bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery of plant diversity following N cessation: effects of recruitment, litter, and elevated N cycling
Authors: Clark Christopher M. , Tilman David
Published: December 2010

Plant species richness has declined and composition shifted in response to elevated atmospheric deposition of biologically active nitrogen over much of the industrialized world. Litter thickness, litter nitrogen (N) content, and soil N mineralization rates often remain elevated long after inputs cease, clouding the prospects that plant community diversity and composition would recover should N inputs be reduced. Here we determined how N cycling, litter accumulation, and recruitment limitation influenced community recovery following cessation of long‐term N inputs to prairie‐like grasslands. We alleviated each of these potential inhibitors through a two‐year full‐factorial experiment involving organic carbon addition, litter removal, and seed addition. Seed addition had the largest effect on increasing seedling and species numbers and may be necessary to overcome long‐term burial of seeds of target perennial grassland species. Litter removal increased light availability and bare sites for colonization, though it had little effect on reducing the biomass of competing neighbors or altering extractable soil N. Nonetheless, these positive influences were enough to lead to small increases in species richness within one year. We found that, although C addition quickly altered many factors assumed favorable for the target community (decreased N availability and biomass of nearby competitors, increased light and site availability), these changes were insufficient to positively impact species richness or seedling numbers over the experimental duration. However, only carbon addition had species‐specific effects on the existing plant community, suggesting that its apparent limited utility may be more a result of slow recovery under ambient recruitment rather than from a lack of a restorative effect. There were dramatic interactions among treatments, with the positive effects of litter removal largely negated by carbon addition, and the positive effects of seed addition generally amplified by litter removal. It remains unclear whether each mechanism explored here will induce community recovery, but over different temporal scales. Long‐term monitoring will help resolve these remaining questions. Regardless, our results suggest that reversal of species loss and compositional shifts from N deposition in prairies may be more inhibited by habitat fragmentation, recruitment limitation, and long‐term suppression of fire than from continued effects of elevated N.
Bigger is not always better: Offspring size does not predict growth or survival for seven ascidian species
Authors: Jacobs Molly W. , Sherrard Kristin M.
Published: December 2010

The presumed trade‐off between offspring size and quality predicted by life history theory is often invoked to explain the wide range of propagule sizes observed in animals and plants. This trade‐off is broadly supported by intraspecific studies but has been difficult to test in an interspecific context, particularly in animals. We tested the fitness consequences of offspring size both intra‐ and interspecifically for seven species of ascidians (sessile, suspension‐feeding, marine invertebrates) whose offspring volumes varied over three orders of magnitude. We measured two major components of fitness, juvenile growth rates and survival, in laboratory and field experiments encompassing several food conditions. Contrary to the predictions of life history theory, larger offspring size did not result in higher rates of growth or survival, and large offspring did not perform better under nutritional stress, either intraspecifically or interspecifically. In fact, two of the four species with small offspring grew rapidly enough to catch up in size to the species with large offspring in as little as eight weeks, under wild‐type food conditions. Trade‐offs between growth potential and defense may overwhelm and obscure any trade‐offs between offspring size and survival or growth rate. While large initial size may still confer a competitive advantage, we failed to detect any consequences of interspecific variation in initial size. This implies that larger offspring in these species, far from being inherently superior in growth or survival, require compensation in other aspects of life history if reproductive effort is to be efficient. Our results suggest that the importance of initial offspring size is context dependent and often overestimated relative to other life history traits.
Bioengineers and their associated fauna respond differently to the effects of biogeography and upwelling
Authors: Cole Victoria J. , McQuaid Christopher D.
Published: December 2010

Temperature and primary production (often linked to nutrient supply) are two of the few factors influencing species diversity and abundances across mesoscale gradients, while at smaller scales the habitat complexity offered by bioengineers is important. Previous studies have illustrated effects of upwelling and biogeography on intertidal bioengineers, but it is not known if these processes influence assemblages associated with those bioengineers in a similar way. We examined the habitat structure offered by two species of mussels and their associated fauna in five regions across 3000 km and three biogeographic provinces of the South African coast, replicating upwelling and non‐upwelling areas within each region. Upwelling and region influenced the structure of mussel beds (the density and size of mussels). In contrast, upwelling did not influence mesoscale differences in composition, abundance, and numbers of species of crustaceans, mollusks, or polychaetes in mussel beds. Regardless of trophic level or mode of reproduction, mussel bed fauna were influenced only by region. Regional differences were strongly influenced by biogeography. The associated fauna was, however, also strongly correlated with the structure of the habitats created by mussels. Our results support the importance of upwelling to a critical ecosystem engineer, but show that these effects do not extend directly to the assemblages of associated fauna, which are more influenced by regional‐scale effects and biogeography. We suggest that mesoscale patterns in the associated fauna of this bioengineered habitat are driven by the direct effects of biogeography, combined with the influence of biogeography and upwelling on mussel bed structure.
Field evidence for pervasive indirect effects of fishing on prey foraging behavior
Authors: Madin Elizabeth M. P. , Gaines Steven D. , Warner Robert R.
Published: December 2010

