Volume of a liquid drop detaching from a sphere

A theoretical and experimental study is conducted to investigate the detached volume from a pendant drop on the surface of a sphere. Observation of drop detachment by high‐speed video camera reveals that the movement of the upper part of the neck of the drop is quite slow compared to that of the detaching lower part. The surface profile of the upper part was calculated approximately as a static problem using the axisymmetric Laplace equation. Using the drop profile, the system energy, including the work done by the solid–liquid wetting behavior, was calculated. Based on the condition of minimum energy, the volume of the detached part V was calculated. The volume V increases with the sphere diameter and approaches the value for the pendant drop attached to a plate. In addition, V is strongly dependent on the wettability between the sphere and the liquid and decreases with the receding contact angle. The detached volume of the water drop was measured for spheres of porous brick of various diameters. The experimental and theoretical results were found to be in good agreement. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20305     

某柴油机附件支架仿真优化与试验

利用ABAQUS与FEMFAT软件对柴油机附件支架进行结构应力、接触面滑移、结构模态以及高周疲劳分析.根据分析结果,对支架不满足限值项进行优化并再次仿真分析,直到满足设计要求.为验证仿真分析结果,对支架进行了柴油机台架试验,测试支架上各个测点的振动加速度.将支架上各个测点的振动加速度整理为X,Y,Z方向的colormap图进行了分析,试验结果表明,附件支架测试最大加速度为12.45 g低于仿真分析边界载荷15 g;模态一阶频率仿真分析结果为141 Hz,样件试验结果为130 Hz,误差为7.7％,测试结果进一步验证了仿真分析的可靠性.     

岩石中稀土元素中子活化分析时Na、Sc、Fe Cr等干扰元素的去除

稀土元素的分离、分析,在地球化学、宇宙化学、环境化学等学科中起着极为重要的作用。近年来,国内外利用高分辨率γ谱仪中子活化分析法测定岩石中稀土元素的报道很多,虽然对放射化学分析流程都在不同程度上有所改进,但对超基性岩石中大量存在的~(24)Na、~(46)Sc、~(59)Fe和~(51)Cr等核素的去除,解决被测元素γ谱之间相互干扰(包括重峰干扰和康普顿本底干扰)     

Environmental Effects on Microstructural Stability of SiC/SiC Composites

LowZmaterialshavemanyadvantagesinnuclearenvirOInnellts,suchaslessProductionofradioactivewastesduetosubstantiallylowactivation,andhigherconVergentefficiencyduetothecapabilityofhightemp~OPeration.HopkinhasdiscussedSiC-basedmaterialsforfhaionreactorsfor...     

Evaluation of the Fracture Strength for Silicon Carbide Layers in the Tri-Isotropic-Coated Fuel Particle

A program to develop new methods to measure the fracture strength of the chemical vapor deposition SiC coatings in nuclear fuel particles has been carried out. Internal pressurization and crush test techniques were developed and applied to prototype-sized tubular and hemispherical shell specimens. The fracture strength measured from each test method applying the Weibull two-parameter distribution, and Weibull parameters were measured. It was shown that data generated with each test technique were independent of the test technique applied. This implies that the developed test methods are reliable and provide reasonable strength data. For the same material, fracture strength varied with the specimen geometry and loading configuration. These size and loading configuration effects on the fracture strength are explained with the concept of effective surface.     

The mathematical model for the formaldehyde emission from wood-based board in room

A mathematical model which describes the influence of various parameters on formaldehyde concentration in the atmosphere of a room containing wood-based boards was developed. The physical meanings and measuring methods of the parameters of the model are also discussed. Based on this model, two indices for commenting the formaldehyde emission process of wood-based boards are proposed, and inequality estimation for the formaldehyde content of wood-based boards at any moment and a time estimation which shows when the room satisfies the environment quality standard are also given.     

