Fabrication of nanocrystalline alloys Cu–Cr–Mo super satured solid solution by mechanical alloying

This work discusses the extension of solid solubility of Cr and Mo in Cu processed by mechanical alloying. Three alloys processed, Cu–5Cr–5Mo, Cu–10Cr–10Mo and Cu–15Cr–15Mo (weight%) using a SPEX mill. Gibbs free energy of mixing values 10, 15 and 20 kJ mol⁻¹ were calculated for these three alloys respectively by using the Miedema's model. The crystallite size decreases and dislocation density increases when the milling time increases, so Gibbs free energy storage in powders increases by the presence of crystalline defects. The energy produced by crystallite boundaries and strain dislocations were estimated and compared with Gibbs free energy of mixing values. The energy storage values by the presence of crystalline defects were higher than Gibbs free energy of mixing at 120 h for Cu–5Cr–5Mo, 130 h for Cu–10Cr–10Mo and 150 h for Cu–15Cr–15Mo. During milling, crystalline defects are produced that increases the Gibbs free energy storage and thus the Gibbs free energy curves are moved upwards and hence the solubility limit changes. Therefore, the three alloys form solid solutions after these milling time, which are supported with the XRD results.     

The Synthesis and Biological Evaluation of Multifunctionalised Derivatives of Noscapine as Cytotoxic Agents

Noscapine, a phthalideisoquinoline alkaloid derived from Papaver somniferum, is a well‐known antitussive drug that has a relatively safe in vitro toxicity profile. Noscapine is also known to possess weak anticancer efficacy, and since its discovery, efforts have been made to design derivatives with improved potency. Herein, the synthesis of a series of noscapine analogues, which have been modified in the 6′, 9′, 1 and 7‐positions, is described. In a previous study, replacement of the naturally occurring N‐methyl group in the 6′‐position with an N‐ethylaminocarbonyl was shown to promote cell‐cycle arrest and cytotoxicity against three cancer cell lines. Here, this modification has been combined with other structural changes that have previously been shown to improve anticancer activity, namely halo substitution in the 9′‐position, regioselective O‐demethylation to reveal a free phenol in the 7‐position, and reduction of the lactone to the corresponding cyclic ether in the 1‐position. The incorporation of new aryl substituents in the 9′‐position was also investigated. The study identified interesting new compounds able to induce G2/M cell‐cycle arrest and that possess cytotoxic activity against the human prostate carcinoma cell line PC3, the human breast adenocarcinoma cell line MCF‐7, and the human pancreatic epithelioid carcinoma cell line PANC‐1. In particular, the ethyl urea cyclic ether noscapinoids and a compound containing a 6′‐ethylaminocarbonyl along with 9′‐chloro, 7‐hydroxy and lactone moieties exhibited the most promising biological activities, with EC₅₀ values in the low micromolar range against all three cancer cell lines, and these derivatives warrant further investigation.     

1, 5-Bis (2-hydroxyacetophenone)thiocarbohydrazone: A novel colorimetric and fluorescent dual-mode chemosensor for the recognition of fluoride

1,5-Bis (2-hydroxyacetophenone)thiocarbohydrazone (H₄L) has been synthesized and characterized by means of spectroscopic and single crystal X-ray diffraction methods. Interactions of the H₄L with a variety of anions were investigated using a combination of UV–visible and fluorescence spectroscopic methods in a biological competing solvent DMSO. The H₄L has a high degree of selectivity for fluoride over other anions. ¹H NMR titration experiments indicate that a deprotonation process is involved in the chemo sensing process.     

The computer analysis of space frames with offset members

The problems involved in the analysis of three dimensional frames having offset prismatic members are investigated. The sources of offset considered are the rigid gusset plate effects and misalignment of members from specified joint positions. The secondary effects due to axial forces are also considered in the analysis. The displacement method of structural analysis is used with an iterative procedure to take into account the secondary effects. The complete stiffness matrix has been derived. The computer program developed, based on this analysis, is also explained. From the example of steel frame folded plate it is seen that the difference in maximum axial forces and bending moments due to the offset members are about 20%. It appears that the method, developed herein, for analysing space frames having offset members, offers a very direct and versatile approach to the problem of analysing structures having misaligned members.     