The indirect, ecosystem‐level consequences of ocean fishing, and particularly the mechanisms driving them, are poorly understood. Most studies focus on density‐mediated trophic cascades, where removal of predators alternately causes increases and decreases in abundances of lower trophic levels. However, cascades could also be driven by where and when prey forage rather than solely by prey abundance. Over a large gradient of fishing intensity in the central Pacific's remote northern Line Islands, including a nearly pristine, baseline coral reef system, we found that changes in predation risk elicit strong behavioral responses in foraging patterns across multiple prey fish species. These responses were observed as a function of both short‐term (“acute”) risk and longer‐term (“chronic”) risk, as well as when prey were exposed to model predators to isolate the effect of perceived predation risk from other potentially confounding factors. Compared to numerical prey responses, antipredator behavioral responses such as these can potentially have far greater net impacts (by occurring over entire assemblages) and operate over shorter temporal scales (with potentially instantaneous response times) in transmitting top‐down effects. A rich body of literature exists on both the direct effects of human removal of predators from ecosystems and predators' effects on prey behavior. Our results draw together these lines of research and provide the first empirical evidence that large‐scale human removal of predators from a natural ecosystem indirectly alters prey behavior. These behavioral changes may, in turn, drive previously unsuspected alterations in reef food webs.
Economic Benefits of Achieving Realistic Smoking Cessation Targets in Australia
Authors: Magnus Anne , Cadilhac Dominique , Sheppard Lauren , Cumming Toby , Pearce Dora , Carter Rob
Published: December 2010

Objectives. We estimated the economic impact of reductions in the prevalence of tobacco smoking on health, production, and leisure in the 2008 Australian population.

Methods. We selected a prevalence target of 15%. Cohort lifetime health benefits were modeled as fewer incident cases of tobacco-related diseases, deaths, and disability-adjusted life-years. We estimated production gains by comparing surveyed participation and absenteeism rates of adult smokers and ex-smokers valued according to the human capital and friction cost approaches. We estimated household production and leisure gains from time use surveys and valued these gains with the appropriate proxy.

Results. In the 2008 Australian population, an absolute reduction in smoking prevalence of 8% would result in 158 000 fewer incident cases of disease, 5000 fewer deaths, 2.2 million fewer lost working days, and 3000 fewer early retirements and would reduce health sector costs by AUD 491 million. The gain in workforce production was AUD 415 million (friction cost) or AUD 863 million (human capital), along with gains of 373 000 days of household production and 23 000 days of leisure time.

Conclusions. Lowering smoking prevalence rates can lead to substantial economic savings and health benefits.
Symbolic Capital, Consumption, and Health Inequality
Authors: Sweet Elizabeth
Published: December 2010

Research on economic inequalities in health has been largely polarized between psychosocial and neomaterial approaches. Examination of symbolic capital—the material display of social status and how it is structurally constrained—is an underutilized way of exploring economic disparities in health and may help to resolve the existing theoretical polarization. In contemporary society, what people do with money and how they consume and display symbols of wealth may be as important as income itself. After tracing the historical rise of consumption in capitalist society and its interrelationship with economic inequality, I discuss evidence for the role of symbolic capital in health inequalities and suggest directions for future research.
Lifting Boats Without Closing Gaps: Child Health Outcomes in Distressed US Cities From 1992–2002
Authors: Silver Diana , Mijanovich Tod , Uyei Jenny , Kapadia Farzana , Weitzman Beth C.
Published: December 2010

Objectives. We compared cause-specific mortality and birth rates for children and youths aged younger than 18 years in 100 US cities from 1992 through 2002.

Methods. We used 5 census indicators to categorize the 100 most populous US cities in 1990 as economically distressed or nondistressed. We used Poisson regression to calculate rate ratios for cause-specific mortality and birth rates, comparing distressed cities to nondistressed cities overall and by race/ethnicity from 1992 through 2002. We also calculated rates of change in these variables within each city over this period.

Results. Despite improvements in health for the study population in all cities, disparities between city groups held steady or widened over the study period. Gaps in outcomes between Whites and Blacks persisted across all cities. Living in a distressed city compounded the disparities in poor outcomes for Black children and youths.

