Techno-economic assessment of fossil fuel power plants with CO2 capture – Results of EU H2-IGCC project

In order to address the ever-increasing demand for electricity, need for security of energy supply, and to stabilize global warming, the European Union co-funded the H₂-IGCC project, which aimed to develop and demonstrate technological solutions for future generation integrated gasification combined cycle (IGCC¹) plants with carbon capture. As a part of the main goal, this study evaluates the performance of the selected IGCC plant with CO₂ capture from a techno-economic perspective. In addition, a comparison of techno-economic performance between the IGCC plant and other dominant fossil-based power generation technologies, i.e. an advanced supercritical pulverized coal (SCPC²) and a natural gas combined cycle (NGCC³), have been performed and the results are presented and discussed here. Different plants are economically compared with each other using the cost of electricity and the cost of CO₂ avoided. Moreover, an economic sensitivity analysis of every plant considering the realistic variation of the most uncertain parameters is given.     

Historical trends in mercury sedimentation and mixing in the Strait of Georgia, Canada

Seventeen sediment cores collected in the Strait of Georgia reveal a history of mercury contamination that began in the 1860s and include episodic contamination during World War II and in the late 1960s. Surface sediment mercury concentrations ranged from 60 to 420 ng/g dry weight and the current fluxes to sediments are estimated at 5-181 ng cm(-2) a(-1). In one location in Port Moody Arm, a Hg spill seems to have sufficiently poisoned the sediments to eliminate biomixing for about 20 years. Although the surface concentration of Hg is likely to decrease at all stations in coming years, sites in the industrialized Vancouver Harbor and Port Moody Arm will continue to be sufficiently contaminated to endanger benthic organisms. Variations in sedimentation and mixing rates among sites result in surface sediment Hg concentration patterns that do not reflect accurately the distribution of Hg flux. In particular, the concentration of Hg in sediments near the mouth of the Fraser River is low, despite the high Hg load of that river, because of dilution by other particles. A preliminary Hg budget indicates that most of the Hg enters the Strait of Georgia via the Fraser River (2090 kg a(-1)), and that, while burial in Strait of Georgia sediments is a major sink (1800 kg a(-1)), there may be a significant outflow of Hg through Juan de Fuca Strait (approximately 3400 kg a(-1)).     

Influence of genotype and protein content on the baking quality of hearth bread

The relationships between protein content and quality and the loaf characteristics of hearth breads made from the respective flours were investigated for 20 wheat genotypes, comprising both commercially grown cultivars and advanced breeding lines, grown in 1997 and 1998. In both years the average protein content was increased by increasing the level of nitrogenous fertiliser application, this effect being more pronounced in 1997 than in 1998. Grain samples were milled and evaluated for endosperm hardness, protein content, SDS sedimentation volume, mixing properties and baking quality determined by a hearth bread baking test using optimal mixing and fixed proving time. When producing hearth bread, both the form (height/width) ratio and loaf volume are critical external characteristics. Genotype differences, mainly due to differences in protein quality, were more important for both form ratio and loaf volume than differences in protein content. The dough development time of the Farinograph, operated at high speed (126 rev min^?1), was the best indicator of heart bread baking quality, giving high positive correlations to both the volume (r = 0.89) and form ratio of the loaf (r = 0.90). Climatic differences between the two years, in particular temperature during ripening, also affected the quality parameters studied. Copyright © 2004 Society of Chemical Industry     

CYP2E1 in Alcoholic and Non-Alcoholic Liver Injury. Roles of ROS,Reactive Intermediates and Lipid Overload

