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从气体灭火系统、供货厂家、施工组织设计方案、试压方案、调试方案、验收成本等方面对气体灭火系统在投标预算实践中出现的问题进行了分析,并提出了一系列有参考价值的建议,以合理确定投标价。 相似文献
3.
Pursuant to the Energy Policy Act of 2005, the High Temperature Gas-Cooled Reactor (HTGR) has been selected as the reference design for the Next Generation Nuclear Plant (NGNP). Stemming from a U.S. Nuclear Regulatory Commission (NRC) HTGR research initiative, a need was identified for validation of systems-level computer code modeling capabilities in anticipation of the eventual need to perform licensing analyses. Because the NRC has used MELCOR for light water reactors (LWR) in the past and because MELCOR was recently updated to include gas-cooled reactor (GCR) physics models, MELCOR is among the system codes of interest to the NRC. This paper describes MELCOR modeling of the General Atomics' Modular High Temperature Gas-Cooled Reactor (MHTGR). The MHGTR is a suitable design for demonstration of MELCOR GCR modeling competency for two reasons: 1) the MHTGR is a predecessor to the more advanced General Atomics’ Gas-Turbine Modular High Temperature Reactor (GTMHR), and 2) experimental data useful for benchmark calculations may soon become available. Using the most complete literature references available for the MHTGR design, researchers at Texas A&M University (TAMU) constructed a MELCOR input deck for the MHTGR to partially validate MELCOR GCR modeling capabilities. Normal and off-normal system operating conditions were modeled with appropriate boundary and initial conditions. MELCOR predictions of system response were obtained for steady-state, pressurized conduction cool-down (PCC), and depressurized conduction cool-down (DCC) scenarios. Code results were checked against nominal MHTGR design parameters, physical intuition, and anticipated GCR thermal hydraulic response. No inherent deficiencies in MELCOR modeling capability were observed, suggesting that the newly-implemented GCR models are adequate for systems-level analysis. If and when experimental benchmark data becomes available, further validation activities may proceed given the modeling efforts discussed herein. 相似文献
4.
《国际计算机数学杂志》2012,89(11):1201-1209
In [5] a new iterative method is given for the linear system of equations Au=b , where A is large, sparse and nonsymmetrical and A^{\rm T}+A is symmetric and positive definite (SPD) or equivalently A is positive real. The new iterative method is based on a mixed-type splitting of the matrix A and is called the mixed-type splitting iterative method. The iterative method contains an auxiliary matrix D_1 that is restricted to be symmetric. In this note, the auxiliary matrix is allowed to be more general and it is shown that by proper choice of D 1 , the new iterative method is still convergent. It is also shown that by special choice of D_{1} , the new iterative method becomes the well-known (point) accelerated overrelaxation (AOR) [1] method. Hence, it is shown that the (point) AOR method applied to the positive real system is convergent under the proper choice of the overrelaxation parameters y and . 相似文献
5.
To date, there is little evidence that modular reasoning about fault-tolerant systems can simplify the verification process in practice. This question is studied using a prominent example from the fault tolerance literature: the problem of reliable broadcast in point-to-point networks subject to crash failures of processes. The experiences from this case study show how modular specification techniques and rigorous proof re-use can indeed help in such undertakings. 相似文献
6.
R. L. Jones 《Materials at High Temperatures》2013,30(4):187-193
Demands for high efficiency and power in the future will bring the use of advanced materials including ceramics, composites and augmented metals in engines and other technologies. In many cases, these materials may be subject to corrosion by high temperature gases and molten salt deposits resulting from contaminants (eg sodium, sulphur and vanadium) in the fuel or environment. This paper gives a short overview of the state of knowledge that exists today concerning ceramics and metals corrosion by fuel contaminants, and of possible new avenues for research and materials development. 相似文献
7.
《Ergonomics》2012,55(13):1102-1117
The main objective of this paper is to give an overview of basic concepts and definitions of terms related to the ‘measurement of slipperiness’ from the onset of a foot slide to a gradual loss of balance and a fall. Other unforeseen events prior to falls (e.g. tripping) are sparingly dealt with. The measurement of slipperiness may simply comprise an estimation of slipping hazard exposures that initiate the chain of events ultimately causing an injury. However, there is also a need to consider the human capacity to anticipate slipperiness and adapt to unsafe environments for avoiding a loss of balance and an injury. Biomechanical and human-centred measurements may be utilized for such an approach, including an evaluation of relevant safety criteria for slip/fall avoidance and procedures for validation of slip test devices. Mechanical slip testing approaches have been readily utilized to measure slipperiness in terms of friction or slip resistance but with conflicting outcomes. An improved understanding of the measurement of slipperiness paradigm seems to involve an integration of the methodologies used in several disciplines, among others, injury epidemiology, psychophysics, biomechanics, motor control, materials science and tribology. 相似文献
8.
《Ergonomics》2012,55(7):920-930
Looking at the past there are more or less fragmented approaches in ergonomics as well as in management. Especially in Germany, the ‘Lean Management wave’ weakened ergonomics in industry. On the other hand, there is a growing demand for holistic concepts—and ergonomics can by definition be understood as holistic. Many of the newer approaches in management include ODAM or macroergonomics elements. In building up a stronger relationship between macro- and micro-ergonomics, the whole discipline could be promoted. This also requires the fulfilment of some preconditions like systematically gathering and presenting ‘best practices’, which show that ergonomics pays off. 相似文献
9.
《Ergonomics》2012,55(10):1519-1526
This paper presents a method for objective assessment of physical work load at the workplace. The method is based on the DynaPort ADL Monitor. Using accelerometry, this monitor enables the assessment of gross motor activity as it occurs during the activities of daily living (ADL). A case study is conducted to explore the usefulness of the monitor in support of occupational research. The focus is on the cause and reduction of mechanical low back pain (LBP). A patient suffering from mechanical LBP participated in the study. He worked as messenger in contrast with his usual occupation. The patient was examined in both occupations using the monitor. The ADL profiles indicated that the messenger job was more likely to cause LBP than the other occupation of a mechanic. 相似文献
10.
通过对湖南省洞口县石江镇钟元帅庙及当地祠庙中的仪式行为及空间特色的比较分析,试图以文化人类学的观点,找到不同使用行为所对应的空间形式,分析两者之间的转换过程,从而得出仪式与空间之间的关系。 相似文献