Conclusions. A strong national economy during the study period may have facilitated improvements in health outcomes for children and youths in US cities, but these benefits did not close gaps between distressed and nondistressed cities.
Assessing Creatinine Clearance from Modification of Diet in Renal Disease Study Equations in the ADEMEX Cohort
Authors: Sloand James A. , Leypoldt John K. , Culleton Bruce F. , Gellens Mary E. , Paniagua Ramon , Amato Dante , Vonesh Edward F.
Published: December 2010

Background and objectives

Twenty-four-hour urine and dialysate collections provide accepted means to assess adequacy in peritoneal dialysis (PD). Recent publications suggest that creatinine clearance (CrCl) estimated from the Modification of Diet in Renal Disease (MDRD) equations (eCrCl) accurately approximates measured CrCl (mCrCl) derived from 24-hour collections of urine and dialysate and might serve as an alternative means to assess small-solute clearance and adequacy in PD.

Design, setting, participants, & measurements

Post hoc analysis of data from patients enrolled in ADEMEX was used to assess agreement between mCrCl and eCrCl derived by four- and six-variable MDRD equations (4V-MDRDE and 6V-MDRDE, respectively). Additionally, associations among mCrCl, eCrCl, and survival were determined.

Results

Acceptable precision was observed between mCrCl and 4V-MDRDE-eCrCl and 6V-MDRDE-eCrCl for the entire cohort. Precision was markedly diminished when analysis was limited to functionally anuric patients with mCrCl < 12 ml/min per 1.73 m2. Although there was no association between survival and mCrCl, for every 1-ml/min per 1.73 m2 increase in 4V- and 6V-MDRDE-eCrCl, there was a 6% and 4% increase in risk of death, respectively. There was a negative association between MDRDE-eCrCl and creatinine appearance rates, suggesting MDRDE-eCrCl is significantly confounded by individual differences in muscle mass.

Conclusions

MDRDE-eCrCl provides demographically comparable values to 24-hour urine and dialysate collections across the ADEMEX cohort. However, MDRDEs should not be used to assess small-solute removal or adequacy in individual PD patients or to predict outcome in any cohort of patients over narrow ranges of limited clearance.
Influence of substituent type on properties of starch derivates
Authors: Stojanovic Zeljko , Jeremic Katarina , Jovanovic Slobodan , Nierling Wolfgang , Lechner Manfred
Published: December 2010

The subject of the study was investigation of influence of substituent type
on the properties of starch derivates in diluted solutions. Three samples
were prepared: two anionic (carboxymethyl starch, CMS) and one cationic
starch (KS). Starch derivates were synthesized in two steps. The first step
was preparation of alkali starch by the addition of sodium-hydroxide to the
starch dispersed in ethanol or water. In the second step, the required amount
of sodium monocloracetate or 3-chloro-2-hydroxypropyl-threemethylamonium
chloride was added to the obtained alkali starch in order to prepare CMS or
KS, respectively. The degree of substitution of carboxymethyl starch was
determined by back titration method, and the degree of substitution of
cationic starch was determined by potentiometric titration. The degrees of
substitution of prepared samples were: 0.50 (assigned as CMS-0.50) and 0.70
(assigned as CMS-0.70) for carboxymethyl starch and 0.30 (assigned as
KS-0.30) for cationic starch. The properties of starch derivatives in dilute
solutions were investigated by the methods of static and dynamic light
scattering. Aqueous solutions of sodium chloride of different concentrations
were used as solvent. The values of the mass average molar mass, MW, radius
of gyration, Rg, and second virial coefficient, A2, were determined for all
samples together with hydrodynamic radius, Rh. Molar masses of the samples
were: 5.06?106, 15.4?106 and 19.2?106 g/mol for CMS-0.50, CMS-0.70 and
KS-0.30, respectively. The samples, CMS-0.70 and KS-0.30 had similar molar
mass and hydrodynamic radius, but radius of gyration of KS-0.30 was smaller
then radius of gyration of CMS-0.70 at all sodium chloride concentrations.
Consequently, ? value for KS-0.30 was smaller then for CMS-0.70, as a result
of more compact architecture of KS-0.30 then of CMS-0.70. Kratky graph
confirmed this result. For all samples, radius of gyration and hydrodynamic
radius decreased with increasing of sodium chloride concentration, but
decrease of the radius was greater for CMS-0.50 then for other two samples
due to its significantly lower molar mass. On the other hand, change of both
radius of gyration and hydrodynamic radius of CMS-0.70 and of KS-0.30 with
increasing sodium chloride concentration were similar. It can be concluded
that the decrease of both Rg and Rh with increasing sodium chloride
concentration in water depends far more on molar mass than on degree of
substitution.
Shock safety modeling method for low-voltage electric devices
Authors: Korniluk Włodzimierz , Sajewicz Dariusz
Published: December 2010

Shock safety modeling method for low-voltage electric devices

The article describes a shock safety modeling method for low-voltage electric devices, based on using a Bayesian network. This method allows for taking into account all possible combinations of the reliability and unreliability states for the shock protection elements under concern. The developed method allows for investigating electric shock incidents, analysing and assessing shock risks, as well as for determining criteria of dimensioning shock protection means, also with respect to reliability of the particular shock protection elements. Dependencies for determining and analysing the probability of appearance of reliability states of protection as well as an electric shock risk are presented in the article.
The price stability oriented monetary policy of the European Central Bank
Authors: Gasiński Wojciech , Misztal Anna
Published: December 2010

