Evaluation of Expansion Process to Improve Corrosion Resistance of Copper Tubes with High Residual Carbon on the Inner Surface

Residual carbon on the inner surface of copper tubes is known to be a cause of pitting corrosion. We showed previously that the rapid filling test was useful to evaluate the pitting corrosion resistance of copper tubes. Immersion tests using the rapid evaluation test solution showed that corrosion occurs on the entire surface of copper tubes with low residual carbon amounts, while those with high residual carbon amounts show pitting corrosion. Therefore, it is necessary to improve the corrosion resistance of copper tubes with high residual carbon amount, which are expected to undergo pitting corrosion. As pitting corrosion occurs when anodes are locally concentrated on part of the metal surface, it has been suggested that anodes be dispersed over the entire surface by the processing of the metal surface. Metal processing methods have various purposes, including changing the shape and properties of metals, and in this case, leading to desirable surface properties (such as expansion and drawing processes). Here, we focused on the expansion process and its effects on corrosion resistance of copper tubes. The results showed that hydraulic expansion has a significant effect on the inner copper surface by improving corrosion resistance as the anode area increases.

STUDY ON TESTING TECHNIQUE FOR MEASUREMENT OF FATIGUE－CREEP INTERACTION RESISTANCE

By using dropped stress creep method a new testing technique for measurement of the fa-tigue-creep interaction resistance is developed. At varied adjusted mean stresses the creep testingwas performed repeatedly When an unlimited extensive incubation period with zero creep rate oc-curred. the stress cavsing zero creep rate is defined as fatigue-creep resistance. The developped test-ing technique was used to measure the fatigue-creep resistance in F anc C regions. The dynamic ef-fective stress could yield a better descrption of fatigue and creep interaction. The fatigue-creep rateequations with varied exponents inF of C region are established. The different deformation mecha-nisms in F or C regions are indicated

Resistance and Reactance of Monopole Fields Induced by a Test Charge Drifting Off-Axis in a Cold and Collisional Cylindrical Plasma

We study the interaction of a uniform, cold and collisional plasma with a test charged particle moving off-axis at a constant speed down a cylindrical tube with a resistive thick metallic wall. Upon matching the electromagnetic field components at all interfaces, the induced monopole electromagnetic fields in the plasma are obtained in the frequency domain. An expression for the plasma electric resistance and reactance is derived and analyzed numerically for some representative parameters. Near the plasma resonant frequency, the plasma resistance evolves with frequency like a parallel RLC resonator with peak resistance at the plasma frequency pe, while the plasma reactance can be capacitive or inductive in nature depending on the frequency under consideration.

Dent Resistance for Automobile Body Panels

Dent resistance of automobile body panels is an important property for automobile design and manufacture, but the study on this aspect is not still profound. This study is to summarize the testing methods and physical significations of static and dynamic dent resistance of automobile body panels combined with the author＇s study, and to analyze the dent behaviors in the round. Several influence factors on dent resistance are expatiated including the mechanical properties of materials, stress states after forming, bake hardening ability, modulus, methods of testing, and structure of specimens and so on. The automotive lightweight and application of high strength steel sheets and aluminum alloys sheets are analyzed, and the significance of testing of dent resistance, especially for dynamic dent resistance of auto-panels, and the finite element simulation analysis are emphasized. To explain the physical phenomenon of dent behaviors, the latest and concerned study results are also discussed. According to this study, a dent resistance test and evaluation standard of Society of Automotive Engineers of China for automotive body panel is presented and is being carried out, and an industry conference is hold to discuss the working-out of the standard, a primary schedule of this standard is confirmed now. The study can guide the further testing and study of dent resistant of auto-panels.

