Automated generation of NC part programs for turned parts based on 2-D drawing image files

This paper describes a novel method for automated generation of process plans and numerical control (NC) part programs from 2D drawing image files. Four algorithms are introduced in this paper. First algorithm deals with extraction of geometrical data, second algorithm used to recognise turned features from the extracted geometrical data base. Recognised features are then passed to third and fourth algorithms for generation of process plans and NC part programs respectively. Using proposed system, it is possible to achieve fully automation of recognition of turned features, generation of process plans and NC part programs. Thus, it becomes possible to go from scanned image to finished product in a fully automated fashion. These algorithms have been implemented on mini-computer to process image data, and display recognised turned features, process plans and creates output files containing NC part programs. These NC part programs are verified through CNC train simulation package. The results are satisfactory.     

Removal of mercury by foam fractionation using surfactin, a biosurfactant

The separation of mercury ions from artificially contaminated water by the foam fractionation process using a biosurfactant (surfactin) and chemical surfactants (SDS and Tween-80) was investigated in this study. Parameters such as surfactant and mercury concentration, pH, foam volume, and digestion time were varied and their effects on the efficiency of mercury removal were investigated. The recovery efficiency of mercury ions was highly sensitive to the concentration of the surfactant. The highest mercury ion recovery by surfactin was obtained using a surfactin concentration of 10 × CMC, while recovery using SDS required < 10 × CMC and Tween-80 >10 × CMC. However, the enrichment of mercury ions in the foam was superior with surfactin, the mercury enrichment value corresponding to the highest metal recovery (10.4%) by surfactin being 1.53. Dilute solutions (2-mg L(-1) Hg(2+)) resulted in better separation (36.4%), while concentrated solutions (100 mg L(-1)) enabled only a 2.3% recovery using surfactin. An increase in the digestion time of the metal solution with surfactin yielded better separation as compared with a freshly-prepared solution, and an increase in the airflow rate increased bubble production, resulting in higher metal recovery but low enrichment. Basic solutions yielded higher mercury separation as compared with acidic solutions due to the precipitation of surfactin under acidic conditions.     

Sol–gel mediated surface modification of nanocrystalline NiFe2O4 spinel powders with amorphous SiO2

Surface modification of nanocrystalline NiFe₂O₄ spinel particles with amorphous SiO₂ by the sol–gel process at 350 °C was demonstrated. Amorphous phase of the SiO₂ layer was evaluated by X-ray diffraction technique. Structural coordination of the pristine and SiO₂ coated NiFe₂O₄ particles as investigated by employing FTIR analysis. Thickness of the SiO₂ layer was investigated through transmission electron microscopy and it was identified to be ～10–23 nm over nanocrystalline NiFe₂O₄ particles. The magnetic behavior of pristine and surface modified NiFe₂O₄ particles were investigated using vibrating sample magnetometer (VSM). Magnetic studies showed the retention of magnetic property of surface modified NiFe₂O₄ particles with the reduced saturation magnetization and coercivity compared to the pristine NiFe₂O₄ particles, which is respectively due to the lower fraction of the magnetic component and the formation of interfacial structure.     

Tris(acetylacetonato)rhodium(III)‐Catalyzed α‐Alkylation of Ketones, β‐Alkylation of Secondary Alcohols and Alkylation of Amines with Primary Alcohols

The tris(acetylacetonato)rhodium(III) catalyst is shown to be a versatile catalyst in the presence of DABCO (1,4‐diazabicyclo[2.2.2]octane) as ligand for the α‐alkylation of ketones followed by transfer hydrogenation, for the one‐pot β‐alkylation of secondary alcohols with primary alcohols and for the alkylation of aromatic amines in the presence of an inorganic base in toluene.     

Flux decline during ultrafiltration of kraft black liquor using different flow modules: a comparative study

Ultrafiltration of black liquor was studied in three different modules, namely, radial cross flow, rectangular cross flow and stirred cell over a wide range of operating conditions. Effects of different cut-off membranes on the permeate flux and observed rejection were also studied in the stirred cell module. Effects of operating conditions, e.g. pressure difference, Reynolds number and feed concentration on the permeate flux and observed rejection were also investigated. Such comparative study may be useful to select a suitable module, membrane and a set of optimum operating conditions to achieve a desired quantity and quality of permeate flux. A comparative analysis of flux decline for different modules is also presented using a simple resistance-in-series model.     

Spectrophotometric determination of tyrosine in proteins

A new spectrophotometric method for the determination of tyrosine in proteins has been developed. Tyrosine forms a red coloured coupled product with 4-aminophenazone-sodium metaperiodate reagent in an ammoniacal solution which absorbs at 470 nm. Beer's law is obeyed in the range 1·5–15 μg/ml. The method is simple, sensitive, reproducible and accurate within ±1·5% and applicable to the assay of tyrosine in protein hydrolysates.     

Comments on “Analysis of wide inclined slot coupled narrowwall coupler between dissimilar rectangular waveguides”[and reply]

Comments by D. Satyanarayana and Ajay Chakrabarty claim that the original paper [see IEEE Trans. Antennas Propagat., vol. AP-37, no. 9, p. 1116-23, 1989] has not considered the contribution of TE_no mode in the scattered fields in the waveguide region and imply that the Green's function employed is incomplete. However there is a discussion on the singular contribution with a mathematical expression containing the appropriate Dirac delta function. It is also obvious that the specific terms of the cavity Green' s functions that treat the waveguide wall thickness do not have such a singular contribution present. Therefore, Green's functions employed in the paper are complete and rigorous. D. Satyanarayana and Ajay Chakrabarty reply to these further comments by the original author     

Absorption and emission spectra of Eu3 doped Fluoroborate glasses

This paper reports the preparation of certain newly developed Eu³⁺ - doped fluoroborate glasses with H₃BO₃ and Na₂CO₃ as the network formers (NWF) and the fluorides of alkali (Na or Li) as the network intermediates (NWL). Further, by adding AIF₃ to the fluoroborate glasses, properties such as glass transparency; hardness; resistivity towards moisture and IR-transmission ability were found improved significantly. Under a UV source, these colourless Eu³⁺ - glasses did reveal brighter red emission. Compositional effects on the absorption and photoluminescence spectra of Eu: fluoroborate glasses were examined from their measured spectrophotometric profiles.     

Analogue neural networks with distributed neurons

A new technique is proposed for implementing neurons in analogue electronic neural networks. It features integrating a fraction of a neuron with each synapse. Each neuron is distributed over all associated synapses. This methodology operates with just one building block, the distributed-neutron synapse, in contrast to existing techniques which are based on two distinct blocks, the neuron and synapse. This approach can be applied to a variety of implementations, including transconductor and MOSFET-op-amp neural networks. Modularity, ease of interconnectivity, expandability and reconfigurability are the advantages of this technique.<>     

The role of active elements in Fe-Cr-Al alloys for heating element applications

The role of active elements (zirconium, cerium and yttrium) in grain growth and its subsequent effect on room-temperature tensile fracture behaviour of Fe-Cr-Al alloys has been investigated. The alloys containing active elements exhibited improved resistance to grain growth. Yttrium-containing alloy retained higher room-temperature tensile ductility even after heating at higher temperatures because of its superior resistance to grain coarsening. All the alloys, with and without active elements, exhibited a sudden drop in room-temperature tensile ductility, with concommitant change in fracture mode from dimple rupture to cleavage, in a narrow band of 39–44μm grain size. The ductile-brittle transition temperatures (DBTT) of these alloys were found to be 150°C and 215°C for grain sizes 25μm and 100μm respectively. The accelerated life test showed that the alloys containing active elements exhibited longer lives.