The aim of this paper is to present the price stability oriented monetary policy of the European Central Bank. The European Central Bank began activities in 1998 and the primary objective of the European System of Central Banks is to maintain price stability and the ESCB should also support the general economic policies in the Community. Monetary policy is a special tool that national governments and central banks uses to influence on its economy, especially to control the supply of money and to influence on the level of economic indicators. This paper investigates the assumed objective of the European System of Central Banks which is to maintain price stability. What is more, we would like to present the monetary policy strategy of the European Central Bank and analysis of the Harmonized Index of Consumer Prices.
Project management and presentation of information in financial statements - company performance measurement or project performance measurement
Authors: Kalinowski Jacek
Published: December 2010

Realization of projects is such form of operation which in the recent years – in the age of globalization of economy and growing competition – has become more and more significant, both in Poland and worldwide. The value and the number of projects realized are gradually growing and include not only the branches traditionally related to such form of operation (e.g. construction and IT industry) but in practice all fields of our life. A necessary element that determines the success of project realization is timely information which also needs to be reliable and useful. The source of such information is the accounting system composed of two subsystems: financial accounting (focused on the external recipient of the information) and management accounting (providing information to internal recipients). One of the basic determinants of creating information for external recipients (such as investors, banks, insurance companies, treasuryadministration organs etc.) is comparability. Keeping it influences the quality of information regarding project activity taken from financial reports created according to the selected regulations of accounting (e.g. IAS/IFRS, US GAAP and the PL GAAP). The aim of the article is to draw the attention to the problems related tothe presentation of the operational result in case of companies realizing projects contained in a financial report. The article is of discursive nature since the issues that it deals with usually depend on what given solution is selected bya unit in question. Moreover, some of the areas are subject to detailed regulations of the balance law (both domestically – the Act on Accounting and PL GAAP No. 3, and internationally – AS/IFRS). However, their applicationmay lead to ‘blurring’ a realistic and true picture of the capital and financialsituation of a company realizing long-term projects.
Integrated information about the multifaceted performance of the entity
Authors: Kabalski Przemysław
Published: December 2010

The objective of the paper is to present a proposal concerning the scope and structure of information made available to external users about various aspects of business entities' performance, as well as to ascertain if the largest Polish listed companies disclose comprehensive and balanced information about their performance. Research has revealed that such information is published on a very limited scale.
Application of activity - based costing in companies in Poland
Authors: Wnuk-Pel Tomasz
Published: December 2010

The purpose of this paper is to explore the application of activity-based costing in companies in Poland, and more specifically, to analyse problems In ABC implementation, the structure of ABC systems and the ways in which ABC information is used. Findings of the research have both practical and theoretical implications. First, from the practical point of view, future implementers of ABC systems should be aware of factors actually influencing ABC implementation as well as problems which can be encountered during the implementation process. Managers considering activity-based costing implementation may see level of detail and methods of construction of an ABC information model. They may also benefit from the knowledge of how information generated by an ABC systems is actually used by companies. All this may help to make better decision about ABC implementation and if the decision is to implement ABC, it may help to implement it successfully. From the theoretical point of view the research carried out makes it possible to establish a general tendency: modifications in costing systems applied in Polish enterprises and development of management accounting practice such as ABC follows the same general direction as management accounting practice in the world.
The winner takes it all? Multidimensional assessment of economic growth factors in Bundesländer
Authors: Götz Marta
Published: December 2010

This paper seeks to offer a thorough assessment of current state of the play as well as developments taking place in 1989-2008 with respect to various determinants of economic growth in Germany. The primary aim is to evaluate the growth potential by constructing and consequently calculating the summary index encompassing various dimensions of economy. In order to take a holistic and comprehensive view on economic growth factors, conceptual framework of five modules encapsulating numerous factors and thus incorporating various growth aspects has been put forward. Competitiveness (production function), Sectors (output approach), Business cycle (expenditure approach), General economic condition (main macroindices) and Catalysts (residual - all other factors) are taken into account. Preliminary results confirm to some extent earlier studies pointing to existing West-East Germany's discrepancies. It seems particularly visible when taking into account elements of the first module and - key for long term growth - factors of the fifth unit.
Multirobot system architecture: environment representation and protocols
Authors: Ambroszkiewicz S. , Bartyna W. , Faderewski M. , Terlikowski G.
Published: December 2010