Herd Level Antimicrobial Resistance in Beef Calves in Switzerland 1986 through 2011

The increasing emergence of antimicrobial resistance in food animals is a growing global concern and is closely linked to animal husbandry practices. In this study we describe the changement of antimicrobial resistance in beef calf production in Switzerland from 1986 through 2011. Data were collected from farms with known calf herd problems, such as diarrhoea or pneumonia, along with antimicrobial resistance from those herds. The Herd Health Section of the University of Zu-rich visited each farm. Samples were analysed for bacterial growth and resistance test commonly indicated in diseases such as calf pneumonia and diarrhoea. Each resistance test comprised of samples from at least three diseased animals. For diarrhoea, a faeces sample was used, for pneu-monia a deep nasal swab was taken. In nasal swabs, only batches yielding considerable bacterial growth in three individual animal samples were included for diagnosis. Other growth of bacteria was considered as contamination. The results consisted of bacterial resistance to antibiotics against defined diseases such as calf diarrhoea and calf pneumonia at herd level. This approach is reflecting the situation as found in practice when a calf has to be treated without delay and without results from further laboratory diagnostics. In diarrhoea cases, four antibiotics showed no bacterial resistance. Bacterial resistance of below 10% was observed to three antibiotics. Up to 20% bacterial resistance was found to two antibiotics. Eighty per cent and over was found to be six antibiotics. Bacterial resistance to two antibiotics was found in over 90% of samples and all samples were resistant to one antibiotic. In pneumonia three antibiotics showed no resistance;one was below 10%;four antibiotics were below 20%. Over 80% of samples were resistant to four antibiotics. One resistance was over 90% and all bacterial samples were resistant to two antibiotics. Differences in bacterial resistance between pneumonia and diarrhoea in two study periods with equal cases, i.e. 1986-2006 and 2007-2011 were found. A reduction in bacterial resistance can be found in 5 out of 7 cases, when the amount of the respective antibiotic was reduced over time. This finding raises the obvious question whether antibiotics should be removed from the marked ones by a period of about 10 years. This would help to control not only bacterial resistance but also the use of the limited amount of antimicrobial drugs available. Such a control program would need to be established by international and national drug agencies as well as the pharmaceutical industry. Such a program would require extensive international validation.

Nondestructive testing and assessment of consolidation effects of earthen sites

Earthen sites are widely distributed throughout China, and most of them belong to archaeological sites with significant values, which not only directly witness the origin, formation and development of Chinese civilization, but also possess important values for conservation and exhibition. Many researches and practices on their conservation and consolidation have been carried out; however, the consolidation effect is mainly judged by visual observation and expert evaluation. Scientific assessment of conservation and consolidation effects is a challenging issue. Many instruments in other fields cannot be directly applied to the conservation of cultural relics due to their peculiarity. In order to assess the effects of field conservation experiments, this paper tries to understand the consolidation effects at Liangzhu site using nondestructive or micro-damage methods, including thermo-physical parameters testing, infrared thermal imaging, high-density microelectrode resistivity testing, portable microscope observation, and hydrophilic and hydrophobic testing, and thereby explores the practicable methods for evaluating the properties of consolidation materials for earthen sites treatment.

无腹杆钢筋混凝土拱型屋架单层厂房振动台模型试验研究

本项研究通过模型结构的振动台模拟地震试验和计算分析，对采用无腹杆钢筋混凝土拱型层架的单层墙柱厂房的抗震性能作出评价，其成果已在实际工程中得到应，并被新修订的《建筑抗震鉴定标准》所采纳。在本项试验研究中特别注意输入地震动的频谱特性与模型结构动力特性的关系，以使试验结果有效。

Evaluation and Genetic Analysis of Five Parental Varieties Resistant to Rice Blast Pathogen in Heilongjiang Province

Five F2 segregation populations, derived from crosses between the susceptible japonica cultivars （cvs.） Kongyul31 and donor cvs. Aichi Asahi （AA）, BL1, Digu, Pai-kan-tao （PKT） and Oryzica Llanos 5 （ORL5）, were used to evaluate their natural resistance to blast in cold region. The field test of their blast resistance was conducted in 858 Farm, which showed that Aichi Asahi, BL 1 and Digu were highly resistant to either leaf blast or neck blast and could be used to develop molecular breeding by design, and genetic analysis indicated that the field resistance of Aichi Asahi, BLland Digu to leaf blast and neck blast was controlled by a single dominant gene, and the leaf blast and neck blast resistance in the donor cv. Pai-kan-tao was inherited as a single recessive gene, the neck blast resistance of the donor cv. Oryzica Llanos 5 was controlled by a single recessive gene while its leaf blast resistance was not controlled by this gene. These results suggested that five parental varieties positively contributed to resistance to either leaf blast or neck blast and could be used to expand the genetic germplasms resistant to blast in cold region using molecular assisted selection.

