Life Cycle Of Components Research Articles

Is there an environmental advantage of using magnesium components for light-weighting cars?

Light-weighting of automobiles has been a key issue for reasons of meeting stringent requirements on greenhouse gas (GHG) emissions. Weight reduction in cars can be achieved by design optimisation and/or direct substitution of heavier steel components with lighter metals. In respect to direct substitution, aluminium alloys are widely used and accepted by the industry, though magnesium is lighter than aluminium and has superior casting properties that make it attractive. This apparent advantage of using magnesium has to be assessed in light of the environmental burden created in the entire life cycle of the magnesium component, including the fuel savings in the use stage. This study reports on such an assessment, using lifecycle assessment (LCA) of an engine block (EB) that can be substituted for light-weighting. At each stage of production, the impact of adopting more sustainable technologies (such as the use of low-impact cover gas for protecting magnesium melt from oxidation in place of high-impact sulphur hexafluoride) are taken into account. The environmental performance of the magnesium EB is compared with functionally equivalent blocks made from aluminium and conventional cast iron and the new compacted graphite iron (CGI).

The experimental study for the solder joint reliability of high I/O FCBGAs with thermal loaded bend test

In this study, the reliability of flip-chip ball-grid array package (FCBGA) is explored by a cyclic four-point bend test executed at different controlled temperature. The test vehicle is put in a heated chamber and the resulting daisy chain resistance and strains variations are monitored to check its failure. The strain gauges are mounted near the component corners to get the strains of the test boards when under bending. A data logger records the daisy chain resistance simultaneously during the test. The component failure is detected with a self-written program by judging when the failure resistance of the daisy chain is larger than 20% of its initial resistance. The test results at various temperatures showed that the component life cycle is reduced with the increase of the temperature during the cyclic bend test when under a fixed maximum deflection setting. If tested at room temperature by varying the maximum deflections, the component life cycle is also reduced with the increase of the maximum deflection in the cyclic bend test. Through the fitted curve of all these test data, it is then possible to get relating equations among the variables of temperature, deflection, and life cycle. An extra test is conducted to verify these deduced equations with an error of only 6% approximately. Furthermore, the optic microscope is utilized to observe the failure mode of the FCBGA component after the test. It is found that all the failures are the delamination at the interface of solder balls and substrate. Also, from the results of tested curves, it can be used to predict the component life cycle at elevated temperatures based on the results tested at room temperature.

DETECTION OF DENSITY DEPENDENCE REQUIRES DENSITY MANIPULATIONS AND CALCULATION OF λ

To investigate density-dependent population regulation in the perennial bunchgrass Bouteloua rigidiseta, we experimentally manipulated density by removing adults or adding seeds to replicate quadrats in a natural population for three annual intervals. We monitored the adjacent control quadrats for 14 annual intervals. We constructed a population projection matrix for each quadrat in each interval, calculated lambda, and did a life table response experiment (LTRE) analysis. We tested the effects of density upon lambda by comparing experimental and control quadrats, and by an analysis of the 15-year observational data set. As measured by effects on lambda and on N(t+1/Nt in the experimental treatments, negative density dependence was strong: the population was being effectively regulated. The relative contributions of different matrix elements to treatment effect on lambda differed among years and treatments; overall the pattern was one of small contributions by many different life cycle stages. In contrast, density dependence could not be detected using only the observational (control quadrats) data, even though this data set covered a much longer time span. Nor did experimental effects on separate matrix elements reach statistical significance. These results suggest that ecologists may fail to detect density dependence when it is present if they have only descriptive, not experimental, data, do not have data for the entire life cycle, or analyze life cycle components separately.

