Four-leg converters with improved common current sharing and selective voltage-quality enhancement for islanded microgrids

Four-leg dc-ac power converters are widely used for the power grids to manage grid voltage unbalance caused by the interconnection of single-phase or three-phase unbalanced loads. These converters can further be connected in parallel to increase the overall power rating. The control of these converters poses a particular challenge if they are placed far apart with no links between them (e.g., in islanded microgrids). This challenge is studied in this paper with each four-leg converter designed to have improved common current sharing and selective voltage-quality enhancement. The common current sharing, including zero sequence component, is necessary since loads are spread over the microgrid and they are hence the common responsibility of all converters. The voltage-quality enhancement consideration should however be more selective since different loads have different sensitivity levels towards voltage disturbances. Converters connected to the more sensitive load buses should therefore be selectively triggered for compensation when voltage unbalances at their protected buses exceed the predefined thresholds. The proposed scheme is therefore different from conventional centralized schemes protecting only a common bus. Simulation and experimental results obtained have verified the effectiveness of the proposed scheme when applied to a four-wire islanded microgrid.

Identification d'un nouveau gène suppresseur de tumeurs candidat (EphA10) dans les tumeurs mammaires des souris transgéniques MMTV/neu

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Identification d'un nouveau gène suppresseur de tumeurs candidat (EphA10) dans les tumeurs mammaires des souris transgéniques MMTV/neu

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Table 4. Trace gas concentrations from samples taken at Ginninderra

We assess the performance of an inverse Lagrangian dispersion technique for its suitability to quantify leakages from geological storage of CO2. We find the technique is accurate ((QbLS/Q)=0.99, sigma=0.29) when strict meteorological filtering is applied to ensure that Monin-Obukhov Similarity Theory is valid for the periods analysed and when downwind enrichments in tracer gas concentration are 1% or more above background concentration. Because of their respective baseline atmospheric concentrations, this enrichment criterion is less onerous for CH4 than for CO2. Therefore for geologically sequestered gas reservoirs with a significant CH4 component, monitoring CH4 as a surrogate for CO2 leakage could be as much as 10 times more sensitive than monitoring CO2 alone. Additional recommendations for designing a robust atmospheric monitoring strategy for geosequestration include: continuous concentration data; exact inter-calibration of up- and downwind concentration measurements; use of an array of point concentration sensors to maximise the use of spatial information about the leakage plume; and precise isotope ratio measurement to confirm the source of any concentration elevations detected.

A compendium of myeloma-associated chromosomal copy number abnormalities and their prognostic value.

To obtain a comprehensive genomic profile of presenting multiple myeloma cases we performed high-resolution single nucleotide polymorphism mapping array analysis in 114 samples alongside 258 samples analyzed by U133 Plus 2.0 expression array (Affymetrix). We examined DNA copy number alterations and loss of heterozygosity (LOH) to define the spectrum of minimally deleted regions in which relevant genes of interest can be found. The most frequent deletions are located at 1p (30%), 6q (33%), 8p (25%), 12p (15%), 13q (59%), 14q (39%), 16q (35%), 17p (7%), 20 (12%), and 22 (18%). In addition, copy number-neutral LOH, or uniparental disomy, was also prevalent on 1q (8%), 16q (9%), and X (20%), and was associated with regions of gain and loss. Based on fluorescence in situ hybridization and expression quartile analysis, genes of prognostic importance were found to be located at 1p (FAF1, CDKN2C), 1q (ANP32E), and 17p (TP53). In addition, we identified common homozygously deleted genes that have functions relevant to myeloma biology. Taken together, these analyses indicate that the crucial pathways in myeloma pathogenesis include the nuclear factor-κB pathway, apoptosis, cell-cycle regulation, Wnt signaling, and histone modifications. This study was registered at http://isrctn.org as ISRCTN68454111.

Gene mapping and expression analysis of 16q loss of heterozygosity identifies WWOX and CYLD as being important in determining clinical outcome in multiple myeloma.

We performed fluorescent in situ hybridization (FISH) for 16q23 abnormalities in 861 patients with newly diagnosed multiple myeloma and identified deletion of 16q [del(16q)] in 19.5%. In 467 cases in which demographic and survival data were available, del(16q) was associated with a worse overall survival (OS). It was an independent prognostic marker and conferred additional adverse survival impact in cases with the known poor-risk cytogenetic factors t(4;14) and del(17p). Gene expression profiling and gene mapping using 500K single-nucleotide polymorphism (SNP) mapping arrays revealed loss of heterozygosity (LOH) involving 3 regions: the whole of 16q, a region centered on 16q12 (the location of CYLD), and a region centered on 16q23 (the location of the WW domain-containing oxidoreductase gene WWOX). CYLD is a negative regulator of the NF-kappaB pathway, and cases with low expression of CYLD were used to define a "low-CYLD signature." Cases with 16q LOH or t(14;16) had significantly reduced WWOX expression. WWOX, the site of the translocation breakpoint in t(14;16) cases, is a known tumor suppressor gene involved in apoptosis, and we were able to generate a "low-WWOX signature" defined by WWOX expression. These 2 genes and their corresponding pathways provide an important insight into the potential mechanisms by which 16q LOH confers poor prognosis.