Multirobot system architecture: environment representation and protocols

An approach to the problem of interoperability in open and heterogeneous multirobot system is presented. It is based on the paradigm of Service Oriented Architecture (SOA) and a generic representation of the environment. A robot, and generally a cognitive and intelligent device, is seen as a collection of its capabilities exposed as services. Several experimental protocols (for publishing, discovering, arranging, and executing the composite services) are proposed in order to assure the interoperability in the system. The environment representation, the description language for tasks and service interfaces definition, as well as the protocols constitute together the proposed information technology for automatic task accomplishment in an open heterogeneous multirobot system.
Whether the opinion about superiority of fuzzy controllers is justified
Authors: Gessing R.
Published: December 2010

Whether the opinion about superiority of fuzzy controllers is justified

In the paper, using some MATLAB fuzzy logic toolbox Demos, in which the fuzzy controllers are compared with the classical PID ones, it is shown that the well tuned classical PID controllers are significantly better than those fuzzy presented in the Demos. It is shown, that using fuzzy approach, it is very difficult to shape the input-output nonlinearity, describing the so called fuzzy block of the fuzzy controller. It is also shown, that the linear fuzzy block (created to obtain comparable results with the classical PID controllers) is not justified at all, because it may be replaced by the usual summing junction, which is significantly simpler. The considerations of the paper do not support the idea of fuzzy controllers.
Robust control of distributed parameter mechanical systems using a multidimensional systems approach
Authors: Cichy B. , Augusta P. , Rogers E. , Gałkowski K. , Hurák Z.
Published: December 2010

Robust control of distributed parameter mechanical systems using a multidimensional systems approach

The unique characteristic of a repetitive processes is a series of sweeps, termed passes, through a set of dynamics defined over a finite duration. On each pass an output, termed the pass profile is produced which acts as on forcing function, and hence contributes to, the dynamics of the next pass profile. This leads to the possibility that the output, i.e. the sequence of pass profiles, will contain oscillations that increase in amplitude in the pass-to-pass direction. Such behavior cannot be controlled by application of standard linear systems control laws and instead they must be treated as two-dimensional (2D) systems where information propagation in two independent directions, termed pass-to-pass and along the pass respectively, is the defining feature. Physical examples of such processes include long-wall coal cutting and metal rolling. In this paper, stability analysis and control law design algorithms are developed for discrete linear repetitive processes where a plane, or rectangle, of information is propagated in the pass-to-pass direction. The possible use of such a model in the control of distributed parameter systems has been investigated in previous work and this paper considers an extension to allow for uncertainty in the model description.
Heat dissipation and temperature distribution in long interconnect lines
Authors: Gnidzinska K. , De Mey G. , Napieralski A.
Published: December 2010

Heat dissipation and temperature distribution in long interconnect lines

Thermal and time delay aspects of long interconnect lines have been investigated. To design a modern integrated circuit we need to focus on very long global interconnects in order to achieve the desired frequency and signal synchronization. The long interconnection lines introduce significant time delays and heat generation in the driver transistors. Introducing buffers helps to spread the heat production more homogenously along the line but consumes extra power and chip area. To ensure the functionality of the circuit, it is compulsory to give priority to the time delay aspect and then the optimized solution is found by making the power dissipation as homogenous as possible and consequently the temperature distribution T (relative to ambient) as low as possible. The technology used for simulations is 65 nm node. The occurring phenomena have been described in a quantitative and qualitative way.
Axi-symmetric deformation in the micropolar porous generalized thermoelastic medium
Authors: Kumar R. , Gupta R.
Published: December 2010

Axi-symmetric deformation in the micropolar porous generalized thermoelastic medium

In the present article we studied the thermodynamical theory of micropolar porous material and derived the equations of the linear theory of microploar porous generalized thermoelastic solid. Then the general solution to the field equations for plane axi-symmetric problem are obtained. The Laplace and Hankel transforms have been employed to study the problem, which are inverted numerically by using numerical inversion technique. An application of normal force and thermal source has been taken to show the utility of the approach. The technique developed in the present paper is simple, straightforward and convenient for numerical computation. Effect of micropolarity and porosity on the components of stress, temperature distribution and volume fraction field together with the effect of generalized theory of thermoelasticity have been depicted graphically for a specific model. Some particular cases are also deduced from the present problem.
Boiling in micro-channels
Authors: Hetsroni G.
Published: December 2010

