53 research outputs found
Pan-deanery assessment of core surgery educational training days – Are we getting the same deal?
No full textFire performance of concrete flat slabs
No full text© 2020 Pasindu Laknath Weerasinghe Thalpe GurugeConcrete flat slabs are widely used, especially in multi-storey buildings, because of their resource efficiency and fast construction. The requirements for fire safety critically affect the overall design of these slabs. Fire design guidelines which are based on research carried out a few decades ago hinder the effective use of concrete flat slabs as they impose strict thickness and cover requirements. Since then, material properties of concrete have significantly changed, and construction methods have evolved considerably. Therefore, new research is needed to assess the fire performance of concrete flat slabs and provide a research base to improve the current fire safety design guidelines for concrete flat slabs.
Among the limited number of fire tests performed on concrete flat slabs, most of them were simply supported isolated specimens which did not take into account the continuity of the slab. Therefore, the author conducted a large-scale fire test on a laterally restrained flat slab specimen simulating the effect of adjacent slab panels in case of a fire. Recent studies emphasise the importance of capturing the behaviour during the cooling phase as there is a risk of failure also during that phase. Hence, the experiment was extended to measure the thermal and structural response during the cooling phase. Results indicate that the fire resistance level (FRL) of the restrained flat slab has been improved compared to the FRLs predicted by the design standards. The use of restrained support conditions which allows the development of membrane actions could be the reason for improved FRL.
Although fire tests provide vital information on the behaviour of flat slabs in fire, they are very expensive and time-consuming. As an alternative, numerical methods can be utilized to capture the effects of elevated temperatures on concrete flat slabs. Building upon the existing material models for concrete and steel at elevated temperatures, the author introduced the use of explicit coupled-temperature analysis technique in finite element software ABAQUS to determine the thermal and structural response of concrete flat slabs in fire. The models also account for the transient thermal creep of concrete when heated and change of material properties during the cooling phase. The developed models were validated with the experimental results from the fire test carried out by the author, along with two more independent fire tests.
A validated numerical modelling technique was then employed in a parametric study to evaluate the influence of the thickness, the span between columns and the reinforcement arrangement on the FRL of concrete flat slabs. The aim of the study was to further understand the new design rules imposed by the latest Australian concrete design code. Outcomes of the analysis further validate some amendments incorporated in the design code while suggesting improvements to the critical distance rule.
The current construction industry prefers performance-based fire design over prescription-based fire design as it yields more optimized solutions on a case by case basis. In order to apply such methods to concrete flat slab fire design, a case study was conducted to model an actual fire scenario within a compartment in a multi-storey building and its effects on the flat slab. Fire Dynamics Simulator (FDS), a computational fluid dynamics based fire simulation software was implemented to capture the growth and decay of a compartment fire incorporating the combustible material characteristics of the furniture inside. Different fire scenarios were simulated, taking into account the different ventilation conditions. Critical temperature fields generated from the fire simulation were then applied to a FE model to assess the structural response. The predicted structural response for the actual fire scenario is significantly different from the response when the flat slab was subjected to standard design fire. This observation further highlights the importance of performance-based fire design approach, which takes building-specific parameters into account rather than generalized fire curves
Improving Citation Network Scoring by Incorporating Author and Program Committee Reputation
No full textPublication venues play an important role in the
scholarly communication process. The number of publication
venues has been increasing yearly, making it difficult for
researchers to determine the most suitable venue for their
publication. Most existing methods use citation count as the metric
to measure the reputation of publication venues. However, this
does not take into account the quality of citations. Therefore, it is
vital to have a publication venue quality estimation mechanism.
