A web-based system for design interface management of construction projects

Planning methods such as CPM and PERT cannot model the iterative details of design processes. It has been demonstrated that the Dependency Structure Matrix (DSM) is an effective method to model iterative process. However, formulating the DSM on large construction projects, using current methodologies is challenging. To address this challenge, a structured methodology called Design Interface Management System “diMs” has been proposed. As the documents and interactions required for implementing the “diMs” process are voluminous, support of an IT based tool is essential. This paper presents the design and the development of the tool. It includes the design of class structure, relational database and communication engine using object oriented concepts. In addition, the design of user interface which consists of a set of dynamic web pages is also explained. The paper also illustrates the usage of the tool for the design of a glass factory and discusses the utility of the tool in assisting design interface management.     

Vibration characteristics of orthotropic shaft–disk system with different constrained damping layers: experimental and numerical study

This paper reports the results of an investigation carried out to study the effect of various constrained layers (viscoelastic layer (VEL), electrorheological fluid, and magnetorheological fluid) on natural frequency and damping factor. The different fiber orientations (0°, 30°, 45°, 60°, and 90°) were considered for glass/epoxy (G/E) and graphite/epoxy (GR/E) shaft–disk systems. Experimental evaluation and finite element technique are employed to investigate the natural frequency and damping factor for various combinations. The vibrational characteristics of the composite sandwich shaft–disk system are also compared in this present study. From the study, it is evident that the VEL core shows excellent frequency and damping loss factor performances, and the 90° fiber-oriented composites are dominant in vibration damping performances. The GR/E shaft–disk system outperforms the G/E shaft–disk system.     

Effect of constrained layers on vibrational characteristics of a composite sandwich system��A finite element based critical investigation

The main aim of this paper is to investigate the effect of various constrained layers (viscoelastic layer (VEL), electro-rheological fluid (ERF), and magneto-rheological fluid (MRF)) over natural frequency and the damping loss factor with two different fiber orientations (0° and 90°) for a Graphite/Epoxy (GR/E) composite sandwich shaft disc system. The finite element technique is used to investigate the natural frequency and loss factor for various combinations. Furthermore, the vibrational characteristics of the composite sandwich shaft disc system are compared with those of the base structure without constrained layers. The study shows that introducing various constrained layers reduces the magnitude of natural frequency by up to 80%. The results also show that GR/E composite with 90° fiber orientation acquires the highest frequency reduction. Among the proposed layers, VEL has the highest damping loss factor.     

Aryloxy and benzyloxy compounds of hafnium: Synthesis, structural characterization and studies on solvent-free ring-opening polymerization of ε-caprolactone and δ-valerolactone

A large variety of aryloxy compounds and benzyloxy derivatives of Hf(IV) were synthesized from Hf(O-tBu)₄ using the alcoholysis route. These compounds were completely characterized using various spectroscopic and analytical methods along with single crystal X-ray diffraction studies. Multinuclear NMR studies prove high degree of fluxional behavior of these compounds in solution. They adopt a dimeric structure in the solid-state as seen from X-ray diffraction studies on a few of them. These compounds are powerful catalysts for the ring-opening polymerization of ε-caprolactone (CL) and δ-valerolactone (VL) resulting in high number average molecular weight (M_n) polymers and controlled molecular weight distributions (MWDs). Significant control in the polymerization was achieved with these compounds as initiators in comparison to their titanium and zirconium analogues. Kinetic studies reveal that the rates of such polymerizations are in general slower than the corresponding titanium and zirconium derivatives. ¹H NMR and MALDI-TOF studies of low molecular weight oligomers suggest that these polymerizations proceed by the activated monomer mechanism.     

Effect of food matrix and processing on release of almond protein during simulated digestion

The aims of the present work were to assess digestibility of almond protein in the upper gastrointestinal tract, evaluate the effects of food matrix on protein release and assess the persistence of immunoreactive polypeptides generated during simulated digestion. Prunin, the most abundant protein in almond flour, was sensitive to pepsin, with complete digestion after 20 min in the gastric phase. Addition of the surfactant phosphatidylcholine did not affect the rate and kinetic of digestion, as observed by SDS-PAGE analysis and HPLC, in the stomach and the small intestine of either natural or blanched almond flour. However, incorporation of almond flour into a food matrix, such as chocolate mousse and Victorian sponge cake, decreased the rate of almond protein degradation by pepsin and immunoreactivity of almond polypeptides detected by dot blots and sandwich ELISA retained better. Most of the almond protein identified by in-gel tryptic digestion and MALDI-TOF analysis corresponded to prunin, with pI values of 5–7.     

