Fabrication of lotus-type porous carbon steel by the continuous zone melting method and its mechanical properties

A lotus-type porous carbon steel with cylindrical pores was fabricated by the continuous zone melting method in a pressurized mixture of hydrogen and helium gases. The porosity increases with increasing partial pressure of the hydrogen gas, while the pore diameter remains almost constant, independent of the pressure. The ultimate tensile strength of the specimen with cylindrical pores parallel to the tensile direction is lower than the estimated value, assuming that the strength is decreased in proportion to the decrease of the cross-sectional area of the specimen, while the yield strength is higher than the estimated value. The compressive yield strength is also higher than the estimated value. The increase in yield strength is considered to be due to precipitation strengthening. The tensile strength is increased by quenching and tempering, while the elongation decreases. Such mechanical properties are discussed in terms of the microstructural analysis.     

Membrane separation of indigenous noroviruses from sewage sludge and treated wastewater.

In this study, feasibility of membrane separation for the removal of indigenous noroviruses (NVs) is evaluated. The indigenous NV gene was never detected from ultrafiltration (UF) permeates of sewage sludge and treated wastewater. Indigenous NV gene was also not detected from permeates of sewage sludge and treated wastewater by microfiltration (MF) with a pore size of 0.1 microm (MF0.1). Even though the pore size of MF (0.1 microm) was much larger than the diameter of virus particle (approximately 30-40nm), more than 4-log10 reduction value (LRV) at maximum was achieved by membrane separation with MF0.1. NV genes were often detected from permeates of sewage sludge and treated wastewater by MF with a pore size of 0.45 microm (MF0.45), although the maximum log10 reduction values were more than 3.59 for sewage sludge and more than 2.90 for treated wastewater. It is important to verify factors determining the removal efficiency of viruses with MF membranes.     

Crosslinked acrylic pressure‐sensitive adhesives. II. Effect of humidity on the crosslinking reaction

The effect of humidity during storage on the crosslinking reactions of isocyanate groups was investigated with attenuated total reflectance Fourier transform infrared spectroscopy with pressure‐sensitive adhesives composed of poly[ethyl acrylate‐co‐(2‐ethylhexyl acrylate)‐co‐(2‐hydroxyethyl methacrylate)] as a base resin and polyisocyanate as a crosslinker. A peak‐resolving analysis of the amide II region revealed four bands. According to an analysis of the Fourier transform infrared spectra of the model compounds, these four bands were assigned to free urethane linkages, hydrogen‐bonded urethane linkages, free urea linkages, and hydrogen‐bonded urea linkages. As expected, storage under humid conditions led to the formation of free and hydrogen‐bonded urea linkages corresponding to the promotion of isocyanate consumption. Peak resolution of the amide II region was found to be a reasonable way of monitoring urethane and urea linkages during crosslinking reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3039–3045, 2003     

Design for Consecutive Testability of System-on-a-Chip with Built-In Self Testable Cores

This paper introduces a new concept of testability called consecutive testability and proposes a design-for-testability method for making a given SoC consecutively testable based on integer linear programming problem. For a consecutively testable SoC, testing can be performed as follows. Test patterns of a core are propagated to the core inputs from test pattern sources (implemented either off-chip or on-chip) consecutively at the speed of system clock. Similarly the test responses are propagated to test response sinks (implemented either off-chip or on-chip) from the core outputs consecutively at the speed of system clock. The propagation of test patterns and responses is achieved by using interconnects and consecutive transparency properties of surrounding cores. All interconnects can be tested in a similar fashion. Therefore, it is possible to test not only logic faults but also timing faults that require consecutive application of test patterns at the speed of system clock since the consecutively testable SoC can achieve consecutive application of any test sequence at the speed of system clock.     

Preparation and antibacterial activity of novel fluoroalkyl end-capped oligomers/silica nanocomposites-encapsulated low molecular biocides

Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [R_F-(DOBAA) _n -R_F] reacted with tetraethoxysilane (TEOS) and silica nanoparticles in the presence of low-molecular weight biocides such as hibitane, hinokitiol, and hinokioil under alkaline conditions to afford R_F-(DOBAA) _n -R_F/silica nanocomposites-encapsulated these biocides in excellent to moderate isolated yields. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer [R_F-(DMAA) _n -R_F] and acrylic acid oligomer [R_F-(ACA) _n -R_F]/silica nanocomposites-encapsulated hibitane were obtained under similar conditions. Dynamic light scattering measurements showed that the size of these fluorinated nanocomposites-encapsulated biocides thus obtained is nanometer size-controlled. Additionally, these fluorinated nanocomposites were shown to have a good dispersibility and stability in methanol and water. Of particular interest, these fluorinated nanocomposites-encapsulated biocides were found to have a good antibacterial activity against Staphylococcus aureus, and these nanocomposites were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate).     

