Advances in Switched-Mode Power Conversion Part II

A number of important practical extensions to the basic ?uk converter are presented. They include dc isolation, multiple-output power sources, and a physical realization of the sought for hypothetical dc-to-dc transformer, a device which converts from pure dc (no voltage or current ripple) at one terminal, to pure dc (at a different voltage) at the other terminal. The application of the circuit in a highly efficient amplifier for the servo control of a dc motor or other loads is also presented.     

Piezoresistivity and electro-thermomechanical degradation of a conducting layer of nanoparticles integrated at the liquid crystal elastomer surface

When a liquid crystal elastomer (LCE) is reprocessed with conducting nanosized particles a conducting layer can be formed at the LCE surfaces. Here, two different LCE materials and two different conducting carbon particles were used. These four reprocessed LCEs were investigated when subject to a thermal phase transition and mechanical extension. Here it is shown that the resistance change with strain ('piezoresistivity') for these reprocessed LCEs can be described through lattice percolation and geometrical changes in the LCE shape. The mechanisms and rate of degradation are also described for the conducting layer as a function of the number of electro-thermomechanical strain cycles performed.     

Development of an independent hydrology audit methodology to support flood risk assessment in the planning process in Scotland

The recent flooding in the North–East of Scotland has highlighted issues around climate change due to significant changes in duration, severity and volume of precipitation events. The Planning (PA) and Flood Authorities (FA) often do not have the capacity or resources to review and check the accuracy and robustness of the SUD schemes nor the calculations submitted by developers. This study demonstrates the development and application of an Independent Hydrology Audit (IHA) service aimed at auditing and reviewing ‘in principle’ planning applications from the aspect of flooding risk to the wider community the development is located within. The output of this service is to establish a more accurate representation of surface water impact from developments through the use of adequate green/blue infrastructure, provide a greater assurance to the communities at risk of flooding, and help the PA and FA meet their statutory obligations at the initial stage of planning.     

A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding

A vehicle exposed to flooding, after losing stability, becomes buoyant and may be washed away with potential injuries and fatalities. Such vehicles cause additional disruption to traffic that is already affected by flooding, which may lead to substantial indirect economic impact, especially in urban areas. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce damages and hazards. In this research, based on an experimental campaign that included a range of twelve car models, a new methodology to obtain the stability threshold for any real vehicle exposed to flooding is developed. A stability coefficient (SC_mod) is derived with which the vehicles can be sorted by stability against water flows and their stability functions may be determined. The experiments were conducted with three different model scales (1:14, 1:18 and 1:24) and involved analysis of both friction and buoyancy effects, which made this the most comprehensive research study to date. This methodology enables the definition of a stable area in the flow depth-velocity domain for any real vehicle. A tool is provided that decision-makers in the field of urban flood risk management can employ and after defining a design vehicle they can obtain its corresponding stability threshold.     

便携电源管理市场需求旺盛——预计2012年营业额将增长到78亿美元

iSuppli公司认为,能够访问互联网的便携产品旺销,刺激了市场对于面向此类产品的电源管理半导体的需求快速增长。到2012年,全球便携电源管理半导体销售额将从2007年的47亿美元上升到78亿美元,复合年增长率为10．6％。如图所示为iSuppli公司对于2007年-2012年电源管理半导体销售额的预测。笔记本电脑和3G手机将是电源管理半导体的最大应用领域,2007年-2012年复合年增长率将分别为18．7％和26．8％。     

An improvement in the calculation of the magnetic field for an arbitrary geometry coil with rectangular cross section Int. J. Numer. Model. 2005; 18(6):493–504

The above article was published in Volume 18, Issue 6, Pages 493–504, (October 2005). A number of imperfections were subsequently identified and have been corrected below. On page 497, the following equation has been corrected to: On page 501, the following equation has been corrected to: On page 502, the following equation has been corrected to:      

Calculation of excess molar volumes with different cubic equations of state and different mixing rules

The effects of the simple composition-dependent combining rules (conventional, Adachi-Sugie and van Laar-Stryjek-Vera-type) and Huron-Vidal-NRTL mixing rules and different cubic equations of state (Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson and Peng-Robinson-Stryjek-Vera) on excess molar volume correlation are examined. The results obtained for some asymmetric non-ideal mixtures indicate very good agreement between correlated and experimental data in all cases when Huron-Vidal-NRTL mixing rules are coupled with the Peng-Robinson-Stryjek-Vera equation of state.     

The Value of Considering Autocorrelation Between Inflows in the Stochastic Planning of Water Resource Systems

Reliability programming formulations offer a family ofexplicit stochastic models for planning the operationof complex water resources systems. These models usecumulative probability distributions of the sum ofinflows to characterize their variability in theplanning period. Applicability of these models for avariety of problems has been limited, mainly due tothe assumption of independence between inflows indifferent time periods that leads to the derivation ofconservative operating policies. This paper presentsthree new approaches to overcome this limitation. Theperformance of the proposed approaches is demonstratedthrough comparison of the operating policies derivedfrom these approaches and the Independent Approach. Operational planning of the Manitoba Hydro energygeneration system, a predominantly hydro-based utilitycompany in Manitoba (Canada), is used as the case study.     

Two-dimensional correlation analysis of nuclear magnetic resonance metabonomics data

Two-dimensional (2D) correlation analysis has been used in this study to identify changes in complex nuclear magnetic resonance (NMR) metabonomics spectra of rat urine samples obtained during a study in which vasculitis (vascular injury), an important safety element in preclinical trials, was induced. Two types of correlation analysis were performed, along the variables and along the samples, and both 2D covariance and correlation coefficient maps were calculated. The binned and 'raw' NMR spectra were analyzed (0.04 and 0.001 ppm resolution, respectively). Good correlation was found among the major peaks of the binned spectra, and two groups of samples were identified using sample-sample 2D correlation maps. Much more complex correlation features were obtained from the 'raw' spectra, in which the specific, butterfly-like patterns were obtained in the covariance map but with only a few significant correlation coefficients in the corresponding 2D correlation maps. In terms of classification, the same group of the last nine spectra that indicated the end of the process and clustered in the 2D sample-sample covariance map of the binned data was also found in the 2D sample-sample covariance map of the raw NMR spectra but, again, not in the 2D correlation coefficient map. A discussion is given on the details of the application of the correlation analysis with regard to spectral data resolution, alignment, the effect of actual intensities of the NMR signal, and reference to various results from 2D correlation analysis of vibrational spectra.