Influence of yield strength levels on crack growth mode in delayed fracture of structural steels

A mechanistic aspect of the susceptibility to the delayed fracture is studied with an emphasis on the critical behaviour of the subsurface growth of Quasi-Cleavage (QC) and Inter-Granular (IG) cracks. The materials employed are 0.35%C plain carbon steel and boron added bolt steel which were quenched and tempered to have various levels of yield strength ranging from 500 to 1400 MPa. Fractographic analysis shows us that QC + IG cracking process can be an essential mode in the delayed fracture of steels. A low susceptibility to delayed fracture can be explained by the crack growth behavior when the crucial blunting occurs at the crack tip.     

Millimeter-Wave Radiometer for the Measurement of Stratospheric ClO Using a Superconductive (SIS) Receiver Installed in the Southern Hemisphere

A new sensitive radiometer for atmospheric minor constituents has been developed by Nagoya University and the National Institute for Environmental Studies (NIES). The instrument equipped low-noise superconducting (SIS) mixer with a system noise temperature of ≈200K (SSB) at 204GHz. The SIS mixer is operated in a single side band mode with a side band ratio grater than 10dB by adjusting the two tunable backshorts of the mixer. Since any additional SSB filters are not necessary, we can simplify the quasi-optical system and reduce the standing waves which makes difficult to achieve a flat spectral baseline. We installed the observation system at Las Campanas Observatory, Chile in December 1999, and started the test observation from 2000 October. We have detected significant ClO emission at 204.3 GHz with an actual observation time of only 4 hours. This is the first detection of the ClO at 40km altitude from the mid-latitude region of the southern hemisphere. The Nagoya-NIES system has enabled continuous monitoring of ClO in the stratosphere with a time resolution of 4 or 5 hours.     

基于 EVD 的一种高速公路路基压实度快速检测方法研究

路基的压实质量直接决定路基承载能力和抗变形能力,也同时影响道路的服务水平和使用寿命。传统的路基压实度采用环刀法、灌砂法、灌水法等,其操作复杂、投入人力多、测试时间长。本文将便携式动态变形模量测试仪(LFGpro)测得的动态变形模量(EVD)与压实度(K)之间建立相关关系,从而快速、高效的得到路基的压实度。本文分别建立了黄土(低液限粉土ML)、红砂岩(黏土质砂)、红泥岩(高液限黏土CH)路基EVD与K之间的相关关系,相关性良好。     

桥梁铰缝加固用环氧树脂力学性能的影响因素分析

研究了时间、配比和温度对桥梁铰缝加固用环氧树脂力学性能的影响。试验结果表明,随着固化温度的升高,胶体固化时间减少,树脂自身强度增加,抗弯、抗压和劈裂强度增大,断裂伸长率降低,胶体发生脆断所需拉伸力减小;不同温度下,抗弯、抗压和劈裂抗拉强度随时间的增长,基本呈现上升趋势。升高温度有利于树脂的早期粘结强度,但是后期可能存在老化,使得粘结能力下降;固化剂的含量在一定范围内增加,树脂固化时间缩短,但是对最终粘结强度影响不大。     

Numerical Modeling of an Earthquake-Induced Landslide Considering the Strain-Softening Characteristics at the Bedding Plane

The damage caused by an earthquake-induced landslide can generally be classified as either a limited deformation or a catastrophic failure. From an engineering point of view, the latter can be much more dangerous because the sliding mass may continue moving until it collides with another object. If a catastrophic failure occurs near a river, the debris may block the river, causing serious damage to the adjacent area. Therefore, examination of the mechanism of such catastrophic slope failures is important with respect to the mitigation of earthquake disasters in mountainous districts, although numerical modeling of such phenomena is rather difficult. In the present study, a new numerical model is developed to simulate an earthquake-induced catastrophic landslide that occured at a typical dip slope, namely, the Yokowatashi Landslide in Japan. In this case, the upper part of the bedrock on the planer tectonic dip surface slid more than 70 m. Only shear-strength degradation at the bedding plane could cause such a long-distance traveling failure. To investigate the strain-softening characteristics of the materials that filled the bedding plane, a series of laboratory tests involving undisturbed block samples was performed. The measured stress-displacement relationships under cyclic loading were numerically modeled as a newly proposed elasto-plastic constitutive model to be used in numerical simulations of landslide, based on the dynamic finite element method. The observed phenomena were appropriately simulated by the proposed method. The mechanism of catastrophic failure is discussed in detail in this paper in order to clarify the relationships between the strain-softening characteristics and the global slope stability. Our newly proposed method to evaluate the possibility of a catastrophic failure was applied to the landslide, and the moment when the slope becomes unstable was able to be predicted. The results confirm that the proposed method can predict the catastrophic failure of a slope.     

