Microstructure and properties of a C–Mn–Si–dual-phase steel

A study has been carried out on an Fe–0.11% C–1.58% Si–0.4% Mn-dual phase steel. The dual-phase microstructures and properties are significantly affected by both the intercritical temperature and cooling rate from (α + γ) field. Upon rapid cooling (water or oil quench) from the temperature range 735–820°C, the structure comprises ferrite + martensite. On the other hand, slow cooling (air cooling) from the temperature range 735–820°C produces microstructures containing ferrite + martensite + pearlite/bainite and more favourable mechanical properties as: σ_0,2 = 281–296 MPa, σ_UTS = 632–690 MPa, TE = 26–30% and continuous yielding behaviour.     

Retardation of the photoyellowing of untreated wool and wool treated with fluorescent whitening agents by the action of reducing agents

Different chemically treated wools have been exposed to radiation in the presence of different aqueous reductive bleaching agent solutions. It was observed that thiourea dioxide gave the best performance and, in the case of wool serge, led to a fabric having a better light fastness. An interesting beneficial synergistic effect was uncovered when the reducing agents were used in conjunction with formaldehyde. Biphenols (models for dityrosine) have also been padded onto wool and exposed to light in the wet state to mimic the photoyellowing of dityrosine. 0, 0′-Biphenol-treated wool was exposed to light in the presence of the reducing agents and these were found to decrease the amount of discoloration produced by degradation of 0, 0′-biphenol.     

The strategies and parameters of tabu search for job-shop scheduling

This paper presents a tabu search approach for the job-shop scheduling problem. Although the problem is NP-hard, satisfactory solutions have been obtained recently by tabu search. However, tabu search has a problem-specific and parametric structure. Therefore, in the paper, we focussed on the tabu search strategies and parameters such as initial solution, neighborhood structure, tabu list, aspiration criterion, elite solutions list, intensification, diversification and the number of iteration. In order to compare some neighborhood strategies and tabu list length methods, a computational study is done on the benchmark problems.     

Evaluation of Legal Risks for E-Commerce in Construction

E-commerce is steadily becoming a reality in the construction industry. However, despite the increasing rate of utilization by owners and contractors alike, the legal implications of using e-commerce in construction have not been studied in depth. This paper fills this gap in literature. It identifies and analyzes the different types of legal risks involved in the use of e-commerce in construction. It also outlines the risk that contractors and professionals may face in their e-commerce implementations. A classification of e-commerce legal risks is also introduced. The legal risks discussed include agency, jurisdiction, contract formation, validity and errors, authentication, attribution, nonrepudiation, privacy, conflict of laws, and conflict between law and technology.     

An interative procedure to determine depth and time of primary oil migration and expulsion efficiency of source rocks

This study seeks to propose an iterative procedure for estimating time and depth of primary oil migration and expulsion efficiency of a source rock. The procedure is based on two assumptions: (a) oil moves out of the source rock as a separate phase; and (b) oil migration does not start until residual oil saturation is reached. Oil saturation increases with oil generation and porosity reduction during burial. Changes in total volume, pore and oil volumes by oil generation and compaction are calculated at discrete time steps. Oil expulsion begins when oil saturation reaches residual oil saturation and relative permeability of oil rises above zero. The volume of oil expulsion can also be calculated iteratively after oil migration starts. The difference between oil generation and residual oil gives the volume of oil expulsion at each time step. The mass ratio of oil expelled to total oil that is generated provides the expulsion efficiency of the source rock.     

Thermotropic polyesters: Synthesis and properties of poly(p-oxybenzoate-co-m-phenylene terephthalate)s

DSC, TMA, hot-stage microscopy and WAXS have been used to examine the effect of concentration of angular units and molecular weight on the thermal transitions of poly(p-oxybenzoate-co-m-phenylene terephthalate)s. Copolymers containing molar fractions of m-phenylenedioxy units between 0·20 and 0·30 are melt processable nematogenic materials. In contrast, poly(p-oxybenzoate-co-p-phenylene isophthalate)s remain nematogenic over a wider concentration range (0·20–0·40) of angular isophthaloyl units. Comparison of fibres produced from copolymers with the same fraction of angular units (0·25) indicates that those with isophthaloyl units have a higher modulus than those with m-phenylenedioxy units. These differences are ascribed to differences in planarity of chains containing isophthaloyl and m-phenylenedioxy units, respectively.     

A SiGe HBT Translinear Harmonic Mixer

A novel even-order harmonic mixer is proposed. Based on the translinear loop of BJT/HBTs, frequency doubling and single-to-differential conversion circuits have been employed in the design of harmonic mixer. The proposed mixer has been verified in a SiGe HBT process by SpectreRF simulations.