Acalypha indica–mediated green synthesis of ZnO nanostructures under differential thermal treatment: Effect on textile coating,hydrophobicity, UV resistance,and antibacterial activity

In this study, ZnO nanoparticles were green-synthesized from Acalypha indica leaf extract using zinc acetate as a precursor. The prepared ZnO nanoparticles were calcined at three different temperatures, namely 100, 300, and 600?°C. The structure/morphology of the green-synthesized ZnO nanoparticles was ascertained through X-ray diffraction, particle size analysis, scanning electron microscopy, transmission electron microscopy, and surface area analysis techniques. It was observed from the physico-chemical and biological characterization studies that ZnO nanoparticles calcined at high temperature (600?°C) exhibit high surface area (230?m²?g^?1) and small particle size (20?nm) with good antibacterial activity against Escherichia coli (22.89?±?0.06?mm) and Staphylococcus aureus (24.62?±?0.08?mm). In addition, cotton fabrics coated with these nanoparticles showed higher UV-protection (87.8?UPF), hydrophobicity (155°), and maximum zone of bacterial inhibition against E. coli and S. aureus (25.13?±?0.05 mm and 30.17?±?0.03?mm) than those coated with particles calcined at 100?°C and 300?°C. High temperature calcination has a vital role in the crystallization of the particles towards nanoscale with increased resistivity to UV exposure, washing treatments, and microbial infection in fabrics. Thus, the cost-effective ZnO nanoparticles obtained through green synthesis method proves their potential applications in the field of biomedical, textile, and cosmetic applications.     

Influence of ball milling on the particle size and antimicrobial properties of Tridax procumbens leaf nanoparticles

The herbal nanoparticles were prepared from shade dried Tridax procumbens plant leaves employing ball milling technique using different process parameters, like ball ratio/size and milling time. The obtained nanoparticles were comprehensively characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, UV–visible spectroscopy, dynamic light scattering, scanning electron microscopy and antimicrobial analysis techniques. The crystallinity of the nanoparticles was retained without altering even though the particle size changes due to milling periods. The antibacterial activities of the prepared herbal nanoparticles against Staphylococcus aureus and Escherichia coli were explored to understand the influence of particle size on antimicrobial activities and their functional properties. The increase in ball ratio and milling time periods leads to a decrease in nanoparticle size from 114 to 45 nm which in turn increases the antimicrobial activities. The above study confirms that antimicrobial activity relies on nanoparticle size. The observed knowledge on influence of particle size on antimicrobial activities will help to optimise the production of potential herbal nanoparticles for different biomedical applications.Inspec keywords: nanoparticles, antibacterial activity, biomedical materials, nanomedicine, X‐ray diffraction, Fourier transform infrared spectra, scanning electron microscopy, ultraviolet spectra, visible spectra, microorganisms, particle sizeOther keywords: antimicrobial properties, Tridax procumbens leaf nanoparticles, herbal nanoparticles, ball milling technique, X‐ray diffraction, Fourier transform infrared spectroscopy, UV‐visible spectroscopy, dynamic light scattering, scanning electron microscopy, antimicrobial analysis techniques, Staphylococcus aureus, Escherichia coli, nanoparticle size     

Sintering of Tungsten and Tungsten Heavy Alloys of W–Ni–Fe and W–Ni–Cu: A Review

Tungsten is a refractory metal possessing good mechanical properties of high strength, high yield point, and high resistance to creep. Therefore, tungsten and its alloys are used in many high temperature applications. Due to the high melting point, they are generally processed through powder metallurgy method. The powders are compacted using die pressing or isostatic pressing. The compacts are sintered in a sintering furnace to achieve high density, thereby, making the metal suitable for further processing. This article reviews the recent research findings of consolidating tungsten and its alloys (W–Ni–Fe and W–Ni–Cu), from preparation of powder alloys to sintering of the compact. The advances in sintering are based on the objective of achieving good densification of the metal at lower temperature and at faster rate. The use of microwave sintering and spark plasma sintering techniques resulted in significant reduction in sintering time and producing products of good mechanical properties.