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Fire behavior of mining vehicles in underground hard rock mines

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International journal of Mining Science and Technology 2017年第4期27卷 627-634页

作者： Hansen rickard Malmfaltens Brandkonsult Taljstensagen Nykoping 611 67 Sweden

The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire safety and fire protection measures with respect to the mining vehicle fire *** studies on fires in underground hard rock mines have shown that vehicles or mobile equipment are the dominant sources of fire. A better knowledge about the fire behavior of vehicles in underground hard rock mines is therefore needed. During the analysis the direction and flow rate of the ventilation in a drift was found to have a significant impact on the fire behavior, causing for example flame tilt with rapid fire spread. The shielded sections of a vehicle will be less affected by the ventilation flow resulting in for example a decreased flame spread. It was also found that spray fires may result in considerable heat release rate but are generally of shorter duration and will not make any significant contributions to the overall heat release rate of the fully developed vehicle fire. The fire duration of a loader tire from a full-scale fire experiment was found to be at least 200 min and will largely determine the total fire duration of the vehicle. A different scenario with different conditions with for example a slower flame spread resulted in an even longer fire duration. The radiative and convective fraction will be a key factor when determining the heat transfer mechanisms involved in a fire and will vary from material to *** show that the radiative fraction of the tire fires on two mining vehicles is significantly lower than found in earlier experiments. The design and construction of the mining vehicle will have an important impact on the fire behavior and could possibly mitigate the consequences of a fire and allow fire personnel to extinguish a fire that otherwise would have had a too high heat release rate.

关键词： Fire behavior Mining vehicle Underground mine Full-scale fire experiments

Retardation of an IGG gas flow along a mine drift due to condensation and temperature decrease

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International journal of Mining Science and Technology 2019年第6期29卷 831-839页

作者： rickard Hansen Sustainable Minerals Institute The University of Queensland

The progress of the GAG gas flow in a conveyor drift is *** output of a calculation model is evaluated and compared with experimental results from full-scale inertisation *** presenting the fastest and most extensive condensation of water resulted in well fitted arrival times of the GAG gas front.A common denominator for the two sets of expressions is that the type of flow is considered and thus better fitted to the actual flow *** model was further refined to include the surface roughness factor in the condensation calculations,which resulted in time lengths even closer to the measured time *** measured rapid temperature increase at certain positions along the conveyor drift was found to fit well with the calculated GAG gas front arrival at the corresponding *** magnitude of the GAG flow was found to have a large impact on the arrival time of the GAG gas *** and understanding the GAG gas behaviour would increase the likelihood of successful inertisation of all or part of a mine.

关键词： GAG Inert gas Condensation Temperature decrease Gas velocity Mine drift

Fire behaviour of multiple fires in a mine drift with longitudinal ventilation

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International journal of Mining Science and Technology 2019年第2期29卷 245-254页

作者： rickard Hansen Sustainable Minerals Institute The University of Queensland

The fire behaviour involving multiple fires in a mine drift with longitudinal ventilation was analysed. The conditions and fire phenomena occurring were described. The analysis was based upon experimental data from model-scale fire experiments. A fire involving several fuel items may lead to flames tilted horizontally and filling up the entire cross section, leading to earlier ignition, higher fire growth rates, higher fire spread rate and severe fire behaviour. Longer flame lengths will also result due to decreased air entrainment. A correlation for the continuous flame length was proposed. The results of the analysis will help identifying and preventing potentially dangerous fire situations with several large combustible items distributed along a mine drift.

关键词： Multiple fires Mine drift Fire spread Flame length Fire growth

Indications and surgical options for small bowel, large bowel and perianal Crohn's disease

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World journal of Gastroenterology 2016年第40期22卷 8892-8904页

作者： james WT Toh Peter Stewart matthew j.x rickard Rupert Leong Nelson Wang Christopher j Young Department of Colorectal Surgery Concord Repatriation General Hospital South Western Sydney Clinical School University of New South Wales Liverpool Hospital School of Medicine Western Sydney University Liverpool Hospital Ingham Institute of Applied Research Liverpool Hospital Discipline of Surgery Sydney Medical School the University of Sydney Department of Gastroenterology Concord Repatriation General Hospital Department of Colorectal Surgery Royal Prince Alfred Hospital

Despite advancements in medical therapy of Crohn's disease(CD), majority of patients with CD will eventually require surgical intervention, with at least a third of patients requiring multiple surgeries. It is important to understand the role and timing of surgery, with the goals of therapy to reduce the need for surgery without increasing the odds of emergency surgery and its associated morbidity, as well as to limit surgical recurrence and avoid intestinal failure. The profile of CD patients requiring surgical intervention has changed over the decades with improvements in medical therapy with immunomodulators and biological agents. The most common indication for surgery is obstruction from stricturing disease, followed by abscesses and fistulae. The risk of gastrointestinal bleeding in CD is high but the likelihood of needing surgery for bleeding is low. Most major gastrointestinal bleeding episodes resolve spontaneously, albeit the risk of re-bleeding is high. The risk of colorectal cancer associated with CD is low. While current surgical guidelines recommend a total proctocolectomy for colorectal cancer associated with CD, subtotal colectomy or segmental colectomy with endoscopic surveillance may be a reasonable option. Approximately 20%-40% of CD patients will need perianal surgery during their lifetime. This review assesses the practice parameters and guidelines in the surgical management of CD, with a focus on the indications for surgery in CD(and when not to operate), and a critical evaluation of the timing and surgical options available to improve outcomes and reduce recurrence rates.

