The Voluntary Adjustment of Railroad Obligations

Automatic memory management techniques eliminate many programming errors that are both hard to find and to correct. However, these techniques are not yet used in embedded systems with hard realtime applications. The reason is that current methods for automatic memory management have a number of drawbacks. The two major ones are: (1) not being able to always guarantee short real-time deadlines and (2) using large amounts of extra memory. Memory is usually a scarce resource in embedded applications. In this paper we present a new technique, Real-Time Reference Counting (RTRC) that overcomes the current problems and makes automatic memory management attractive also for hard real-time applications. The main contribution of RTRC is that often all memory can be used to store live objects. This should be compared to a memory overhead of about 500% for garbage collectors based on copying techniques and about 50% for garbage collectors based on mark-and-sweep techniques

Simulation and life cycle assessment of algae gasification process in dual fluidized bed gasifiers

We present simulation results for the production of algae-derived syngas using dual fluidized bed (DFB) gasifiers.Part of this work was funded by the Technology Strategy Board (TSB) grant programme, “Carbon Abatement Technologies, Phase 2 competition for collaborative R&D and feasibility”, Grant No. TS/J004553. MK acknowledges support by the Singapore National Research Foundation under its Campus for Research Excellence And Technological Enterprise (CREATE) program.This is the accepted manuscript. The final version is available at http://pubs.rsc.org/en/Content/ArticleLanding/2015/GC/c4gc01698j#!divAbstract

The impact of delayed development on the quality of life of adults with end-stage renal disease since childhood

Little is known about the impact of the course of life of children with end-stage renal disease (ESRD) on their quality of life in adulthood. We therefore assessed the course of life of adult patients with onset of ESRD at an age of <15 years between 1972 and 1992 and compared it with that of the general population. Furthermore, we explored how course of life is associated with quality of life (QoL) in young adulthood. A total of 75 young adult patients who had had ESRD since childhood, aged between 20 years and 30 years, completed the RAND-36 Health Survey and a questionnaire, which retrospectively assesses the achievement of development milestones. Patients achieved fewer milestones than peers with respect to autonomy, social, and psycho-sexual development, and displayed less risk behaviour. Patients who achieved fewer social milestones while growing up experienced more emotional problems and less vitality, and they had a lesser overall mental quality of life. Paediatric nephrologists should pay more attention to the development of social and independent functioning of children with ESRD in order to prepare them for active participation in society in adult life. © IPNA 2006

Insect pathogens as biological control agents: back to the future

The development and use of entomopathogens as classical, conservation and augmentative biological control agents have included a number of successes and some setbacks in the past 15 years. In this forum paper we present current information on development, use and future directions of insect-specific viruses, bacteria, fungi and nematodes as components of integrated pest management strategies for control of arthropod pests of crops, forests, urban habitats, and insects of medical and veterinary importance. Insect pathogenic viruses are a fruitful source of MCAs, particularly for the control of lepidopteran pests. Most research is focused on the baculoviruses, important pathogens of some globally important pests for which control has become difficult due to either pesticide resistance or pressure to reduce pesticide residues. Baculoviruses are accepted as safe, readily mass produced, highly pathogenic and easily formulated and applied control agents. New baculovirus products are appearing in many countries and gaining an increased market share. However, the absence of a practical in vitro mass production system, generally higher production costs, limited post application persistence, slow rate of kill and high host specificity currently contribute to restricted use in pest control. Overcoming these limitations are key research areas for which progress could open up use of insect viruses to much larger markets. A small number of entomopathogenic bacteria have been commercially developed for control of insect pests. These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest insects of crops and forests, and B. thuringiensis sub-species israelensis and L. sphaericus are the primary pathogens used for medically important pests including dipteran vectors,. These pathogens combine the advantages of chemical pesticides and microbial control agents (MCAs): they are fast acting, easy to produce at a relatively low cost, easy to formulate, have a long shelf life and allow delivery using conventional application equipment and systemics (i.e. in transgenic plants). Unlike broad spectrum chemical pesticides, B. thuringiensis toxins are selective and negative environmental impact is very limited. Of the several commercially produced MCAs, B. thuringiensis (Bt) has more than 50% of market share. Extensive research, particularly on the molecular mode of action of Bt toxins, has been conducted over the past two decades. The Bt genes used in insect-resistant transgenic crops belong to the Cry and vegetative insecticidal protein families of toxins. Bt has been highly efficacious in pest management of corn and cotton, drastically reducing the amount of broad spectrum chemical insecticides used while being safe for consumers and non-target organisms. Despite successes, the adoption of Bt crops has not been without controversy. Although there is a lack of scientific evidence regarding their detrimental effects, this controversy has created the widespread perception in some quarters that Bt crops are dangerous for the environment. In addition to discovery of more efficacious isolates and toxins, an increase in the use of Bt products and transgenes will rely on innovations in formulation, better delivery systems and ultimately, wider public acceptance of transgenic plants expressing insect-specific Bt toxins. Fungi are ubiquitous natural entomopathogens that often cause epizootics in host insects and possess many desirable traits that favor their development as MCAs. Presently, commercialized microbial pesticides based on entomopathogenic fungi largely occupy niche markets. A variety of molecular tools and technologies have recently allowed reclassification of numerous species based on phylogeny, as well as matching anamorphs (asexual forms) and teleomorphs (sexual forms) of several entomopathogenic taxa in the Phylum Ascomycota. Although these fungi have been traditionally regarded exclusively as pathogens of arthropods, recent studies have demonstrated that they occupy a great diversity of ecological niches. Entomopathogenic fungi are now known to be plant endophytes, plant disease antagonists, rhizosphere colonizers, and plant growth promoters. These newly understood attributes provide possibilities to use fungi in multiple roles. In addition to arthropod pest control, some fungal species could simultaneously suppress plant pathogens and plant parasitic nematodes as well as promote plant growth. A greater understanding of fungal ecology is needed to define their roles in nature and evaluate their limitations in biological control. More efficient mass production, formulation and delivery systems must be devised to supply an ever increasing market. More testing under field conditions is required to identify effects of biotic and abiotic factors on efficacy and persistence. Lastly, greater attention must be paid to their use within integrated pest management programs; in particular, strategies that incorporate fungi in combination with arthropod predators and parasitoids need to be defined to ensure compatibility and maximize efficacy. Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis are potent MCAs. Substantial progress in research and application of EPNs has been made in the past decade. The number of target pests shown to be susceptible to EPNs has continued to increase. Advancements in this regard primarily have been made in soil habitats where EPNs are shielded from environmental extremes, but progress has also been made in use of nematodes in above-ground habitats owing to the development of improved protective formulations. Progress has also resulted from advancements in nematode production technology using both in vivo and in vitro systems; novel application methods such as distribution of infected host cadavers; and nematode strain improvement via enhancement and stabilization of beneficial traits. Innovative research has also yielded insights into the fundamentals of EPN biology including major advances in genomics, nematode-bacterial symbiont interactions, ecological relationships, and foraging behavior. Additional research is needed to leverage these basic findings toward direct improvements in microbial control