The Importance of Being Mature: the Effect of Demographic Maturation on Global Per-Capita Gdp

Given that savings behaviour and worker productivity have strong life-cycle components and given that demographic profiles vary across countries, population age structure should be linked to differences in levels of economic development. In this paper we measure the economic importance of age structure variation for the global economy. We find that even after adjusting for country-specific effects, demographic maturation has been associated with nearly half of the evolution of global per-capita GDP since 1960. We also find that age structure differences can account for just over half of the variation in worldwide per capita GDP (i.e. the lack of sigma convergence) observed since 1960. Taken as a whole, these results complement recent theoretical and empirical work on the importance of population size and economic development and reinforce empirical work linking mature demographic age structures with faster cross-country economic growth rates. JEL Classification: J13, J22, J24, O11, O40

The Effects of Dispersal Gradient and Pathogen Life Cycle Components on Epidemic Velocity in Computer Simulations

ABSTRACT The velocity of expansion of focal epidemics was studied using an updated version of the simulation model EPIMUL, with model parameters relevant to wheat stripe rust. The modified power law, the exponential model, and Lambert's general model were fit to primary disease gradient data from an artificially initiated field epidemic of stripe rust and employed to describe dispersal in simulations. The exponential model, which fit the field data poorly (R (2) = 0.728 to 0.776), yielded an epidemic that expanded as a traveling wave (i.e., at a constant velocity), after an initial buildup period. Both the modified power law and the Lambert model fit the field data well (R(2) = 0.962 to 0.988) and resulted in dispersive epidemic waves (velocities increased over time for the entire course of the epidemic). The field epidemic also expanded as a dispersive wave. Using parameters based on the field epidemic and modified power law dispersal as a baseline, life cycle components of the pathogen (lesion growth rate, latent period, infectious period, and multiplication rate) and dispersal gradient steepness were varied within biologically reasonable ranges for this disease to test their effect on dispersive wave epidemics. All components but the infectious period had a strong influence on epidemic velocity, but none changed the general pattern of velocity increasing over time.

Modeling tensile response and flow localization effects in 316SS after exposure to spallation and fission irradiation environments

The mechanical stability of structural materials under irradiation is a major concern for reactor component design and life cycle evaluation. The most important issue is the loss of ductility due to the development of radiation damage defect structures in the material. The acute loss of material tensile ductility is often characterized by a process where the material necks at very low uniform elongations in tensile loading, just following the yield point, a process commonly referred to as flow localization. The process where small tensile strains lead to plastic instability is examined through the analysis of tensile test data for 316SS irradiated either in a fission neutron spectrum or in a mixed proton and neutron spectrum characteristic of spallation sources. In both cases, it is found that uniform elongation levels are limited by a critical material strength. It is shown that there is a direct correlation between the material yield strength and the uniform elongation for the materials examined here. It is also shown that the large differences in He and H production between the two kinds of radiation environments have little or no effect on tensile properties. A further implication of the work is that the specifics of the post-yield flow and strain hardening processes are less important than the critical stress for determining the onset of plastic instability.

Measuring Availability Indexes With Small Samples for Component and Network Reliability Using the Sahinoglu–Libby Probability Model

With the advances in pervasive computing and wireless networks, the quantitative measurements of component and network availability have become a challenging task, especially in the event of often encountered insufficient failure and repair data. It is well recognized that the Forced Outage Ratio (FOR) of an embedded hardware component is defined as the failure rate divided by the sum of the failure and the repair rates; or FOR is the operating time divided by the total exposure time. However, it is also well documented that FOR is not a constant but is a random variable. The probability density function (pdf) of the FOR is the Sahinoglu-Libby (SL) probability model, named after the originators if certain underlying assumptions hold. The SL pdf is the generalized three-parameter Beta distribution (G3B). The failure and repair rates are taken to be the generalized Gamma variables where the corresponding shape and scale parameters, respectively, are not identical. The SL model is shown to default to that of a standard two-parameter Beta pdf when the shape parameters are identical. Decision Theoretic (Bayesian) solutions are employed to compute small-sample Bayesian estimators by using informative and noninformative priors for the component failure and repair rates with respect to three definitions of loss functions. These estimators for component availability are then propagated to calculate the network expected input-output or source-target (s-t) availability for four different fundamental networks given as examples. The proposed method is superior to using a deterministic way of estimating availability simply by dividing total up-time by exposure time. Various examples will illustrate the validity of this technique to avoid over- or underestimation of availability when only small samples or insufficient data exist for the historical lifecycles of components and networks.