关键词： Surgery Crohn’s disease Major abdominal surgery Perianal Inflammatory bowel disease Colon cancer

Improving rail vehicle dynamic performance with active suspension

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High-Speed Railway 2023年第1期1卷 23-30页

作者： Sebastian Stichel rickard Persson Rocco Giossi KTH Royal Institute of Technology KTH Railway GroupTeknikringen 8S-10044 StockholmSweden

Today,it is difficult to further improve the dynamic performance of rail vehicles with conventional passive ***,simplified vehicle respectively running gear layouts that significantly could reduce vehicle weights are difficult to realize with modern requirements on passenger vibration comfort and wheel and rail *** suspension is a powerful technology that can improve the vehicle dynamic performance and make simplified vehicle concepts *** KTH Railway group has,together with external partners,investigated active suspensions both numerically and experimentally for 15 *** paper provides a summary of the activities and the most important *** major project carried out in close collaboration with the vehicle manufacturer Bombardier and the Swedish Transport Administration was the Green Train project,where a 2-car EMU test bench was used to demonstrate different active *** ongoing projects,a concept of single axle-single suspension running gear is developed with active suspension both for comfort improvement and reduced wheel wear in *** results from on-track tests in the Green Train project were so good that the technology is now implemented in commercial trains and the simulation results for the single-axle running gear are very promising.

关键词： Rail Vehicle dynamics Active suspension Ride comfort Active wheelset steering Wheel wear

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一种用于温度超过800C的奥氏体球墨铸铁

铸造 1989年第4期38卷 35-37页

作者： j.rickard 杨清顺

自古以来,非合金铸铁被用于炉条、炉栅炉衬垫等抗热件上.在普通铸铁中加少量Ni和Cr时,其耐热性有所改善,但其使用寿命不能满足重要件的高要求.在球铁中加入Si和Mo,其性能可进一步改善,但是,即使是合金含量更高的球铁,仍不能用于超过800... 详细信息

自古以来,非合金铸铁被用于炉条、炉栅炉衬垫等抗热件上.在普通铸铁中加少量Ni和Cr时,其耐热性有所改善,但其使用寿命不能满足重要件的高要求.在球铁中加入Si和Mo,其性能可进一步改善,但是,即使是合金含量更高的球铁,仍不能用于超过800℃的零件上.因而导致了本文所述的一种用于温度超过800℃的耐热铸铁的发展.

关键词：奥氏体球墨铸铁 D-5S铸铁

Time-resolved, defect-hosted, trace element mobility in deformedWitwatersrand pyrite

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Geoscience Frontiers 2019年第1期10卷 55-63页

作者： Denis Fougerouse Steven M.Reddy Christopher L.Kirkland David W.Saxey William D.rickard Robert M.Hough School of Earth and Planetary Sciences The Institute for Geoscience Research (TIGeR) Curtin University Geoscience Atom Probe Advanced Resource Characterisation Facility John de Laeter Centre Curtin University CSIRO Minerals Resources

The Pb isotopic composition of rocks is widely used to constrain the sources and mobility of melts and hydrothermal fluids in the Earth's crust. In many cases, the Pb isotopic composition appears to represent mixing of multiple Pb reservoirs. However, the nature, scale and mechanisms responsible for isotopic mixing are not well known. Additionally, the trace element composition of sulphide minerals are routinely used in ore deposit research, mineral exploration and environmental studies, though little is known about element mobility in sulphides during metamorphism and deformation. To investigate the mechanisms of trace element mobility in a deformed Witwatersrand pyrite(FeS_2), we have combined electron backscatter diffraction(EBSD) and atom probe microscopy(APM). The results indicate that the pyrite microstructural features record widely different Pb isotopic compositions, covering the entire range of previously published sulphide Pb compositions from the Witwatersrand basin. We show that entangled dislocations record enhanced Pb, Sb, Ni, Tl and Cu composition likely due to entrapment and short-circuit diffusion in dislocation cores. These dislocations preserve the Pb isotopic composition of the pyrite at the time of growth(~3 Ga) and show that dislocation intersections, likely to be common in deforming minerals, limit trace element mobility. In contrast, Pb, As, Ni, Co, Sb and Bi decorate a highangle grain boundary which formed soon after crystallisation by sub-grain rotation *** isotopic composition within this boundary indicates the addition of externally-derived Pb and trace elements during greenschist metamorphism at ~2 Ga. Our results show that discrete Pb reservoirs are nanometric in scale, and illustrate that grain boundaries may remain open systems for trace element mobility over 1 billion years after their formation.

关键词： Atom probe microscopy Nanoscale Nanogeochronology Microstructure Isotope geochemistry Common Pb

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如何申请助学金

中学生英语(高中版) 2014年第23期 23-26页

作者： jenny rickard 布林莫尔学院招生和助学金办公室

在美国,大学教育可以说是一项重大的投资。如今许多最优秀、最有声望的美国学院和大学每年的花销都超过了50000美元。你可以计算一下——4年的总数超过20万美元!我们需要了解的一点是,虽然美国院校的助学金项目种类繁多,但是如果你是一... 详细信息

在美国,大学教育可以说是一项重大的投资。如今许多最优秀、最有声望的美国学院和大学每年的花销都超过了50000美元。你可以计算一下——4年的总数超过20万美元!我们需要了解的一点是,虽然美国院校的助学金项目种类繁多,但是如果你是一个国际学生的话,要获得资助,竞争是非常激烈的。美国顶尖大学更愿意提供"基于需求"的助学金,即根据你的家庭能够给你支付教育费用的能力来判定是否向你提供资

关键词：助学金学校录取国际学生

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