Microstructure and Mechanical Properties of Mullite–Silicon Carbide Composites

Mullite-SiC-whisker composites were prepared by powder processing using two commercial SiC whiskers. These composites were prepared by sintering rather than hot-pressing. A mulliteSlC-powder composite and a base line mallite material were also prepared for comparison with the two whisker composite materials. Fracture toughness measurements showed significant enhancement in only one of the whisker composite materials. The microstructure of the four materials was examined by scanning electron microscopy and transmission electron microscopy to assist in the explanation of the mechanical behavior of these composites. The examinations suggested that most of the toughening results from second-phase particles, with only limited toughening from effects associated with whiskers per se. In one case, higher toughness was partially associated with the formation of sialon phase by reaction with the whiskers and the furnace environment.     

New sesquiterpenes fromMaytenus species (Celastraceae). Taxonomic and chemotaxonomic considerations concerning chileanMaytenus

Three new dihydro--agarofuran sesquiterpenes from two species ofMaytenus were isolated and their structures were elucidated by means of¹H and¹³C NMR studies. The differences and similarities noted in the chemical content of the dihydro--agarofuran sesquiterpenes from the fourMaytenus species from Chile are in line with the taxonomic characterization of these species; their geographical distribution is also given.     

Valorization of Al slag in the production of green ceramic tiles: Effect of experimental conditions on microstructure and crystalline phase composition

This work reports the results of an investigation aimed at the development of sintered glass-ceramic tiles by the sinter-crystallization of mixtures composed of aluminum slag and reclaimed packaging glass. The thermal behaviors of mixtures incorporating 50 and 60 wt% Al slag were established by differential thermal analysis (DTA). Green compacts were sintered in a temperature range of 800°C-1050°C and then soaked for 10-60 minutes. The mineralogical characterizations of the sintered materials were obtained by X-ray diffraction (XRD). The achieved results indicated that the sintering of aluminum slag and packaging glass reclaimed led to a glass-ceramic material composed mainly of needle-like crystals of wollastonite (CaSiO₃). The bloating of samples during firing was evaluated according to a Cougny predictive diagram. After initial observations and according to bending strength characterizations, sintered tiles prepared from aluminum slag and glassy sand are appropriate for floor pavement and wall covering.     

Influence of different reactor types on Nannochloropsis oculata microalgae culture for lipids and fatty acid production

Greenhouse gases emitted into the atmosphere by burning of fossil fuels cause global warming. One option is obtaining biodiesel. Nannochloropsis oculata was cultured under different light intensities and reactors at 25°C for 21 days with f/2 medium to assess their effects on cell density, lipid, and fatty acids (FAs). N. oculata improved cell density on fed-batch glass tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹, yielding 3.5 × 10⁸ cells ml⁻¹, followed by fed-batch Erlenmeyer flask (1 L) at 650 μmol E m⁻² s⁻¹ with 1.7 × 10⁸ cells ml⁻¹. The highest total lipid contents (% g lipid × g dry biomass⁻¹) were 44.4 ± 0.8% for the reactor (1 L) at 650 μmol E m⁻² s⁻¹ and 35.2 ± 0.2% for the tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹, until twice as high compared with the control culture (Erlenmeyer flask 1 L, 80 μmol E m⁻² s⁻¹) with 21.2 ± 1%. Comparing the total lipid content at 200 μmol E m⁻² s⁻¹, tubular reactor (7 L) and reactor 1 L achieved 35.2 ± 0.2% and 28.3 ± 1%, respectively, indicating the effect of shape reactor. The FAs were affected by high light intensity, decreasing SFAs to 2.5%, and increased monounsaturated fatty acids + polyunsaturated fatty acids to 2.5%. PUFAs (20:5n-3) and (20:4n-3) were affected by reactor shape, decreasing by half in the tubular reactor. In the best culture, fed-batch tubular reactor (7 L) at 200 μmol E m⁻² s⁻¹ contains major FAs (16:0; 38.06 ± 0.16%), (16:1n-7; 30.74 ± 0.58%), and (18:1n-9; 17.15 ± 0.91%).     

Interactive visualization of medical volume models in mobile devices

Interactive visualization of volume models in standard mobile devices is a challenging present problem with increasing interest from new application fields like telemedicine. The complexity of present volume models in medical applications is continuously increasing, therefore increasing the gap between the available models and the rendering capabilities in low-end mobile clients. New and efficient rendering algorithms and interaction paradigms are required for these small platforms. In this paper, we propose a transfer function-aware compression and interaction scheme, for client-server architectures with visualization on standard mobile devices. The scheme is block-based, supporting adaptive ray-casting in the client. Our two-level ray-casting allows focusing on small details on targeted regions while keeping bounded memory requirements in the GPU of the client. Our approach includes a transfer function-aware compression scheme based on a local wavelet transformation, together with a bricking scheme that supports interactive inspection and levels of detail in the mobile device client. We also use a quantization technique that takes into account a perceptive metrics of the visual error. Our results show that we can have full interaction with high compression rates and with transmitted model sizes that can be of the order of a single photographic image.     