Component-based Development Process and Component Lifecycle

In recent years component-based development has become an established approach. Component-based Software Engineering (CBSE) that deals with the entire lifecycle of component-based products has been focused on technologies related to design and implementation of software components and systems built from software components. The experience has shown that pure technologies alone are not enough. A CBSE approach requires certain changes in development and life cycle processes. However, very few CBSE works, either research or practical, have addressed these topics. This paper describes principle differences of component-based and non- component based processes. Also we give an overview of a case study from a company that applies component-based approach.

Bad Health Informatics Can Kill – Is Evaluation the Answer?

Health care is entering the age of information society. It is evident that the use of modern information and communication technology (ICT) offers tremendous opportunities to improve health care. However, there are also hazards associated with ICT in health care. We want to present an overview of typical hazards associated with ICT in health care, and to discuss how ICT evaluation can be a solution. We analyze examples of failures and problems associated with ICT in health care. This collection is also made available on a website. Systematic, continuous evaluation of quality and effects of ICT during the whole life cycle of ICT components seems to be one important approach to detect and prevent possible ICT hazards and failures, supporting a higher quality of patient care. However, empirical studies proving this assumption are needed.

Komponento specifikacijos formalizavimas

This paper deals with the component specification and formalisation problems. It defines the notion of component model, gives the formalised concept of a component, compound component, and proposes to use hierarchical finite state machines as the formalism to specify component's life cycle.

An Infrastructure for Open Service Architectures in MMM Industries

The business opportunities in after-sales services such as condition based maintenance were noticed by many vendors of process and automation equipment before adequate standards and architectures became available. Consequently, at a client’s premises there are many units of process equipment, software modules and Internet connections that have been installed by different vendors, and this uncoordinated work has created serious interoperability, maintainability and security problems. This paper proposes an open standards-based service architecture for condition based maintenance that supports interoperability, software component lifecycle management and secure execution and communication of components in a multi-vendor environment. Copyright© 2004 IFAC

Myco-heterotroph-fungus marriages - is fidelity over-rated?

Myco-heterotroph-fungus marriages - is fidelity over-rated?

6.4.3 Risk Informed Design for System Life Cycle

AbstractMany facilty life cycle activities including design, construction, fabrication, inspection and maintenance are evolving from a deterministic to a risk‐informed basis. The risk informed approach uses probabilistic methods to evaluate the contribution of individual system components to total system performance. Total system performance considers both safety and cost considerations including system failure, reliability, and availability. By necessity, a risk‐informed approach considers both the component's life cycle and the life cycle of the system.In the nuclear industry, risk‐based approaches, namely probabilistic risk assessment (PRA) or probabilistic safety assessment (PSA), have become a standard tool used to evaluate the safety of nuclear power plants. Recent studies pertaining to advanced reactor development have indicated that these new power plants must provide improved safety over existing nuclear facilities and be cost‐competitive with other energy sources. Risk‐based approaches, beyond traditional PRA, offer the opportunity to optimize design while considering the total life cycle of the plant in order to realize these goals.The use of risk‐based design approaches in the nuclear industry is only beginning, with recent promulgation of risk‐informed regulations and proposals for risk‐based codes. This paper briefly summarizes the current state of affairs regarding the use of risk‐based approaches in design. Key points to fully realize the benefit of applying a risk‐based approach to nuclear power plant design are then presented and illustrated in a case study. These points are equally applicable to non‐nuclear facilities where optimization for cost competitiveness and/or safety is desired.

