) with one of the bis-maleimides afforded PIs in a good yield. Systematic work on PIs based on these monomers is under progress.

A series of new polyimides containing an s-triazine ring have been synthesized via Diels-Alder intermolecular polymerization of 2,6-bis(2-furanyl methyl imino)-4-n-propoxy-1,3,5-triazine with different bis(maleimide) compounds, rather than aromatization of corresponding Diels-Alder products; All the poly(imino-s-triazine imide)s were characterized by elemental analysis, FTIR spectral studies, number average molecular weight (Mn) by non-aqueous conductometric titration and thermogravimetry. Glass fibre reinforced composites were prepared via in-situ Diels-Alder intermolecular reaction between 2,6-bis(2-furanyl methyl imino)-4-n-propoxy-1,3,5-triazine and different bis(maleimide) compounds without evolution of by-products. The composites were characterized by chemical resistivity and mechanical properties.

A computer imaging system was used to obtain gray level images of grade A eggs, eggs with blood spots, and eggs with dirt stains. Histograms based on the number of pixels at each gray level intensity were generated from the images and used to train neural network models. After training, the neural networks were evaluated on an independent testing set. The neural network models for blood spot detection had an accuracy of 85.6% (91.1% on grade A eggs and 86.7% on blood spotted eggs). The neural network model for dirt stain detection had an accuracy of 80.0% (88.9% on grade A eggs and 71.1% on dirt stained eggs). These accuracy levels were sufficient to produce final graded samples which were close to USDA requirements.

A color vision system was used to obtain images of single stationary eggs. Images of cracked eggs and grade-A eggs were used to generate training, testing, and validating data for an artificial neural network. Three histograms of the primary colors of red, green, and blue were constructed from each color image. A composite histogram was constructed by concatenating each primary histogram and, optionally, reducing the number of cells. Various artificial neural networks with different parameters and structures were trained using the composite histograms. The artificial neural networks were tested and validated on independent data sets. The artificial neural networks trained with histograms of color images produced graded samples that exceeded USDA requirements and achieved higher accuracy than neural networks trained on data from gray scale images.

Pulsatile flow in an excised canine larynx was investigated with simultaneous recordings of air velocity, subglottal pressure, volume flow rate, and the signal from an electro-glottograph (EGG) for various conditions of phonation. Canine larynges were mounted on a pseudotrachea and sustained oscillations were established and maintained with sutures attached to cartilages to mimic the function of laryngeal muscles. The pitch and amplitude of the oscillations were controlled by varying the airflow, and by adjusting glottal adduction and vocal-fold elongation. Measurements with hot-wire probes suggest that subglottal inlet flow to the larynx is pulsatile but mostly laminar, while the exiting jet is non-uniform and turbulent. In the typical ranges of flow rate, subglottal pressure, and oscillation frequencies, the Reynolds number based on the mean glottal velocity and glottal hydraulic diameter varied between 1600 to 7000, the Strouhal number based on the same parameters varied between 0.002 and 0.032, and the Womersley number ranged from 2.6 to 15.9. These results help define the conditions required for computational models of laryngeal flow.

SummaryBradshaw’s method of calculating the development of two-dimensional turbulent boundary layers involves the simultaneous solution of partial differential equations of mean motion and turbulent kinetic energy. The present approach avoids the computational complexities of this procedure.The use of Thompson’s two-parameter family of velocity profiles and associated skin-friction law enables the momentum integral equation to be satisfied, along with Bradshaw’s version of the turbulent kinetic-energy equation at a specified fraction of the boundary layer thickness. This fraction (y/δ = 0·5) is chosen as representing the position in the boundary layer where Bradshaw’s equation, which contains several empirical functions, is shown by comparisons with experiment to hold with greatest accuracy. Thus the present simplified approach leads not only to a reduction in computing time but also to an appreciable increase in the general accuracy of prediction.

Measurements of skin friction and mean-velocity profiles have been made in fully developed flows in pipes and channels in the Reynolds number range 1000 < Re < 10000. These measurements, and observations of hot-wire signals, indicate rather remarkable differences between two-dimensional and axially symmetric flows and also make it difficult to give a precise definition of the term ‘fully developed turbulent flow’.

The preparations of bis(hydroxyethylethylenediamine)copper(II) as the nitrate and perchlorate salts are reported. These compounds react with acetone to form copper(II) complexes of 1,15-dihydroxy-7,9,9-trimethyl-3,6,10,13-tetra-azapentadeca-6-ene. I.r. and visible–u.v. spectra are reported.

It has been shown experimentally that quite large departures occur from the universal inner-law velocity distribution in the presence of severe favourable pressure gradients in turbulent boundary layers and that these departures are associated with the tendency for the turbulent boundary layer to revert to a laminar state. From the measurements a criterion for the onset of reverse transition has been deduced in terms of the mean shear-stress gradient in the wall region of the flow. Experiments in fully developed pipe and channel flows suggest that the proposed criterion may be quite generally applicable to all fully turbulent shear flows.

Preston's method of measuring skin friction in the turbulent boundary layer makes use of a circular Pitot tube resting on the wall. On the assumption of a velocity distribution in the wall region common to boundary layer and pipe flows the calibration curve for the Pitot tube can be obtained in fully developed pipe flow. Earlier experiments suggested that Preston's original calibration was in error, and a revised calibration curve has been obtained and is presented here.From experiments in strong favourable and adverse pressure gradients, limits are assigned to the pressure-gradient conditions within which the calibration can be used with prescribed accuracy. It is shown that in sufficiently strong favourable gradients the ‘inner-law’ velocity distribution breaks down completely, and it is suggested that this breakdown is associated with reversion to laminar flow.As an incidental result, values have been obtained for the constants occurring in the logarithmic expression for the inner-law velocity distribution.

The Virtual Plant Demonstration Model (VPDM) programme has participants from UK companies and academia, and is receiving support from the DTI Carbon Abatement Technologies Programme. The VPDM objective is to provide a whole plant modelling environment that allows secure web interfacing and data exchange with individual heterogeneous component models located remotely at partner sites. Thus, companies can allow access to their in-house component models without compromising the intellectual property contained within the models. The VPDM framework and the availability of such models will provide the opportunity to investigate, through simulation studies, accurate novel power plant solutions which are capable of producing power in a reliable, cost-effective and environmentally friendly manner. This paper presents the development of the VPDM framework, the issues faced and how these were overcome. Copyright © ALSTOM 2006