The Response of Dispersion-Strengthened Copper Alloys to High Fluence Neutron Irradiation at 415⁰C

Various oxide-dispersion-strengthened copper alloys have been irradiated to 150 dpa at 415°C in the Fast Flux Test Facility (FFTF). The Al2O3-strengthened GlidCop™ alloys, followed closely by a HfO2-strengthened alloy, displayed the best swelling resistance, electrical conductivity, and tensile properties. The conductivity of the HfO2-strengthened alloy reached a plateau at the higher levels of irradiation, instead of exhibiting the steady decrease in conductivity observed in the other alloys. A high initial oxygen content resulted in significantly higher swelling for a series of castable oxide-dispersion-strengthened alloys, while a Cr2O3 -strengthened alloys showed poor resistance to radiations

An experimental study of the dual-fuel performance of a small compression ignition diesel engine operating with three gaseous fuels

A dual-fuel engine is a compression ignition (CI) engine where the primary gaseous fuel source is premixed with air as it enters the combustion chamber. This homogenous mixture is ignited by a small quantity of diesel, the ‘pilot’, that is injected towards the end of the compression stroke. In the present study, a direct-injection CI engine, was fuelled with three different gaseous fuels: methane, propane, and butane. The engine performance at various gaseous concentrations was recorded at 1500 r/min and quarter, half, and three-quarters relative to full a load of 18.7 kW. In order to investigate the combustion performance, a novel three-zone heat release rate analysis was applied to the data. The resulting heat release rate data are used to aid understanding of the performance characteristics of the engine in dual-fuel mode. Data are presented for the heat release rates, effects of engine load and speed, brake specific energy consumption of the engine, and combustion phasing of the three different primary gaseous fuels. Methane permitted the maximum energy substitution, relative to diesel, and yielded the most significant reductions in CO2. However, propane also had significant reductions in CO2 but had an increased diffusional combustion stage which may lend itself to the modern high-speed direct-injection engine

Observations of Low Frequency Solar Radio Bursts from the Rosse Solar-Terrestrial Observatory

The Rosse Solar-Terrestrial Observatory (RSTO; www.rosseobservatory.ie) was established at Birr Castle, Co. Offaly, Ireland (53 05'38.9", 7 55'12.7") in 2010 to study solar radio bursts and the response of the Earth's ionosphere and geomagnetic field. To date, three Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (CALLISTO) spectrometers have been installed, with the capability of observing in the frequency range 10-870 MHz. The receivers are fed simultaneously by biconical and log-periodic antennas. Nominally, frequency spectra in the range 10-400 MHz are obtained with 4 sweeps per second over 600 channels. Here, we describe the RSTO solar radio spectrometer set-up, and present dynamic spectra of a sample of Type II, III and IV radio bursts. In particular, we describe fine-scale structure observed in Type II bursts, including band splitting and rapidly varying herringbone features

Performance Evaluation Of Composite Sandwich Structures With Additively Manufactured Aluminum Honeycomb Cores With Increased Bonding Surface Area

Modern aerostructures, including wings and fuselages, increasingly feature sandwich structures due to their high-energy absorption, low weight, and high flexural stiffness. The face sheet of these sandwich structures are typically thin composite laminates with interior honeycombs made of Nomex or aluminum. Standard cores are structurally efficient, but their design cannot be varied throughout the structure. With additive manufacturing (AM) technology, these core geometries can be altered to meet the design requirements that are not met in standard honeycomb cores. This study used a modified aluminum honeycomb core, with increased surface area on the top and bottom, as the core material in sandwich panels. The modified honeycomb core was produced through the laser powder bed fusion method. The behavior of the modified sandwich composite panels was evaluated through three-point bend, edgewise compression, and impact tests, and their performance was compared to that of a conventional honeycomb core sandwich panel. The three-point bend test results indicated that the sandwich structure\u27s ultimate shear strength improved by 12.6% with the modified honeycomb core. Additionally, the displacement at the failure of the structure increased by 11%. The edgewise compression tests showed that the ultimate edgewise compressive strength improved by 19.1% when using the modified core. The impact test results revealed that the peak force increased by 8% and the energy-absorbing capacity of the sandwich structure increased by 20% with the use of the modified honeycomb core

Retrotransposition creates sloping shores: a graded influence of hypomethylated CpG islands on flanking CpG sites