A virtual laboratory to support chemical reaction engineering courses using real-life problems and industrial software

A virtual laboratory has been developed to support chemical reaction engineering courses. Real-life engineering challenges that are difficult to address in a university laboratory give the opportunity to illustrate basic concepts of chemical reaction engineering such as the relationship between temperature and reaction rate, space time and conversion, and inert concentration and selectivity. Six virtual experiments covering topics from petroleum refining, diesel combustion, nanoparticle growth, and hydrogen combustion form the basis of the virtual laboratory. The characteristics embedded in the experiments include the use of economic analysis to give closure to open-ended problems, the solution of engineering problems with high environmental relevance and finally, the ability to solve complex engineering problems related to state-of-the-art technologies, for example the synthesis of functionalized nanoparticles. Trial tests with senior students, with continual feedback and freedom in terms of the delivery date were used to evaluate and improve the experiments. Subsequently, a classroom test with 45 undergraduate students with a fixed deadline was performed. The challenges and opportunities to use virtual experiments supported by industrial software to teach real-life problems to undergraduate students have been critically assessed

Automated advanced calibration and optimization of thermochemical models applied to biomass gasification and pyrolysis

This paper presents a methodology that combines physicochemical modeling with advanced statistical analysis algorithms as an efficient workflow, which is then applied to the optimization and design of biomass pyrolysis and gasification processes. The goal was to develop an automated flexible approach for the analyses and optimization of such processes. The approach presented here can also be directly applied to other biomass conversion processes and, in general, to all those processes for which a parametrized model is available. A flexible physicochemical model of the process is initially formulated. Within this model, a hierarchy of sensitive model parameters and input variables (process conditions) is identified, which are then automatically adjusted to calibrate the model and to optimize the process. Through the numerical solution of the underlying mathematical model of the process, we can understand how species concentrations and the thermodynamic conditions within the reactor evolve for the two processes studied. The flexibility offered by the ability to control any model parameter is critical in enabling optimization of both efficiency of the process as well as its emissions. It allows users to design and operate feedstock-flexible pyrolysis and gasification processes, accurately control product characteristics, and minimize the formation of unwanted byproducts (e.g., tar in biomass gasification processes) by exploiting various productivity-enhancing simulation techniques, such as parameter estimation, computational surrogate (reduced order model) generation, uncertainty propagation, and multi-response optimization

Distributed Operating Systems

Distributed operating systems have many aspects in common with centralized ones, but they also differ in certain ways. This paper is intended as an introduction to distributed operating systems, and especially to current university research about them. After a discussion of what constitutes a distributed operating system and how it is distinguished from a computer network, various key design issues are discussed. Then several examples of current research projects are examined in some detail, namely, the Cambridge Distributed Computing System, Amoeba, V, and Eden. © 1985, ACM. All rights reserved

Parameterisation of a biodiesel plant process flow sheet model

© 2016 Elsevier Ltd This paper presents results of parameterisation of typical input–output relations within process flow sheet of a biodiesel plant and assesses parameterisation accuracy. A variety of scenarios were considered: 1, 2, 6 and 11 input variables (such as feed flow rate or a heater's operating temperature) were changed simultaneously, 3 domain sizes of the input variables were considered and 2 different surrogates (polynomial and high dimensional model representation (HDMR) fitting) were used. All considered outputs were heat duties of equipment within the plant. All surrogate models achieved at least a reasonable fit regardless of the domain size and number of dimensions. Global sensitivity analysis with respect to 11 inputs indicated that only 4 or fewer inputs had significant influence on any one output. Interaction terms showed only minor effects in all of the cases.This project is funded by the National Research Foundation (NRF), Prime Minister's Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme