109 research outputs found
Effect of Rust Inhibitor in Brine on Corrosion Properties of Copper
In this study, the effects of rust inhibitors in brine on corrosion behaviors of copper were investigated by measurement of cathode and anode polarization curves and an immersion test. For rust inhibitors, benzotriazole, sodium benzoate and sodium nitrite were prepared. From measurement results of cathode and anode polarization curves, it was found that the corrosion rate of copper in the benzotriazole solution is low and a stable passive film with excellent corrosion resistance generates on the surface of copper in the solution. In the case of the sodium benzoate solution, the corrosion resistance of the passive film was inferior to that in the benzotriazole solution although the passive film generated on the surface of copper. In contrast, the passive film scarcely generated on the surface of copper in the sodium nitrite solution. The result shows that the rust preventive effect of the solution to copper is weak. Furthermore, the immersion test revealed that the benzotriazole solution has the rust preventive effect to copper. In contrast, the effect of the sodium benzoate solution is weak and that of the sodium nitrite solution is scarcely expected
Strain Rate Concentration Factor for Double-Edge-Notched Specimens Subjected to High Speed Tensile Loads
Engineering plastics provide superior performance to ordinary plastics for wide range of the use. For polymer materials, dynamic stress and strain rate may be major factors to be considered when the strength is evaluated. Recently, high speed tensile test is being recognized as a standard testing method to confirm the strength under dynamic loads. In this study, therefore, high speed tensile test is analyzed by the finite element method; then, the maximum dynamic stress and strain rate are discussed with varying the tensile speed and maximum forced displacement. The strain rate concentration factor found to be constant independent of tensile speed, which is defined Ktέ as the maximum strain rate appeared at the notch root over the average nominal strain rate at the minimum section. The maximum strain rate is controlled by the tensile speed alone independent of the magnitude of the forced displacement. It is found that the difference between static and dynamic maximum stress concentration (σmax-σst) at the notch root is proportional to the tensile speed when u/t≦5000mm/s.13th International Conference on Fracture, June 16–21, 2013, Beijing, Chin
Absence of in vivo mutagenicity of multi-walled carbon nanotubes in single intratracheal instillation study using F344 gpt delta rats
Abstract
Introduction
It is known that fibrous particles of micrometer length, such as carbon nanotubes, which have same dimensions as asbestos, are carcinogenic. Carcinogenicity of nanomaterials is strongly related to inflammatory reactions; however, the genotoxicity mechanism(s) is unclear. Indeed, inconsistent results on genotoxicity of multi-walled carbon nanotubes (MWCNTs) have been shown in several reports. Therefore, we analyzed the in vivo genotoxicity induced by an intratracheal instillation of straight MWCNTs in rats using a different test system\u2014the Pig-a gene mutation assay\u2014that can reflect the genotoxicity occurring in the bone marrow. Since lungs were directly exposed to MWCNTs upon intratracheal instillation, we also performed the gpt assay using the lungs.
Findings
We detected no significant differences in Pig-a mutant frequencies (MFs) between the MWCNT-treated and control rats. Additionally, we detected no significant differences in gpt MFs in the lung between the MWCNT-treated and control rats.