Boiling in micro-channels

Boiling heat transfer in micro-channels is a subject of intense academic and practical interest. Though many heat transfer correlations have been proposed, most were empirically formulated from experimental data. However, hydrodynamic and thermal aspects of boiling in micro-channels are not well understood. Moreover, there are only a few theoretical models that link the heat transfer mechanism with flow regimes in micro-channels. Also, there are discrepancies between different sets of published results, and heat transfer coefficients have either well exceeded, or fallen far below, those predicted for conventional channels. Here we consider these problems with regard to micro-channels with hydraulic diameters ranging roughly from 5 μm to 500 μm, to gain a better understanding of the distinct properties of the measurement techniques and uncertainties, the conditions under which the experimental results should be compared to analytical or numerical predictions, boiling phenomenon, as well as different types of micro-channel heat sinks. Two-phase flow maps and heat transfer prediction methods for vaporization in macro-channels are not applicable in micro-channels, because surface tension dominates the phenomena, rather than gravity forces. The models of convection boiling should correlate the frequencies, sizes and velocities of the bubbles and the coalescence processes, which control the flow pattern transitions, together with the heat flux and the mass flux. Therefore, the vapour bubble size distribution must be taken into account. The flow pattern in parallel micro-channels is quite different from that in a single micro-channel. At same values of heat and mass flux, different, time dependent, flow regimes occur in a given micro-channel. At low vapour quality, heat flux causes a sudden release of energy into the vapour bubble, which grows rapidly and occupies the entire channel cross section. The rapid bubble growth pushes the liquid-vapour interface on both caps of the vapour bubble, at the upstream and the downstream ends, and leads to a reverse flow. We term this phenomenon as explosive boiling. One of the limiting operating conditions with flow boiling is the critical heat flux (CHF). The CHF phenomenon is different from that observed in conventional size channels.
Robin heart progress - advances material and technology in surgical robots
Authors: Nawrat Z.
Published: December 2010

Robin heart progress - advances material and technology in surgical robots

The paper presents the current state of works conducted by the Zabrze team under the Robin Heart surgical robot and the Robin Heart Uni System mechatronic surgical tools project as a example of introducing technology and materials advances for progress in surgical robots. The special intention of the author is to show the review of the current and futuristic medical robots needs in the area of material science.
Interactive evolutionary multiobjective optimization driven by robust ordinal regression
Authors: Branke J. , Greco S. , Słowiński R. , Zielniewicz P.
Published: December 2010

Interactive evolutionary multiobjective optimization driven by robust ordinal regression

This paper presents the Necessary-preference-enhanced Evolutionary Multiobjective Optimizer (NEMO), which combines an evolutionary multiobjective optimization with robust ordinal regression within an interactive procedure. In the course of NEMO, the decision maker is asked to express preferences by simply comparing some pairs of solutions in the current population. The whole set of additive value functions compatible with this preference information is used within a properly modified version of the evolutionary multiobjective optimization technique NSGA-II in order to focus the search towards solutions satisfying the preferences of the decision maker. This allows to speed up convergence to the most preferred region of the Pareto-front.
Cellular automata model of self-organizing traffic control in urban networks
Authors: Szklarski J.
Published: December 2010

Cellular automata model of self-organizing traffic control in urban networks

A model of city traffic based on Nagel-Schreckenberg cellular automaton (CA) model is presented. Traffic control is realized at intersections with two conflicting streams each (at any time at most one stream can have "green light" assigned to it). For simple and regular lattice-like networks which are considered, it is easy to find optimal switching periods giving maximum possible flow rates. These optimal strategies are compared with a self-controlling approach proposed by [1], which has not been implemented in a CA model until now. Previous work proved that generally this method gives superior results when compared to classical methods. In this paper we show that for deterministic scenario such control leads to self-organization, and that the solution always quickly converges to the optimal solution which is known in this case. Moreover, we consider also non-deterministic case, in the sense that possibility of turning with given probability is allowed. It is shown that the self-controlling strategy always gives better results than any solution based on fixed cycles with green waves.
Computational electromagnetics for design optimisation: the state of the art and conjectures for the future
Authors: Sykulski J.
Published: December 2010

Computational electromagnetics for design optimisation: the state of the art and conjectures for the future

The paper reviews the state of the art in modern field simulation techniques available to assist in the design and performance prediction of electromechanical and electromagnetic devices. Commercial software packages, usually exploiting finite element and/or related techniques, provide advanced and reliable tools for every-day use in the design office. At the same time Computational Electromagnetics continues to be a thriving area of research with emerging new techniques and methods, in particular for multi-physics applications and in the area of multi-objective optimisation.
Transmission of Elegant Laguerre-Gaussian beams at a dielectric interface - numerical simulations
Authors: Szabelak W. , Nasalski W.
Published: December 2010

Transmission of Elegant Laguerre-Gaussian beams at a dielectric interface - numerical simulations

Behaviour of Laguerre-Gaussian beams impinged at a dielectric interface under distinct angles is discussed. For different incident angles the beams interact with the interface differently. Two ranges of incident angles, specified by a position of a spectral cone of beam field and related to a cross-polarization effect, are analyzed. Boundary between these two ranges is defined. Cases of critical incidence and total internal reflection are also discussed. Paraxial beams near the lower paraxial limit are considered. Theoretical predictions are confirmed by numerical simulations.
A design of DSS for mass production machining systems
Authors: Dolgui A. , Guschinsky N. , Levin G.
Published: December 2010

