125,248 research outputs found
“Pengaruh Rasio Tapper terhadap Performa Spoiler Belakang Mobil”
No full textPerkembangan modifikasi mobil yang meningkat serta kurangnya pemahaman tentang fungsi menggunakan spoiler atau sayap belakang pada kendaraan, mendasari penelitian tentang gaya aerodinamis yang bekerja pada mobil. Pengaruh perangkat aerodinamis ini akan menghasilkan gaya tekan ke bagian bawah kendaraan atau disebut downforce, dimana gaya ini sangat dipengaruhi oleh nilai CL (lift coefficient). Tujuan dari penelitian ini adalah untuk mengetahui pengaruh variasi rasio tapper terhadap nilai downforce dan drag force pada spoiler tipe elemen tunggal yang dibuat menggunakan airfoil NACA 6412. Penelitian dilakukan dengan menggunakan metode Computational Fluid Dynamic menggunakan software ANSYS Fluent dengan steady state pressure based solver. Pada penelitian ini digunakan lima variasi rasio tapper, yaitu: 1:1; 1:0.5; 1:0.7; 0.5:1; dan 0.7:1. Sifat fluida yang digunakan disesuaikan dengan iklim dan cuaca pada kondisi udara umum dan pada kecepatan aliran udara 100 km/jam. Berdasarkan penelitian yang dilakukan, dapat disimpulkan bahwa nilai koefisien angkat tertinggi dicapai dalam variasi rasio tapper 1:1 yang sama dengan CL = -0,2275 dan CD = 0,0195. Nilai downforce tertinggi dicapai dalam variasi rasio tapper 1:1 yang sama dengan L = -107.529 N dan nilai drag force terbesar juga dicapai dalam variasi rasio tapper 1: 1 yang sama dengan D = 9,2269 N. Hasil CL/CD terbaik diperoleh pada variasi rasio tapper 1:05 dengan nilai 12,8
Effect of Tapper Ratio on a Car Rear Spoiler Performance
No full textThe increasing development of car modification and the lack of understanding on the function of using spoilers or rear wings on vehicles, underlies the research on the aerodynamic forces acting on cars. The influence of this aerodynamic device will produce a compressive force to the bottom of the vehicle or called downforce, where this force is greatly influenced by the CL (lift coefficient) value. The purpose of this study was to determine the effect of variations in the tapper ratio on the value of downforce and drag force on on single-element type spoilers made using a NACA 6412 airfoil. The research was conducted using the Computational Fluid Dynamic method using ANSYS Fluent software with steady state pressure based solver. In this study five variations of the tapper ratio were used, namely: 1:1; 1:0.5; 1:0.7; 0.5:1; and 0.7:1. The fluid properties used are adjusted to the climate and weather in general air conditions and at air flow speeds of 100 km/h. Based on the research conducted, it can be concluded that the highest lift coefficient value was achieved in the 1:1 tapper ratio variation which was equal to CL = -0.2275 and CD = 0.0195. The highest downforce value is achieved in the 1:1 tapper ratio variation that is equal to L = -107,529 N and the largest drag force value is also achieved in the 1: 1 tapper ratio variation that is equal to D = 9.2269 N. The best CL/CD results are obtained at the 1:05 tapper ratio variation with a value of 12.82
Effect of Tapper Ratio on a Car Rear Spoiler Performance
No full textThe increasing development of car modification and the lack of understanding on the function of using spoilers or rear wings on vehicles, underlies the research on the aerodynamic forces acting on cars. The influence of this aerodynamic device will produce a compressive force to the bottom of the vehicle or called downforce, where this force is greatly influenced by the CL (lift coefficient) value. The purpose of this study was to determine the effect of variations in the tapper ratio on the value of downforce and drag force on on single-element type spoilers made using a NACA 6412 airfoil. The research was conducted using the Computational Fluid Dynamic method using ANSYS Fluent software with steady state pressure based solver. In this study five variations of the tapper ratio were used, namely: 1:1; 1:0.5; 1:0.7; 0.5:1; and 0.7:1. The fluid properties used are adjusted to the climate and weather in general air conditions and at air flow speeds of 100 km/h. Based on the research conducted, it can be concluded that the highest lift coefficient value was achieved in the 1:1 tapper ratio variation which was equal to CL = -0.2275 and CD = 0.0195. The highest downforce value is achieved in the 1:1 tapper ratio variation that is equal to L = -107,529 N and the largest drag force value is also achieved in the 1: 1 tapper ratio variation that is equal to D = 9.2269 N. The best CL/CD results are obtained at the 1:05 tapper ratio variation with a value of 12.82
Mapping a gene for rheumatoid arthritis on chromosome 18q21
No full textAlthough single chi-square analysis of the North American Rheumatoid Arthritis Consortium (NARAC) data identifies many single-nucleotide polymorphisms (SNPs) with p-values less than 0.05, none remain significant after Bonferroni correction. In contrast, CHROMSCAN evades heavy Bonferroni correction and auto-correlation between SNPs by using composite likelihood to model association across all markers in a region and permutation to assess significance. Analysis by CHROMSCAN identifies a 36-kb interval that includes the most significant SNP (msSNP) observed in a 10-Mb target suggested by linkage. Unexpectedly, stratification by gender and age of onset shows that association evidence comes almost entirely from females with age of onset less than 40. Combining evidence from a meta-analysis of linkage studies and three subsets of the NARAC data provides significant evidence for a determinant of rheumatoid arthritis in a 36-kb interval and illustrates the principle that estimates of location and its information are more powerful than estimates of p-values alone
Nancy Tapper, Bartered brides. Politics, Gender and Marriage in an Afghan Tribal Society
No full textSegalen Martine. Nancy Tapper, Bartered brides. Politics, Gender and Marriage in an Afghan Tribal Society. In: Annales. Économies, Sociétés, Civilisations. 48ᵉ année, N. 5, 1993. pp. 1241-1243
Vindolanda : The Latin Writing-Tablets, By Alan K. Bowman and J. David Thomas, With Contributions By J. N. Adams and Richard Tapper. 1983
No full textTjäder Jan-Olof. Vindolanda : The Latin Writing-Tablets, By Alan K. Bowman and J. David Thomas, With Contributions By J. N. Adams and Richard Tapper. 1983. In: Scriptorium, Tome 40 n°2, 1986. pp. 297-301
Genetic variation in mitotic regulatory pathway genes is associated with breast tumor grade.
No full textMitotic index is an important component of histologic grade and has an etiologic role in breast tumorigenesis. Several small candidate gene studies have reported associations between variation in mitotic genes and breast cancer risk. We measured associations between 2156 single nucleotide polymorphisms (SNPs) from 194 mitotic genes and breast cancer risk, overall and by histologic grade, in the Breast Cancer Association Consortium (BCAC) iCOGS study (n = 39 067 cases; n = 42 106 controls). SNPs in TACC2 [rs17550038: odds ratio (OR) = 1.24, 95% confidence interval (CI) 1.16–1.33, P = 4.2 × 10−10) and EIF3H (rs799890: OR = 1.07, 95% CI 1.04–1.11, P = 8.7 × 10−6) were significantly associated with risk of low-grade breast cancer. The TACC2 signal was retained (rs17550038: OR = 1.15, 95% CI 1.07–1.23, P = 7.9 × 10−5) after adjustment for breast cancer risk SNPs in the nearby FGFR2 gene, suggesting that TACC2 is a novel, independent genome-wide significant genetic risk locus for low-grade breast cancer. While no SNPs were individually associated with high-grade disease, a pathway-level gene set analysis showed that variation across the 194 mitotic genes was associated with high-grade breast cancer risk (P = 2.1 × 10−3). These observations will provide insight into the contribution of mitotic defects to histological grade and the etiology of breast cancer.<br/
Vindolanda : The Latin Writing-Tablets, By Alan K. Bowman and J. David Thomas, With Contributions By J. N. Adams and Richard Tapper. 1983
No full textTjäder Jan-Olof. Vindolanda : The Latin Writing-Tablets, By Alan K. Bowman and J. David Thomas, With Contributions By J. N. Adams and Richard Tapper. 1983. In: Scriptorium, Tome 40 n°2, 1986. pp. 297-301
A metric linkage disequilibrium map of a human chromosome
No full textWe used LDMAP (Maniatis et al. 2002) to analyse SNP data spanning chromosome 22 (Dawson et al. 2002), to obtain a whole-chromosome metric LD map. The LD map, with map distances analogous to the centiMorgan scale of linkage maps, identifies regions of high LD as plateaus ('blocks') and characterises steps which define the relationship between these regions. From this map we estimate that block regions comprise between 32% and 55% of the euchromatic portion of chromosome 22 and that increasing marker density within steps may increase block coverage. Steps are regions of low LD which correspond to areas of variable recombination intensity. The intensity of recombination is related to the height of the step and thus intense recombination hot-spots can be distinguished from more randomly distributed historical events. The LD maps are more closely related to the high-resolution linkage map (Kong et al. 2002) than average measures of ? with recombination accounting for between 34% and 52% of the variance in patterns of LD (r = 0.58 – 0.71, p = 0.0001). Step regions are closely correlated with a range of sequence motifs including GT/CA repeats. The LD map identifies holes in which greater marker density is required and defines the optimal SNP spacing for positional cloning, which suggests that some multiple of around 50,000 SNPs will be required to efficiently screen Caucasian genomes. Further analyses which investigate selection of informative SNPs and the effect of SNP allele frequency and marker density will refine this estimate
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