Bone metastasis from colorectal cancer in autopsy cases

The incidence of bone metastasis from colorectal cancer is reported to be 10.7% in autopsy cases. However, the characteristics of the primary cancers, as well as the patterns of bone metastasis, remain unclear. We analyzed the clinical and autopsy records of 118 patients with primary colorectal cancer treated either surgically or conservatively and eventually autopsied between 1970 and 1987 at Toranomon Hospital in Tokyo. Bone metastasis was detected in 23.7% (28/118). The average age of patients with bone metastasis was lower than that in patients without bone metastasis (P < 0.02). Cancers to the rectum and cecum were accompanied by bone metastasis more frequently than cancers of other portions of the colon. Signet-ring cell carcinoma showed a high incidence of bone metastasis (P = 0.041). Bone metastasis from colorectal cancer was associated with liver or lung metastases (P < 0.0001). These results indicated that bone metastasis from colorectal cancer is not as infrequent as previously described.     

Morphologic analysis of the facet joint in the immature lumbosacral spine with special reference to spondylolysis

STUDY DESIGN: Morphological analysis was performed of the facet joint of the normal and spondylolytic lumbosacral spine in children and adolescents. OBJECTIVES: This study was performed to estimate the influence of spondylolysis on growth of the neural arch of the lumbosacral spine. SUMMARY OF BACKGROUND DATA: The development of the facet joint and its relation to spondylolysis have not been documented in the literature. METHODS: The dimension and orientation of the facet joint at L5/S were measured on radiographs and computed tomography scans from 144 boys without pars defects and 104 boys with pars defects. The latter group was further investigated according to the stage of pars defects. Patients in both groups were between 9 and 18 years of age. RESULTS: Growth of the facet joint in the sagittal and transverse directions and the increase of the transverse angle were remarkable up to approximately 13 years of age. Concavity of the facet joints also progressed in children of the same age. The growth of the facet joint in patients with spondylolysis was significantly retarded as the pars defects advanced from the progressive to the terminal stage. The joint surface was more coronal in orientation and flatter in shape compared with controls. CONCLUSIONS: The present results suggest that pars defects occurring in children disturb or retard the growth of the facet joint and that the morphological characteristics of the joint surfaces in patients with spondylolysis are the consequence of these defects.     

L—ECD20W／40柴油机油的研制

以蜡裂解聚－α烯烃合成减二线油和烷基高沸物为基础油，加入由石油化工科学研究院生产的复合剂研制的Ｌ－ＥＣＤ ２０Ｗ／４０柴油机油，其性能符合ＧＢ１１１２３－８９Ｌ－ＥＣＤ柴油机油技术标准。     

Increased production of eicosanoids, TXA2, PGI2 and LTC4 in experimental spinal cord injuries

Arachidonate metabolites have many kinds of bioactivities. Thromboxane A2 (TXA2) stimulates platelet aggregation and vasoconstriction, whereas prostaglandin I2 (PGI2) antagonises its activities. Thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) are determined in biological materials. Production of TXB2, 6-keto-PGF1 alpha and leukotriene C4 (LTC4), which have potent vascular permeability, was measured by radioimmunoassay in experimental spinal cord injured animals. TXB2 level in the rat spinal cord reached a peak concentration of 133.6 +/- 3.8 pmol/g cord, and 6-keto-PGF1 alpha increased to 26.2 +/- 11.7 pmol/g cord 5 minutes after the injury. There was good correlation between TXB2 production and vascular damage as monitored by fluorescein uptake. When OKY-046 ((E)-3-[4-(1-imidazolylmethyl) phenyl]-2-propenoic acid), which selectively inhibits TXA2 synthetase activity, was administered 10 minutes before injury, the increase in TXB2 production was inhibited by more than 80%, but the degree of vascular damage was reduced by only 40%. In the guinea pig spinal cord, LTC4 levels reached a peak concentration of 2.2 +/- 0.4 pmol/g cord 10 minutes after compression, while that of TXB2 reached 146.8 +/- 6.2 pmol/g cord. The increased production of TXB2 was correlated with the degree of compression injury while that of LTC4 production did not. These findings suggest that vasoactive eicosanoids, TXA2, PGI2 and LTC4, play important roles in secondary damage following spinal cord injury, although their roles may be different among species of animals.