Fractal fracture and transformation toughening in CuNiAl single crystal

The fracture toughness J _Ic (ρ) and fractal dimension D _f of fractured surfaces of CuNiAl single crystal have been measured at temperatures in the range 20 °C to 120 °C, in which thermoelastic martensitic transformation takes place. The parent phase has higher fracture toughness than the martensite phase due to stress-induced transformation. The relationship between J _Ic (ρ) and D _f has been studied. It was found that log J _Ic (ρ) is linearly related to D _f if the failure involves a single mechanism. The slope of the plot may either be positive or negative for brittle or ductile failure, respectively. The difference in the J _Ic (ρ)-D _f correlation can be understood in terms of the micromechanism of fracture.     

Minimum entropy and information measure

Kapur et al. (1995) introduced the MinMax information measure, which is based on both maximum and minimum entropy. The major obstacle for using this measure, in practice, is the difficulty in finding the minimum entropy. An analytical expression has already been developed for calculating the minimum entropy when only variance is specified. An analytical formula is obtained for calculating the minimum entropy when only mean is specified, and numerical examples are given for illustration     

ATM与帧中继互连技术

ＡＴＭ技术是ＩＴＵ－Ｔ推荐的Ｂ－ＩＳＤＮ交换技术，而帧中继在提供广域网业务方面很成功。因此，在ＡＴＭ发展的初期不可避免地会与帧中继技术并存。本文阐述了ＡＴＭ与帧中继网络互加和业务互连的相关技术及其存在的问题。     

“中国式”非显形奢华

奢侈品在中国逐渐成为热门产业,建立在精神层面上的“非显形奢华”也渐为众人关注。中国拥有深厚的文化底蕴,足以创造撼动视觉新体验的新“奢华”美学。当创意市场不断推进,变得成熟之后,中国的“非显形奢华”定会有更高的价值,奢华不再是炫耀身份的代名词,而是融合民族特色、具有独特的设计品位,真正意义上的顶级产品或服务,是一种低调、内敛、优雅的“非显形奢华”。     

Precipitation behavior of σ phase in fusion zone of dissimilar stainless steel welds during multi-pass GTAW process

The purpose of this study is to investigate the precipitation characteristics of σ phase in the fusion zone of stainless steel welds at various welding passes during a tungsten are welding (GTAW) process. The morphology, quantity, and chemical composition of the δ-ferrite and σ phase were analyzed using optical microscopy (OM), a ferritscope (FS), a X-ray diffractometer (XRD), scanning electron microscopy (SEM), an electron probe micro-analyzer (EPMA), and a wavelength dispersive spectrometer (WDS), respectively. Massive δ-ferrite was observed in the fusion zone of the first pass welds during welding of dissimilar stainless steels. The σ phase precipitated at the inner δ-ferrite particles and decreased δ-ferrite content during the third pass welding. The σ and δ phases can be stabilized by Si element, which promoted the phase transformation of σ→ϱ+λ₂ in the fusion zone of the third pass welds. It was found that the σ phase was a Fe−Cr−Si intermetallic compound found in the fusion zone of the third pass welds during multi-pass welding.     

Analysing the Diversity of Water Pricing Structures: The Case of France

This paper presents the results of a 2003 national survey of urban water pricing structure implemented by 429 district level water utilities. After providing some background elements on the diversity of existing water pricing structures, the paper shows how each structure can be used to achieve different management objectives (water allocation efficiency, costs recovery, and equity). It then describes the structures adopted by French water utilities, showing that flat rate are rarely adopted; declining blocks frequently used; and increasing blocks pricing which should be used to promote water use efficiency remain extremely rare. A statistical clustering is then conducted and a typology of situations elaborated. The paper concludes with highlighting that current pricing structures are influenced by past practices and that the dominant objective of water utilities is to cover costs.     

Asymptotic reduced-dimensional steering strategies for CMG singularity-free control

The geometric singularity problem is one of principal difficulty when using single-gimbal control moment gyros as spacecraft attitude control devices. To overcome singularity, new steering logics are suggested in this paper which results in a reduction in the difficulty of generating gimbal rates around a singular state. One of the suggested steering laws presented is the reduced dimensional singular value decomposition steering law, which adopts the singular value decomposition in reduced dimensional forms. Two other steering laws make use of the least square method in reduced dimensional forms. All of the suggested steering laws have been generated for the compensation of the torque insufficiency. These logics are verified mathematically and simulations at a singular condition and non-singular condition are performed to see how well they work.     

Optimization of the power ascension path for a boiling water reactor using genetic algorithms

To ensure the core status can meet the requirements of thermal limits, stability and other constraints during the power ascension process of a nuclear power plant, operators usually gradually increase power based on onsite measurements and experience. To reduce the operator’s burden, this research develops a method to find an optimal power ascension path that can be followed by operators. The power ascension path is formulated as a multiobjective optimization problem with the following constraints: power ascension time, thermal limits, core stability and maximum rod line. A genetic algorithm is adopted to obtain the optimal power ascension path. The results show that using our approach full power can be achieved quickly, while maintaining reasonable margins of thermal limit and stability, in addition to satisfying maximum rod line criteria.     

浅析结构化在岗培训模式

结构化在岗培训模式(S-OJT)具有计划性强、目标明确、一对一培训、培训场景真实等特点。S-OJT的设计和实施为6个步骤:确定是否采用S-OJT、工作分析、培养培训指导老师、制作S-OJT模块、实施S-OJT和培训过程评估与改进。     

Use of climate scenarios to aid in decision analysis for interannual water supply planning

This work addresses the issue of climate change in the context of water resource planning on the time scale of a few years. Planning on this time scale generally ignores the role of climate change. However, where the climate of a region has already shifted, the use of historical data for planning purposes may be misleading. In order to test this, a case study is conducted for a region, the Australian Capital Territory, where long term drought is raising concerns of a possible climate shift. The issue is cast in terms of a particular planning decision; the option to augment water supply in the next few years to hedge against the drought persisting. A set of climate scenarios are constructed for the region corresponding to the historical climate regime and to regimes where progressively greater levels of change are assumed to have already taken place (5%, 10%, 20% reductions in mean rainfall). Probabilities of the drought persisting are calculated for each of the scenarios. The results show substantial increases in the probability of the drought persisting for even moderate reductions in mean rainfall. The sensitivity of the decision to augment supply to the scenario results depends ultimately on the planners tolerable thresholds for the probability of the drought persisting. The use of different scenarios enables planners to explore the sensitivity of the decision in terms of their risk tolerance to ongoing drought and to their degree of belief in each of the scenarios tested.