Relationship between Corrosion Form and Elution Behavior of Copper Tubes Surfaces with Different Residual Carbon Amounts

It was well known that residual carbon on the inner surface of copper tubes was a cause of pitting corrosion, and copper tube surfaces with different residual carbon amount were different corrosion forms. In this study, the relation between corrosion form and elution of copper in immersion tests by accelerated corrosion test solutions was examined. Generally, pitting corrosion that occurs in actual machines was reported to observe chloride ion at the bottom of the pitting corrosion of copper tubes. Energy dispersive X-ray (EDX) mapping analysis indicated that chlorine was concentrated in the upper layer of the samples where copper was not detected under conditions of low residual carbon amount, while chlorine was concentrated under part of the micromounds (including the bottom of the pits) under conditions of high residual carbon amount. It was also suggested that the amount of copper eluted was related to the amount of residual carbon.

Evidence-Based Use of Antibiotics in Meat Calves

Abuse of antibiotics is an increasing commonly feature in the media. Widespread preventive use of antibiotics without diagnostics in meat calf husbandry is a major public health concern. In this study, we compare a “trial and error” method, comprising of a first choice antibiotic, followed by a second and third choice (as recommended by the WHO), with a method which utilizes an antibiotic resistance test to first identify the best antibiotic out of first, second or third choice alternatives using decision tree analysis. Data were collected from farms with a known calf herd problem along with antibiograms from those herds. Samples were analysed for resistance to antibiotics against calf pneumonia on a herd level, rather than for resistance against specific antibiotics. Resistance tests were performed on batch samples composed of at least three diseased animals. A deep nasal swap was taken. In nasal swaps only ++ or +++ growth in all 3 samples were used for diagnosis. Other growth of bacteria was considered as contamination. A comparison of resistance rates across a range of antibiotics between farms with known calf pneumonia and calf diarrhoea issues was performed. The decision tree analysis presented provides strong support in favour of an evidence-based approach to antimicrobial treatment by using an antimicrobial resistance test, providing an advantage of 58% per meat calf against the “trial and error” method, giving a financial gain of some CHF 320.09 under Swiss economic circumstances.

花岗岩干挂石板材结构振动台试验分析

详尽地分析了广州市某大厦外墙面装饰干挂石板材结构体系的足尺振动试验结果，评估了该结构体系的抗震性能。结果表明，板材构造不同，其抗震性能不同；处于结构不同部位的板材。

High-temperature performance study of chromium-containing stuffing sand for ladles

High-temperature performance tests of chromium-containing stuffing sand for a steel ladle w ith different ratios w ere performed. A high-temperature simulation test furnace w as used to analyze the influence of the composition ratio of ladle filler sand and sintering time on the high-temperature compression resistance of chromium-containing stuffing sand in the temperature range of 1 500- 1 600 ℃. The results show that the refractoriness of ladle filler sand w as the low est（ only 1 610 ℃） w hen the composition ratio of chromite sand and silica sand w as 6∶ 4. M oreover,the high-temperature compression resistance w as high w hen the content of chromite sand w as at 70%; the resistance increased w ith increasing sintering time. When the sintering time w as extended at a temperature of 1 600 ℃,the high-temperature compression resistance of ladle filler sand first increased and then decreased after being overburnt.

Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically Alternate Corrosion Environments

Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450 EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450 EW weathering steel is closely related to chromium content. The addition of chromium significantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m-2·h-1. The rust of S450 EW weathering steel was mainly constituted of Fe OOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-Fe OOH. The fine precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneficial for the cure of original defects and cracks of the rust layer via the enrichment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450 EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.