A design of DSS for mass production machining systems

In this paper, we present a decision support tool (DSS) for preliminary design of transfer machines with rotary or mobile tables. In these transfer machines, the machining operations are executed on working positions equipped by standard multi-spindle heads. A part is sequentially machined onmworking positions and is moved from one position to the next using a rotary or a mobile table. The operations are grouped into blocks, where the operations of the same block are simultaneously performed by one multi-spindle head. At the preliminary design stage, the goal is to select the number of working positions and to decide which spindle heads will be installed minimizing the machine cost while respecting a given production rate. The paper presents the overall approach and depicts mathematical and decision-support methods developed and implemented in a software for the optimization of preliminary design (or reconfiguration) of such machining systems.
Cooperation of induction squirrel-cage generator with grid connected AC/DC/AC converter
Authors: Sikorski A. , Kuźma A.
Published: December 2010

Cooperation of induction squirrel-cage generator with grid connected AC/DC/AC converter

The paper presents a squirrel-cage induction machine operating as a generator principally designed for use in small wind and hydroelectric power stations. The main advantages of such a generator are its high reliability, low price and costs of operation and maintenance. The asynchronous generator coupled to the grid through the AC/DC/AC converter is capable of generating energy even at low turbine speed. The results of investigations on the AC/DC and DC/AC converters controlled by linear and nonlinear current regulators are also discussed.
Control and modulation methods of voltage source converter
Authors: Radomski G.
Published: December 2010

Control and modulation methods of voltage source converter

Control and modulation methods of Voltage Source Converter (VSC) have been presented in the paper. Model of VSC with three value transistor branch state function is introduced to describe operation of VSC. Predictive-corrective control method of VSC system is presented. Two variants of Space Vector PWM methods for VSC system are developed. Algorithm of cancelation of negative influence of dead time on the AC voltages is implemented in the proposed modulation methods. Correctness of introduced method is validated by simulation and experiment investigations.
High efficiency contactless energy transfer system with power electronic resonant converter
Authors: Moradewicz A. , Kazmierkowski M.
Published: December 2010

High efficiency contactless energy transfer system with power electronic resonant converter

A novel Inductive Contactless Energy Transfer (ICET) system is presented in this paper. The energy is transferred using a rotatable air gap transformer and a power electronic converter. To minimize total losses of the system a series resonant circuit is applied, assuring zero current switching condition for IGBT power transistors. The analytical expression of the transfer dc voltage gain is given and discussed. The developed ICET system is characterized by high efficiency and fast FPGA based controller and protection system. The resonant frequency is adjusted by extreme regulator which follows instantaneous value of primary peak current. Simulated and experimental results which verify and illustrate operation of developed 3 kW laboratory model are presented.
A quantitative modeling of the unloading behavior of metals during a tensile test
Authors: Allain Se´bastien , Bouaziz Olivier
Published: December 2010

This work proposes an original quantitative approach to understand the backward plastic strain resulting from the unloading of a polycrystalline metal during an interrupted tensile test. Based on a prior model by Salama and Roberts, the main assumption is that the relaxed plastic strain is due to the small relaxation of mobile dislocation loops, also responsible for the internal stresses. During unloading, the number of dislocation loops per active source remains constant, but they move backwards as the applied stress decreases. Thus, the main challenge consists in the quantitative estimation of each hardening component and their variations, upon loading and during the unloading sequences, without reverse straining. The model is applied in the case of an interstitial-free steel, with excellent agreement. This study provides a more consistent framework related to the evaluation of the Bauschinger effects in metals avoiding the ambiguity on the choice of the plastic strain offset.
Tensile and in-vitro degradation study of electro spun fibrous mat produced from eri silk fibroin
Authors: Muthumanickkam A. , Elankavi E. , Gayathri R. , Sampathkumar S. Kubera , Vijayakumar G. , Muthukumar K. , Subramanian S.
Published: December 2010

Fibrous mat was produced from eri silk fibroin by electro spinning. The fibrous mat was tested for tensile properties and in-vitro bio-degradation by enzymatic treatment. The tensile strength of the mat was 5.3 MPa and its elastic modulus was 49 MPa before bio-degradation. The weight loss obtained after 30 days of degradation was 34%. The in-vitro enzymatic degradation of fibrous mat was confirmed through Scanning electron microscopy and Fourier transform infrared spectroscopy studies.
An investigation on Incoloy800-SS304 clad plate by explosive welding
Authors: Zhao Hui , Huang Zhanghong , Li Pingcang , Zhou Yigang , Wang Hunian
Published: December 2010