Service components for managing the life-cycle of service compositions

Web services are becoming the prominent paradigm for distributed computing and electronic business. This has raised the opportunity for service providers and application developers to develop value-added services by combining existing web services. However, current web service composition solutions do not address software engineering principles for raising the level of abstraction in web-services by providing facilities for packaging, re-using, specializing and customizing service compositions. In this paper we propose the concept of service component that packages together complex services and presents their interfaces and operations in a consistent and uniform manner in the form of an abstract class definition. Service components are internally synthesized out of reused, specialized, or extended complex web services and just like normal web services are published and can thus be invoked by any service-based application. In addition, we present an integrated framework and prototype system that manage the entire life-cycle of service components ranging from abstract service component definition, scheduling, and construction to execution.

Impact of ice microphysics on multiscale organization of tropical convection in two-dimensional cloud-resolving simulations

This paper documents the impact of ice microphysics on the multiscale organization of tropical convection as simulated in two-dimensional cloud-resolving model simulations. Results from simulations which apply warm-rain microphysics are compared with results from a simulation which includes ice processes presented previously in this journal. In these simulations, moist convection and large-scale dynamics interact on an unprecedented range of spatial and temporal scales, albeit within a limited two-dimensional dynamical framework. In general, the large-scale organization of convection is similar in all simulations, although the scale and propagation speed of convectively-coup led gravity waves are different between the warm-rain and ice simulations. The most striking differences are on the mesoscale. The warm-rain simulations feature mesoscale convective systems with a reduced stratiform component and shorter life cycle than mesoscale systems in the simulation with ice microphysics. These impacts are consistent with previous modelling studies of the impact of ice microphysics on organized convection. It is hypothesized that the shorter life cycle of mesoscale convective systems in warm-rain simulations influences scale selection of the large-scale convectively-coup led gravity waves. Moreover, the vertical transport of horizontal momentum is affected as well. To the author's knowledge this is the first time the impact of cloud microphysics on mesoscale convective systems is shown to affect the coupling between deep convection and large-scale perturbations in the tropics. Copyright © 2003 Royal Meteorological Society

A Formal Composition and Interaction Model for a Web Component Platform

A framework for components on the Web needs a formal model that captures essential concepts such as contractual information and service matching. We propose a typed π-calculus-based model for Web components that formalises an extension of the currently discussed Web Services framework. We address in particular activities in the stages of a component life cycle – such as matching, commitment, connection and interaction – that are part of the process that a component is involved in.

The range of insect dormancy responses

Insect dormancy responses, in the broad sense of modifications of development, are examined from a general perspective. The range of responses is extraordinarily wide because environments are diverse, different taxa have different evolutionary histories, adaptations are needed for both seasonal timing and resistance to adversity, and not only development but also many other aspects of the life-cycle must be coordinated. Developmental options are illustrated by examining the wide range of ways in which development can be modified, the fact that each individual response consists of several components, and the different potential durations of the life-cycle. The concepts of alternative life-cycle pathways (chosen according to current and likely future environmental conditions) and of active and passive default responses are treated. Also introduced are aspects of variation and trade-offs.Some general conclusions that help in understanding dormancy responses emerge from such an examination. Many options are available (cf. Table 1). The nature of the habitat, especially its predictability, determines the potential effectiveness of many of the developmental options. Any particular set of responses reflects evolutionary history and hence depends on past as well as current environments. It is not necessarily obvious what kinds of selection, especially requirements for timing versus resistance to adversity, explain a particular life cycle. Life-cycle pathways have multiple components, so that components cannot be analyzed in isolation. A given feature, such as delayed development, can have multiple roles. Default responses can be either active (development continues unless signalled otherwise) or passive (development stops unless signalled otherwise), making necessary a broad approach to understanding the action of environmental cues. Even relatively minor effects that fine-tune dormancy responses enhance survival, but may be difficult to detect or measure. Trade-offs are not inevitable, not only when certain resources are surplus, but also because resources in very short supply (constraints) cannot be traded off. Life-cycle components are widely, but not universally, coordinated. These conclusions confirm that the range of dormancy responses is wider, more complex and more integrated than has often been recognized.

