Automated Dynamic Error Analysis Methods for Optimization of Computer Arithmetic Systems

Computer arithmetic is one of the more important topics within computer science and engineering. The earliest implementations of computer systems were designed to perform arithmetic operations and cost if not all digital systems will be required to perform some sort of arithmetic as part of their normal operations. This reliance on the arithmetic operations of computers means the accurate representation of real numbers within digital systems is vital, and an understanding of how these systems are implemented and their possible drawbacks is essential in order to design and implement modern high performance systems. At present the most widely implemented system for computer arithmetic is the IEEE754 Floating Point system, while this system is deemed to the be the best available implementation it has several features that can result in serious errors of computation if not implemented correctly. Lack of understanding of these errors and their effects has led to real world disasters in the past on several occasions. Systems for the detection of these errors are highly important and fast, efficient and easy to use implementations of these detection systems is a high priority. Detection of floating point rounding errors normally requires run-time analysis in order to be effective. Several systems have been proposed for the analysis of floating point arithmetic including Interval Arithmetic, Affine Arithmetic and Monte Carlo Arithmetic. While these systems have been well studied using theoretical and software based approaches, implementation of systems that can be applied to real world situations has been limited due to issues with implementation, performance and scalability. The majority of implementations have been software based and have not taken advantage of the performance gains associated with hardware accelerated computer arithmetic systems. This is especially problematic when it is considered that systems requiring high accuracy will often require high performance. The aim of this thesis and associated research is to increase understanding of error and error analysis methods through the development of easy to use and easy to understand implementations of these techniques

Microfluidics-based observations to monitor dynamic processes occurring in food emulsions and foams

Food design is often done based on a trial-and-error basis, using structure properties as an indicator of product quality. Although this has led to many good products in the market, this ‘cook and look’ approach could benefit from insights into dynamic processes as they occur during food formation, storage, and digestion. Currently microfluidic devices are being developed to allow these types of observations, and here we show the latest examples in the field of emulsions and foams, including effects that occur during digestion. We expect that these techniques will supply a stepping stone to thorough understanding at various length and timescales that are all instrumental in designing high-quality food products, and ultimately creating foods with health benefits.</p

Demographic Change in European Towns 2001–11: A Cross-National Multi-Level Analysis

© 2017 Royal Dutch Geographical Society KNAG The unique contribution of this paper is to empirically compare and contrast demographic change in settlements with a population between 5,000 and under 50,000 (defined as towns) across different national urban systems in Europe with common definitions for the first time. The analysis uses a new data set based on harmonised small area data and harmonised morphological definitions of what a town is. The paper hypothesises first that a general model of demographic growth can be applied across national urban systems and secondly that regional demographic change is a significant predictor of demographic change in towns nested within those regions within this generalised model. A fixed effect multi-level regression analysis tests the importance of town-level and regional factors among towns from five national systems but also within two individual national urban systems. The findings suggest that national context still matters and within some national systems, regional context also strongly predicts demographic change in towns

Water Governance in Decentralising Indonesia

Under new democratic regimes in the country of the South, governance innovation is often found at the regional level. This article, using the concept of institutional capacity, shows that powerful efforts affecting regional water resource coordination emerge locally. The paper analyzes fresh water cooperation in the urban region of Cirebon, Indonesia. It is shown that city and their surrounding regions in decentralizing Indonesia show signs of increasing institutional capacity between local actors. An informal approach and discretionary local decision-making, influenced by logic of appropriateness and tolerance are influential. At the same time, these capacities are compromised by significant inequality and a unilateral control of water resources, and they are being challenged by a strong authoritarian political culture inherited from a history of centralized government. The paper points to the need to establish greater opportunities for water governance at the regional level to transcend inter-local rivalry, and thus improve decentralized institutional capacity further

Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture

Carbon dioxide (CO2) emitted from conventional coal-based power plants is a growing concern for the environment. Chemical looping combustion (CLC), pre-combustion and oxy-fuel combustion are promising CO2 capture technologies which allow clean electricity generation from coal in an integrated gasification combined cycle (IGCC) power plant. This work compares the characteristics of the above three capture technologies to those of a conventional IGCC plant without CO2 capture. CLC technology is also investigated for two different process configurations—(i) an integrated gasification combined cycle coupled with chemical looping combustion (IGCC–CLC), and (ii) coal direct chemical looping combustion (CDCLC)—using exergy analysis to exploit the complete potential of CLC. Power output, net electrical efficiency and CO2 capture efficiency are the key parameters investigated for the assessment. Flowsheet models of five different types of IGCC power plants, (four with and one without CO2 capture), were developed in the Aspen plus simulation package. The results indicate that with respect to conventional IGCC power plant, IGCC–CLC exhibited an energy penalty of 4.5%, compared with 7.1% and 9.1% for pre-combustion and oxy-fuel combustion technologies, respectively. IGCC–CLC and oxy-fuel combustion technologies achieved an overall CO2 capture rate of ∼100% whereas pre-combustion technology could capture ∼94.8%. Modification of IGCC–CLC into CDCLC tends to increase the net electrical efficiency by 4.7% while maintaining 100% CO2 capture rate. A detailed exergy analysis performed on the two CLC process configurations (IGCC–CLC and CDCLC) and conventional IGCC process demonstrates that CLC technology can be thermodynamically as efficient as a conventional IGCC process

Heat Resistance Mediated by pLM58 Plasmid-Borne ClpL in Listeria monocytogenes

Listeria monocytogenes is one of the most heat-resistant non-sporeforming food-borne pathogens and poses a notable risk to food safety, particularly when mild heat treatments are used in food processing and preparation. While general heat stress properties and response mechanisms of L. monocytogenes have been described, accessory mechanisms providing particular L. monocytogenes strains with the advantage of enhanced heat resistance are unknown. Here, we report plasmidmediated heat resistance of L. monocytogenes for the first time. This resistance is mediated by the ATP-dependent protease ClpL. We tested the survival of two wildtype L. monocytogenes strains-both of serotype 1/2c, sequence type ST9, and high sequence identity-at high temperatures and compared their genome composition in order to identify genetic mechanisms involved in their heat survival phenotype. L. monocytogenes AT3E was more heat resistant (0.0 CFU/ml log(10) reduction) than strain AL4E (1.4 CFU/ml log(10) reduction) after heating at 55 degrees C for 40 min. A prominent difference in the genome compositions of the two strains was a 58-kb plasmid (pLM58) harbored by the heat-resistant AT3E strain, suggesting plasmid-mediated heat resistance. Indeed, plasmid curing resulted in significantly decreased heat resistance (1.1 CFU/ml log(10) reduction) at 55 degrees C. pLM58 harbored a 2,115-bp open reading frame annotated as an ATP-dependent protease (ClpL)-encoding clpL gene. Introducing the clpL gene into a natively heat-sensitive L. monocytogenes strain (1.2 CFU/ml log(10) reduction) significantly increased the heat resistance of the recipient strain (0.4 CFU/ml log(10) reduction) at 55 degrees C. Plasmid-borne ClpL is thus a potential predictor of elevated heat resistance in L. monocytogenes. IMPORTANCE Listeria monocytogenes is a dangerous food pathogen causing the severe illness listeriosis that has a high mortality rate in immunocompromised individuals. Although destroyed by pasteurization, L. monocytogenes is among the most heat-resistant non-spore-forming bacteria. This poses a risk to food safety, as listeriosis is commonly associated with ready-to-eat foods that are consumed without thorough heating. However, L. monocytogenes strains differ in their ability to survive high temperatures, and comprehensive understanding of the genetic mechanisms underlying these differences is still limited. Whole-genome-sequence analysis and phenotypic characterization allowed us to identify a novel plasmid, designated pLM58, and a plasmid-borne ATP-dependent protease (ClpL), which mediated heat resistance in L. monocytogenes. As the first report on plasmid-mediated heat resistance in L. monocytogenes, our study sheds light on the accessory genetic mechanisms rendering certain L. monocytogenes strains particularly capable of surviving high temperatures-with plasmid-borne ClpL being a potential predictor of elevated heat resistance.Peer reviewe

Exergy analysis of energy-intensive production processes: advancing towards a sustainable chemical industry

Exergy analysis is becoming a very powerful strategy to evaluate the real efficiency of a process. Its application in the chemical industry is still at an early stage but many interesting remarks can be obtained from the recent research in the most energy intensive processes of the chemical industry: the production of chemicals, the cement industry, the paper industry and, the iron and steel industry. The present review analyzes the opportunities and challenges in those sectors by considering exergy analyses as the first required step (although not sufficient) to advance towards a more sustainable chemical industry. Social, environmental and economic factors play a role in the critical evaluation of a process and exergy could be considered as the property that joins together those three cores of sustainability