Turboprop cargo aircraft systems study

The effects of using advanced turboprop propulsion systems to reduce the fuel consumption and direct operating costs of cargo aircraft were studied, and the impact of these systems on aircraft noise and noise prints around a terminal area was determined. Parametric variations of aircraft and propeller characteristics were investigated to determine their effects on noiseprint areas, fuel consumption, and direct operating costs. From these results, three aircraft designs were selected and subjected to design refinements and sensitivity analyses. Three competitive turbofan aircraft were also defined from parametric studies to provide a basis for comparing the two types of propulsion

Turboprop Cargo Aircraft Systems study, phase 1

The effects of advanced propellers (propfan) on aircraft direct operating costs, fuel consumption, and noiseprints were determined. A comparison of three aircraft selected from the results with competitive turbofan aircraft shows that advanced turboprop aircraft offer these potential benefits, relative to advanced turbofan aircraft: 21 percent fuel saving, 26 percent higher fuel efficiency, 15 percent lower DOCs, and 25 percent shorter field lengths. Fuel consumption for the turboprop is nearly 40 percent less than for current commercial turbofan aircraft. Aircraft with both types of propulsion satisfy current federal noise regulations. Advanced turboprop aircraft have smaller noiseprints at 90 EPNdB than advanced turbofan aircraft, but large noiseprints at 70 and 80 EPNdB levels, which are usually suggested as quietness goals. Accelerated development of advanced turboprops is strongly recommended to permit early attainment of the potential fuel saving. Several areas of work are identified which may produce quieter turboprop aircraft

Technical and Economic Assessment of Span-Distributed Loading Cargo Aircraft Concepts

A 700,000 kg (1,540,000-lb) aircraft with a cruise Mach number of 0.75 was found to be optimum for the specified mission parameters of a 272 155-kg (600,000-lb) payload, a 5560-km (3000-n.mi.) range, and an annual productivity of 113 billion revenue-ton km (67 billion revenue-ton n. mi.). The optimum 1990 technology level spanloader aircraft exhibited the minimum 15-year life-cycle costs, direct operating costs, and fuel consumption of all candidate versions. Parametric variations of wing sweep angle, thickness ratio, rows of cargo, and cargo density were investigated. The optimum aircraft had two parallel rows of 2.44 x 2.44-m (8 x 8-ft) containerized cargo with a density of 160 kg/cu m (10 lb/ft 3) carried throughout the entire 101-m (331-ft) span of the constant chord, 22-percent thick, supercritical wing. Additional containers or outsized equipment were carried in the 24.4-m (80-ft) long fuselage compartment preceding the wing. Six 284,000-N (64,000-lb) thrust engines were mounted beneath the 0.7-rad (40-deg) swept wing. Flight control was provided by a 36.6-m (120-ft) span canard surface mounted atop the forward fuselage, by rudders on the wingtip verticals and by outboard wing flaperons

Induction of Androgenesis as a Consequence of Wide crossing in chickpea.

Androgenesis was observed in a wide cross of Cicer arietinum × C. pinnatifidum. Hybrids between C. arietinum × C. pinnatifidum were obtained after rescuing the hybrid embryos in vitro. The hybrids were initially devoid of any chlorophyll pigment and were albinos. Upon continuous culture in a zeatin-rich medium and in the presence of light, the hybrids turned semi-green. Hybrid shoots were grafted to chickpea rootstocks to obtain hybrid plants. None of the hybrid plants flowered. When the nutrient solution with zeatin (1.0 mg/litre) was added, flower buds were observed on hybrid plants. Flower buds were fragile, albino to semi-green, but with normal morphology. Anthers were squashed in acetocarmine and divisions were observed in some of the microspores. The number of divisions varied from 4 to 6. Adding nutrient solution with zeatin (1.0 mg/litre) to in vivo-grown chickpea plants did not induce division in the microspores. Sixteen hybrid plants were obtained. The number of microspores/pollen grains in an anther varied from 11 to 151, compared to more than 500 pollen grains in cultivated chickpea. The number of pollen grains that had undergone microsporogenesis and induction of androgenesis varied from plant to plant. Percent androgenic pollen grains varied from 0 to 100%. Plant nos. 8, 11 and 12 did not have any androgenic pollen grains, whereas in plant nos. 14 and 16, all the pollen grains were androgenic or had multicellular microspores. The number of cells in multicellular microspores in plant nos. 14 and 16 varied from 8 to 10 unlike 4-6 cells in multicellular microspores in other hybrid plants that had androgenic microspores. This is the first report of the production of multicellular microspores as a result of wide crossing

