Effect of toughness distribution in the thickness direction on long brittle crack propagation/arrest behaviour of heavy gauge shipbuilding steel

ABSTRACT

Brittle crack arrestability of the heavy gauge steel plates for shipbuilding is now an important issue for the recent mega container ships. In the present work, the brittle crack arrestability of the steel plate with different toughness distributions in thickness is examined in ultra-wide duplex ESSO tests. It is examined whether a running long brittle crack arrests or not in flat temperature condition in ultra-wide duplex ESSO test that are harder mechanical conditions similar to an actual ship hull condition. Test temperatures are selected at which arrest toughness, Kca, evaluated by temperature gradient type standard ESSO test is the same for two test plates. The steel plate with higher toughness in mid-thickness (t/2) than that in quarter thickness (t/4) could arrest a running long brittle crack although the plate with lower toughness in mid-thickness than that in quarter thickness could not arrest it. The typical split-nail shape appeared at the arrested crack front in the plate with higher toughness in mid-thickness than that in quarter thickness. The numerical analyses also demonstrate that the local stress intensity factor at the arrested crack tip is changing sensitively to the crack front shape. It suggests that the higher brittle crack arrestability appears due to the split-nail shape of the arrested crack front enhanced by the inhomogeneous toughness in thickness.     

Simultaneous Estimation of the Thermophysical Properties of Selected Liquid Dairy Products by a Transient Heat Flow Probe Method

The thermophysical properties of reconstituted whole milk, skim milk, and whey were measured at various temperatures and concentrations. A new method for the simultaneous determination of thermophysical properties using a modified version of current probe theory method was proposed. Two new correction coefficients were introduced, and using the values of these coefficients and an approximate solution of the heat conduction equation, the thermal conductivity and thermal diffusivity of each sample were determined. The specific heat of each sample was estimated from the definition of thermal diffusivity. These properties were expressed as a function of concentration and temperature.     

叶片附着物对直线翼垂直轴风力机性能的影响

采用黏土作为附着物模拟了直线翼垂直轴风力机叶片表面前缘的结冰情况,并通过风洞试验测试分析了附着物对自行设计制作的直线翼垂直轴风力机模型转速和功率特性的影响.结果表明:附着物的存在降低了风力机的稳定转数、减少了输出功率,且随着附着质量的增加和风速的增大,影响效果越明显.通过将同等质量的黏土附着在叶表和嵌入叶片内的对比试验表明:在本试验条件下,附着物质量轻时,附着质量与翼型变化对风力机性能的影响基本为同等程度;随着附着物质量的增加,附着质量对风力机性能的影响占居主导地位.     

Interactions between nano-spacing flying head sliders and ultra-thin liquid lubricant films with non-uniform distribution in hard disk drives

This paper describes the effect of ultra-thin liquid lubricant films on air bearing dynamics and flyability of less than 10 nm spacing flying head sliders in hard disk drives. In particular, the effect of non-uniform lubricant film distributions on head/disk interface dynamics are studied. The disks with lubricant on one half of disk surface thicker than the other half were used in this study. The dynamics of sliders is monitored using acoustic emission (AE) and the interactions between the slider and disk are investigated experimentally. The disks were also examined with a scanning micro-ellipsometer before and after each test. Complicated slider responses were observed and clarified. In addition, it was found that the periodic lubricant film thickness modulations or non-uniformity caused by the slider-disk contact interactions could be observed. It is suggested that this lubricant film thickness non-uniformity will be one of the technical issues in order to achieve ultra-low head/disk contact interface of less than 10 nm.     

Investigation of mechanism of smear formation from diamond-like carbon films on heating

Microsystem Technologies - The formation of head smears during the heat-assisted magnetic recording is a significant problem that must be addressed to ensure the reliability of the head-disk...     

Relationship between morphological diversity and AgNORs or cathepsin B expression in colorectal cancers

The biological characteristics associated with the morphological diversity of colorectal cancers were investigated to elucidate the causes of this diversity. We examined the proliferative and infiltrating activity of tumor cells, indicated by the mean number of Ag nucleolar organizer region associated proteins (NORs) per nucleus (MNA) and the immunohistochemical response to cathepsin B(CB), in various morphological types of early and advanced colorectal cancers. We examined 73 colorectal cancers obtained by endoscopic and surgical resection. MNA values for sessile and flat-elevated cancers were greater than the values for pedunculate, subpedunculate, and flat-or-depressed early cancers (sessile, P < 0.05). In advanced cancers invading the muscularis propria, protruding cancers showed significantly higher MNA values than small ulcerative cancers (P < 0.01). CB expression increased significantly with the progression of colorectal cancers (P < 0.01), but was not related to morphological diversity in early and advanced cancers. In both sessile and flat cancers, CB expression was higher in moderately differentiated than in well differentiated adenocarcinomas. These results indicate that, in colorectal cancers, protruding early cancers without stalks and protruding advanced cancers have higher proliferative activity than pedunculate or flat early cancers and small ulcerative advanced cancers, respectively, and that CB expression is not associated with morphological diversity, but with depth of invasion and histological differentiation.     

Cholinergic neuron-specific ganglioside GQ1b alpha a possible target molecule for serum IgM antibodies in some patients with sensory ataxia

In neurological diseases the presence of certain anti-glycosphingolipid antibody species is associated with the clinical features. We recently isolated the novel cholinergic neuron-specific gangliosides GQ1b alpha and GT1a alpha from bovine brain. A monoclonal antibody specific for GQ1b alpha and GT1a alpha reacted strongly with the dorsal born of human spinal cord but not with human motor neurons. We investigated the serum antibodies to these minor gangliosides in a number of neurologic diseases and found that 4 patients with sensory ataxic neuropathy had a remarkably high IgM anti-GQ1b alpha antibody titer. GQ1b alpha may be a target molecule for serum IgM antibodies in some patients with sensory ataxic neuropathy.     

Numerical aberration of chromosome 17 is correlated with multiple primary cancer in colorectal carcinoma

In order to test the hypothesis that attention deficit hyperactivity disorder (ADHD) is related to deficits in somatosensory processing, 49 ADHD male children and 49 matched controls were tested on a wide range of tactile tasks, and somatosensory evoked potentials (SEP) were also recorded. In addition, parents' and teachers' ratings on the children's typical responses to tactile stimuli were obtained. The results show that the ADHD children were less skilled on suprathreshold, but not on threshold tasks than were the controls. Further, a larger percentage of ADHD children were 'tactile defensive'. Finally, the ADHD children showed larger-than-normal amplitudes of late, but not early components of the SEP. These data suggest that some aspects of somatosensory processing by ADHD children are deficient.