Investigation of opening position on natural cross ventilation for an isolated building

The opening position is one of the factors that affect the ventilation performance of a building. In this study, the effect of opening position on natural cross ventilation of isolated building was investigated. The airflow pattern and ventilation rate under different opening configurations were analyzed. Eight different opening configurations were considered, including aligned and unaligned openings, as well as vertical-opening design. Computational fluid dynamics (CFD) simulation with 3D steady-state RANS equation Shear Stress Transport (SST) k-ω turbulence model was used. The parameters of streamwise dimensionless wind speed ratio (U/Uref), pressure coefficient (Cp) and dimensionless flow rate (DFR) were analyzed in this study. The results show that the aligned opening configuration Top-Top has the highest DFR at 0.60. This result is similar to that obtained from the literature. In addition, the design of vertical openings can improve the DFR of the building. The DFR of the building is mainly affected by the position of the opening on the windward side. This concludes that the opening positions exert an imperative role in affecting the internal airflow pattern, air recirculation and DFR of a naturally cross ventilated building

Effect of opening ratios with and without louvers in cross ventilation using CFD

As the world marches forward implementing concepts of sustainable buildings, higher reliance on natural ventilation can be obtained through louvers. In this research of cross ventilation in a generic isolated building, the leeward opening sizes were manipulated to 1:1, 1:0.25 and 1:0.5, with louver angles of 0°, 15°, 30°, 45° and no louvers. An Atmospheric Boundary Layer (ABL) condition was applied at the inlet of the flow domain and a 3D-steady Reynolds-Averaged Navier–Stokes (RANS) equation was solved with the Shear Stress Transport (SST) k-ω turbulence model. Mesh sensitivity analysis and model validation were performed as per best practices. The results show that as the size of the leeward opening decreases, the acceleration through the louver blades increases. In the absence and presence of louvers, as the windward-louver (W-L) ratio increased from 1:0.25 to 1:1, its dimensionless flow rate (DFR) increases. Highest DFR was obtained when the W-L ratio was 1:1 and the louver angle was 0°, second to louver angle of 15°, followed by the configuration without louvers present. Their respective DFR values were 0.588, 0.544 and 0.522. As the louver angle increased from 0° to 45°, the DFR reduced for all opening W-L ratios

Abbreviations: GAs

Abstract. It is known that modelling a finite population genetic algorithm as a Markov chain requires a prohibitively large number of states. In an attempt to resolve this problem, a number of state aggregation techniques have been proposed. We consider two different strategies for aggregating populations, one using equal average fitness and the other using equal best fitness. We examine how the approximation scales with population size, in addition to studying the effects of other parameters (such as mutation rate). We find that a large reduction in the number of states is possible, sometimes with surprisingly small loss of accuracy

Factors that affect the mechanical properties of kenaf fiber reinforced polymer: A review

Kenaf fibre has emerged as an important plant cultivated in Malaysia and has been regarded as an industrial crop. The utilization of natural fibres, such as kenaf fibre, in the polymer matrix composites has, in fact, received much attention due to certain attributes, such as low in cost and density, as well as its biodegradability feature. Moreover, numerous potential applications using the kenaf fibre can be explored due to its vast physical and mechanical properties. For instance, chemical treatment, fibre content and form, interfacial adhesion, and water absorption are some of the factors that affect the mechanical properties of kenaf fibre reinforced polymer. Besides, the study on the mechanical properties of kenaf fibre composites is indeed important as it plays an important role in determining a suitable application for various industrial products. In this review work, the factors that affect the mechanical properties of kenaf fibre reinforced polymer composite are highlighted to provide a source of literature for further researches concerning the use of kenaf fibre polymer composites on various applications

Reinitiation of mRNA translation in a patient with X-linked infantile spasms with a protein-truncating variant in ARX

Mutations in the Aristaless-related homeobox gene (ARX) lead to a range of X-linked intellectual disability phenotypes, with truncating variants generally resulting in severe X-linked lissencephaly with ambiguous genitalia (XLAG), and polyalanine expansions and missense variants resulting in infantile spasms. We report two male patients with early-onset infantile spasms in whom a novel c.34G>T (p.(E12*)) variant was identified in the ARX gene. A similar variant c.81C>G (p.(Y27*)), has previously been described in two affected cousins with early-onset infantile spasms, leading to reinitiation of ARX mRNA translation resulting in an N-terminal truncated protein. We show that the novel c.34G>T (p.(E12*)) variant also reinitiated mRNA translation at the next AUG codon (c.121-123 (p.M41)), producing the same N-terminally truncated protein. The production of both of these truncated proteins was demonstrated to be at markedly reduced levels using in vitro cell assays. Using luciferase reporter assays, we demonstrate that transcriptional repression capacity of ARX was diminished by both the loss of the N-terminal corepressor octapeptide domain, as a consequence of truncation, and the marked reduction in mutant protein expression. Our study indicates that premature termination mutations very early in ARX lead to reinitiation of translation to produce N-terminally truncated protein at markedly reduced levels of expression. We conclude that even low levels of N-terminally truncated ARX is sufficient to improve the patient's phenotype compared with the severe phenotype of XLAG that includes malformations of the brain and genitalia normally seen in complete loss-of-function mutations in ARX.Ching Moey, Scott Topper, Mary Karn, Amy Knight Johnson, Soma Das, Jorge Vidaurre and Cheryl Shoubridg

An emerging female phenotype with loss-of-function mutations in the Aristaless-related homeodomain transcription factor ARX

The devastating clinical presentation of X-linked lissencephaly with abnormal genitalia (XLAG) is invariably caused by loss-of-function mutations in the Aristaless-related homeobox (ARX) gene. Mutations in this X-chromosome gene contribute to intellectual disability (ID) with co-morbidities including seizures and movement disorders such as dystonia in affected males. The detection of affected females with mutations in ARX is increasing. We present a family with multiple affected individuals, including two females. Two male siblings presenting with XLAG were deceased prior to full-term gestation or within the first few weeks of life. Of the two female siblings, one presented with behavioral disturbances, mild ID, a seizure disorder, and complete agenesis of the corpus callosum (ACC), similar to the mother's phenotype. A novel insertion mutation in Exon 2 of ARX was identified, c.982delCinsTTT predicted to cause a frameshift at p.(Q328Ffs* 37). Our finding is consistent with loss-of-function mutations in ARX causing XLAG in hemizygous males and extends the findings of ID and seizures in heterozygous females. We review the reported phenotypes of females with mutations in ARX and highlight the importance of screening ARX in male and female patients with ID, seizures, and in particular with complete ACC.Tessa Mattiske, Ching Moey, Lisenka E. Vissers, Natalie Thorne, Peter Georgeson, Madhura Bakshi and Cheryl Shoubridg