Proteomics identification of differentially expressed proteins in the muscle of dysferlin myopathy patients

The muscular dystrophies are a large and heterogeneous group of neuromuscular disorders that can be classified according to the mode of inheritance, the clinical phenotype and the molecular defect. To better understand the pathological mechanisms of dysferlin myopathy we compared the protein-expression pattern in the muscle biopsies of six patients with this disease with six patients with limb girdle muscular dystrophy 2A, five with facioscapulohumeral dystrophy and six normal control subjects. To investigate differences in the expression levels of skeletal muscle proteins we used 2-DE and MS. Western blot or immunohistochemistry confirmed relevant results. The study showed specific increase expression of proteins involved in fast-to-slow fiber type conversion (ankyrin repeat protein 2), type I predominance (phosphorylated forms of slow troponin T), sarcomere stabilization (actinin-associated LIM protein), protein ubiquitination (TRIM 72) and skeletal muscle differentiation (Rho-GDP-dissociation inhibitor ly-GDI) in dysferlin myopathy. As anticipated, we also found differential expression of proteins common to all the muscular dystrophies studied. This comparative proteomic analysis suggests that in dysferlin myopathy (i) the type I fiber predominance is an active process of fiber type conversion rather than a selective loss of type II fibers and (ii) the dysregulation of proteins involved in muscle differentiation further confirms the role of dysferlin in this process.     

Parallel interval-based reasoning in medical knowledge-based system Clinaid

The paper continues a series of papers and a monograph [33], where we have described the conceptual structures as well as the basic architecture of a knowledge-based systemCunaid.     

RUSHES—an annotation and retrieval engine for multimedia semantic units

Multimedia analysis and reuse of raw un-edited audio visual content known as rushes is gaining acceptance by a large number of research labs and companies. A set of research projects are considering multimedia indexing, annotation, search and retrieval in the context of European funded research, but only the FP6 project RUSHES is focusing on automatic semantic annotation, indexing and retrieval of raw and un-edited audio-visual content. Even professional content creators and providers as well as home-users are dealing with this type of content and therefore novel technologies for semantic search and retrieval are required. In this paper, we present a summary of the most relevant achievements of the RUSHES project, focusing on specific approaches for automatic annotation as well as the main features of the final RUSHES search engine.     

Bayesian networks for enhancement of requirements engineering: a literature review

Requirements analysis is the software engineering stage that is closest to the users’ world. It also involves tasks that are knowledge intensive. Thus, the use of Bayesian networks (BNs) to model this knowledge would be a valuable aid. These probabilistic models could manage the imprecision and ambiguities usually present in requirements engineering (RE). In this work, we conduct a literature review focusing on where and how BNs are applied on subareas of RE in order to identify which gaps remain uncovered and which methods might engineers employ to incorporate this intelligent technique into their own requirements processes. The scarcity of identified studies (there are only 20) suggests that not all RE areas have been properly investigated in the literature. The evidence available for adopting BNs into RE is sufficiently mature yet the methods applied are not easily translatable to other topics. Nonetheless, there are enough studies supporting the applicability of synergistic cooperation between RE and BNs. This work provides a background for understanding the current state of research encompassing RE and BNs. Functional, non-functional and -ilities requirements artifacts are enhanced by the use of BNs. These models were obtained by interacting with experts or by learning from databases. The most common criticism from the point of view of BN experts is that the models lack validation, whereas requirements engineers point to the lack of a clear application method for BNs and the lack of tools for incorporating them as built-in help functions.     

The Great Lakes Region and Bulk Water Exports

Abstract

The article provides an overview of the latest developments in the debate concerning the bulk water export of Great Lakes water. It examines the policy and legal dimensions of this new debate. The policy dimension focuses on the public attention and concern, in Canada, regarding bulk water removals from the Great Lakes basin. This concern has triggered the new Canadian federal legislation banning water exports from the region (Bill C-15). Is this a sign that the Canadian government now embraces a water conservation ethic? Is its position in line with the recent recommendations on the issue of the International Joint Commission (IJC), the joint body created by the United States and Canada to manage its shared waters? The attempt by investors to export water from the Great Lakes basin raises issues regarding Canada's obligations under international and regional trade agreements, most notably the General Agreement on Tariffs and Trade (GATT) and the North American Free Trade Agreement (NAFTA). The article examines the provisions of those two trade agreements in the context of the water export debate in Canada and concludes that increased clarity on Canada/US transboundary water issues is required.