CYP2E1 is one of the fifty-seven cytochrome P450 genes in the human genome and is highly conserved. CYP2E1 is a unique P450 enzyme because its heme iron is constitutively in the high spin state, allowing direct reduction of, e.g., dioxygen, causing the formation of a variety of reactive oxygen species and reduction of xenobiotics to toxic products. The CYP2E1 enzyme has been the focus of scientific interest due to (i) its important endogenous function in liver homeostasis, (ii) its ability to activate procarcinogens and to convert certain drugs, e.g., paracetamol and anesthetics, to cytotoxic end products, (iii) its unique ability to effectively reduce dioxygen to radical species causing liver injury, (iv) its capability to reduce compounds, often generating radical intermediates of direct toxic or indirect immunotoxic properties and (v) its contribution to the development of alcoholic liver disease, steatosis and NASH. In this overview, we present the discovery of the enzyme and studies in humans, 3D liver systems and genetically modified mice to disclose its function and clinical relevance. Induction of the CYP2E1 enzyme either by alcohol or high-fat diet leads to increased severity of liver pathology and likelihood to develop ALD and NASH, with subsequent influence on the occurrence of hepatocellular cancer. Thus, fat-dependent induction of the enzyme might provide a link between steatosis and fibrosis in the liver. We conclude that CYP2E1 has many important physiological functions and is a key enzyme for hepatic carcinogenesis, drug toxicity and liver disease.     

Phase behavior, nucleation and optical properties of the binary system isotactic polypropylene/N,N′,N″-tris-isopentyl-1,3,5-benzene-tricarboxamide

The phase behavior of the binary system consisting of isotactic polypropylene (i-PP) and N,N′,N″-tris-isopentyl-1,3,5-benzene-tricarboxamide (1)—a selected member of a class of novel, versatile ‘designer’ nucleating/clarifying agents—was investigated over the entire additive concentration range by means of differential scanning calorimetry (DSC) and optical microscopy. Experimental phase diagrams were constructed from data obtained in melting and crystallization studies, and a simple monotectic is advanced, very similar to the previously studied binary system i-PP/1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS). In contrast to the latter, the crystallization temperature in the present system i-PP/1 was found to increase to ∼120 °C already at the lowest additive concentration employed and remained constant at further increasing additive concentration. Liquid-liquid phase separation was observed at elevated temperatures for i-PP/1 mixtures comprising more than ∼2 wt% of 1. A study on the optical properties of the i-PP/1 system revealed that the values for haze and clarity of injection-molded plaques progressively decreased and increased, respectively, in the concentration range up to 0.15 wt%. An intermediate region of fairly concentration-independent optical properties was found between 0.15 and 1 wt%, followed by a rapid increase in haze at concentrations exceeding 2 wt%.     

Inelastic transport through molecules: comparing first-principles calculations to experiments

We present calculations of the elastic and inelastic conductance through three different hydrocarbon molecules connected to gold electrodes. Our method is based on a combination of the nonequilibrium Green's function method with density functional theory. Vibrational effects in these molecular junctions were previously investigated experimentally by Kushmerick et al. (Nano Lett. 2004, 4, 639). Our results are in good agreement with the measurements and provide insights into (i) which vibrational modes are responsible for inelastic scattering, (ii) the width of the inelastic electron tunneling signals, and (iii) the mechanisms of heating and cooling of the vibrational modes induced by the coupling to the charge carriers.     

Screening of human antibiotic substances and determination of weekly mass flows in five sewage treatment plants in Sweden

Twelve antibiotic substances for human use, including trimethoprim and representatives of the fluoroquinolone (FQ), sulfonamide (SA), penicillin (PE), cephalosporin (CE), nitroimidazole (NI), tetracycline (TC), and macrolide (MA) groups, were subjected to a screening study at five Swedish sewage treatment plants (STPs) during one week in 2002 and one week in 2003. The analytes were extracted from raw sewage water, final effluent, and sludge by solid-phase extraction (SPE) or liquid-solid extraction (as appropriate) and then identified and quantified by liquid chromatography/tandem mass spectrometry. The mostfrequently detected antibiotics in the matrices considered in this study were norfloxacin, ofloxacin, ciprofloxacin, trimethoprim, sulfamethoxazole, and doxycycline. The other analytes were only detected in a few samples. Analysis of the weekly mass flows through each STP showed that FQs were partly eliminated from the water during sewage water treatment and the highest amounts of these substances were found in sludge. Sulfamethoxazole and trimethoprim were mainly found in raw sewage water and final effluent, but these substances had balancing mass flows, indicating that they too can withstand sewage water treatment. The mass flow patterns for doxycycline were more complex, with high amounts occurring in sludge in some cases, suggesting thatthe behavior of this analyte may be more strongly influenced by the treatment process and other variables at individual STPs. The environmental load (the sum of the amounts in the final effluent and sludge) normalized to the number of inhabitants in the catchment area of each investigated STP compared with theoretical predictions based on consumption data (in parentheses) showed good correlations: norfloxacin, 0.8 (0.9); ofloxacin, 0.3 (0.2); ciprofloxacin, 1.3 (3.5); sulfamethoxazole, 0.2 (0.4); trimethoprim, 1.1 (1.0); and doxycycline, 0.7 (0.4) mg per person per week. The results show that reasonably accurate predictions of environmental load of these antibiotics can be time-effectively derived from consumption data without additional measurements.     