The ultimate goal of this research project is to develop a novel
approach for ranking publication venues by considering
publication history. The main aim of this research work is to
propose a mechanism to identify the key Computer Science
journals and conferences from various fields of research. Our
approach is completely based on the citation network represented
by publications. A modified version of the PageRank algorithm is
used to compute the ranking scores for each publication. In our
publication ranking method, there are many aspects that
contribute to the importance of a publication, including the
number of citations, the rating of the citing publications, the time
metric and the authors’ reputation. Known publication venue
scores have been formulated by using the scores of the
publications. New publication venue ranking is taken care by the
scores of Program Committee members which derive from their
ranking scores as authors. Experimental results show that our
publication ranking method reduces the bias against more recent
publications, while also providing a more accurate way to
determine publication quality
Improving citation network scoring by incorporating author and program committee reputation
No full textChromium oxide loaded silica aerogels: novel visible light photocatalytic materials for environmental remediation
No full textVarious photocatalytic systems have been reported for degradation of harmful air pollutants. Most of the reported catalysts are based on well-known semiconducting material, Titanium Dioxide (TiO[subscript 2]), while some are based on other materials such as Silicon Dioxide (SiO[subscript 2]), various Zeolites. However, titania based systems are very popular in this regard and the most of the photocatalytic processes that involve titania are considered non-localized. Thus, to study the photocatalytic ability of a localized system, novel aerogel based samples were studied using silica and chromium and tested for photocatalytic activities. The new photocatalytic systems were prepared to obtain aerogel silica as the matrix material by cohydrolyzing silica precursor with chromium(III) ions to obtain chromium loaded silica materials. Later, these prepared samples were compared to chromium loaded titania and mixed silica-titania systems. All the prepared systems have high surface areas compared to the systems that have been reported in literature. Samples were characterized by X-ray diffraction, Diffusive reflectance UV spectroscopy, and BET surface analysis methods. The kinetics of photocatalytic degradation of a model pollutant, acetaldehyde, was performed using a Shimadzu GCMS-QP 5000 instrument and a glass reactor with a quartz window. Change in photocatalytic activity was found with various molar ratios of SiO[subscript 2] to TiO[subscript 2]. From all the systems, chromium loaded pure SiO[subscript 2] showed the highest activity towards acetaldehyde degradation compared to mixed systems and TiO[subscript 2] based systems. The interesting photocatalytic activity of silica based materials occurs due to the efficient insertion of chromium ions into silica matrix to generate reactive sites. The photo excitation is believed to occur at molecular orbital level at localized chromium sites
Particle Swarm Optimization Simulation via Optimal Halton Sequences
No full textAbstractInspired by the social behavior of the bird flocking or fish schooling, the particle swarm optimization (PSO) is a population based stochastic optimization method developed by Eberhart and Kennedy in 1995. It has been used across a wide range of applications. Faure, Halton and Vander Corput sequences have been used for initializing the swarm in PSO. Quasirandom(or low-discrepancy) sequences such as Faure, Halton, Vander Corput etc are deterministic and suffers from correlations between radical inverse functions with different bases used for different dimensions. In this paper, we investigate the effect of initializing the swarm with scrambled optimal Halton sequence, which is a randomized quasirandom sequence. This ensures that we still have the uniformity properties of quasirandom sequences while preserving the stochastic behavior for particles in the swarm. Numerical experiments are conducted with benchmark objective functions with high dimensions to verify the convergence and effectiveness of the proposed initialization of PSO
Intramolecular (4+2); and tandem intermolecular (4+2);/intramolecular (3+2); cycloaddition of nitroalkenes with achiral and chiral dienophiles
No full textNitroalkenes tethered with activated and unactivated olefins were prepared. Intramolecular cycloadditions with both acyclic and cyclic dienophiles in the presence of SnCl\sb4 were investigated. Nitroalkenes tethered with three methylene units to a Z-dienophile afforded trans fused nitronates. The cycloaddition towards larger rings were unsuccessful. Cyclic dienophiles cyclized to form fused ring nitronates with extremely high selectivity. The ring fusion between the carbocycles was dependent on the ring size of the dienophile. However, cycloaddition to afford spiro ring nitronates were unsuccessful.The tandem intermolecular (4+2) intramolecular (3+2) cycloaddition with 2,3-dimethyl-2-butene afforded nitroso acetals in good yields. Using enol ethers as dienophiles, nitroso acetals were obtained as a mixture of anomers. These anomers were transformed to either -hydroxy lactams or 1,3-amino alcohols upon hydrogenolysis. The rate of the (3+2) cycloaddition