Estimating the burden of acute gastroenteritis and foodborne illness caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus by using population-based telephone survey data, Miyagi Prefecture, Japan, 2005 to 2006

Most cases of acute gastroenteritis and foodborne disease are not ascertained by public health surveillance because the ill person does not always seek medical care and submit a stool sample for testing, and the laboratory does not always test for or identify the causative organism. We estimated the total burden of acute gastroenteritis in Miyagi Prefecture, Japan, using data from two 2-week cross-sectional, population-based telephone surveys conducted in 2006 and 2007. To estimate the number of acute gastroenteritis illnesses caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus in Miyagi Prefecture, we determined the number of cases for each pathogen from active laboratory-based surveillance during 2005 to 2006 and adjusted for seeking of medical care and submission of stool specimens by using data from the population-based telephone surveys. Monte Carlo simulation was used to incorporate uncertainty. The prevalence of acute gastroenteritis in the preceding 4 weeks was 3.3% (70 of 2,126) and 3.5% (74 of 2,121) in the winter and summer months, yielding an estimated 44,200 episodes of acute gastroenteritis each year in this region. Among people with acute gastroenteritis, the physician consultation rate was 32.0%, and 10.9% of persons who sought care submitted a stool sample. The estimated numbers of Campylobacter-, Salmonella-, and V. parahaemolyticus -associated episodes of acute gastroenteritis were 1,512, 209, and 100 per 100,000 population per year, respectively, in this region. These estimates are significantly higher than the number of reported cases in surveillance in this region. Cases ascertained from active surveillance were also underrepresented in the present passive surveillance, suggesting that complementary surveillance systems, such as laboratory-based active surveillance in sentinel sites, are needed to monitor food safety in Japan.     

超临界流体技术在苎麻织物中的应用研究

对影响超临界CO2流体处理苎麻纤维的因素，如温度、压力、时间以及助溶剂进行正交试验，对处理后的苎麻纤维的含杂情况、微结构、机械物理性能和热稳定性等性质作了测试分析。结果表明，超临界CO2流体处理苎麻织物的最佳工艺条件为：工作温度120℃、压力25MPa、时间40min、助溶剂0．1％。该处理可改善苎麻纤维的性能，提高其膨胀性，有利于后续加工，并为其进一步改性打下基础。     

Expression of a retrovirally transduced gene under control of an internal housekeeping gene promoter does not persist due to methylation and is restored partially by 5-azacytidine treatment

BACKGROUND: Tachykinins, such as substance P, might be involved in the development of airway hyperresponsiveness and airway inflammation. OBJECTIVE: This study was designed to investigate the effects of the tachykinin NK1 receptor antagonist SR 140333 (Nolpitantium) and the NK2 receptor antagonist SR 48968 (Saredutant) on the activation of alveolar macrophages in the guinea-pig. METHODS: Guinea-pigs sensitized and challenged by ovalbumin administered by aerosol or naive guinea-pigs were exposed by aerosol to the neutral endopeptidase, phosphoramidon and, 15 min later, to substance P. Twenty-four hours later, bronchoalveolar lavages were performed and the cell composition of bronchoalveolar lavage fluids and the arachidonate release from alveolar macrophages stimulated in vitro with fMLP were evaluated. RESULTS: Antigen challenge in sensitized guinea-pigs induced an increase in the total number of cells and granulocytes in the bronchoalveolar lavage fluids that was not reduced by pre-treatment of guinea-pigs with a single dose of SR 140333 or SR 48968 (1 mg/kg). Substance P exposure in phosphoramidon-pretreated guinea-pigs did not induce an increase in the total number of cells. In contrast, antigen or substance P exposure induced a significant increase in the in vitro fMLP-induced arachidonate release from alveolar macrophages. Pre-treatment of the guinea pigs with SR 140333 or SR 48968 did not reduce the increase in arachidonate release from fMLP-stimulated alveolar macrophages from sensitized and challenged guinea-pigs. Pre-treatment of the animals by SR 140333 and SR 48968 reduced the enhanced arachidonate release induced by fMLP from substance P-exposed guinea-pigs. CONCLUSION: The present data demonstrate the importance of NK1- and NK2-receptor stimulation in the development of substance P-induced increased reactivity of alveolar macrophages.     

Characterization of alternative plasticizers in poly(vinyl chloride) sheets for blood containers

This study aimed to optimize the ratio of dioctyl 4‐cyclohexene‐1,2‐dicarboxylate (DOTH) and di‐isononyl‐cyclohexane‐1,2‐dicarboxylate (DINCH^®) for use as plasticizers in poly(vinyl chloride) (PVC) sheets. We also evaluated the biological safety of DOTH for its potential to be part of a safe PVC‐based blood container. The suppression of hemolysis in mannitol‐adenine‐phosphate / red cell concentrates (MAP/RCC) with DOTH/(DINCH^®‐PVC) sheets and the elution of plasticizers from the sheets increased with higher DOTH compositions. The properties of the PVC sheet containing DOTH and DINCH^® in the ratio of 25:33 parts against PVC 100 parts as a weight were almost identical to the PVC sheet made of di(2‐ethylhexyl) phthalate. From a subchronic toxicity test, DOTH did not show any adverse effects on all organs, including the testes, epididymis, liver, and kidneys. The no‐observed‐adverse‐effect level was 300 mg/kg body weight/day in a rat. These results suggest that DOTH/DINCH^® (25:33) is a promising candidate for the replacement of di(2‐ethylhexyl) phthalate in blood containers. J. VINYL ADDIT. TECHNOL., 22:520–528, 2016. © 2015 Society of Plastics Engineers