Integration of global SNP-based mapping and expression arrays reveals key regions, mechanisms, and genes important in the pathogenesis of multiple myeloma.

Multiple myeloma is characterized by genomic alterations frequently involving gains and losses of chromosomes. Single nucleotide polymorphism (SNP)-based mapping arrays allow the identification of copy number changes at the sub-megabase level and the identification of loss of heterozygosity (LOH) due to monosomy and uniparental disomy (UPD). We have found that SNP-based mapping array data and fluorescence in situ hybridization (FISH) copy number data correlated well, making the technique robust as a tool to investigate myeloma genomics. The most frequently identified alterations are located at 1p, 1q, 6q, 8p, 13, and 16q. LOH is found in these large regions and also in smaller regions throughout the genome with a median size of 1 Mb. We have identified that UPD is prevalent in myeloma and occurs through a number of mechanisms including mitotic nondisjunction and mitotic recombination. For the first time in myeloma, integration of mapping and expression data has allowed us to reduce the complexity of standard gene expression data and identify candidate genes important in both the transition from normal to monoclonal gammopathy of unknown significance (MGUS) to myeloma and in different subgroups within myeloma. We have documented these genes, providing a focus for further studies to identify and characterize those that are key in the pathogenesis of myeloma.

A New Method for Estimating the Moisture Content and Flexibility of Polymerised Bentonite Clay Mat

This paper presents a scientific development to address the current absence of a convenient technique to identify the ductile to brittle transition of bentonite clay mats. The instrumented indentation and 3-point bending tests were performed on different liquid polymer hydrated bentonite clay mats at varying moisture content. Properties measured include modified Brinell Hardness Number (BHN) and elastic structural stiffness (EI). The dependence of flexural stiffness on moisture content is demonstrated to conform to a best power function variation. The ductile to brittle transition of clay mat is affected primarily by the change in the moisture content and for the clay mat to remain flexible, critical moisture content of 1.7 times of its plastic limit is required. Results also indicate that a strong correlation between indentation hardness and the structural stiffness. The subsequent outcome in the development of a portable quality control device to monitor the acceptable moisture content level to ensure flexibility of the clay mats was also described in this paper.

Moisture Desorption Studies on Polymer Hydrated and Vacuum Extruded Bentonite Clay Mat

Moisture desorption observations from two bentonite clay mats subjected to ten environmental zones with individually different combinations of laboratory-controlled constant temperatures (between 20 °C and 40 °C) and relative humidity (between 15% and 70%) are presented. These laboratory observations are compared with predictions from mathematical models, such as thin-layer drying equations and kinetic drying models proposed by Page, Wang and Singh, and Henderson and Pabis. The quality of fit of these models is assessed using standard error (SE) of estimate, relative percent of error, and coefficient of correlation. The Page model was found to better predict the drying kinetics of the bentonite clay mats for the simulated tropical climates. Critical study on the drying constant and moisture diffusion coefficient helps to assess the efficacy of a polymer to retain moisture and control desorption through water molecule bonding. This is further substantiated with the Guggenheim–Anderson–De Boer (GAB) desorption isotherm model which is presented.

Finite Population Inference for Causal Parameters

Thesis (Ph.D.)--University of Washington, 2016-08

Functional analysis of a transcriptional variant of matrix gla protein (MGP)

Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2014

Determination of borneol and other chemical compounds of essential oil of Dryobalanops aromatica exudate from Malaysia

Purpose: To determine borneol and other chemical compounds of essential oil derived from the exudate of Dryobalanops aromatica aromatica in Malaysia. Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was performed to characterize the composition of the isolated essential oil. Results: Essential oil (7.58 %) was obtained with the highest yield (3.24 %) in the first 2 h of fractional distillation. Thirty compounds which accounted for 97.56 % of total essential oil composition were identified by GC-MS, and they include sesquiterpenes (46.87 %), monoterpenes (31.05 %), oxygenated monoterpenes (16.76 %) and oxygenated sesquiterpenes (2.13 %). Borneol (0.74 %) was also detected in the essential oil. Conclusion: Borneol and other terpenoid compounds are present in the essential oil of the exudate of D. aromatica