Materials Literature
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With the advances made in clean steel technology in recent times, most current techniques to quantify inclusion contents fail to provide relevant feed-back to process engineering. This is a particular dilemma in that the larger a defect, the more dangerous it is, and the harder it is to find as inclusion size distribu…
Two families of liquid crystalline compounds: 4-hexyl-4-alkoxyazobenzenes and 4-heptyl-4'-alkoxyawbenzenes have been synthesised for alkyl chain from methoxy up to octadecyloxy. On the base of the DSC calorimetry and polarizing microscopy rich polymorphism was detected. Maximum four mesophases were found: nematic, sme…
Five-membered rings are of interest as building blocks for nonlinear optical (NLO) materials. We found easy access to the title compounds: thiazolo[5,4-d]thiazole 1 has been obtained in three simple steps starting with the chlorination of ethyl isothiocyanatoacetate 8, followed by dehydrohalogenation to the diethyl 2,…
This paper outlines the mechanism of Stress Corrosion Cracking (SCC) and how it can cause premature failure of rock bolts. SCC occurs due to the progressive development and growth of cracks in the surface of a metal, and it is caused by the combined effects of stress and a corrosive environment affecting susceptible m…
The silica gels derived from triethoxysilane and tetraethoxysilane were studied by Raman spectroscopy. The vibrational band at 492cm-1, ordinally labeled D1, was shifted to 506cm-1 with the introduction of Si-H groups into the silica network. This suggests that this band is ascribable to the symmetric stretch oxygen v…
Complexation of triosmium clusters to pyridyl functionalised metalloporphyrins gives heterometallic derivatives that possess the overall recognition and spectroscopic properties of the porphyrin fragment, while incorporating the electronic and structural characteristics of the cluster.
The different reaction routes of n-pentoxy radicals in O2/N2 mixtures were investigated in the temperature range 423–523 K under atmospheric pressure. Flow experiments were performed in several reactors, with wall efficiencies increasing from passivated quartz to Pyrex, and with a great variety of mol fractions of O2…
Abstract The surface reactions involved in the palladium‐catalyzed formation of benzene from acetylene are discussed as an example of the way in which such strategies can be used to understand catalytic reaction pathways in detail. This provides an ideal system for surface science/catalysis studies since benzene is fo…
By creating and developing materials whose properties could be fully characterized, Professor George W. Gray has played a pivotal role in advancing our knowledge of liquid crystal states of matter. To honour him on his birthday, I briefly sketch some of my experimental results where the purity and stability of his cya…
Frost growth on cooling surfaces held at subfreezing temperatures has been shown to cause degradation of the heat transfer performance of the cooler. Despite the initial increase in the heat transfer rate due to the temporary increase in the heat transfer area, periodic frost removal is necessary. This paper presents…
The choice of the empirical pseudopotential method for studying the electronic band structure of SbSI-type crystals is discussed. The method is applied to study the SbSI crystal in the paraelectric and ferroelectric phases. Differently from previous studies, a covalent crystal structure is assumed. The total density o…
The UV–VIS–NIR absorption of the rhombohedral NdOF was measured at selected temperatures between 9 and 300 K. The emission spectra of NdOF, LaOF:Nd3+ and GdOF:Nd3+ were obtained at 4.2, 9, 77 and 300 K. The energy level scheme of the Nd3+ ion (the 4 configuration) derived from the optical spectra was simulated with a…
Uniaxial elongational viscosity of low density polyethylene (LDPE) gave the strain-hardening property. However, talc-filled LDPE showed almost no strain-hardening property and glass-fiber-filled LDPE exhibited the strain-softening property. The cause of almost no strain-hardening property or strain-softening property…
The effect of stress ratio (R=σmin/σmsx) on subsurface fatigue crack initiation behavior in high-cycle fatigue of beta-type titanium alloy, Ti-15V-3Cr-3Sn-3Al, was investigated using smooth specimen subjected to axial reversed loading in air at room temperature. Two types of microstructure prepared using different agi…
In acid media, the corrosion inhibition offered by ethanol amines, benzoic acids, acetylinic alcohols for iron and nickel was investigated. These molecules absorbed on the metal surface and offered inhibition. A correlation between inhibition and electronic configuration of the molecules was attempted. In benzoic acid…
Despite the progress made in imaging modalities based on nonionizing radiation such as ultrasound and magnetic resonance imaging, X-ray is still the primary imaging method in most radiology departments. In recent years, digital electronics and manufacturing methods have led to many approaches for the design and constr…
The 3D leakage magnetic field in a transformer is calculated by using the surface impedance method based on two scalar magnetic potentials. The leakage magnetic flux density and the highest temperature rise of the tie plate calculated are compared with the measured values, and the results are satisfied for engineering…
Ferroelectric behavior was investigated for aliphatic odd polyamides, nylon 77, nylon 79, nylon 97, and nylon 99, that were prepared by polycondensation of heptamethylenediamine and nonamethylenediamine with heptan-1,7-dioic acid and nonan-1,9-dioic acid. Polyamides obtained were melt-pressed into films, followed by t…
ZnAl 2 S 4 single crystals with spinel (α-phase) and wurtzite (w-phase) structures have been studied by Raman spectroscopy under hydrostatic pressures of up to 300 kbar. Significant changes in the phonon spectrum of the α-phase have been observed at the critical pressure of 230 kbar, which are attributed to a reversib…
The effect of fiber waviness, which develops during the processing and manufacture of fiber-reinforced composite structures, on compressive failure was investigated. Analytical and experimental evidence has shown that out-of-plane waviness (also referred to as layer or ply waviness) is a major contributing factor in c…