In this paper, Incoloy800 and 304 stainless steel (SS304) were clad by explosive welding. Accordingly, hardness, tensile strength, shearing strength, bending properties and microstructure of the clad plates were evaluated. The bonding interface showed a wavy morphology. Line scanning results indicated that there was no diffusion area through the bonding interface. Whereas, a colorful zone was observed at the wave ridge of the base metal (white area in optical microscopy and black area in scanning electronic microscopy). Energy dispersive spectroscopy analysis indicated that compositions and contents of the colorful zone were the same as that in the base metal. Hardness testing showed that the highest value of hardness was obtained in the colorful zone. Thus, the colorful zone was an intensive deformation area in SS304, which was produced by shock pressure from collision. Mechanical tests showed that the clad plate was acceptable according to ASTM specification.
A technique for diameter enlargement in SiC crystal growth
Authors: Lin Shenghuang , Chen Zhiming , Jiang Dong , Liang Peng , Wan Jun , Liu Bo , Xie Huajie , Feng Xianfeng
Published: December 2010

The availability of large high-quality silicon carbide (SiC) single crystals is a key issue in the development of the full potential of SiC-based device technology. This paper mainly discusses SiC crystal growth in the graphite crucible with several geometrical structures by using the physical vapor transport method to investigate the influence of graphite crucible structures on SiC crystal diameter enlargement. Metallographic microscopy and X-ray diffraction are applied to the obtained cross-sectional slice of SiC ingot. In a growth run with a crucible structure of cylinder platform seed-holder and additional cone-shaped inner furnace close to the seed crystal, the SiC crystal diameter increases only 4–5 mm and the growth front exhibits a smooth segment of spherical shape; but the diameter of SiC single crystal decreases when the inside diameter of the crucible is close to that of the seed crystal and the angle α between the cone-shaped platform and cylinder platform is larger than 20°. When using the crucible with a cone-shaped platform seed-holder and cone-shaped inner wall, the SiC crystal growth will proceed along the axial direction as well as the radial direction, and the diameter can be enlarged by about 12 mm in a single growth run.
Experimental investigation of the Zn–Fe–V system at 450°C
Authors: Wu Changjun , Su Xuping , Liu Daniel , Wang Xinming , Yin Fucheng , Zhu Zhongxi , Li Zhi
Published: December 2010

The 450°C isothermal section of the ZnüFeüV ternary phase diagram has been determined experimentally using X-ray diffraction and scanning electron microscopy coupled with energy/wave dispersive spectroscopy. A new ternary compound T, containing 1.4 to 4.5 at.% V, 5.6 to 15.5 at.% Fe and 82.3 to 92.2 at.% Zn, was positively identified for the first time in this study. The existence of the rphase, together with two ZnüV compounds, VZn3 and V4Zn5, at 450°C has been confirmed. Fe has no detectable solubility in ZnüV compounds. But it was proved that about 3.0 at.% Zn can dissolve into α-V at 450°C. Experimental results indicated that the maximum solubility of V in d, γ1, and γ was 0.5 at.%, 1.3 at.% and 1.8 at.% respectively, whereas that in ζ was less than 0.2 at.%.
Thermal and chemical stability of Cr2AlC in contact with α-Al2O3and NiAl
Authors: Hajas David E. , Scholz Mirjam , Ershov Sergey , Hallstedt Bengt , Palmquist Jens-Petter , Schneider Jochen M.
Published: December 2010

The thermal and chemical stability of Cr2AlC, Cr2AlC–NiAl and Cr2AlC–α-Al2O3have been studied. No enthalpic effects indicating phase transformations or chemical reactions were observed for the Cr2AlC–α-Al2O3powder mixtures at T < 1476°C, while a melting onset temperature of 1310°C was measured for the Cr2AlC–NiAl powder mixture by differential thermal analysis. However, the formation of chromium carbide is also predicted to occur below this temperature based on our thermodynamic calculations, and was observed by X-ray diffraction of powders annealed at 1000 and 1300°C. The carbide formation is caused by the reaction of Cr2AlC with NiAl and can be understood by considering the large solid solution range of Al in NiAl. These results indicate that the application potential of Cr2AlC–NiAl composites is limited by the Al solubility in the NiAl.
Progress in chemistry modelling for vapour and aerosol transport analyses
Authors: Kaye Matthew H. , Kissane Martin P. , Mason PaulK.
Published: December 2010

The ASTEC/Sophaeros computer code has been developed to model transport of reactive gases and aerosols in pipe flows with extensive coverage of chemical and physical phenomena. As part of the ASTEC severe-accident code co-developed by IRSN in France and GRS (Gesellschaft für Anlagen- und Reaktorsicherheit) in Germany, it is principally used to evaluate so-called radioactive source terms released to the environment in the event of potential accidents affecting water-cooled nuclear reactors. A major uncertainty in the past concerned the impact of chemistry on radioactivity transfer where the treatment of chemical phenomena was recognized as inadequate. Work described here, involving mainly systematic identification of relevant species and thermodynamic- data verification, has vastly improved this situation leading in particular to creation of a comprehensive database with fully-referenced sources of information. Further prospective improvements in this area are described.