Materials Literature
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Urea-formaldehyde (UF), polymerized in situ in aqueous media, is a rigid polymer that can be used in the controlled release of bioactive molecules. During the process of polymerization, liquid neem seed oil (NSO) was encapsulated at three different loadings, which was then replaced by diclofenac sodium (DS), the prese…
Characterizing the morphology of modified multiphasic polymer systems, as are often applied for improving the impact strength, is normally a complicated and tedious task. Nevertheless, knowledge about the volume fraction and particle-size distribution of the elastomer phase is important for the specific development of…
Formulas for the wave aberrations introduced into a beam by a prism or a plane grating are derived from the theory of plane symmetric systems. Emphasis is made on the field-dependent aberrations.
Interactions between macrofouling and corrosion have been studied on two duplex stainless steels (UNS S31803 and UNS S32760), an austenitic stainless steel (UNS S31354), a nickel base alloy (UNS N06625), and a cobalt base alloy (UNS R30006) in long term tests conducted in natural sea water off the west coast of Scotla…
Changes in the dynamic response of glass-reinforced phenolic composites following thermal exposure at 180oC for periods of time up to 28 days were monitored using dynamic mechanical analysis. Four phenolic resins were investigated: a resol/novolac blend, a phenolic–furan novolac/resol graft copolymer, a novolac, and a…
Abstract Polyglycols are used in a wide range of applications, including lubrication. Many advantageous properties can be obtained for lubricant applications by manipulating the four variables in polyglycol preparation: the initiator, the alkylene oxides, the molecular build‐up, and the mole weight. However, it has lo…
Phenanthro[b]phenazine, a new heterocyclic ring structure of both biological and physical interests, has been prepared by coupling 1, 2-phenylenediamine with triphenylene-2, 3-quinone derivative. The first derivative of this novel core, 2,3,6,7-tetrapentyloxyphenanthro[b]phenazine, shows a monotropic columnar phase.
We investigated the solid-solution (1 − x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 relaxors by means of Raman spectroscopy. A detailed temperature-dependent study in the range 70–580 K was carried out on (1 − x)PZN–xPT relaxors with compositions x = 0.02 and 0.05 using Raman scattering under different optical and electric field varia…
The relationship between the rheological properties and composition of eight thermoplastic polyurethane elastomers (TPUEs) was evaluated using a stress-controlled rheometer. The composition of the TPUEs was changed by varying the OH/NCO ratio, the chain extender and the molecular weight of the macroglycol used in the…
Dense α-Si3N4 ceramics were fabricated by the tape casting technique using La2O3 as a sintering additive to effectively suppress the α-β transformation. Addition of a small amount of elongated β-Si3N4 seed particles significantly improved the toughness of sintered bodies from about 2 to 6MPa·m1/2. It was found that bo…
The oxidation behavior of stoichiometric SiC fiber (Hi-Nicalon-S) was investigated and compared with those of Nicalon and Hi-Nicalon fibers. Hi-Nicalon-S fiber was oxidized in Ar-O2 gas mixtures with 25-100% O2 at 1273-1773K. The oxidation rates were measured with thermobalance experiments. The thickening in SiO2 film…
Iron losses in electrical machines are difficult to predict. Discrepancies between tested and calculated no-load core losses are sometimes large. In induction motors, a large portion of the stator core is subjected to flux that rotates in the plane of the laminations. Losses due to rotating flux differ from those obse…
In this paper the measurement results of a series of standstill frequency response tests, performed at different magnetization levels, are discussed. For each data set an individual model is estimated, which allows the variation of the different parameters to be seen as a function of the saturation. Further, an estima…
Blends of cellulose acetate butyrate (CAB) and polyestercarbonate (PEC) in the composition range of 0–100 wt % in each component were prepared by thermal compounding. The mechanical, thermal, and rheological properties of the polymer blends were studied. Analysis of the DSC curve showed that CAB was an amorphous polym…
Zinc salts of ethyl, isopropyl, and butyl xanthates were prepared in the laboratory. They were purified by reprecipitation and were characterized by IR, NMR, and thermogravimetric analysis techniques. The melting points were also determined. The rubber compounds with different xanthate accelerators were cured at tempe…
This work reports on the redox behaviour of different ceria–praseodymia mixed oxides with two different chemical compositions (Ce/Pr molar ratios of 4 : 1 and 9 :1). The samples consist of bulk oxides and ceria-supported samples with varying mixed oxide loading (equivalent to 7 or 12 mixed oxide layers). As revealed b…
Since the critical exponent of the elastic modulus is related to the spatial dimension and the critical exponent of the correlation length, depending on the characteristics of elasticity, we experimentally evaluated both the elastic modulus of a sol-gel transition system and also the correlation length. We could deter…
[reaction: see text] N-alkyl-substituted meso-tetrapyrrolylporphyrin (TPyrP) and its derivatives were synthesized for the first time via an acid-catalyzed condensation between N-alkyl-2,4-diformylpyrrole and unsubstituted pyrrole and a subsequent deformylation reaction. X-ray structural analysis of formyl-substituted…
Abstract Now we can use several temperature control modes, for example, isothermal run including stepwise heating and cooling, constant rate heating (or cooling), temperature control for sample thermal history, sample-controlled thermal analysis (SCTA or controlled-rate thermal analysis, CRTA), temperature jump, rate…
Aluminum titanate (Al2TiO5) based ceramics are used as excellent thermal shock resistant, corrosive and insulating materials because of their low thermal conductivity, low thermal expansion and low Young's modulus. However, these materials have a low mechanical strength due to the presence of microcracks developed by…