Long interspersed elements (LINEs), through both self-mobilization and trans-mobilization of short interspersed elements and processed pseudogenes, have made an indelible impact on the structure and function of the human genome. One consequence is the creation of new CpG islands (CGIs). In fact, more than half of all CGIs in the genome are associated with repetitive DNA, three-quarters of which are derived from retrotransposons. However, little is known about the epigenetic impact of newly inserted CGIs. We utilized a transgenic LINE-1 mouse model and tracked DNA methylation dynamics of individual germline insertions during mouse development. The retrotransposed GFP marker sequence, a strong CGI, is hypomethylated in male germ cells but hypermethylated in somatic tissues, regardless of genomic location. The GFP marker is similarly methylated when delivered into the genome via the Sleeping Beauty DNA transposon, suggesting that the observed methylation pattern may be independent of the mode of insertion. Comparative analyses between insertion- and non-insertion-containing alleles further reveal a graded influence of the retrotransposed CGI on flanking CpG sites, a phenomenon that we described as "sloping shores." Computational analyses of human and mouse methylomic data at single-base resolution confirm that sloping shores are universal for hypomethylated CGIs in sperm and somatic tissues. Additionally, the slope of a hypomethylated CGI can be affected by closely positioned CGI neighbors. Finally, by tracing sloping shore dynamics through embryonic and germ cell reprogramming, we found evidence of bookmarking, a mechanism that likely determines which CGIs will be eventually hyper- or hypomethylated

Effects of rapeseed variety and oil extraction method on the content and ileal digestibility of crude protein and amino acids in rapeseed cake and softly processed rapeseed meal fed to broiler chickens

We examined the effects of rapeseed variety and oil extraction method on crude protein (CP) and amino acid (AA) content in rapeseed co-products, and determined their coefficient of apparent (AID) and standardised ileal digestibility (SID) in broiler chickens. Sixteen rapeseed samples were de-oiled; four were cold-pressed producing rapeseed cake (RSC) and twelve were mild processed and hexane-extracted producing soft rapeseed meal (SRSM). One batch of the variety Compass, grown on the same farm, was processed using both methods obtaining Compass RSC and Compass SRSM. DK Cabernet rapeseed variety, grown on three different farms, was used to produce two SRSM batches and one RSC batch. All rapeseed co-products were ground through a 4 mm screen and mixed into semi-synthetic diets at a level of 500 g/kg. Day-old Ross 308 male broilers were fed a commercial diet for 14 days. A total of 96 pairs of birds were then allotted to 1 of 16 dietary treatments (n = 6) and fed a test diet for 8 days. Birds were then culled allowing removal of ileal digesta from Meckel’s diverticulum to the ileal-caecal junction. Digestibility of CP and AA was determined using titanium dioxide as an inert marker. The SRSM samples had an increased content of CP (419–560 g/kg DM) compared to RSC samples (293–340 g/kg DM). Both AID and SID of lysine, and SID of arginine, histidine and threonine were greater in Compass RSC compared to its SRSM counterpart (P 0.05). The SID of lysine was on average 0.03 units greater (P < 0.001) in RSC than in SRSM. The SRSM produced from variety PR46W21 showed similar or greater AID and SID of individual AA than the RSC from four other rapeseed varieties. It is concluded that selection of rapeseed varieties, and extraction method have a potential to deliver high-protein dietary ingredients with a good digestibility value

Multiwavelength Study on Solar and Interplanetary Origins of the Strongest Geomagnetic Storm of Solar Cycle 23

We study the solar sources of an intense geomagnetic storm of solar cycle 23 that occurred on 20 November 2003, based on ground- and space-based multiwavelength observations. The coronal mass ejections (CMEs) responsible for the above geomagnetic storm originated from the super-active region NOAA 10501. We investigate the H-alpha observations of the flare events made with a 15 cm solar tower telescope at ARIES, Nainital, India. The propagation characteristics of the CMEs have been derived from the three-dimensional images of the solar wind (i.e., density and speed) obtained from the interplanetary scintillation data, supplemented with other ground- and space-based measurements. The TRACE, SXI and H-alpha observations revealed two successive ejections (of speeds ~350 and ~100 km/s), originating from the same filament channel, which were associated with two high speed CMEs (~1223 and ~1660 km/s, respectively). These two ejections generated propagating fast shock waves (i.e., fast drifting type II radio bursts) in the corona. The interaction of these CMEs along the Sun-Earth line has led to the severity of the storm. According to our investigation, the interplanetary medium consisted of two merging magnetic clouds (MCs) that preserved their identity during their propagation. These magnetic clouds made the interplanetary magnetic field (IMF) southward for a long time, which reconnected with the geomagnetic field, resulting the super-storm (Dst_peak=-472 nT) on the Earth.Comment: 24 pages, 16 figures, Accepted for publication in Solar Physic