is dependent on the tether length, geometry and the substitution on the dipolarophile and nitronate. For two methylene tethered nitroalkenes, the (3+2) cycloaddition undergoes via a syn endo pathway while three methylene tethered nitroalkenes undergo a syn exo pathway.The use of camphor derived chiral enol ethers allowed the demonstration asymmetric tandem cycloadditions. These nitroso acetals were transformed to optically active -hydroxy lactams with high recovery of the chiral auxiliary. The optical purities 98% ee were achieved with the vinyl and the (E)-1-propenyl ethers, while only 50% ee was obtained with the (Z)-1-propenyl ether. The high diastereoselectivity arises from a strong endo preference for the enol ethers during the (4+2) cycloaddition step. The mechanism and transition structures for cycloadditions are described.Made available in DSpace on 2011-05-07T12:05:35Z (GMT). No. of bitstreams: 2
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Human perception of haptic force direction
No full textIn this paper we investigate the accuracy of human perception of haptic force direction applied to the hand. Haptic interfaces are commonly used in many applications and understanding the limitations of human perception would facilitate the design of these interfaces and the associated applications. The literature contains work related to force perception; however, none of which address the issue of the accuracy of haptic force direction perception. We discuss the design and implementation of the experiment used to evaluate the accuracy. Also presented are results related to training effects, fatigue and accuracy across angular regions. © 2006 IEEE.BOVY GB, 2003, EUROHAPTIC 2003 JUL; CHOI S, 2004, IEEE COMPUT GRAPH, P40; DARUWALLA JH, 2002, SIDWELL FRIENDS MAR; DEBUS T, 2000, EXP ROB 7 5 INT S DE; FATTOUH A, 2000, IEEE T CONTROL SYSTE; LEE S, 2002, P IEEE RSJ IROS; LEE S, 2004, P INT C ART TEL; Minsky M., 1990, ACM T COMPUT-HUM INT, V24, P235, DOI 10.1145-91394.91451; RICHARD C, 2000, P ASEE ANN C EXP, V3668; SIKORA T, 1997, IEEE SIGNAL PROC SEP; Stanney KM, 1998, PRESENCE-TELEOP VIRT, V7, P327, DOI 10.1162-105474698565767; TAN HZ, 1994, DSC55 ASME; Toffin D, 2003, J NEUROPHYSIOL, V90, P3040, DOI 10.1152-jn.00271.2003; WALLACE GK, 1991, COMMUN ACM, V34, P30, DOI 10.1145-103085.103089; YAMASHITA J, 1998, ACM SIGGRAPH 98, P274, DOI 10.1145-280953.28224640
Promoting cultural diversity in hybrid libraries among immigrant communities, Case: Library Ambassadors in Tampere, Finland
No full textMultilingual services and community-based approaches enabled by public libraries in Finland assist the integration of immigrants. In this thesis, the author evaluates a project in Tampere, the Library Ambassador program, where volunteers provide free services to newcomers, speaking multiple languages, to help them navigate the hybrid library services. Through the five dimensional model of confidence and self-esteem, trust and relationships, cultural integration and preservation, community awareness and engagement, and political integration, the study examines the role of ambassadors in culturally inclusive library practices using the five-dimensional framework developed by Grossman et al. (2021). Further, this study used a qualitative, interpretive approach to get insights into the experiences of the volunteers. The researcher interviewed seven language and cultural specific Library Ambassadors through semi-structured interviews to collect appropriate data. The data analysis was done through thematic analysis and it showed that ambassadors have a significant mediating effect on making new immigrants feel confident using library services, particularly overcoming language barriers and use of online systems. Ambassadors can help build trust by means of empathetic communication and shared migration or by means of culturally sensitive advice that will strengthen the idea of the library as a secure and friendly environment. The study concludes by finding that the Library Ambassador program enhances the ability of libraries to serve diverse populations. The recommendations are comprised with suggestions such as to add multilingual collections, provide more ambassador training and make more outreach to underrepresented groups. For future studies, it is necessary to include service users and library personnel, investigate long-term effects, and investigate the possible role of libraries in civic education
Carfilzomib Induced Tumor Lysis Syndrome and Other Adverse Events
No full text© The Author(s) 2018. In the area of multiple myeloma (MM) therapy, proteasome inhibitors (PI) have emerged with promising responses both in the first- and second-line setting. Carfilzomib (CFZ) is a second-generation, selective PI approved in 2012 for the treatment of relapsed/refractory multiple myeloma (RRMM) in patients who received 2 prior therapies or have evidence of disease progression within 60 days of completion of last therapy. Its safety profile reported adverse events (AEs) ranging from drug-related AEs (nausea and vomiting), hematologic AEs (neutropenia and thrombocytopenia), and nonhematologic AEs (electrolyte imbalances). As CFZ use is gaining popularity, various hematological, renal, cardiovascular, pulmonary, and neurological toxicities have been reported. We are presenting this case to describe a rare occurrence of tumor lysis syndrome (TLS) with the use of this novel targeted therapy
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