Assessing the effect of hydrocarbon oil type and thickness on a remote sensing signal: A sensitivity study based on the optical properties of two different oil types and the HYMAP and Quickbird sensors

We measured the light absorption properties of two naturally occurring Australian hydrocarbon oils, a Gippsland light crude oil and a North West Shelf light condensate. Using the results from these measurements in conjunction with estimated sensor environmental noise thresholds, the theoretical minimum limit of detectability of each oil type (as a function of oil thickness) was calculated for both the hyperspectral HYMAP and multispectral Quickbird sensors. The Gippsland crude oil is discernable at layer thickness of 20 µm or more in the Quickbird green channel. The HYMAP sensor was found to be theoretically capable of detecting a layer of Gippsland crude oil with a thickness of 10 µm in approximately six sensor channels. By contrast, the North West Shelf light condensate was not able to be detected by either sensor for any thickness up to 200 µm. Optical remote sensing is therefore not applicable for detecting diagnostic absorption features associated with this light condensate oil type, which is typical of the chemistry of many hydrocarbon oils found in the Australian Northwest Shelf area and condensates world wide. We conclude that oil type is critical to the applicability of optical remote sensing for natural oil slick detection and identification. We recommend that a sensor- and oil-specific sensitivity study should be conducted prior to applying optical remote sensors for oil exploration.The oil optical properties were obtained using two different laboratory methods, a reflectance-based approach and transmittance-based approach. The reflectance-based approach was relatively complex to implement, but was chosen in order to replicate as closely as possible real world remote sensing measurement conditions of an oil film on water. The transmittance-based approach, based upon standard laboratory spectrophotometric measurements was found to generate results in good agreement with the reflectance-based approach. Therefore, for future oil- and sensor-specific sensitivity studies, we recommend the relatively accessible transmittance-based approach, which is detailed in this paper.     

Evolutionary Rule Mining in Time Series Databases

Data mining in the form of rule discovery is a growing field of investigation. A recent addition to this field is the use of evolutionary algorithms in the mining process. While this has been used extensively in the traditional mining of relational databases, it has hardly, if at all, been used in mining sequences and time series. In this paper we describe our method for evolutionary sequence mining, using a specialized piece of hardware for rule evaluation, and show how the method can be applied to several different mining tasks, such as supervised sequence prediction, unsupervised mining of interesting rules, discovering connections between separate time series, and investigating tradeoffs between contradictory objectives by using multiobjective evolution.     

Piece rates and their effects on health and safety - A literature review

The purpose of this study was to carry out a broad survey and analysis of relevant research articles about piece rate wages and their effects on health and safety that were published internationally until the fall of 2008. The aim was to summarize and describe the state of the art of the research in this field and if possible draw conclusions from the accumulated research results. A total of 75 research articles were examined extensively and 31 of these were found relevant and had sufficient quality to serve the purpose of this study. The findings of these relevant articles are summarized and analyzed in the survey. Since the late 1980s, there has been a change of research focus regarding piece rates and their effects on health and safety. More recent research shows a clear interest for health, musculoskeletal injuries, physical workload, pains and occupational injuries. The previous interest in risk behavior, security and accidents is still there, but no longer dominates the research scene.Although research is still sparse and fragmented, much of the accumulated knowledge about the effects of piece rate work tells us that piece rates in many situations have a negative effect on health and safety. The fact that 27 of the 31 studied articles found negative effects of piece rates on different aspects of health and safety does not prove causality, but together they give very strong support for the hypothesis that in most situations piece rates have negative effects on health and safety.In order to achieve better knowledge about the effects of piece rates in branches where piece rates are regarded problematic, further research is needed and such research has to be designed to meet the specific questions that are to be answered.