Crack opening displacement of a through-wall crack in a plate subjected to bending load

This study was performed in order to clarify crack opening displacement (COD) of through-wall cracks in a plate subjected to bending load. The former COD evaluation methods were mainly developed corresponding to tensile load, but there has been nothing that has been developed corresponding to bending load. Therefore, the authors evaluated CODs of the through-wall cracks in plates which were subjected to a bending load using finite element method (FEM) analyses, and proposed a simplified COD evaluation method accounting for both tensile and bending loads. The proposed method is useful for leakage evaluation at a crack opening of an elbow crown or in the vicinity of the coolant surface of a vessel in which the bending stress is relatively large.     

Effect of light source spectral modulation on wavelength interrogation in fiber Bragg grating sensors and its reduction

In the fiber Bragg grating sensing using a superluminescent diode as the light source and an arrayed waveguide grating as the wavelength interrogator, the wavelength measurement error due to the spectral modulation of the superluminescent diode is theoretically formulated and quantitatively analyzed by computer simulation. It is shown that the wavelength measurement errors produced with the use of real superluminescent diodes are in very good agreement with the theoretical results. In order to reduce the wavelength measurement error due to the spectral modulation of superluminescent diode, two different types of remedies are proposed that utilize the temperature switching of superluminescent diode and that adjust the bandwidths of fiber Bragg grating and arrayed waveguide grating, and their efficacies are experimentally demonstrated together with good quantitative agreement with the theoretical calculation.     

A 322 MHz random-cycle embedded DRAM with high-accuracy sensing and tuning

A 16 Mb embedded DRAM macro in a fully CMOS logic compatible 90 nm process with a low noise core architecture and a high-accuracy post-fabrication tuning scheme has been developed. Based on the proposed techniques, 61% improvement of the sensing accuracy is realized. Even with the smallest 5 fF/cell capacitance, a 322 MHz random-cycle access while 32 ms data retention time which contributes to save the data retention power down to 60 /spl mu/W are achieved.     

Geochemical characteristics of the Yufuin outflow plume, Beppu hydrothermal system, Japan

Thermal water at Yufuin (Kyushu Island, Japan) is tapped through about 820 shallow wells and used mainly for hot-spring bathing purposes. Chemical and isotopic data for fluids from wells and fumaroles in Yufuin and Beppu indicate that the thermal activity at Yufuin represents a dilute, westward-flowing hydrothermal outflow plume from the Beppu hydrothermal system. Two other (eastward-flowing) outflow plumes have long been recognized at Beppu, but the Yufuin outflow plume is first recognized here. The Yufuin outflow plume is apparently a mixture of two end-member fluids: (1) deep high-temperature (250–300°C) fluid from the Beppu system having high chloride concentration (1400–1600 mg/L) and a δ¹⁸O value near −6.0%, and (2) meteoric water having low chloride concentration (≤7 mg/L) and a δ¹⁸O value near −9.2%.A permeable conduit for the vertical and lateral transport of deep fluid from the Beppu system is provided by the Yufuin Fault zone, which extends westward from the southern flank of Mt. Tsurumi volcano to the town of Yufuin. Stable isotope ratios and chloride concentrations for shallow groundwaters near the eastern end of the fault, at an elevation near 700 m, are consistent with those required for the low-chloride meteoric end-member of the Yufuin thermal waters. Recharge of this meteoric water, as well as mixing with the Beppu deep fluid, may occur along the Yufuin Fault. Enthalpy-chloride relations indicate additional conductive heating of the Yufuin waters, in the amount of 350–500 kJ/kg beyond that which can be accounted for by mixing between Beppu deep fluid and meteoric water. This could be a result of conductive heating with convection to a depth of 1–2 km. Estimates of the magnitude of the heat source for the Beppu hydrothermal system should take into account the heat being discharged at Yufuin.     

The validity of new memory complaints in the elderly

OBJECTIVE: To determine the validity of new subjective memory complaints (MCs) from individuals who previously, when without dementia, denied having MCs. DESIGN: Prospective cohort. SETTING: Longitudinal, community-based study of aging and dementia. PATIENTS: One hundred thirty-three community-dwelling elderly individuals who were part of a registry for the study of conditions related to aging in North Manhattan, NY. Patients were selected if they were initially without dementia and had completed at least 2 successive annual clinical and neuropsychological evaluations and provided their own medical history. MAIN OUTCOME MEASURES: Performance on memory tests--the Buschke Selective Reminding Test and a visual memory task--and global performance on a neuropsychological test battery and clinical evaluation, by which questionable dementia or dementia was diagnosed according to a well-defined paradigm. RESULTS: Fifty-three subjects with MCs at the initial evaluation performed no worse on the memory test than the 80 subjects who denied MCs initially. There was a weak association between MCs and the diagnosis of questionable dementia at baseline (P = .04), but this was nonsignificant after adjusting for age and education. At 1-year follow-up, 21 of the 80 without baseline MCs now reported MCs. At the follow-up evaluation, these 21 subjects performed significantly worse on the memory tests, were 5 times more likely to have significant cognitive impairment, and had shown significantly greater decline over the preceding year on several of the cognitive measures than the 59 who continued to deny MCs. CONCLUSION: New MCs from individuals, who when without dementia recently denied MCs, may suggest the presence of significant impairment of memory or cognition.