Identification of Large-Seeded High-Yielding Diverse Kabuli Accessions in Newly Assembled Chickpea Germplasm

Chickpea (Cicer arietinum L.) is an important grain legume grown for easily digestible quality protein and its nitrogen fixing capability that improves soil fertility. It is cultivated on 10.38 million ha in 45 countries across the globe producing 8.57 million tons with productivity of 0.83 t ha-1 (FAO 2004), which is rather low. India, Pakistan, Myanmar, Turkey, and Iran in Asia; Mexico in North Central America; and Ethiopia in Africa are the largest chickpea producing countries. Of late chickpea is being cultivated on considerable area in Canada, Australia, and USA. Two types of chickpeas – kabuli and desi – are recognized. The kabuli types have owl-shaped, large beige colored seeds with thin seed coat and white colored flowers; while the desi types have angular-shaped seeds with thick seed coat, generally colored flowers and seeds. Kabuli types account for about 15% of the world chickpea production

Mendelian and Non-Mendelian Regulation of Gene Expression in Maize

Transcriptome variation plays an important role in affecting the phenotype of an organism. However, an understanding of the underlying mechanisms regulating transcriptome variation in segregating populations is still largely unknown. We sought to assess and map variation in transcript abundance in maize shoot apices in the intermated B73×Mo17 recombinant inbred line population. RNA-based sequencing (RNA-seq) allowed for the detection and quantification of the transcript abundance derived from 28,603 genes. For a majority of these genes, the population mean, coefficient of variation, and segregation patterns could be predicted by the parental expression levels. Expression quantitative trait loci (eQTL) mapping identified 30,774 eQTL including 96 trans-eQTL "hotspots," each of which regulates the expression of a large number of genes. Interestingly, genes regulated by a trans-eQTL hotspot tend to be enriched for a specific function or act in the same genetic pathway. Also, genomic structural variation appeared to contribute to cis-regulation of gene expression. Besides genes showing Mendelian inheritance in the RIL population, we also found genes whose expression level and variation in the progeny could not be predicted based on parental difference, indicating that non-Mendelian factors also contribute to expression variation. Specifically, we found 145 genes that show patterns of expression reminiscent of paramutation such that all the progeny had expression levels similar to one of the two parents. Furthermore, we identified another 210 genes that exhibited unexpected patterns of transcript presence/absence. Many of these genes are likely to be gene fragments resulting from transposition, and the presence/absence of their transcripts could influence expression levels of their ancestral syntenic genes. Overall, our results contribute to the identification of novel expression patterns and broaden the understanding of transcriptional variation in plants. © 2013 Lin et al

Intragenic Meiotic Crossovers Generate Novel Alleles with Transgressive Expression Levels

Meiotic recombination is an evolutionary force that generates new genetic diversity upon which selection can act. Whereas multiple studies have assessed genome-wide patterns of recombination and specific cases of intragenic recombination, few studies have assessed intragenic recombination genome-wide in higher eukaryotes. We identified recombination events within or near genes in a population of maize recombinant inbred lines (RILs) using RNA-sequencing data. Our results are consistent with case studies that have shown that intragenic crossovers cluster at the 5\u27 ends of some genes. Further, we identified cases of intragenic crossovers that generate transgressive transcript accumulation patterns, that is, recombinant alleles displayed higher or lower levels of expression than did nonrecombinant alleles in any of ~100 RILs, implicating intragenic recombination in the generation of new variants upon which selection can act. Thousands of apparent gene conversion events were identified, allowing us to estimate the genome-wide rate of gene conversion at SNP sites (4.9 X 10-5). The density of syntenic genes (i.e., those conserved at the same genomic locations since the divergence of maize and sorghum) exhibits a substantial correlation with crossover frequency, whereas the density of nonsyntenic genes (i.e., those which have transposed or been lost subsequent to the divergence of maize and sorghum) shows little correlation, suggesting that crossovers occur at higher rates in syntenic genes than in nonsyntenic genes. Increased rates of crossovers in syntenic genes could be either a consequence of the evolutionary conservation of synteny or a biological process that helps to maintain synteny