Conclusions
Our findings indicated that a single intratracheal instillation of MWCNTs was non-mutagenic to both the bone marrow and lung of rats
Observation of nonvolatile magneto-thermal switching in superconductors
Applying a magnetic field to a solid changes its thermal-transport
properties. Although such magneto-thermal-transport phenomena are usually small
effects, giant magneto-thermal resistance has recently been observed in
spintronic materials1,2 and superconductors3,4, opening up new possibilities in
thermal management technologies. However, the thermal conductivity
conventionally changes only when a magnetic field is applied due to the absence
of nonvolatility, which limits potential applications of thermal switching
devices5,6. Here, we report the observation of nonvolatile thermal switching
that changes the thermal conductivity when a magnetic field is applied and
retains the value even when the field is turned off. This unconventional
magneto-thermal switching, surprisingly, arises in commercial Sn-Pb solders and
is realized by phase-separated superconducting states and resultant nonuniform
magnetic flux distributions. This result confirms the versatility of the
observed phenomenon and aids the development of active solid-state thermal
management devices.Comment: 33 pages, 5 figures & 9 extended data figure
A 90-day Feeding Toxicity Study of l-Serine in Male and Female Fischer 344 Rats
A subchronic feeding study of l-serine (l-Ser) was conducted with groups of 10
male and 10 female Fischer 344 rats fed a powder diet containing 0, 0.06, 0.5,
1.5 or 5.0% concentrations of l-Ser for 90 days. There were no toxicologically
significant, treatment-related changes with regards to body weight, food intake,
water intake or urinalysis data. In several of the hematology, serum
biochemistry and organ weight parameters, significant changes were observed
between some of the treated groups and the controls. All these changes, however,
were subtle and lacked any corresponding pathological findings. In addition, the
increased or decreased values remained within the range of the historical
control values. In fact, histopathological assessment revealed only sporadic
and/or spontaneous lesions. In conclusion, the no-observed-adverse-effect-level
(NOAEL) for l-Ser was, therefore, determined to be at least a dietary dose of
5.0% (2765.0 mg/kg body weight/day for males and 2905.1 mg/kg body weight/day
for females) under the present experimental conditions
Results of the search for inspiraling compact star binaries from TAMA300's observation in 2000-2004
We analyze the data of TAMA300 detector to search for gravitational waves
from inspiraling compact star binaries with masses of the component stars in
the range 1-3Msolar. In this analysis, 2705 hours of data, taken during the
years 2000-2004, are used for the event search. We combine the results of
different observation runs, and obtained a single upper limit on the rate of
the coalescence of compact binaries in our Galaxy of 20 per year at a 90%
confidence level. In this upper limit, the effect of various systematic errors
such like the uncertainty of the background estimation and the calibration of
the detector's sensitivity are included.Comment: 8 pages, 4 Postscript figures, uses revtex4.sty The author list was
correcte
Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses
We present data-analysis schemes and results of observations with the TAMA300
gravitational-wave detector, targeting burst signals from stellar-core collapse
events. In analyses for burst gravitational waves, the detection and
fake-reduction schemes are different from well-investigated ones for a
chirp-wave analysis, because precise waveform templates are not available. We
used an excess-power filter for the extraction of gravitational-wave
candidates, and developed two methods for the reduction of fake events caused
by non-stationary noises of the detector. These analysis schemes were applied
to real data from the TAMA300 interferometric gravitational wave detector. As a
result, fake events were reduced by a factor of about 1000 in the best cases.
The resultant event candidates were interpreted from an astronomical viewpoint.
We set an upper limit of 2.2x10^3 events/sec on the burst gravitational-wave
event rate in our Galaxy with a confidence level of 90%. This work sets a
milestone and prospects on the search for burst gravitational waves, by
establishing an analysis scheme for the observation data from an
interferometric gravitational wave detector
Recent Progress of Flower Colour Modification by Biotechnology
Genetically-modified, colour-altered varieties of the important cut-flower crop carnation have now been commercially available for nearly ten years. In this review we describe the manipulation of the anthocyanin biosynthesis pathway that has lead to the development of these varieties and how similar manipulations have been successfully applied to both pot plants and another cut-flower species, the rose. From this experience it is clear that down- and up-regulation of the flavonoid and anthocyanin pathway is both possible and predictable. The major commercial benefit of the application of this technology has so far been the development of novel flower colours through the development of transgenic varieties that produce, uniquely for the target species, anthocyanins derived from delphinidin. These anthocyanins are ubiquitous in nature, and occur in both ornamental plants and common food plants. Through the extensive regulatory approval processes that must occur for the commercialization of genetically modified organisms, we have accumulated considerable experimental and trial data to show the accumulation of delphinidin based anthocyanins in the transgenic plants poses no environmental or health risk
平成28年度「T-GAP」実践報告
SGH事業の中心的課題は課題研究活動である。この授業では課題研究活動の基礎的素蓑である課題発見力および課題解決力の育成を目指した。あわせてSGH事業の対象地域としている「ASEAN」についで学ぶ時間を設定した。また本科目は本校総合学科教育の柱としての役割を担うものでもある。本年度の実践について報告する
- …