Degradation of nylon-6/clay nanocomposites in NO x

Nylon-6 is an important engineering polymer that, in its fully spherulitic (bulk) form, has many applications in gears, rollers, and other long life cycle components. In 1993, Toyota commercialized a nylon-6/clay nanocomposite out of which it produced the timing belt cover for the Camry. Although these hybrid nanocomposites show significant improvements in their mechanical response characteristics, including yield strength and heat distortion temperature, little is known about the degradation of these properties due to environmental pollutants like NO x . Nylon-6 fibers are severely degraded by interaction with NO x and other pollutants, showing a strong synergy between applied load and environmental degradation. While the nanocomposites show a significant reduction in permeability of gases and water due to the incorporation of lamellar clay, their susceptibility to nondiffusional mechano-chemical degradation is unknown. The fracture toughness of these nylon-6/clay nanocomposites increases, not as a function of clay content, but as a function of the volume of nylon-6 polymer chains influenced by the clay lamellae surfaces. Both the clay and the constrained volume offer the nanocomposites some protection from the deleterious effects of NO x . The time-to-failure at a given stress intensity factor as a function of clay content and constrained volume is discussed along with fracture toughness of the materials.

Global Supply Chain Management in the Telecommunications Industry: The Role of Information Technology in Integration of Supply Chain Entities

In just the past few years, options have been examined for determining optimal operations and logistics strategies for competing in the global market. In terms of advances in technology and globalization of markets, organizations have had to improve their internal processes just to stay competitive. However, as a result of these changes, organizations are determining that these internal improvements were not enough. Where once information technologies allowed businesses to reengineer and streamline their internal business processes - streamlining the global supply chain will require the internal information systems extended beyond a firm's enterprise and include electronic connections between each of the global supply chain partners. An in-depth case study is used to illustrate a broad view of an entire supply chain to reveal full product and component life cycle that not only reveals opportunities for cost reduction but also stimulates revenue growth. It makes the point that organizations must get more involved in the management of their global supply chain network of all upstream firms that provide inputs as well as the network of all downstream firms that provide outputs of the product to the final customer.

Assessment of possible ecological risks and hazards of transgenic fish with implications for other sexually reproducing organisms.

Transgenic technology is developing rapidly; however, consumers and environmentalists remain wary of its safety for use in agriculture. Research is needed to ensure the safe use of transgenic technology and thus increase consumer confidence. This goal is best accomplished by using a thorough, unbiased examination of risks associated with agricultural biotechnology. In this paper, we review discussion on risk and extend our approach to predict risk. We also distinguish between the risk and hazard of transgenic organisms in natural environments. We define transgene risk as the probability a transgene will spread into natural conspecific populations and define hazard as the probability of species extinction, displacement, or ecosystem disruption given that the transgene has spread. Our methods primarily address risk relative to two types of hazards: extinction which has a high hazard, and invasion which has an unknown level of hazard, similar to that of an introduced exotic species. Our method of risk assessment is unique in that we concentrate on the six major fitness components of an organism's life cycle to determine if transgenic individuals differ in survival or reproductive capacity from wild type. Our approach then combines estimates of the net fitness parameters into a mathematical model to determine the fate of the transgene and the affected wild population. We also review aspects of fish ecology and behavior that contribute to risk and examine combinations of net fitness parameters which can lead to invasion and extinction hazards. We describe three new ways that a transgene could result in an extinction hazard: (1) when the transgene increases male mating success but reduces daily adult viability, (2) when the transgene increases adult viability but reduces male fertility, and (3) when the transgene increases both male mating success and adult viability but reduces male fertility. The last scenario is predicted to cause rapid extinction, thus it poses an extreme risk. Although we limit our discussion to aquacultural applications, our methods can easily be adapted to other sexually reproducing organisms with suitable adjustments of terminology.