Thermo-Oxidative aging of a primary lightguide coating in films and dual-coated fibers

The thermo-oxidative aging of a polyether urethane lightguide primary coating has been studied in films and dual-coated fibers, In films, oxygen absorption is correlated with changes in modulus, yellowness, glass transition temperature, and sample weight. Thermal aging of fibers shows similar trends with regards to coating weight loss and discoloration as those observed with films. In addition, the force to mechanically strip the fiber follows the same patterns of change as the modulus of aged films. For both films and fibers, the time for onset of property changes varies inversely with temperature and can be delayed by the incorporation of an antioxidant.     

Effect of retained austenite on the hydrogen content and effective diffusivity of martensitic structure

In this work, the effects of retained austenite on the hydrogen content and the effective hydrogen diffusivity of an otherwise fully martensitic structure have been studied. In the electrochemical permeation experiment, the results on the first permeation transient indicate that high-carbon as-quenched specimens have a lower effective diffusivity than those with an additional subzero treatment. This was due to the presence of retained austenite in the former specimens, which afforded more sites for hydrogen trapping throughout the specimen membrane, hence lowering the hydrogen diffusion during the first transient. As the hydrogen traps were filled up, however, the second permeation transients gave similar effective diffusivity for both as-quenched and quenched + subzero-treated specimens. After hydrogen charging in hydrogen sulfide solution, the hydrogen contents of the specimens were determined using the vacuum hot extraction method. The results show that the hydrogen contents of as-quenched specimens were higher than those of the specimens subjected to quenched + subzero treatment. This again was due to the existence of retained austenite in as-quenched martensitic matrix, where the interfaces between the retained austenite and martensitic plates provided extra sites for hydrogen trapping. The hydrogen content of the presenting retained austenite in the martensite was independent of the carbon content of the specimen, but only depended on the hydrogen-charging period.     

Highly Packaged Terahertz Down-Converter Modules Using 3-D Integration

This letter describes the design of highly packaged heterodyne receivers for terahertz applications. The 3-D integration of a terahertz mixer with a low-noise intermediate frequency amplifier is implemented for the first time using off-the-shelf components. Thereby, an-order-of-magnitude volume and weight reduction are accomplished. We validate our packaging approach experimentally, demonstrating performance comparable to that of a similar receiver assembled with planar interconnects. These 3-D receivers can in principle constitute the basis of close-fitting, densely populated focal plane arrays.     

Image decomposition combining staircase reduction and texture extraction

This paper proposes a natural and efficient way to achieve staircase reduction in texture extraction models of image processing. Moreover, we propose a precise framework for this amalgamation. In a sense, we utilize the best of both worlds: (I) the use of higher order derivatives through a variant of the Chambolle–Lions inf convolution energy (an image decomposition model in itself) along with (II) approximations to Meyer’s G and E norms including the H⁻¹ negative norm for ameliorating staircasing in image decomposition and restoration problems.     

A method to control the dispersion of carbon black in an immiscible polymer blend

The dispersion of carbon black (CB) in an immiscible polymer blend of poly‐(methyl methacrylate) (PMMA) and polypropylene (PP) was studied as the viscosity of PMMA increased. It was found that the dispersion of carbon black was strongly influenced by the viscosity of PMMA. The CB was dispersed in the PMMA phase when the viscosities of PMMA and PP are comparable, as predicted by Sumita's model. As the viscosity of PMMA increases, the CB was found to be located at the interface between the PMMA and PP phases. On further increase in the viscosity of PMMA, the CB was found to be dispersed in the PP phase. In addition, the CB dispersion in the PP/PMMA blends can significantly influence the positive temperature coefficient (PTC) intensity of the blends.     

Fuzzy multiwavelet denoising on ECG signal

Since different multiwavelets, pre- and post-filters, have different impulse and frequency response characteristics, different multiwavelets, preand post-filters, should be selected, integrated and applied at different noise levels if a signal is corrupted by an additive white Gaussian noise (AWGN). Some fuzzy rules on selecting and integrating different multiwavelets, pre- and post-filters together, are proposed. These fuzzy rules are set up based on the training results of the denoising performances of applying different multiwavelets, pre- and post-filters, at different noise levels. When a new electrocardiogram (ECG) signal is applied, the appropriate multiwavelets, pre- and post-filters, are selected and integrated based on fuzzy rules and the noise level of the signal. A hard thresholding is applied on the multiwavelet coefficients. According to an extensive simulation, it was found that the proposed fuzzy rule-based multiwavelet denoising algorithm achieves 30% improvement compared to traditional multiwavelet denoising algorithms.     

Compensating for the mutual coupling effect in a normal-mode helical antenna array for adaptive ing

A practical normal-mode helical antenna array together with a new method for the compensation of the mutual coupling effect is proposed for the efficient adaptive ing of interferences in a mobile communication environment. The helical antenna array is shown to be able to generate deeper s than an equivalent monopole antenna array in the presence of the mutual coupling effect. The helical antenna elements are smaller in size and less susceptible to the mutual coupling effect than monopole antenna elements. The new method for compensation of the mutual coupling effect is shown to have a greater ability and flexibility than previous methods. A new definition of mutual impedance is introduced and used to find the coupling-free signal voltages across the antenna terminal loads. Numerical examples demonstrate the superior performance of the proposed adaptive array and the new compensation method.     

Trisomy 5 in two cases of acute monocytic leukemia with hyperdiploid clones

Although numerical chromosomal aberrations are commonly seen in acute myeloid leukemia (AML), trisomy 5 (+ 5) is very rarely detected. We report two patients, both of whom suffered from acute monocytic leukemia, in which + 5 was found in hyperdiploid clones. A review of the English literature shows 17 additional cases of AML with + 5 in at least one of the abnormal clones, making a total of 19 such cases including ours. Trisomy 5 has been reported in all FAB subtypes of AML except acute promyelocytic leukemia. In the 19 cases identified in this report, + 5 was found in association with other numerical changes (four cases), structural changes (five cases) or both (eight cases). Trisomy 5 as a sole karyotypic abnormality was exceedingly rare (two cases). Its biologic and prognostic significance remains to be determined.     

Interfacial reaction-controlled reprecipitation of W atoms in liquid matrix phase during the sintering of W-8 pct Mo-7 pct Ni-3 pct Fe

Microstructural evolution and variation in phase composition of W-8 pct Mo-7 pct Ni-3 pct Fe alloy were investigated with respect to various isothermal holding times, ranging from 5 to 240 minutes, at a sintering temperature of 1480 °C. Mass transfer was found to proceed actively in both the liquid matrix phase and the tungsten-based solid phase during the initial stage of the isothermal hold. Formation of large jagged grains was found to be a result of excessive interdiffusion between molybdenum and tungsten. The jagged grains gradually developed into spheroidal grains with the reprecipitation of supersaturated tungsten atoms in the liquid matrix phase, which also resulted in crystallization of the matrix phase with less lattice dilation during cooling. Based on model fitting, reprecipitation of tungsten atoms from the liquid matrix phase to grains is proposed to be controlled by a first-order interfacial reaction.