Conditioning of sludge produced through chemical treatment of radioactive liquid waste – Operating experiences

At Centralised Waste Management Facility (CWMF) 160 m³ of radioactive chemical sludge, generated from treatment of several batches of category-II and category-III radioactive liquid wastes by chemical precipitation method was stored in clariflocculator (CF) for downstream processing. The sludge needed conditioning before disposal. The analysis of the sludge samples collected at different radial locations and depths from the CF showed suspended solid content of 2.37–13.07% and radioactive content of gross β–γ 5000–27,000 Bq/g and α 100–600 Bq/g. After comparing different options available for conditioning of the sludge based on their technological and economical aspects, it was decided to dewater it using centrifuge before fixing in cement matrix with additives. Process Control Laboratory of CWMF studied the process in detail to optimize the relevant parameters for fixation of the concentrate obtained from centrifuge. Based on these results, conditioning of the stored sludge was undertaken.     

Electrochemical oxidation of acidic Alberta coal slurries

The electrochemical oxidation of four different types of Alberta coals of bituminous and subbituminous rank have been studied in 1 M H₂SO₄ slurries at 90°C under potentiostatic conditions at an applied potential of 1.0 V with respect to RHE. Two particle sizes (>200 and <60 mesh) were used to determine the rate constant for the electrochemical oxidation of coal mediated by Fe³⁺. Two rate constants,k _c.1, andk _c.2, representing initial (0-6 h) and subsequent (6–24 h) stages of electrochemical oxidation of coal, respectively, were observed. A correlation between the rate constants and the fixed carbon content (rank) of the coals was drawn. Gas chromatographic analysis of the gaseous oxidation products indicated the production of carbon dioxide. The rate and current efficiency for this production was determined as a function of electrolysis time with the rate of production reaching a steady-state level after a few hours of electrolysis. Possible mechanisms, for the oxidation of coal are discussed, based on structural and functional group models.     

Behaviour of multibay steel frame folded plate roofs

The behaviour of single bay steel frame folded plate roofs is fairly well understood[4]. In actual practice, multibay frames are mostly used to cover large column-free areas and as the behaviour of these is not well known an attempt has been made to predict their behaviour taking into account the action of laterals, edge trusses, lack of fit, support conditions and buckling. From this study, it is found that for efficient layout the laterals and edge trusses need to be provided only in the edge bays. Practical considerations like lack offit and settlement of supports do not adversely affect the stresses in most of the members.     

Tolerance design optimization of machine elements using genetic algorithm

An important problem that faces design engineers is how to assign tolerance limits. In practical applications, tolerances are most often assigned as an informal compromise between functionality, quality and manufacturing cost. Frequently, the compromise is obtained iteratively by trial and error. A more scientific approach is often desirable for better performance. In this paper, a genetic algorithm (GA) is used for the design of tolerances of machine elements to obtain the global optimal solution. The objective is to design the optimum tolerances of the individual components to achieve the required assembly tolerance, zero percentage rejection of the components and minimum cost of manufacturing. The proposed procedure using GA is described in this paper for two tolerance design optimization problems: gear train and overrunning clutch assemblies. Results are compared with conventional techniques and the performances are analyzed.     

Overall throughput effectiveness (OTE) metric for factory-level performance monitoring and bottleneck detection

Seiichi Nakajima provided overall equipment effectiveness (OEE) to measure productivity and perform diagnostics at the equipment level. However, a literature review indicates that such metrics are lacking at the factory level. In order to address this gap, an overall throughput effectiveness (OTE) metric is developed. The purpose of OTE is twofold: it measures factory-level performance and can also be used for performing factory-level diagnostics such as bottleneck detection and identifying hidden capacity. The task of coming up with such a metric was achieved by defining a set of commonly occurring predefined subsystems including series, parallel, assembly and expansion. OTE was developed for each of these predefined subsystems. It also accounts for subsystems processing multiple products and performing rework. Any factory layout can be modelled using a combination of the predefined subsystems, which allows determination of the overall factory effectiveness (OFE). More importantly, OTE has the potential to automate the entire factory-level performance diagnostics, hence drive continuous productivity improvement quantitatively. This paper explains the OTE development methodology, validates the developed OTE metrics and demonstrates its diagnostic ability. Application of OTE to a wafer fab and glass manufacturing case study showed that productivity bottleneck and opportunities for improvement can be identified quantitatively.