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Wall Assembly (wall + assembly)
Selected AbstractsFire resistance of structural components protecting escape routesFIRE AND MATERIALS, Issue 2-4 2004Geoff Thomas Abstract Generally, fire resistant structures are expected to survive a fire in an adjoining compartment. Some structures, such as floors, may be designed to provide time for the occupants to escape from compartments other than the one where the fire occurs. In the fire compartment smoke development governs the time available for egress. A common misconception is that the fire resistance rating (FRR), the time an assembly will survive in a test furnace, is the time available to escape. In small compartments such as those in residential accommodation their FRR is significantly longer than the times the assemblies would survive in real compartment fires. Some fire engineering designs for retrofitted accommodation buildings use FRR times for light timber frame walls and floors as the available egress time, which is unconservative. The method of time equivalence can provide a prediction of the FRR required to survive a compartment burnout. The ratio of the total burning time of the fire to the time equivalent for the compartment and fuel load can be used to provide an estimate of the time taken for an assembly of given fire resistance to fail by multiplying the FRR by the ratio. Although this method is shown to be non-conservative when a computer model of light timber frame wall assemblies is run using both realistic time-temperature curves and the ISO-834 standard fire test time-temperature curve, it is more conservative than assuming that an assembly will last as long in a compartment fire as predicted by the FRR. Copyright © 2004 John Wiley & Sons, Ltd. [source] A model to predict fire resistance of non-load bearing wood-stud wallsFIRE AND MATERIALS, Issue 1 2003H. Takeda Abstract The author has developed a series of computer models to predict the fire resistance of wood-framed walls and floors. The models utilize two-dimensional heat-conduction equations and thermo-physical property data to describe heat transfer through the assemblies. The model for wall assemblies WALL2D, the basic version of the wall model, has already been published in Fire and Materials. Recently, WALL2D has been extended to WALL2DN to analyse heat transfer through insulated walls and walls that experience openings at the joints between adjacent sheets of gypsum board. Since gypsum board shrinks at high temperatures, the joints between adjacent sheets of gypsum board open. Hot fire gases, thereby, enter the openings and heat the edge of the gypsum board and wood studs. The new model WALL2DN simulates the joint opening and describes the resultant effect of openings. The model also calculates heat transfer through insulation in the stud cavity and depicts the effect of insulation on the fire resistance of non-load bearing wall assemblies. Insulation selected in WALL2DN is glass-fibre insulation, rock-fibre insulation, polystyrene foam and polyurethane foam. When walls are exposed to fire, the insulation in the cavity shrinks (and/or melts) and an empty space appears at the interface between insulation and gypsum board. The model simulates this shrinking behaviour of insulation in the cavity. Finally, the model was validated by comparing the predicted results to those from full-scale standard fire-endurance tests. Copyright © 2003 John Wiley & Sons, Ltd. [source] Characterization and functional analysis of the ,-1,3-glucanosyltransferase 3 of the human pathogenic fungus Paracoccidioides brasiliensisFEMS YEAST RESEARCH, Issue 1 2009Nadya Da Silva Castro Abstract The fungus Paracoccidioides brasiliensis causes paracoccidioidomycosis, a systemic granulomatous mycosis prevalent in Latin America. In an effort to elucidate the molecular mechanisms involved in fungus cell wall assembly and morphogenesis, ,-1,3-glucanosyltransferase 3 (PbGel3p) is presented here. PbGel3p presented functional similarity to the glucan-elongating/glycophospholipid-anchored surface/pH-regulated /essential for pseudohyphal development protein families, which are involved in fungal cell wall biosynthesis and morphogenesis. The full-length cDNA and gene were obtained. Southern blot and in silico analysis suggested that there is one copy of the gene in P. brasiliensis. The recombinant PbGel3p was overexpressed in Escherichia coli, and a polyclonal antibody was obtained. The PbGEL3 mRNA, as well as the protein, was detected at the highest level in the mycelium phase. The protein was immunolocalized at the surface in both the mycelium and the yeast phases. We addressed the potential role of PbGel3p in cell wall biosynthesis and morphogenesis by assessing its ability to rescue the phenotype of the Saccharomyces cerevisiae gas1, mutant. The results indicated that PbGel3p is a cell wall-associated protein that probably works as a ,-1,3-glucan elongase capable of mediating fungal cell wall integrity. [source] Absence of Gup1p in Saccharomyces cerevisiae results in defective cell wall composition, assembly, stability and morphologyFEMS YEAST RESEARCH, Issue 7 2006Célia Ferreira Abstract Saccharomyces cerevisiae Gup1p and its homologue Gup2p, members of the superfamily of membrane-bound O -acyl transferases, were previously associated with glycerol-mediated salt-stress recovery and glycerol symporter activity. Several other phenotypes suggested Gup1p involvement in processes connected with cell structure organization and biogenesis. The gup1, mutant is also thermosensitive and exhibits an altered plasma membrane lipid composition. The present work shows that the thermosensitivity is independent of glycerol production and retention. Furthermore, the mutant grows poorly on salt, ethanol and weak carboxylic acids, suggestive of a malfunctioning membrane potential. Additionally, gup1, is sensitive to cell wall-perturbing agents, such as Calcofluor white, Zymolyase, lyticase and sodium dodecyl sulphate and exhibits a sedimentation/aggregation phenotype. Quantitative analysis of cell wall components yielded increased contents of chitin and ,-1,3-glucans and lower amounts of mannoproteins. Consistently, scanning electron microscopy showed a strikingly rough surface morphology of the mutant cells. These results suggest that the gup1, is affected in cell wall assembly and stability, although the Slt2p/MAP kinase from the PKC pathway was phosphorylated during hypo-osmotic shock to a normal extent. Results emphasize the pleiotropic nature of gup1,, and are consistent with a role of Gulp1p in connection with several pathways for cell maintenance and construction/remodelling. [source] Performance of a non-load-bearing steel stud gypsum board wall assembly: Experiments and modelling,FIRE AND MATERIALS, Issue 5 2007Samuel L. Manzello Abstract A gypsum wall assembly was exposed to an intense real-scale compartment fire. For the wall assembly, temperatures were measured at the exposed face, within the stud cavity, and at the unexposed face during the fire exposure. Total heat flux gauges were used to measure the temporal variation of the energy incident on the walls, and cameras, both visual and infrared, were used to image the unexposed face of the wall assembly during the fire exposure. The behaviour of the wall assembly under the fire load is discussed as are current model results for a simulation of the fire test. Copyright © 2006 John Wiley & Sons, Ltd. [source] ANALYSIS OF EXPRESSED SEQUENCE TAGS FROM THE GREEN ALGA ULVA LINZA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 6 2005Michele S. Stanley There is a general lack of genomic information available for chlorophyte seaweed genera such as Ulva, and in particular there is no information concerning the genes that contribute to adhesion and cell wall biosynthesis for this organism. Partial sequencing of cDNA libraries to generate expressed sequence tags (ESTs) is an effective means of gene discovery and characterization of expression patterns. In this study, a cDNA library was created from sporulating tissue of Ulva linza L. Initially, 650 ESTs were randomly selected from a cDNA library and sequenced from their 5, ends to obtain an indication of the level of redundancy of the library (21%). The library was normalized to enrich for rarer sequences, and a further 1920 ESTs were sequenced. These sequences were subjected to contig assembly that resulted in a unigene set of approximately 1104 ESTs. Forty-eight percent of these sequences exhibited significant similarity to sequences in the databases. Phylogenetic comparisons are made between selected sequences with similarity in the databases to proteins involved in aspects of extracellular matrix/cell wall assembly and adhesion. [source] | ||||||||||