The Use of Image Analysis for Determination of Surface Deterioration Level of Improved Alumina Based Materials Subjected to Cavitation

Alumina based specimens having different content of alumina based fibers were investigated for possible application as cavitation resistant material. Cavitation damages of the alumina based specimens were tested by the modified vibratory cavitation set up. Erosion rates were measured based on the method developed for metallic samples, mass loss was measured during the experiment. Surface erosion was determined during the experiment simultaneously to mass loss measurements. Image Pro Plus Program was applied for surface analysis during testing. Results indicate that investigated material exhibit excellent mechanical properties and very good resistance to cavitation erosion

Productivity : state-of-the-art, recording context information, and case study data sets

The goal of this thesis is to contribute to our understanding of construction productivity as a function of methods employed and site conditions encountered for activities such as: excavation, shoring, and forming and concrete placing activities (column footings, columns, walls, and slabs). This goal has been pursued through three objectives: A comprehensive literature search about construction productivity to determine the state-of- the-art of predictive relationships as a function of factors that influence productivity. The major finding is that there is no unique and universal relationship that can be used to predict construction productivity. The carrying out of a detailed case study in order to develop comprehensive data sets for the construction of different elements, recording of the methods used, problems encountered, etc. The case study consisted of a detailed day-to-day data collection for the first 20-week period of the construction at the Kerrisdale Station Project in Vancouver. The testing of a daily site reporting system in order to assist in its development and enhancement for use in project monitoring. A research system called REPCON5, a project scheduling and site reporting system, was chosen as the tool for the collection of the daily events at the site. The daily reporting module allowed recording of construction activities, site condition, environment data, on-site equipment and usage, job-site visitors, inspections, meetings, problems encountered, etc. Findings from the work performed should be of value, to other researchers in their quest for forecasting productivity as a function of various factors that have an impact on construction productivity.Applied Science, Faculty ofCivil Engineering, Department ofGraduat

Implementation of image analysis on thermal shock and cavitation resistance testing of refractory concrete

This paper presents monitoring of changes during thermal shock and cavitation testing for low cement concrete that was synthesized and sintered at 1600 degrees C for 3h. Water quench test was applied as an experimental method for thermal stability testing. Image analysis of the samples showed some level of deterioration at the surface and inside the samples before water quench test. During the testing, the level of samples destruction was increasing. Damages inside the samples and at the surface during the water quench test were correlated to the number of quench experiments. Models based on the damage level of both the surface and inside the bulk were proposed for calculation of the strength degradation. Cavitation damages of the samples were induced by the modified vibratory cavitation set-up. Mass loss and surface erosion were determined during the experiment. The results indicated excellent thermal shock behavior and resistance to cavitation erosion. (c) 2010 Elsevier Ltd. All rights reserved

Decoding the IL-33/ST2 Axis: Its Impact on the Immune Landscape of Breast Cancer

Interleukin-33 (IL-33) has emerged as a critical cytokine in the regulation of the immune system, showing a pivotal role in the pathogenesis of various diseases including cancer. This review emphasizes the role of the IL-33/ST2 axis in breast cancer biology, its contribution to cancer progression and metastasis, its influence on the tumor microenvironment and cancer metabolism, and its potential as a therapeutic target. The IL-33/ST2 axis has been shown to have extensive pro-tumorigenic features in breast cancer, starting from tumor tissue proliferation and differentiation to modulating both cancer cells and anti-tumor immune response. It has also been linked to the resistance of cancer cells to conventional therapeutics. However, the role of IL-33 in cancer therapy remains controversial due to the conflicting effects of IL-33 in tumorigenesis and anti-tumor response. The possibility of targeting the IL-33/ST2 axis in tumor immunotherapy, or as an adjuvant in immune checkpoint blockade therapy, is discussed

Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana

Microalgae have evolved mechanisms to respond to changes in copper ion availability, which are very important for normal cellular function, to tolerate metal pollution of aquatic ecosystems, and for modulation of copper bioavailability and toxicity to other organisms. Knowledge and application of these mechanisms will benefit the use of microalgae in wastewater processing and biomass production, and the use of copper compounds in the suppression of harmful algal blooms. Here, using electron microscopy, synchrotron radiation-based Fourier transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, and X-ray absorption fine structure spectroscopy, we show that the microalga Chlorella sorokiniana responds promptly to Cu2+ at high non-toxic concentration, by mucilage release, alterations in the architecture of the outer cell wall layer and lipid structures, and polyphosphate accumulation within mucilage matrix. The main route of copper detoxification is by Cu2+ coordination to polyphosphates in penta-coordinated geometry. The sequestrated Cu2+ was accessible and could be released by extracellular chelating agents. Finally, the reduction in Cu2+ to Cu1+ appears also to take place. These findings reveal the biochemical basis of the capacity of microalgae to adapt to high external copper concentrations and to serve as both, sinks and pools of environmental copper

Fabrication Technology for Efficient High Power Silicon Carbide Bipolar Junction Transistors

The superior characteristics of Silicon Carbide as a wide band gap semiconductor have motivated many industrial and non-industrial research groups to consider SiC for the next generations of high power semiconductor devices. The SiC Bipolar Junction Transistor (BJT) is one candidate for high power applications due to its low on-state power loss and fast switching capability. However, to compete with other switching devices such as Field Effect Transistors (FETs) or IGBTs, it is necessary for a power SiC BJT to provide a high current gain to reduce the power required from the drive circuit. In this thesis implantation free 4H-SiC BJTs with linearly graded base layer have been demonstrated with common-emitter current gain of 50 and open-base breakdown voltage of 2700 V. Also an efficient junction termination extension (JTE) with 80% of theoretical parallel-plane breakdown voltage was analyzed by fabrication of high voltage PiN diodes to achieve an optimum dose of remaining JTE charge. Surface passivation of 4H-SiC BJT is an essential factor for efficient power BJTs. Therefore different passivation techniques were compared and showed that around 60% higher maximum current gain can be achieved by a newsurface passivation layer with low interface trap density that consists of PECVD oxide followed by post-deposition oxide anneal in N2O ambient. This surface passivation along with doublezone JTE were used for fabrication of high power BJTs that result in successful demonstration of 2800 V breakdown voltage for small area (0.3 × 0.3 mm) and large area (1.8 × 1.8 mm) BJTs with a maximum dc current gain of 55 and 52, respectively. The small area BJT showed RON = 4mΩcm2, while for the large are BJT RON = 6.8 mΩcm2. Finally, a Darlington transistor with a maximum current gain of 2900 at room temperature and 640 at 200 °C is reported. The high current gain of the Darlington transistor is achieved by optimum design for the ratio of the active area of the driver BJT to the output BJT.QC 2011021

Group-level effects of the PEER model-based training

This intervention study is being performed to measure the effects of the PEER model-based training on two group-level criteria: a. the quality of team members' interaction during CPS and b. the quality of their solution to the presented real-world (complex) problems. The obtained results will also serve to make final adjustments to the training